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Background: Osteoarthritis (OA) is marked by the progressive degradation of joint cartilage and subchondral bone. The precise molecular mechanisms driving meniscus deterioration in OA, especially at the single-cell level, remain poorly understood. Method: We analyzed two datasets from the GEO database, GSE220243 and GSE98918, focusing on meniscus tissue sequencing data from OA and non-OA patients. The standard Seurat procedure was employed to process single-cell data and identify differentially expressed genes (DEGs). Immune cell infiltration was assessed using the Microenvironment Cell Populations (MCP) counter and CIBERSORT algorithms. For the microarray data, DEGs were identified with the limma package, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using ClusterProfiler. The overlapping DEGs from both datasets were imported into Cytoscape to generate protein-protein interaction (PPI) networks and identify hub genes. Transcription factor (TF) and miRNA interaction networks were analyzed using NetworkAnalyst, and gene-related predictive drugs were enriched through the DSigDB platform. Result: After quality control, 34,763 cells from the OA patients and 34,145 cells from the healthy controls were analyzed. UMAP identified and SingleR annotated 14 cell clusters. The 10 largest cell clusters were selected for further analysis. The OA group exhibited a notable increase in macrophages and a reduction in cytotoxic lymphocytes and endothelial cells in the meniscus. In GSE98918, 220 DEGs were identified, and the MCODE plug-in in Cytoscape pinpointed a key module containing 12 candidate genes. The MCC methodfiltered the top 20 DEGs in each GSE220243 cluster. Overlapping DEGs from GSE220243 and GSE98918 identified COL1A1, COL3A1, COL5A2, COL6A3, LOX, and VEGFA as significantly decreased in OA, with COL3A1, COL5A2, LOX, and VEGFA upregulated in meniscal chondrocytes. The interaction network highlighted 3 key miRNAs and 13 shared TFs. Ten gene-related predictive drug molecules were identified. Conclusion: This research highlights crucial genes in the OA meniscus and uncovers their differing regulatory patterns between chondrocytes and non-chondrocytes. These findings enhance our understanding of the molecular mechanisms driving OA pathogenesis and aid in identifying potential drug targets. [ABSTRACT FROM AUTHOR]

Repair of the damaged meniscus is a scientific challenge owing to the poor self-healing potential of the white area of the meniscus. Tissue engineering provides a new method for the repair of meniscus injuries. In this study, we explored the superiority of 2% hyaluronic acid chitin hydrogel in temperature sensitivity, in vitro degradation, biocompatibility, cell adhesion, and other biological characteristics, and investigated the advantages of hyaluronic acid (HA) and Transforming Growth Factor β1 (TGF-β1) in promoting cell proliferation and a matrix formation phenotype. The hydrogel loaded with HA and TGF-β1 promoted cell proliferation. The HA + TGF-β1 mixed group showed the highest glycosaminoglycan (GAG) content and promoted cell migration. Hydroxypropyl chitin (HPCH), HA, and TGF-β1 were combined to form a composite hydrogel with a concentration of 2% after physical cross-linking, and this was injected into a rabbit model of a meniscus full-thickness tear. After 12 weeks of implantation, the TGF-β1 + HA/HPCH composite hydrogel was significantly better than HPCH, HA/HPCH, TGF-β1 + HPCH, and the control group in promoting meniscus repair. In addition, the new meniscus tissue of the TGF-β1 + HA/HPCH composite hydrogel had a tissue structure and biochemical content similar to that of the normal meniscus tissue. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence Posterior elongation of the physiological terminal sulcus (TS) due to lateral femoral condyle impaction fracture (LFC‐IF) after an anterior cruciate ligament (ACL) tear could potentially decrease the weight‐bearing area of the tibiofemoral joint, decrease the tension on lateral meniscus and cause flattening of the LFC which would influence rotational knee motion and cause anisometry of the lateral and anterolateral stabilizers. Therefore, the purpose of the study was to assess if the LFC‐IF elongates the physiological TS posteriorly.One hundred patients magnetic resonance images (MRIs) (75 males, 25 females, mean age 32.2 years, SD = 8.2) were included with a 1:1 ratio between the full‐thickness ACL tear group and the control group (patients with knee MRI performed due to other reasons, with no tear of ACL on MRI and negative clinical tests). Two independent raters evaluated the sagittal T1‐weighted preselected MRI scans. The principal measurement of interest was the distance from the intersection of the Blumensaat line with subchondral bone to the posterior border of the TS/LFC‐IF.The median distance from the Blumensaat line to the posterior border of the TS/LFC‐IF was significantly higher in the ACL tear group: 14.3 mm, interquartile range (IQR) = 11.6–16.4 mm versus control group: 12.8 mm, IQR = 9.0–15.0 mm, p = 0.038. Intrarater and inter‐rater reliabilities were >0.90.LFC‐IF after full‐thickness ACL tear significantly elongates the physiological TS in the posterior direction.Level III. [ABSTRACT FROM AUTHOR]

Background: Knee osteoarthritis (KOA) is a progressive musculoskeletal disease that leads to physical impairment and disability. Several nonoperative therapeutic options have been proposed to reduce symptoms, improve physical function, and prevent disability. One of these therapeutic options is dextrose prolotherapy (DPT). The current study aimed to investigate the efficacy of DPT in the treatment of symptomatic KOA and to evaluate its potential proliferative role as assessed by musculoskeletal ultrasound (MSUS) and magnetic resonance imaging (MRI). Results: Seventeen knees (21.25%) dropped out, leaving 63 knees in the final analysis (57 females and 6 males, aged 41–74 years) with KOA. At 24-week follow-up, the visual analogue scale and overall Western Ontario and McMaster Universities scores showed significant improvement (P < 0.001). Moreover, a highly significant increase in cartilage thickness with a decrease in effusion grade and meniscal extrusion was observed by MSUS (P < 0.001). By MRI, there was a statistically significant decrease in effusion grade (P = 0.013) and meniscal extrusion (P = 0.005) and a highly significant increase in cartilage thickness (P < 0.001). Logistic analysis showed that lower patients' body mass index (BMI) at baseline was a significant predictor for clinical improvement following DPT. Conclusion: DPT might be considered a relatively safe minimally invasive intervention for the treatment of KOA with high adherence and satisfaction. It may lead to significant clinical and structural improvement in patients with KOA. Furthermore, lower BMI is a predicting factor for better clinical response to DPT. Trial registration: The study was registered prospectively in ClinicalTrials.gov: clinical trial registration number NCT04178304 on 21 November 2019, https://register.clinicaltrials.gov/XXX. Key points: •DPT showed promising results in improving clinical symptoms in KOA patients. •Significant structural improvement in patients with KOA following DPT warrants its use. [ABSTRACT FROM AUTHOR]

Osteoarthritis is a degenerative disease of synovial joints affecting all tissues, including articular cartilage and subchondral bone. Osteoarthritis animal models can recapitulate aspects of human disease progression and are used to test efficacy of drugs, biomaterials, and cell therapies. The rat medial meniscus transection (MMT) model is a surgically induced posttraumatic osteoarthritis model commonly used for preclinical therapeutic screening. We describe herein, the qualitative and quantitative changes to articular cartilage, subchondral bone, and formation of osteophytes at early‐, mid‐, and late‐stages of osteoarthritis progression. Tibia of MMT‐operated animals showed proteoglycan loss and fibrillation along articular cartilage surfaces as early as 3‐weeks post‐surgery. With contrast‐enhanced micro‐CT technique, quantitative, 3‐dimensional analysis of the tibia showed that the articular cartilage thickened at 3‐ and 6‐weeks post‐surgery and decreased at 12‐weeks post‐surgery. This decreased cartilage thickness corresponded with increased lesions in the articular cartilage that led to its full degradation and exposing the subchondral bone layer. Further, subchondral bone thickening was significant at 6‐weeks post‐surgery and followed cartilage damage. Osteophytes were found as early as 3‐weeks post‐surgery and coincided with articular cartilage degradation. Cartilaginous osteophytes preceded mineralization, suggesting endochondral ossification. The rat MMT model has predominantly been used out to 3‐weeks, and most studies determined the effect of therapies to delay or prevent the onset of osteoarthritis. We provide evidence that an extension of the rat MMT model out to 6‐ and 12‐weeks more resembled severe phenotypes of human osteoarthritis. Thus, evaluating novel therapeutics at late‐stage will be important for eventual clinical translation. [ABSTRACT FROM AUTHOR]

The meniscus tissue is crucial for knee joint biomechanics and is frequently susceptible to injuries resulting in early-onset osteoarthritis. Consequently, the need for meniscal substitutes spurs ongoing development. The meniscus is a composite tissue reinforced with circumferential and radial collagenous fibers; the mechanical role of the latter has yet to be fully unveiled. Here, we investigated the role of radial fibers using a synergistic methodology combining meniscal tissue structure imaging, a computational knee joint model, and the fabrication of simple biomimetic composite laminates. These laminates mimic the basic structural units of the meniscus, utilizing longitudinal and transverse fibers equivalent to the circumferential and radial fibers in meniscal tissue. In the computational model, the absence of radial fibers resulted in stress concentration within the meniscus matrix and up to 800 % greater area at the same stress level. Furthermore, the contact pressure on the tibial cartilage increased drastically, affecting up to 322 % larger areas. Conversely, in models with radial fibers, we observed up to 25 % lower peak contact pressures and width changes of less than 0.1 %. Correspondingly, biomimetic composite laminates containing transverse fibers exhibited minor transverse deformations and smaller Poisson's ratios. They demonstrated structural shielding ability, maintaining their mechanical performance with the reduced amount of fibers in the loading direction, similar to the ability of the torn meniscus to carry and transfer loads to some extent. These results indicate that radial fibers are essential to distribute contact pressure and tensile stresses and prevent excessive deformations, suggesting the importance of incorporating them in novel designs of meniscal substitutes. The organization of the collagen fibers in the meniscus tissue is crucial to its biomechanical function. Radially oriented fibers are an important structural element of the meniscus and greatly affect its mechanical behavior. However, despite their importance to the meniscus mechanical function, radially oriented fibers receive minor attention in meniscal substitute designs. Here, we used a synergistic methodology that combines imaging of the meniscal tissue structure, a structural computational model of the knee joint, and the fabrication of simplistic biomimetic composite laminates that mimic the basic structural units of the meniscus. Our findings highlight the importance of the radially oriented fibers, their mechanical role in the meniscus tissue, and their importance as a crucial element in engineering novel meniscal substitutes. [Display omitted] [ABSTRACT FROM AUTHOR]

Tissue engineering presents a promising approach for the treatment of meniscal injuries, yet the development of meniscal scaffolds that exhibit both superior biomechanical properties and biocompatibility remains a considerable challenge. In this study, decellularized skin matrix (DSM) scaffolds were first prepared using porcine skin through decellularization and freeze-drying techniques. The DSM scaffold has favorable porosity, hydrophilicity, and biocompatibility. Importantly, the collagen content and tensile modulus of the scaffold are comparable to those of native meniscus (44.13 ± 2.396 mg/g vs. 42.41 ± 2.40 mg/g and 103.30 ± 2.98 MPa vs. 128.80 ± 9.115 MPa). Subsequently, the peptide PFSSTKT (PFS) with mesenchymal stem cells (MSCs) recruitment capability was used to modify DSM to construct DSM-PFS scaffolds. Compared to the DSM scaffold, the optimized DSM-PFS scaffold enhanced in vitro collagen and glycosaminoglycan (GAG) production and upregulated the expression of cartilage-specific genes. Furthermore, the DSM-PFS scaffold was more effective in recruiting MSCs in vitro. In vivo studies in rabbit models showed that the DSM-PFS scaffold successfully promoted meniscus tissue regeneration. Three months post-implantation, meniscus tissue formation can be observable, and after six months, the neo-meniscus exhibited tissue structure and tensile properties similar to the native meniscus. Notably, the DSM-PFS scaffold exhibited significant chondroprotective effects, slowing osteoarthritis (OA) progression. In conclusion, the DSM-PFS scaffold may represent a promising candidate for future applications in meniscus tissue engineering. We developed a decellularized skin matrix (DSM) meniscus scaffold using whole-layer porcine skin, demonstrating superior biomechanical strength and biocompatibility. Following modification with the stem cell-recruiting peptide PFS, the optimized DSM-PFS scaffold outperformed the DSM scaffold in cell attraction, collagen and glycosaminoglycan production, and cartilage-specific gene expression. Implanted into rabbit knee joints, the cell-free DSM-PFS scaffold induced meniscal tissue formation within three months, achieving the histological structure and tensile strength of the native meniscus by six months. Moreover, it significantly protected the cartilage. Our findings provide new insights into the fabrication of scaffolds for meniscal tissue engineering, with the DSM-PFS scaffold emerging as an ideal candidate for future applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The latest studies agree that meniscal tears that require surgery should be repaired whenever possible to avoid early-onset osteoarthritis secondary to meniscectomy. Unfortunately, there are several limitations associated with meniscal sutures, making it difficult to put into practice the theory behind the concept of saving the meniscus. Meanwhile, there is an exponential growth in the use of tissue adhesives for surgery, but finding one suited to meniscal repair remains a struggle. This review has two main goals (1) to compile the various bioadhesives used in this field and (2) to list the criteria for an ideal meniscal bioadhesive. The review was conducted in PubMed, Google Scholar, and Web of Science in November 2023 without date restrictions. The inclusion criteria were: Studies published in English and focusing on meniscal repair using bioadhesives. The exclusion criteria were: Studies published in languages other than English. Adhesives used in combination with sutures, as the aim was to determine the adhesive's capabilities for meniscal repair alone. Synthetic adhesives such as polycyanoacrylates, polyethylene glycol, polyurethanes, and polyesters. Among the 11 bioadhesives found, fibrin is the only one that has been studied in humans. There are advantages and disadvantages to all the bioadhesives identified but none that fully meet the requirements for meniscal repair. The anatomy of meniscal tissue is complex and poses unique challenges that are compounded by arthroscopic stresses. The future of meniscal repair probably lies in combining the advantages of several bioadhesives, and this area should be the focus of future research. [ABSTRACT FROM AUTHOR]

Background: Shear Wave Elastography (SWE) offers quantitative insights into the hardness and elasticity characteristics of tissues. The objective of this study is to investigate the correlation between SWE of the menisci and MRI-assessed degenerative changes in the menisci, with the aim of providing novel reference source for improving non-invasive evaluation of meniscal degenerative alterations. Methods: The participants in this study were selected from patients who underwent knee joint MRI scans at our hospital from February 2023 to February 2024. The anterior horns of both the medial and lateral menisci were evaluated using SWE technique. The differences in elastic values of meniscus among different MRI grades were compared. The correlation between elastic values and MRI grades, as well as various parameters, was analyzed. Using MRI Grade 3 as the gold standard, the optimal cutoff value for meniscal tear was determined. The intraclass correlation coefficient (ICC) was employed to evaluate the reliability of repeated measurements performed by the same observer. Results: A total of 104 female participants were enrolled in this study, with 152 lateral menisci (LM) and 144 medial menisci (MM) assessed. For the male group, 83 individuals were included, with 147 LM and 145 MM evaluated. The results demonstrated statistically significant differences in the elasticity values of the menisci at the same anatomical sites across different MRI grades (P < 0.001). Within the same grade, the MM had higher elasticity values than the LM, showing a statistically significant difference (P < 0.001). The elasticity values of the menisci were higher in males compared to females. There were statistically significant positive correlations between the elasticity values of the menisci and age, BMI, and MRI grade. The ICC for repeated measurements within the observer demonstrated good reliability (> 0.79). Conclusions: The meniscal elasticity values measured by SWE exhibit a significant positive correlation with the grades of degeneration assessed by MRI. Furthermore, the elasticity values of the meniscus are found to increase with advancing age and elevated BMI. [ABSTRACT FROM AUTHOR]

Background: Discoid lateral meniscus (DLM) is the most common congenital abnormality of the meniscus. Tears are common; treatment is frequently not definitive, often requiring reoperation. Purpose: To report the clinical manifestations, physical characteristics, operative treatments and findings, complications, and reoperations of DLM in pediatric patients from multiple centers across North America. Study Design: Case series; Level of evidence, 4. Methods: Consecutive patients who underwent treatment for symptomatic DLM at 9 institutions between 2000 and 2020 were included. Patient data, presenting symptoms and signs, surgical findings, treatments rendered, and postoperative complications, including reoperation rates, were collected. Means with ranges and counts with proportions are reported for continuous and categorical variables, respectively, and comparisons were made using either the chi-square or Fisher exact test. Results: In total, 784 patients (867 knees) were included with a mean age at diagnosis of 12 years (range, 1-22 years) and a mean follow-up of 22.6 months (range, 0-154 months). Common preoperative symptoms were locking (33%) and snapping (30%). At surgery, tears in the DLM were present in 647 knees (594 patients [76%]); 95 knees (11%) had multiple tears; and in 140 knees, tears extended into >1 zone. Tears, when present, were more common within the posterior horn (41%) or body (34%) than the anterior horn (25%). Peripheral rim instability was reported in 241 knees (28%). Significantly more knees had instability posteriorly (15%; P =.0004) and anteriorly (9%; P =.0013) than along the body (3%). Tear type was most commonly complex (38%) or horizontal (34%). A total of 358 knees in 333 patients with tears (42% of all patients) underwent repair (55% of knees with tears). A total of 175 complications were reported, occurring in 139 knees in 134 patients (17%); 116 of these knees with complications (83%) had a single complication, while 23 (17%) had >1. Of the 784 patients, 105 (13%) underwent reoperation, undergoing 135 additional procedures related to their DLM. Of those, 60 (44%) were repeat arthroscopy and meniscal trim; 40 (30%), arthroscopy and meniscal repair; and 17 (13%), an articular cartilage procedure. Conclusion: Locking and snapping were common presenting symptoms. Over three-quarters of patients had meniscal tears, which were most often complex and located posteriorly. Seventeen percent of patients experienced complications, and a sixth of patients with complications had >1. Reoperation was typically for persistent symptoms or meniscal retear. [ABSTRACT FROM AUTHOR]

Background: Few studies have compared the characteristics of meniscal allograft tears between medial and lateral meniscal allograft transplantation (MAT) using bone fixation. Purpose: To investigate the prevalence, location, and patterns of allograft tears after MAT with the bone fixation technique and compare tear patterns between medial and lateral compartments according to the time elapsed after surgery. Study Design: Cohort study; Level of evidence, 3. Methods: The charts of consecutive patients who underwent primary medial or lateral MAT between December 1996 and June 2019 were retrospectively reviewed. The location, pattern, and postoperative periods during which allograft tears occurred were evaluated by reviewing all series of follow-up magnetic resonance imaging (MRI) scans, which were performed at 6 weeks, 3 months, 6 months, and 1 year postoperatively and every 2 years thereafter with the patient's agreement. Postoperative periods for allograft tears were defined as the time between surgery and the follow-up MRI scan in which the meniscal tear was first confirmed. Allograft tears were compared between the medial and lateral MAT groups. Results: A total of 327 consecutive patients who underwent MAT (55 medial, 272 lateral) with a minimum 2-year follow-up were retrospectively reviewed. The incidences of allograft tears after medial and lateral MATs were 32.7% and 30.9%, respectively. The mean times for tears were 80.1 ± 81.1 months and 48.9 ± 46.3 months in the medial and lateral MAT groups, respectively (P =.130). In both the medial and lateral MAT groups, allograft tears were observed mainly in the posterior horn, with complex tears being the most commonly identified tear type. In medial MATs, root tears were the second most common at 27.8%, with a significantly higher proportion than the lateral MATs (P =.014). On the other hand, in lateral MATs, meniscocapsular separation and radial tears were the second most common at 15.5% each, albeit not significantly more common than in medial MATs (P =.123 and P =.454, respectively). All root tears in medial MATs and meniscocapsular separations in lateral MATs were observed within 1 year postoperatively. Conclusion: Significant differences in allograft tear patterns were identified between the medial and lateral MAT groups. The proportion of root tears in medial MATs was higher than that in lateral MATs; conversely, the proportion of meniscocapsular separation was more common in lateral MATs. Such tear patterns, which may require surgical repair or graft resection, were observed only within 1 year of surgery. Therefore, close observation and regular follow-up in the earlier postoperative period are necessary after medial or lateral MATs. [ABSTRACT FROM AUTHOR]

Background: Data are lacking as to when a meniscal allograft transplant (MAT) may be biomechanically superior to a partially resected lateral meniscus. Hypothesis: Lateral MAT using a bone bridge technique would restore load distribution and contact pressures in the tibiofemoral joint to levels superior to those of a partial lateral meniscectomy. Study Design: Controlled laboratory study. Methods: Eleven fresh-frozen human cadaveric knees were evaluated in 5 lateral meniscal testing conditions (native, one-third posterior horn meniscectomy, two-thirds posterior horn meniscectomy, total meniscectomy, MAT) at 3 flexion angles (0°, 30°, and 60°) under a 1600-N axial load. Pressure sensors were used to acquire contact pressure, contact area, and peak contact pressure within the tibiofemoral joint. Results: Limited (one-third and two-thirds) partial lateral posterior horn meniscectomy showed no significant increase in mean and peak contact pressures as well as no significant decrease in contact area compared with the intact state. Total meniscectomy significantly increased mean contact pressure at 0° and 30° (P =.008 and P <.001, respectively), increased peak contact pressure at 30° (P =.04), and decreased mean contact area in all flexion angles compared with the native condition (P <.01). Lateral MAT significantly improved mean contact pressure compared with total meniscectomy at 0° and 30° (P =.002 and P =.003, respectively) and increased contact area at 30° and 60° (P =.003 and P =.009, respectively), although contact area was still significantly smaller (24.1%) after MAT relative to the native meniscus (P = 0.015). However, allograft transplant did not result in better tibiofemoral contact biomechanics compared with limited partial meniscectomy (P >.05). Conclusion: The peripheral portion of the lateral meniscus provided the most important contribution to the distribution of contact pressure across the tibiofemoral joint in the cadaveric model. Total meniscectomy significantly increased mean and peak contact pressure in the cadaveric model and decreased contact area. Lateral MAT restored contact biomechanics close to normal but was not superior to the partially meniscectomized status. Clinical Relevance: Surgeons should attempt to preserve a peripheral rim of the posterior lateral meniscus. Meniscal allograft transplant appears to improve but not normalize mean contact pressure and contact area relative to total lateral meniscectomy. [ABSTRACT FROM AUTHOR]

Objective: Accurately predicting knee osteoarthritis (KOA) is essential for early detection and personalized treatment. We aimed to develop and test a magnetic resonance imaging (MRI)‐based joint space (JS) radiomic model (RM) to predict radiographic KOA incidence through neural networks by integrating meniscus and femorotibial cartilage radiomic features. Methods: In the Osteoarthritis Initiative cohort, participants with knees without radiographic KOA at baseline but at high risk for radiographic KOA were included. Patients' knees developed radiographic KOA, whereas control knees did not over four years. We randomly split the participants into development and test cohorts (8:2) and extracted features from baseline three‐dimensional double‐echo steady‐state sequence MRI. Model performance was evaluated using an area under the receiver operating characteristic curve (AUC), sensitivity, and specificity in both cohorts. Nine resident surgeons performed the reader experiment without/with the JS‐RM aid. Results: Our study included 549 knees in the development cohort (275 knees of patients with KOA vs 274 knees of controls) and 137 knees in the test cohort (68 knees of patients with KOA vs 69 knees of controls). In the test cohort, JS‐RM had a favorable accuracy for predicting the radiographic KOA incidence with an AUC of 0.931 (95% confidence interval [CI] 0.876–0.963), a sensitivity of 84.4% (95% CI 83.9%–84.9%), and a specificity of 85.6% (95% CI 85.2%–86.0%). The mean specificity and sensitivity of resident surgeons through MRI reading in predicting radiographic KOA incidence were increased from 0.474 (95% CI 0.333–0.614) and 0.586 (95% CI 0.429–0.743) without the assistance of JS‐RM to 0.874 (95% CI 0.847–0.901) and 0.812 (95% CI 0.742–0.881) with JS‐RM assistance, respectively (P < 0.001). Conclusion: JS‐RM integrating the features of the meniscus and cartilage showed improved predictive values in radiographic KOA incidence. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the optimal posterior tibial plateau inclination for fixed-platform unicondylar knee arthroplasty (UKA) using finite element analysis (FEA). These findings provided a theoretical basis for selecting an appropriate posterior inclination of the tibial plateau during surgery. The present study utilized the FEA method to create models of fixed-platform UKA with tibial plateau posterior inclinations of 3, 6 and 9˚. The stress changes in the internal structures of each model after knee flexion motion were then compared. During knee flexion from 0 to 90˚, the contact and Von Mises equivalent stresses of the femoral condyle prosthesis and tibial platform pad revealed consistent trends of 3˚ posterior inclination, >6˚ posterior inclination and >9˚ posterior inclination. The present study established the first quasi-dynamic fixed-platform UKA model of the knee joint under load-bearing conditions. From a theoretical perspective, it was found that controlling the posterior inclination of UKA between 6 and 9˚ may be more beneficial for the survival of the tibial platform pad than between 3 and 6˚. It is also more effective in reducing pad wear. [ABSTRACT FROM AUTHOR]

Background: Medial meniscal ramp lesions have recently been an area of interest because of their recognized prevalence in association with anterior cruciate ligament (ACL) ruptures. Anatomically, the medial meniscal ramp is composed of the meniscocapsular ligament in continuity with the semimembranosus muscle and the meniscotibial ligament. Diagnosis of ramp semimembranosus complex (RSC) injuries remains challenging, and their prevalence is likely to be underestimated in comparison with ramp lesions. Purpose: To determine the prevalence of RSC lesions after a complete ACL rupture. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective database analysis was performed. The cohort consisted of the first 100 patients with complete ACL rupture confirmed by magnetic resonance imaging (MRI) who underwent knee arthroscopy for ACL reconstruction in 2019. The semimembranosus lesions were identified using MRI by 2 independent radiologists specializing in musculoskeletal imaging. The ramp lesions were initially diagnosed using MRI and then confirmed during arthroscopy by an experienced knee surgeon. The magnitude of rotatory instability was recorded using the pivot-shift test. A multivariate analysis was used to determine the lesions associated with the semimembranosus complex. Results: Of 100 patients, 53 showed lesions of the RSC; among them, 30 ramp lesions were confirmed after arthroscopic evaluation, and 40 semimembranosus lesions (23 without ramp lesion and 17 with ramp lesion) were found using MRI. A positive pivot shift was present in 57% of patients with combined RSC injury (P =.04) compared with 36% in patients without an RSC lesion. Conclusion: Lesions of the RSC were found in more than half of ACL ruptures in this retrospective cohort. Rotational instability could be associated with combined ACL and RSC injury. [ABSTRACT FROM AUTHOR]

Background: Osteochondral allograft transplantation (OCAT) and meniscus allograft transplantation (MAT) have each become more commonly implemented for the treatment of young to middle-aged patients with complex knee pathology. Evidence regarding tibiofemoral OCAT in the setting of concurrent MAT is limited. Purpose/Hypothesis: The purpose of this study was to characterize outcomes for femoral condyle OCAT with concurrent MAT (OCAT+MAT) in the ipsilateral compartment of patients after evidence-based shifts in practice. It was hypothesized that OCAT+MAT would be associated with successful outcomes characterized by statistically significant and clinically meaningful improvements in patient-reported outcome measures (PROMs) of knee pain and function in >80% of patients for at least 2 years after transplantation. Study Design: Case series; Level of evidence, 4. Methods: With institutional review board approval and documented informed consent, patients who underwent primary OCAT+MAT between 2016 and 2020 and enrolled in a lifelong registry for prospective collection of outcomes after OCAT were included. Patients with minimum 2-year follow-up data regarding complications, failures, adherence, and PROMs were analyzed. Patients who required OCAT and/or MAT revision or conversion to arthroplasty were defined as experiencing treatment failures. Results: A total of 23 consecutive patients (mean age, 37.1 years; mean body mass index, 28 kg/m2; 14 men) met the inclusion criteria, with a mean follow-up of 51 months (range, 24-86 months). The initial treatment success rate was 78% based on 5 initial treatment failures, and the overall success rate was 83% based on a successful revision OCAT. All failures occurred in the medial compartment. Older patient age (42.2 vs 32.1 years; P =.046) and nonadherence to postoperative restriction and rehabilitation protocols (P =.033; odds ratio, 14) were significant risk factors for treatment failure. All measured PROMs achieved significant improvements (P <.001) and minimum clinically important differences at a minimum of 2 years postoperatively. Conclusion: OCAT+MAT was associated with successful short- to mid-term outcomes in 83% of cases. Evidence-based shifts in practice were implemented before the enrollment of this patient cohort. Older patients and those who were not adherent to postoperative restriction and rehabilitation protocols had a significantly higher risk for treatment failure and subsequent conversion to arthroplasty. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate tibial cartilage thickness (TCT), T1ρ and T2 values within both loaded and baseline configurations in a cadaveric knee model using a 3D bone based tibial coordinate system. Ten intact cadaveric knees were mounted into an magnetic resonance imaging (MRI) compatible loading device. Morphologic and quantitative MRI (qMRI) images were acquired with the knee in a baseline configuration and after application of 50% body weight. The morphologic images were evaluated for cartilage degeneration using a modified Noyes scoring system. A 3D bone‐based tibial coordinate system was utilized to evaluate regional changes of tibial T1ρ, T2, and cartilage thickness values among regions covered and uncovered by the meniscus. Inter‐regional differences in medial and lateral MRI outcomes were found between loaded and baseline configurations. Cartilage regions covered by the meniscus demonstrated disparate qMRI and TCT results as compared to cartilage regions not covered by the meniscus. The regions covered by meniscus experienced a ~3.5%, ~0.5%, and ~5.5% reduction of T1ρ (p < 0.05, medial and lateral compartments), T2 and TCT, respectively, in both compartments while regions not covered by the meniscus experienced larger reductions of ~10%, ~2%, and ~10.5% reduction of T1ρ (p < 0.05, medial and lateral compartments), T2 and TCT (p < 0.05, lateral compartment only), respectively, in both compartments. T1ρ and T2 decreases following application of 50% body weight load were substantially larger in the tibial regions with modified Noyes grade 3 (n = 2) compared to either healthy regions (n = 85, p < 0.0.003) or regions with modified Noyes grade 2 (n = 13, p < 0.004). Interregional differences in MRI outcomes reflect variations in structure and function, and largely followed a pattern in cartilage regions that were covered or not covered by the meniscus. Results of the current study suggest that ΔT1ρ and ΔT2 values may be sensitive to superficial fissuring, more than baseline or loaded T1ρ or T2 values, or TCT alone, however future studies with additional specimens, with greater variability in OA grade distribution, may further emphasize the current findings. [ABSTRACT FROM AUTHOR]

Background: The diagnosis of anterior cruciate ligament (ACL) tear relies on clinical evaluation and magnetic resonance imaging (MRI). Direct and indirect signs of ACL tear have been described with MRI evaluation. Posterior cruciate ligament (PCL) buckling has been described as an indirect radiographic sign of an ACL tear. Purpose: The aim of the present study was to assess the variations in PCL buckling angles in patients with ACL tears and in patients with isolated lesions in the posterior horn of the medial meniscus. In addition, the influence of different patterns of medial meniscus tears in ACL-deficient knees was investigated. Finally, the influences of risk factors such as tibial slope, delay from injury to surgery, absence of medial meniscus tear, degree of Lachman and pivot shift testing were also assessed. Study design: This was a cohort study. Methods: A total of 154 patients (78 in the group with ACL tear and 76 in the control group) were assessed with MRI and lateral weight-bearing X-ray to assess PCL buckling angle and tibial slope by two independent observers. The presence of a medial meniscus bucket handle or ramp lesion of the medial meniscus was assessed and recorded at the time of surgery. Results: PCL buckling angle measurement was highly reliable, with an ICC of 0.866 and 0.894, respectively, in the study group and the control group for interobserver reliability. The intrarater reliability was found to be high in PCL buckling angle for the study group [ICC = 0.955] and the control group [ICC = 0.943]. The mean angle in patients with ACL tear was 110.7 ± 15.2° and 115.3 ± 16.2° (for the two examiners) and 111.4 ± 12° and 114 ± 14.5° (for the two examiners) in patients with an intact, healthy ACL. An association emerged between bucket handle tears of the medial meniscus (p = 0.010) and a decreased PCL buckling angle and between ramp lesions of the medial meniscus and increased PCL buckling angle both (p = 0.024). Conclusions: Good inter- and intraobserver reliability for the measurement of the PCL buckling angle was observed. Increased PCL buckling angle values were observed in patients with concomitant ACL and bucket handle tears of the medial meniscus, while decreased angle values were observed in those who had ACL tear and ramp lesion of the medial meniscus. No statistically significant difference in the PCL buckling angle emerged between patients with ACL tears and those who had a healthy, intact ACL. [ABSTRACT FROM AUTHOR]

Purpose: Despite extensive literature available on the mechanical properties of knee ligaments and menisci, research on the mechanical properties of the meniscus-capsular junction (MCJ) is lacking. This study aims to investigate the biomechanical behavior of the MCJ of the medial meniscus using a tensile failure test. Materials and methods: Seven dissected cadaveric knees were used for biomechanical analysis. Tensile failure tests were performed using an INSTRON ElectroPuls E1000 stress system to measure stress/strain curves, maximum load at failure, elastic limit load, elongation at break, elongation at the elastic limit, and linear stiffness, were collected and analyzed. Results: All ruptures occurred at the MCJ. The MCJ displayed similar mechanical properties to knee ligaments. Average values were: maximum load at failure (63.9 ± 3.2 N), yield load (52.9 N ± 2.6 N), elongation at break (2.5 mm ± 0.3 mm), elongation at the elastic limit (1.25 mm ± 0.15 mm), strain at break (47.0% ± 3.5%), strain at yield (23.2% ± 2.3%), and stiffness (56.6 ± 9. N/mm−1). Conclusion: The meniscus-capsular junction's mechanical properties are similar to other knee ligaments and may play a role in knee stability. The findings provide insights into the the behavior of the meniscus-capsular junction could have clinical implications for diagnosing and surgical treatment of meniscocapsular lesions. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to study the relationship between the presence of a deep lateral femoral notch sign (DLFNS) in anterior cruciate ligament (ACL)‐injured patients and a higher posterior lateral tibial slope (LPTS), a reduced meniscal bone angle (MBA), a higher LPTS/MBA ratio and a higher incidence of concomitant injuries in primary ACL tears. Methods: A retrospective case‐control study was performed in patients submitted to primary ACL reconstruction with an available preoperative magnetic resonance imaging (MRI) scan. Patients with ACL tears and a femoral impactation with a depth ≥2 mm were assorted to the DLFNS group and patients with ACL tear and without a DLFNS to the control group. LPTS and MBA were measured in MRI. The presence of concomitant injuries (meniscal, posterior cruciate ligament, medial collateral ligament, lateral collateral ligament and bone injuries) was assessed in MRI. Quantitative data are presented in the median ± interquartile range (IQR). Results: There were 206 patients included in the study, with 46 patients assorted to the DLFNS group and 160 patients to the control group. In the DLFNS group, the median LPTS was 6.7° (IQR: 4.0–8.2) versus 4.0° in the control group (IQR: 2.2–6.5) (p = 0.003). The LPTS/MBA ratio was significantly higher in the DLFNS group, with a median of 0.32 (IQR: 0.19–0.44), in comparison to the control group, with a median of 0.19 (IQR: 0.11–0.31) (p < 0.001). The multivariable logistic regression analysis showed that the LPTS is an independent risk factor to having a DLFNS (odds ratio [OR] = 1.161; 95% confidence interval [CI]: 1.042–1.293, p = 0.007). There was a higher incidence of concomitant lateral meniscal injuries in the DLFNS group (67% vs. 48%, p = 0.017). Conclusions: In patients with ACL tears, the presence of a DLFNS is associated with a steeper lateral posterior tibial slope, as well as a higher incidence of concomitant lateral meniscal injuries. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate the association between the progression of medial joint space (MJS) narrowing, medial meniscus extrusion (MME) and clinical scores and the tibial tunnel position in pullout repairs for medial meniscus posterior root tears (MMPRTs). Methods: This retrospective study examined 54 patients. Changes in MJS (ΔMJS), MME (ΔMME) and clinical scores and their relationship with the tibial tunnel position were evaluated using correlation coefficients. The distance from the anatomical to technical attachment position in the tibial tunnel position was measured in the anterior and medial directions, and the direct distance was measured using the Pythagorean theorem. Results: The mean ΔMJS and ΔMME were 0.6 ± 0.8 and 1.3 ± 1.3 mm, respectively, and the mean anterior, medial and direct distances were 1.4 ± 2.3, 2.2 ± 1.7 and 3.4 ± 1.7 mm, respectively. ΔMJS had a significant positive correlation with the medial (r = 0.580, p < 0.001) and direct (r = 0.559, p < 0.001) distances, while ΔMME had a significant positive correlation with direct distance (r = 0.295, p = 0.030). Several clinical scores were significantly negatively correlated with these distances. Conclusion: In transtibial pullout repair for MMPRTs, accurate tibial tunnel position delayed the progression of MJS narrowing and MME, leading to improved clinical outcomes. The progression of MJS narrowing was associated with the mediolateral direction of the tibial tunnel position, while the clinical scores were associated with the anteroposterior direction of the tibial tunnel position. These findings indicate the need to orient the tip of the guide in a more posterolateral direction when creating the tibial tunnel. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background: Repair of posterior medial meniscus root (PMMR) tears has demonstrated favorable outcomes and may prevent rapid progression of knee osteoarthritis; however, there is a paucity of data regarding prognostic factors affecting postoperative outcomes. Purpose/Hypothesis: The purpose of this study was to identify factors on preoperative magnetic resonance imaging (MRI) that predict postoperative outcomes after PMMR repair. It was hypothesized that patients with increasing levels of degenerative changes as evaluated through semiquantitative preoperative MRI scans would have worse postoperative patient-reported outcome (PRO) scores. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent PMMR repair between 2012 and 2020 and had minimum 2-year follow-up data were enrolled. Pre- and postoperative visual analog scale pain scores and postoperative PRO surveys including the Patient-Reported Outcomes Measurement Information System–Physical Function, Lysholm knee score, and Knee injury and Osteoarthritis Outcome Score (KOOS) were collected. Patients who achieved the Patient Acceptable Symptom State (PASS) on the KOOS subscales were reported. Two fellowship-trained musculoskeletal radiologists reviewed preoperative MRIs and calculated the Whole-Organ Magnetic Resonance Imaging Score for meniscus, cartilage, bone marrow edema–like lesions (BMELL), and meniscal extrusion. Statistical analysis was performed using the 2-sample t test, Mann-Whitney test, and Fisher exact test for categorical variables. Results: A total of 29 knees in 29 patients were evaluated (22 female, 7 male; mean age at surgery, 52.3 ± 9.9 years; body mass index, 27.6 ± 5.6 kg/m2; mean follow-up, 59.6 ± 26.5 months). Visual analog scale for pain scores decreased significantly from preoperatively (4.9 ± 2.0) to final follow-up (1.6 ± 1.9) (P <.001), and the percentage of patients meeting the PASS ranged from 44.8% for KOOS Sport and Recreation to 72.4% for KOOS Pain and KOOS Quality of Life. Patients with medial tibial BMELL (MT-BMELL) had significantly lower KOOS Symptoms scores (76.1 ± 17.3 vs 88.4 ± 9.7 without MT-BMELL; P =.032). Cartilage quality and presence of meniscal extrusion were not associated with outcomes. Conclusion: Patients with MT-BMELL on their preoperative MRI in the setting of PMMR tear were found to have worse KOOS Symptoms scores after PMMR repair. [ABSTRACT FROM AUTHOR]

Background: Multiligament reconstruction (MLR) has become the standard surgical approach for treating multiligament knee injuries (MLKIs). Purpose: To identify prognostic factors for patient-reported outcome measures, return to work (RTW), return to sports, and radiographic osteoarthritis (OA) (Kellgren-Lawrence grade ≥2) after MLR for MLKI. Study Design: Case-control study; Level of evidence 3. Methods: Included were 52 consecutive patients (age, 35.5 ± 11 years; 75% men), with MLKI sustained between 2013 and 2019 and treated with MLR. At a mean follow-up of 3.8 ± 1.6 years, patient-reported outcome measure scores—including the International Knee Documentation Committee (IKDC), the Knee injury and Osteoarthritis Outcome Score (KOOS), the Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI), and the 12-Item Short-Form Health Survey—RTW, return to sports, and weightbearing radiographs were obtained. A total of 20 determinants were hypothesized and tested by univariate logistic regression for binary variables or linear regression for continuous variables. Only factors identified as significant (P <.10) were entered into a multivariate logistic regression model. Results: The prevalence of injury severity according to the Schenck knee dislocation (KD) classification was as follows: KD I (44%), KD III (36%), KD IV (10%), and KD V (10%). Increased KD grades resulted in decreased IKDC (P =.002) and all 5 KOOS subscales (P ≤.007 for all) scores. Medial meniscectomy (23%) was associated with a worse ACL-RSI score (P =.007) and RTW failure (odds ratio [OR], 36.8; P =.035). Peroneal nerve palsy (6%) was associated with a worse ACL-RSI score (P ≤.001). Radiographic OA was observed in 38%, with distribution predominantly patellofemoral (80%) and medial tibiofemoral (45%). Traumatic cartilage damage (Outerbridge grade >2 [37%]) was associated with secondary patellofemoral (OR, 10; P =.012) and medial tibiofemoral (OR, 10; P =.019) OA. Anterior cruciate ligament reconstruction failure (7%) was a risk factor for medial tibiofemoral OA (OR, 25.8; P =.006). Conclusion: Increased Schenck KD grade, permanent peroneal nerve palsy, and irreparable medial meniscus lesions were prognostic factors for worse functional outcomes 3.8 years after MLKI was treated with MLR. Traumatic cartilage damage and anterior cruciate ligament failure were associated with the development of early OA. [ABSTRACT FROM AUTHOR]

Background: Medial meniscal extrusion (MME) has been associated with knee osteoarthritis (OA). However, there is no standardized method to measure MME. Purpose/Hypothesis: The purpose of this study was to investigate the relationship between MME and outcome measures related to knee OA and discuss different magnetic resonance imaging (MRI) methods of measuring MME. It was hypothesized that MME would be associated with outcome measures of OA and that the distance extruded over the tibial plateau would be the most common MRI method to measure MME. Study Design: Systematic review; Level of evidence, 3. Methods: The MEDLINE, Embase, Cochrane Library, Scopus, Web of Science Core Collection, Global Index Medicus, and ClinicalTrials.gov databases were systematically searched. The inclusion criteria were studies that (1) measured MME on nonoperated knees using MRI; (2) evaluated knee OA with at least 1 knee OA grading scale, outcome measure, or direct characterization of cartilage or bone; (3) statistically evaluated the association between MME and knee OA outcome measure; (4) were randomized controlled trials, nonrandomized controlled trials, cohort studies, or case series; and (5) reported original results. Results: A total of 19 studies were included, of which 14 reported MME as the distance extruded over the tibial plateau, 7 reported MME as the volume extruded over the tibial plateau, and 1 reported MME as the percentage of the tibial plateau covered by the meniscus. All studies reported that MME was significantly associated with at least 1 OA outcome measure—including increased Kellgren-Lawrence grade, osteophytes, cartilage damage, varus alignment, knee pain, bone marrow lesions, and progression to arthroplasty. Eight studies found that MME was associated with worse OA outcomes over time (range, 2-10 years). Conclusion: All 19 reviewed studies reported that MME was associated with at least 1 knee OA outcome measure reflective of worsening arthritis, suggesting a strong association between OA and MME. Future research is needed to investigate this relationship and standardize the methods of measuring MME. [ABSTRACT FROM AUTHOR]

Meniscus tears are a common cause of knee pain encountered in orthopedics and sports medicine. There are numerous management strategies, from physical therapy and oral medications to surgery. Recent evidence is more favorable for conservative management, as operative treatment has limited clinical benefits and is associated with an accelerated progression toward osteoarthritis. Injections with orthobiologic therapies, such as platelet-rich plasma (PRP), are emerging as an alternative therapeutic tool for degenerative tears. This study aims to evaluate the latest evidence regarding the efficacy of PRP injections for the nonoperative management of degenerative meniscal pathology. Articles were obtained from Embase, PubMed, World of Science, Cochrane, and Galileo databases after searching "Platelet-rich plasma" AND "Meniscus." Inclusion criteria consisted of original, human studies evaluating the use of platelet-rich plasma for nonoperative management of meniscus tears. A total of 384 articles were screened, with ten studies selected for final inclusion. The pooled study population comprised 686 patients, with an average age ranging from 33 to 53 years, and a 38% female population. Three different injection approaches were utilized, categorized as intra-articular alone (IA), intra-meniscal alone (IM), or a combination of both. Most studies demonstrated improved pain and functionality by 3 months that persisted for at least one year. Within the IA and IM groups, the majority of patients were either radiographically stable (30–70%) or demonstrated interval healing (40–60%). Several studies within IM and combined treatment groups evaluated rates and time to arthroscopy, and found lower failure rates and greater arthroscopy-free survival time than control comparison groups. PRP appears to be a safe and efficacious treatment strategy for degenerative meniscal pathology. However, due to diverse periprocedural techniques, PRP injectate characteristics, and a lack of high-quality studies, additional trials are needed to provide greater a degree of confidence in PRP's clinical impact on patients with meniscus tears. Systematic Review. [ABSTRACT FROM AUTHOR]

Background: The outcomes of medial meniscal allograft transplantation (MMAT) combined with high tibial osteotomy (HTO) compared with isolated MMAT remain unclear. Purpose: To compare the clinical and radiological results of MMAT combined with HTO and isolated MMAT. Study Design: Cohort study; Level of evidence, 3. Methods: This retrospective study included 42 consecutive patients, who were divided into group M (isolated MMAT; n = 22) and group H (MMAT combined with HTO with a varus angle >3°; n = 20). Group differences in subjective knee scores, isokinetic muscle strength test, and radiological outcomes (Kellgren-Lawrence grade, mechanical axis, graft extrusion, graft status, and articular cartilage loss) were compared. Results: The mean follow-up period was 29.2 ± 4.9 months and 27.4 ± 5.3 months for groups M and H, respectively. The Lysholm score improved from 55.4 ± 9.5 to 81.3 ± 9.7 and from 52.6 ± 8.9 to 84.2 ± 10.2 in groups M and H, respectively (both P <.001). The International Knee Documentation Committee subjective score improved from 51.4 ± 10.3 to 79.6 ± 9.4 and from 49.3 ± 11.4 to 81.4 ± 8.3 in groups M and H, respectively (both P <.001). Both groups showed no significant differences in subjective knee scores and isokinetic extensor strength at the final follow-up. The rate of preoperative and postoperative high International Cartilage Regeneration & Joint Preservation Society grade (≥3) did not differ between the 2 groups. Group M showed greater coronal graft extrusion than did group H (3.3 ± 0.7 mm vs 2.7 ± 0.8 mm; P =.014); the rate of pathologic graft extrusion (≥3 mm) was not higher in group M (40.9%) than in group H (20%) with the number of patients available (P =.143). Both groups showed no significant difference in the graft status. Graft tears were observed in 2 patients (9%) in group M and 1 patient (5%) in group H (P =.607). Conclusion: Clinical scores significantly improved after isolated MMAT and MMAT combined with HTO compared with preoperative values, and their short-term outcomes were similar. Postoperative graft extrusion was greater in patients who underwent isolated MMAT, implying that active correction of varus alignment during MMAT may help in intra-articular biomechanics. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the changes in contact characteristics of the tibiofemoral joint resulting from a meniscal ramp lesion in the medial meniscus. Methods: Twelve cadaveric knees (six matched pairs) were subjected to a 600 N axial load using a custom testing jig, which allowed for knee positioning at 0°, 45°, and 90° of flexion without other constraints. The knees were randomly assigned to either a ramp lesion group (n = 6) or a posterior root lesion group (n = 6). Four testing conditions were examined: (1) intact, (2) isolated ramp lesion, (3) isolated posterior root tear of the medial meniscus, and (4) combined ramp lesion and posterior root tear of the medial meniscus. Contact characteristics were evaluated using a flexible pressure sensor, the I-Scan System. Results: Peak contact pressure in isolated ramp lesions (4.15 ± 0.98 MPa, P = 0.206) showed non-significant increases compared to the intact condition (3.86 ± 1.32 MPa). Peak contact pressure in isolated posterior root tears (4.58 ± 1.70 MPa, P = 0.040) and, combined ramp and posterior root lesions (4.67 ± 1.47 MPa, P = 0.003) were significantly higher than that in the intact condition. The knee flexion position significantly affected the medial tibiofemoral joint's contact area, contact pressure, and peak contact pressure (P < 0.001 for all). Conclusion: Isolated ramp lesions did not significantly impact force transmission, contact area, or contact pressure. In contrast, isolated root lesions and combined ramp and posterior root tears of the medial meniscus significantly intensified the changes in contact characteristics in the medial tibiofemoral joint compared to the intact condition. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

In this study, we investigated the discriminative capacity of knee morphology in automatic detection of osteophytes defined by the Osteoarthritis Research Society International atlas, using X‐ray and magnetic resonance imaging (MRI) data. For the X‐ray analysis, we developed a deep learning (DL) based model to segment femur and tibia. In case of MRIs, we utilized previously validated segmentations of femur, tibia, corresponding cartilage tissues, and menisci. Osteophyte detection was performed using DL models in four compartments: medial femur (FM), lateral femur (FL), medial tibia (TM), and lateral tibia (TL). To analyze the confounding effects of soft tissues, we investigated their morphology in combination with bones, including bones+cartilage, bones+menisci, and all the tissues. From X‐ray‐based 2D morphology, the models yielded balanced accuracy of 0.73, 0.69, 0.74, and 0.74 for FM, FL, TM, TL, respectively. Using 3D bone morphology from MRI, balanced accuracy was 0.80, 0.77, 0.71, and 0.76, respectively. The performance was higher than in 2D for all the compartments except for TM, with significant improvements observed for femoral compartments. Adding menisci or cartilage morphology consistently improved balanced accuracy in TM, with the greatest improvement seen for small osteophyte. Otherwise, the models performed similarly to bones‐only. Our experiments demonstrated that MRI‐based models show higher detection capability than X‐ray based models for identifying knee osteophytes. This study highlighted the feasibility of automated osteophyte detection from X‐ray and MRI data and suggested further need for development of osteophyte assessment criteria in addition to OARSI, particularly, for early osteophytic changes. [ABSTRACT FROM AUTHOR]

Background: Meniscal allograft transplantation (MAT) is a viable option for patients experiencing unicompartmental knee pain after total or subtotal meniscectomy. Nonetheless, caution is recommended when suggesting this procedure in the presence of knee osteoarthritis (OA) because of the higher risk of poor survival and outcomes. Purpose/Hypothesis: The purpose was to document the long-term survival of MAT performed as a salvage procedure in patients with knee OA. The hypothesis was that MAT would significantly reduce pain and increase the function of the affected joint at a long-term follow-up compared with the preoperative condition, with a low number of failures and knee replacement surgeries. Study Design: Case series; Level of evidence, 4. Methods: A total of 47 patients (37 men and 10 women) with symptomatic knee OA (Kellgren-Lawrence grades 2 or 3) treated with MAT were evaluated at baseline, 5 years, and a minimum 10-year final follow-up (11.1 ± 1 years) using the Lysholm score, the visual analog scale for pain, the Knee injury and Osteoarthritis Outcome Score subscales, and the Tegner score. A total of 44 patients had undergone previous surgeries. Patient satisfaction, revision surgeries, and failures were also recorded. Results: A statistically significant improvement was observed in all clinical scores from the baseline assessment to the final follow-up. The Lysholm score improved significantly from 46.4 ± 17.2 at the preoperative assessment to 77.7 ± 20.4 at the intermediate follow-up (P <.001), with a significant decrease at the final follow-up (71 ± 23.3; P =.018). A similar trend was reported for the visual analog scale scale for pain, Knee injury and Osteoarthritis Outcome Score, and Tegner score, with no complete recovery to the previous sports activity level. A total of 33 patients required concurrent procedures, such as anterior cruciate ligament reconstructions, osteotomies, and cartilage procedures. Five patients underwent reoperation and were considered surgical failures, while 15 patients presented a clinical condition of <65 of the Lysholm score and were considered clinical failures. Among these, 4 patients were considered both surgical and clinical failures. Conclusion: MAT surgery has proven to be a valid option for improving pain and function even in OA joints (Kellgren-Lawrence grades 2 or 3), yielding satisfactory results despite a worsening clinical outcome in the long-term follow-up. Therefore, based on the data from this study, orthopaedic surgeons may consider recommending MAT as a salvage procedure even in knees affected by early to moderate OA, while advising patients that the need for combined interventions could potentially reduce graft survival. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to develop a machine learning model that would predict lateral compartment osteoarthritis (OA) in the discoid lateral meniscus (DLM), from which to then identify factors contributing to lateral compartment OA, with a key focus on the patient's age. Methods: Data were collected from 611 patients with symptomatic DLM diagnosed using magnetic resonance imaging between April 2003 and May 2022. Twenty features, including demographic, clinical and radiological data and six algorithms were used to develop the predictive machine learning models. Shapley additive explanation (SHAP) analysis was performed on the best model, in addition to subgroup analyses according to age. Results: Extreme gradient boosting classifier was identified as the best prediction model, with an area under the receiver operating characteristic curve (AUROC) of 0.968, the highest among all the models, regardless of age (AUROC of 0.977 in young age and AUROC of 0.937 in old age). In the SHAP analysis, the most predictive feature was age, followed by the presence of medial compartment OA. In the subgroup analysis, the most predictive feature was age in young age, whereas the most predictive feature was the presence of medial compartment OA in old age. Conclusion: The machine learning model developed in this study showed a high predictive performance with regard to predicting lateral compartment OA of the DLM. Age was identified as the most important factor, followed by medial compartment OA. In subgroup analysis, medial compartmental OA was found to be the most important factor in the older age group, whereas age remained the most important factor in the younger age group. These findings provide insights that may prove useful for the establishment of strategies for the treatment of patients with symptomatic DLM. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Objectives: Medial meniscus posterior root (MMPR) tears can result in rapidly progressing osteoarthritis if left untreated. Prior research has demonstrated that MMPR tears are frequently preceded by medial meniscotibial ligament (MTL) disruption and medial meniscus extrusion. Although meniscus extrusion is a physiologic phenomenon observed after sustained activity, the impact of excessive medial meniscus extrusion resulting from MTL disruption on forces experienced at the MMPR remains uncertain. Moreover, repairing MMPR tears does not always correct medial meniscus extrusion, suggesting that MTL repair or tenodesis may provide some benefit as a concomitant procedure to MMPR repair in terms of restoring native forces. The aim of this study was to assess the relationship between medial meniscus extrusion and MMPR forces in the setting of MTL insufficiency and following MTL tenodesis while subjecting the joint to progressive cyclic loading. We hypothesized that 1) medial meniscus extrusion resulting from MTL insufficiency would increase MMPR forces; 2) MMPR forces and extrusion would both increase as the number of loading cycles increased; and 3) MTL tenodesis would decrease medial meniscus extrusion and restore MMPR forces to native levels. Methods: Fifteen pairs of fresh-frozen, cadaveric human knees were organized in a balanced incomplete block design (BIBD) consisting of three testing groups: a native group, a group in which the MTL was disrupted (MTL Cut), and a group in which the MTL was disrupted and then repaired via a peripheral centralization procedure using two knotless all-suture anchors (MTL Tenodesis). Specimens were dissected down to the knee capsule, and the femur/tibia bones were potted. A three-axis force sensor was installed inferior to the MMPR such that forces acting on the MMPR could be measured across three axes. Specimens were then mounted in full extension to a dynamic materials testing machine (Fig. 1), and baseline meniscus extrusion and three-dimensional (3D) force measurements were captured. 3D MMPR forces were measured from the force sensor, and ultrasound (US) was used to image the medial meniscus. Each specimen was subjected to compressive cyclic loading over 10,000 cycles at a 1 Hz frequency ranging from 500 N to 20 N. After the 0th cycle, 100th cycle, 1,000th cycle, and 10,000th cycle, a 500 N load was applied, the medial meniscus was imaged, and 3D forces were measured. Medial meniscus extrusion was measured from the resulting US images. To date, means and standard deviations have been calculated for 11 cadaveric pairs, and Pearson correlations were calculated between outcomes. The full data set will be analyzed with an analysis of variance method corresponding to the BIBD. Pairwise group comparisons will be made among the estimated marginal means (Tukey's method). Results: Eleven pairs of specimens have been tested as of this submission: 6 native, 8 MTL Cut, and 8 MTL Tenodesis. For all states, medial meniscus extrusion increased as the number of loading cycles increased. The MTL Cut state demonstrated increased meniscus extrusion relative to the native state, and MTL tenodesis restored extrusion back to the native level (Fig. 2). In all states, MMPR medial shear force and compression decreased as the number of cycles increased. MMPR medial shear force and compression increased to a greater extent in the MTL Cut state compared to the native state, and MTL tenodesis did not restore shear nor compression forces to native levels (Fig. 3 and Fig. 4). Meniscus extrusion was weakly correlated to MMPR medial shear at lower numbers of cycles (0th: R = 0.2, 100th: R = 0.5) and strongly correlated to MMPR medial shear at higher numbers of cycles (1,000th: R = 0.93, p < 0.001; 10,000th: R = 0.82, p = 0.002). Conclusions: As hypothesized, medial meniscus extrusion, MMPR medial shear force, and MMPR compression were higher in the MTL Cut state compared to the native state. While the MTL tenodesis reduced medial meniscus extrusion to the native level, MMPR forces were not restored to native levels. Also in line with our hypothesis, meniscus extrusion increased with progressive loading. Interestingly, MMPR medial shear force decreased with progressive loading cycles, and the Pearson correlation between meniscus extrusion and MMPR medial shear force was stronger at higher levels of cyclic loading. Based on these findings, MTL tenodesis should be considered as an effective treatment option for reducing medial meniscus extrusion both in patients with isolated MTL insufficiency and in the setting of MMPR tears with medial meniscus extrusion. Further research is necessary to determine how the various MTL repair and tenodesis techniques affect MMPR forces. The observed correlation between meniscus extrusion and MMPR medial shear force provides an interesting insight into native meniscal function. As the knee joint undergoes repetitive loading, the medial meniscus undergoes physiologic extrusion, which decreases MMPR medial shear force and may thereby protect the MMPR. Conversely, the MMPR may be at increased risk for injury when the knee undergoes acute loading, and the medial meniscus does not have the opportunity to undergo physiologic extrusion or in the setting of excessive medial meniscus extrusion resulting from MTL insufficiency. This finding also experimentally supports the theoretical assertion that the meniscus, anchored by the roots, transmits femoral compressive loads into circumferential loads. [ABSTRACT FROM AUTHOR]

Objectives: Meniscal allograft transplantation (MAT) is an accepted and effective treatment option in the context of unsalvageable menisci, particularly in young and active patients. It has been shown to reduce pain and improve knee function in previously symptomatic patients. However, there is still limited knowledge about the long-term survival rates of allografts, the durability of clinical results, and the influence of patient-specific parameters, such as leg alignment, tibial slope, and preoperative International Cartilage Regeneration & Joint Preservation Society (ICRS) grade. The purpose of this study was to determine (1) the long-term clinical success rate after MAT with bony fixation in a large, single-center cohort of consecutive patients, and (2) if patient-specific and procedural variables influence the clinical, anatomic, and subjective outcomes and risk of failure. Methods: Data on 185 consecutive knees undergoing MAT in a single institution were prospectively collected and screened for inclusion in this study. The minimum follow-up time was 2 years. Radiographic variables (International Cartilage Regeneration & Joint Preservation Society [ICRS] grade and Kellgren and Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (PROMs), Lysholm score, Knee Disability and Osteoarthritis Outcome Score (KOOS) including subscores, International Knee Documentation Committee (IKDC) score, and visual analog score (VAS) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery due to graft failure or conversion to total knee arthroplasty (TKA). Anatomic failure was considered a tear covering >20% of the allograft, any peripheral tear, and unstable peripheral fixation leading to dislocation of the graft. Subjective failure was defined as Lysholm score ≤65. Preoperative tibial slope and leg alignment were assessed. Survival analyses were performed utilizing the Kaplan-Meier estimate. Univariate and multivariate analyses were performed to determine risk factors for clinical and anatomic failure. Results: A total of 157 knees met inclusion criteria (Table 1). After a mean follow-up time of 7 ± 3.5 years, 127 (80.9%) knees were free of clinical, anatomic, and subjective failure. Fourteen (8.9%) knees experienced clinical failure, 26 (16.6%) knees were identified as anatomic failure, and 13 patients (8.3%) suffered from subjective failure with a reported Lysholm score of ≤65 at a mean follow-up of 7 years. Concurrent osteochondral allograft transplantation was identified as a predictor of both clinical (HR 4.55; 95% CI 1.46-14.17; p=0.009) and anatomic failure (HR 3.05; 95% CI 1.34-6.92; p=0.008). Cartilage damage of ICRS grade 3 or 4 of the index compartment conveyed an increased risk for clinical (HR 3.41; 95% CI 1.05-11.01; p=0.04) and anatomic failure (HR 3.04; 95% CI 1.31-7.11; p=0.01) (Table 2). There were no differences in outcomes between medial and lateral MAT. High-grade cartilage damage (defined as ICRS grades 3 and 4) preoperatively (HR 10.67; 95% CI 1.037-109.768; p=0.046), patients age over 25 (HR 5.44; 95% CI 0.120-246.070; p=0.384), and a body mass index >30 (HR 2.24; 95% CI 0.748-6.705; p=0.149) were associated with subjective failure. Considering the entire study population, PROMs including KOOS and IKDC were significantly improved at final follow-up compared to preoperative scores across all measurements (p<0.005). Conclusions: MAT showed good-to-excellent clinical results at a mean follow-up of 7 years. Low ICRS lesion grade was associated with a higher clinical and anatomic survival rate. Patients with concurrent osteochondral allograft transplantation are at higher risk of clinical and anatomic failure, but still report significantly improved PROMs. These results suggest MAT has a lasting beneficial effect both as in isolation and in complex cases with one or more concurrent procedures. [ABSTRACT FROM AUTHOR]

Symptomatic acetabular labral insufficiency in young, active patients is often treated with labral repair or reconstruction using fresh-frozen allografts. However, fresh-frozen tendon allografts do not have tissue or material properties that closely mimic acetabular labral fibrocartilage. Recent studies suggest meniscal allografts may be a better biomechanical, geometric, and material alternative for acetabular labrum reconstruction (ALR). Patients undergoing open ALR using fresh meniscus allograft transplants (MAT) will have better outcomes than those using fresh-frozen tendon allografts transplants (TAT) when comparing initial treatment success, diagnostic imaging assessments, and patient-reported pain and function scores. Cohort Study. With IRB approval, patients undergoing ALR with either TAT or MAT were included when initial (>1-year) outcomes data related to treatment success, pain, and function were available. In addition, a subcohort of patients underwent magnetic resonance imaging at least 6-months after surgery to evaluate allograft healing. Initial success rate, defined as no need for ALR revision or conversion to total hip arthroplasty (THA), was 88.9% for the entire group (n = 27, TAT = 5, MAT = 22) with 1 (20%) patient in the TAT cohort and 2 patients (9.9%) in the MAT cohort undergoing THA. In the MAT cohort, significant improvements were documented for physical function and pain scores at 1 year and final follow-up (FFU)(mean 26.8 months). Improvements in pain and function were noted at 1-year, but not at FFU (mean 59.6 months) in the TAT group. MRIs completed at least 6 months after labrum reconstruction showed improved allograft integrity and integration in the MAT cohort over the TAT cohort. For acetabular labrum reconstructions, MAT was associated with a higher initial success rate, superior patient reported outcomes, and subjectively better MRI findings when compared to TAT. [ABSTRACT FROM AUTHOR]

Purpose: It is unclear whether different injury mechanisms lead to divergent anterior cruciate ligament (ACL) tear locations. This study aims to analyse the relationship between bone bruise (BB) distribution or depth and ACL tear location. Methods: A retrospective analysis of 446 consecutive patients with acute non‐contact ACL injury was performed. Only patients with complete ACL tears verified during subsequent arthroscopy were included. Magnetic resonance imaging (MRI) was used to classify BB location, BB depth, ACL tear location and concomitant injuries (medial/lateral meniscus and medial/lateral collateral ligament). Demographic characteristics included age, gender, body mass index (BMI), type of sport and time between injury and MRI. Multiple linear regression analysis was used to identify independent predictors of ACL tear location. Results: One hundred and fifty‐eight skeletally mature patients met the inclusion criteria. The presence of BB in the lateral tibial plateau was associated with a more distal ACL tear location (β = −0.27, p < 0.001). Less BB depth in the lateral femoral condyle showed a tendency towards more proximal ACL tears (β = −0.14; p = 0.054). Older age predicted a more proximal ACL tear location (β = 0.31, p < 0.001). No significant relationship was found between ACL tear location and gender, BMI, type of sport, concomitant injuries and time between injury and MRI. Conclusion: ACL tear location after an acute non‐contact injury is associated with distinct patterns of BB distribution, particularly involving the lateral compartment, indicating that different injury mechanisms may lead to different ACL tear locations. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence To elucidate the features of bone cysts at attachment sites of medial meniscus posterior root tears (MMPRTs).Knees treated using arthroscopic surgery for MMPRT between 2015 and 2022 were retrospectively reviewed. Patients without a memory of onset (painful popping), prior knee surgeries, concomitant ligament or meniscus injuries or fractures were excluded. Duration from onset to magnetic resonance imaging (MRI) and type of tear were evaluated during arthroscopy. On radiography, meniscus signs (cleft/ghost/giraffe neck), bone cysts at the attachment site of the MMPRT and posterior shiny‐corner lesions (PSCLs; bone marrow lesions on the meniscal‐covered portion of the posterior tibial plateau) were evaluated. The sensitivity and specificity of the bone cysts were assessed by comparison with matched patients who underwent arthroscopic surgery for medial meniscus posterior horn tear. In addition, subgroups (cyst‐positive/cyst‐negative) among patients with MMPRT were created to assess the features of bone cysts.A total of 275 patients with MMPRT and 275 matched patients with posterior horn tears were evaluated. The sensitivity and specificity of bone cysts for MMPRT in this study were 22.2% and 98.6%, respectively. Among the 275 knees with MMPRT, compared with the cyst‐negative group, the cyst‐positive group had a longer duration from onset to MRI (12.9 ± 13.1 vs. 8.3 ± 10.9 weeks, respectively, p = 0.025) and reduced occurrence of PSCLs (18.0% vs. 42.0%, respectively, p = 0.031).The occurrence of bone cysts at the attachment site was helpful for the accurate diagnosis of MMPRT and related to longer duration from onset to MRI and reduced PSCLs.Level III, cross‐sectional study. [ABSTRACT FROM AUTHOR]

Background: Mechanical unloading of the knee articular cartilage results in cartilage matrix atrophy, signifying the osteoarthritic-inductive potential of mechanical unloading. In contrast, mechanical loading stimulates cartilage matrix production. However, little is known about the response of meniscal fibrocartilage, a major mechanical load-bearing tissue of the knee joint, and its functional matrix-forming fibrochondrocytes to mechanical unloading events. Methods: In this study, primary meniscus fibrochondrocytes isolated from the inner avascular region of human menisci from both male and female donors were seeded into porous collagen scaffolds to generate 3D meniscus models. These models were subjected to both normal gravity and mechanical unloading via simulated microgravity (SMG) for 7 days, with samples collected at various time points during the culture. Results: RNA sequencing unveiled significant transcriptome changes during the 7-day SMG culture, including the notable upregulation of key osteoarthritis markers such as COL10A1, MMP13, and SPP1, along with pathways related to inflammation and calcification. Crucially, sex-specific variations in transcriptional responses were observed. Meniscus models derived from female donors exhibited heightened cell proliferation activities, with the JUN protein involved in several potentially osteoarthritis-related signaling pathways. In contrast, meniscus models from male donors primarily regulated extracellular matrix components and matrix remodeling enzymes. Conclusion: These findings advance our understanding of sex disparities in knee osteoarthritis by developing a novel in vitro model using cell-seeded meniscus constructs and simulated microgravity, revealing significant sex-specific molecular mechanisms and therapeutic targets. [ABSTRACT FROM AUTHOR]

Background: Quantitative techniques such as T2 and T1ρ mapping allow evaluating the cartilage and meniscus. We evaluated multi-interleaved X-prepared turbo-spin echo with intuitive relaxometry (MIXTURE) sequences with turbo spin-echo (TSE) contrast and additional parameter maps versus reference TSE sequences in an in situ model of human cartilage defects. Methods: Standardized cartilage defects of 8, 5, and 3 mm in diameter were created in the lateral femora of ten human cadaveric knee specimens (81 ± 10 years old; nine males, one female). MIXTURE sequences providing proton density-weighted fat-saturated images and T2 maps or T1-weighted images and T1ρ maps as well as the corresponding two- and three-dimensional TSE reference sequences were acquired before and after defect creation (3-T scanner; knee coil). Defect delineability, bone texture, and cartilage relaxation times were quantified. Appropriate parametric or non-parametric tests were used. Results: Overall, defect delineability and texture features were not significantly different between the MIXTURE and reference sequences (p ≤ 0.47). After defect creation, relaxation times significantly increased in the central femur (T2pre = 51 ± 4 ms [mean ± standard deviation] versus T2post = 56 ± 4 ms; p = 0.002) and all regions combined (T1ρpre = 40 ± 4 ms versus T1ρpost = 43 ± 4 ms; p = 0.004). Conclusions: MIXTURE permitted time-efficient simultaneous morphologic and quantitative joint assessment based on clinical image contrasts. While providing T2 or T1ρ maps in clinically feasible scan time, morphologic image features, i.e., cartilage defects and bone texture, were comparable between MIXTURE and reference sequences. Relevance statement: Equally time-efficient and versatile, the MIXTURE sequence platform combines morphologic imaging using familiar contrasts, excellent image correspondence versus corresponding reference sequences and quantitative mapping information, thereby increasing the diagnostic value beyond mere morphology. Key points: • Combined morphologic and quantitative MIXTURE sequences are based on three-dimensional TSE contrasts. • MIXTURE sequences were studied in an in situ human cartilage defect model. • Morphologic image features, i.e., defect delineabilty and bone texture, were investigated. • Morphologic image features were similar between MIXTURE and reference sequences. • MIXTURE allowed time-efficient simultaneous morphologic and quantitative knee joint assessment. [ABSTRACT FROM AUTHOR]

Background/Objective: The effects of concomitant meniscal tears and their associated treatment on strength, lower extremity balance, and functional status after anterior cruciate ligament reconstruction (ACLR) have not been widely investigated. This study aimed to compare the functional outcomes in patients who underwent ACLR with concomitant treatment of the medial meniscus repair versus meniscectomy when returning to unrestricted physical activity. Methods: A total of 85 patients who underwent primary ACLR with combined meniscal repair (MREP; n = 39) or meniscectomy (MRES; n = 46) were assessed. The dataset included the Functional Movement ScreenTM (FMS) outcomes and single-leg balance test (SLBT) with anterior–posterior, medial–lateral, and overall stability indexes. Isokinetic knee extension and flexion strengths were tested at velocities of 60 deg·s−1 and 180 deg·s−1. The peak torque-to-body weight ratio (PT/BW) and limb symmetry index (LSI) were calculated. Results: In the functional assessment, there was no significant inter-group difference in the composite score of the FMS (MREP: 15.08 pts vs. MRES: 15.13 pts; p > 0.05). The SLBT outcomes in inter-group and inter-extremity comparisons were irrelevant (p > 0.05), too. Significant differences emerged in the inter-group comparison of the knee extension strength in the non-operated extremity at both 60 deg·s−1 and 180 deg·s−1 (p = 0.02). Inter-extremity differences were significant in both the MREP and MRES groups for knee extension and flexion at both angular velocities (all p values < 0.05). For knee extension, the LSI values ranged from 82% to 87%, and for flexion, from 77% to 84%, with no significant inter-group differences. Conclusions: Patients undergoing ACLR with concomitant meniscal repair or resection did not exhibit differences in isokinetic muscle strength, lower extremity balance, and functional tests upon returning to activity. However, participants in both groups demonstrated significant differences between the operated and non-operated extremities as far as the knee joint extensor and flexor strengths are concerned. Therefore, rehabilitation protocols should prioritize equalizing inter-extremity strength differences after the ACLR with additional treatment procedures addressing the menisci. [ABSTRACT FROM AUTHOR]

Objective: Early articular cartilage lesion (CL) is a vital sign in the onset of posttraumatic knee osteoarthritis (PTOA) in patients with anterior cruciate ligament deficiency (ACLD). Researchers have suggested that altered kinematics could accelerate CLs and, therefore, lead to the onset of PTOA. However, little is known about whether specific knee kinematics exist that lead to early CL in chronic ACLD knees. Level walking is the most frequent and relevant in vivo activity, which greatly impacts knee health. We hypothesized that the knee kinematics during level walking in chronic ACLD knees with early tibiofemoral CL would significantly differ from those of chronic ACLD knees without early tibiofemoral CL. Methods: Thirty patients with a chronic ACLD history, including 18 subjects with CLs and 12 subjects without CLs, and 35 healthy control subjects were recruited for the study from July 2020 to August 2022. The knee kinematic data during level walking were collected using a three‐dimensional motion analysis system. The kinematic differences between groups were compared using statistical parametric mapping with one dimension for One‐Way ANOVA. The cartilage statuses of the ACLD knees were assessed via MRI examination. The CLs distribution of subjects was evaluated using a modified Noyes scale and analyzed by chi‐square tests. Results: ACLD knees with CLs had significantly greater posterior tibial translation (7.7–8.0mm, 12%–18% gait cycle GC, p = 0.014) compared to ACLD knees without CLs during level walking. ACLD knees with CLs had greater posterior tibial translation (4.6–5.5mm, 0%–23% GC, p < 0.001; 5.8–8.0mm, 86%–100% GC, p < 0.001) than healthy controls during level walking. In the group of ACLD knees with CLs, CL is mainly located in the back of the tibia plateau and front of load bearing area of the medial femoral condyle (p < 0.05). Conclusion: Chronic anterior cruciate ligament deficient knees with cartilage lesions have increased posterior tibial translation compared to anterior cruciate ligament deficient knees without cartilage lesions and healthy subjects. The posterior tibial translation may play an important role in knee cartilage degeneration in ACLD knees. The increased posterior tibial translation and cartilage lesion characteristics may improve our understanding of the role of knee kinematics in cartilage degeneration and could be a helpful potential reference for anterior cruciate ligament deficient therapy, such as physical training to improve abnormal kinematic behavior. [ABSTRACT FROM AUTHOR]

Purpose of the study: This study aimed to reach a consensus for ideal surgical treatment of discoid lateral meniscus (DLM) and to evaluate its long term surgical and radiological outcome. Methods: All authors independently searched for peer reviewed publications with keywords like discoid lateral meniscus, tibial menisci abnormalities, tibial menisci surgery and clinical outcome and their representative Medical Subjects Headings (MeSH) in databases of PubMed, EBSCO, Cochrane Central Register of Controlled Trials, from inception to December 2022. Original articles in English language on discoid lateral meniscus reporting clinical, surgical, or radiological outcomes with five or more years of follow-up were included in this systematic review. Study details and outcome data were analysed according to the age, follow-up period, kind of surgery, DLM type, and alignment. Results: Our search strategy yielded 654 articles in PubMed, 222 articles in EBSCO and 5 articles in CENTRAL i.e. a total of 881 articles. After detailed assessment and screening, 12 articles were included in the final analysis, which included 444 DLM cases. The mean patient age at surgery ranged from 9.9 to 35.9 years, and the mean follow-up period ranged from 5.2 to 16 years. Partial meniscectomy and meniscoplasty are the recommended treatment because of the concerns of degenerative arthritis development after the total and subtotal meniscectomies. Two studies have documented better results with meniscal allograft transplantation. Conclusion: Satisfactory clinico-radiological outcome can be obtained after surgical treatment of discoid lateral meniscus with meniscus reshaping and repair of peripheral unstable part. Meniscal allograft transplantation (MAT) is gaining popularity in patients with total meniscectomy with satisfactory long term functional outcome. [ABSTRACT FROM AUTHOR]

Background: Satisfactory clinical results of meniscal allograft transplantation (MAT) have been reported in recent years. However, it remains unclear whether the clinical outcomes of MAT when combined with an osteotomy are inferior to those of isolated MAT. Purpose: To compare the survival rates and clinical outcomes of patients who received isolated medial MAT with those of patients undergoing medial MAT combined with high tibial osteotomy (HTO). Study Design: Cohort study; Level of evidence, 3. Methods: A total of 55 patients underwent arthroscopic medial MAT using the soft tissue technique and HTO (mean age, 41.3 ± 10.4 years; 9 female); after fuzzy case-control matching on demographics, 55 controls who underwent isolated medial MAT were also included. Survival analyses were performed using the Kaplan-Meier method with surgical failure, clinical failure (Lysholm score, <65), and reoperation as endpoints. Subjective clinical scores were collected preoperatively and at the final follow-up. Results: The mean follow-up time was 5.4 years, up to 8 years. All outcomes significantly improved at the last follow-up (P <.001). No differences were identified between MAT and MAT + HTO groups preoperatively and at the last follow-up (P >.05). At the final follow-up, 8 of 55 (14.5%) of the MAT + HTO patients and 9 of 55 (16.4%) of the MAT patients had a Lysholm score <65 (P =.885). Overall, 90% of the patients declared they would repeat the surgery regardless of the combined procedure. Surgical failure was identified in 6 of 110 (5.5%) patients: 5 of 55 (9.1%) in the MAT + HTO group and 1 of 55 (1.8%) in the MAT group (P =.093). Clinical failure was identified in 19 of 110 (17.3%) patients: 11 of 55 (20%) in the MAT + HTO group and 8 of 55 (14.5%) in the MAT group (P =.447). A significantly lower survivorship from surgical failure was identified in the MAT + HTO group (hazard ratio, 5.1; P =.049), while no differences in survivorship from reoperation and clinical failure were identified (P >.05). Conclusion: Patients undergoing medial MAT + HTO showed similar clinical results to patients undergoing isolated medial MAT at midterm follow-up, and thus a surgically addressed malalignment does not represent a contraindication for medial MAT. However, the need for a concomitant HTO is associated with a slightly higher failure rate over time. [ABSTRACT FROM AUTHOR]

Background: Various suture configurations are available for medial meniscus posterior root tear (MMPRT) repair. The modified Mason-Allen (MMA) technique has been proposed as a refixation technique for MMPRT instead of the conventional 2 simple stitches (TSS). This is in view of its superior biomechanical characteristics. Purpose: To perform a systematic review and meta-analysis to compare MMA and TSS configuration techniques for MMPRT repair and identify any differences between the 2 techniques in terms of clinical outcomes, medial meniscal extrusion (MME), and postoperative healing. Study Design: Meta-analysis; Level of evidence, 4. Methods: The Cochrane Controlled Register of Trials, PubMed, Medline, and Embase databases were used to perform a systematic review and meta-analysis using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria with the following search terms: ("meniscus" OR "meniscal injuries") AND ("Mason-Allen" OR "simple stitch" OR "suture techniques"). Data pertaining to all patient-reported outcome measures, postoperative complications, MME, postoperative healing, cartilage degeneration, and progression of knee osteoarthritis were extracted from each study. The pooled outcome data were analyzed using random- and fixed-effects models. Results: After abstract and full-text screening, 6 clinical studies were included. In total, there were 291 patients; 160 underwent MMA fixation, and 131 underwent the TSS technique. The majority of studies had similar surgical techniques regarding repair technique, suture material, tibial fixation, and number and position of tibial tunnels. There were no differences between the groups in terms of patient-reported outcome measures at 14.2 months. Both techniques were also similar in the degree of postoperative MME and meniscal healing. Conclusion: Both suture configurations were equivalent in terms of clinical outcomes, the extent of meniscal extrusion, and postoperative healing. The TSS technique may offer advantages in terms of faster learning curve and shorter operative time. However, randomized controlled trials with large sample sizes, longer follow-up and assessment of chondral degeneration, and presence of knee osteoarthritis are required to assess whether a true difference exists, as the majority of included studies were limited by their retrospective design. [ABSTRACT FROM AUTHOR]

This article, published in Seminars in Musculoskeletal Radiology, aims to assess the accuracy of magnetic resonance imaging (MRI) in diagnosing tears of the posterior horn of the lateral meniscus (PHLM) in correlation with clinical stability and arthroscopy. The study included 41 patients with surgically verified PHLM tears, and the MRI scans were initially reviewed by radiologists without specialization in musculoskeletal imaging. The results showed that radiologists without musculoskeletal imaging experience only detected 45.2% of the PHLM injuries, while radiologists with musculoskeletal imaging experience detected 85.7% of the injuries. The most commonly missed injuries were root avulsions and tears close to the root of the lateral meniscus. This study highlights the importance of specialized radiologists in accurately diagnosing PHLM tears. [Extracted from the article]

This article, published in Seminars in Musculoskeletal Radiology, aims to enhance the understanding of tibial plateau fractures among radiologists. It provides crucial diagnostic considerations and implications for surgical planning. Tibial plateau fractures are periarticular injuries of the proximal tibia that account for 1 to 2% of all fractures. They have a bimodal distribution, with high-energy trauma affecting men in their 40s and low-energy falls affecting women in their 70s. The article explores the Schatzker classification system, which helps assess and categorize these fractures. It also discusses the use of knee radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) in the diagnosis and assessment of these fractures. The goal of the article is to empower radiologists with a deeper understanding of tibial plateau fractures for more accurate diagnosis, refined surgical planning, and improved patient care. [Extracted from the article]

Purpose: After anterior cruciate ligament reconstruction (ACL‐R), a localised scar tissue called cyclops lesion may develop anterior to the graft causing knee extension deficits, pain, oedema, clicking and reduced knee function. This study determined the incidence of arthroscopic resection of a cyclops lesion within 2 years after ACL‐R and investigated the associations of patient characteristics and surgical techniques with the need for arthroscopic resection of a cyclops lesion. Methods: This study included patients who underwent primary ACL‐R with adult surgical technique from 2005 to 2019 at Aarhus University Hospital, Denmark. The cohort was identified in a national registry. To identify patients who had resected a cyclops lesion within the first 2 years after ACL‐R, patients' surgical records were reviewed. Results: In 2005–2019, 2556 patients underwent primary ACL‐R; 176 developed cyclops lesions that were resected within 2 years, equivalent to an incidence of 6.9% (95% confidence interval [CI]: 5.9–7.9). When stratified by the femoral drilling technique used, this incidence was 8.9% (95% CI: 7.7–10.3) with the anteromedial technique and 1.9% (95% CI: 1.0–3.1) with the transtibial technique. The incidence was 8.5% (95% CI: 6.8–10.3) in women and 5.7% (95% CI: 4.6–7.1) in men. Age, graft choice and the presence of cartilage or meniscal lesions did not affect the incidence. Conclusion: The overall incidence of a cyclops lesion removal within 2 years post‐ACL‐R was 6.9%. This was five times higher with the anteromedial femoral drilling technique than with the transtibial technique. Women had a 47% higher incidence of cyclops lesion removal than men. This is relevant for the surgeon when planning an ACL‐R. Level of Evidence: Level II [ABSTRACT FROM AUTHOR]

Hybrid lateral closed-wedge high tibial osteotomy (HBHTO) carries certain advantages over medial open-wedge high tibial osteotomy (OWHTO). We investigated the potential difference in the required correction angle between HBHTO and OWHTO to achieve an equal amount of whole lower-extremity alignment correction, retrospectively analyzing the preoperative plain radiographic images of 100 patients. The medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), mechanical lateral distal femoral angle (mLDFA), hip–knee–ankle axis (HKA), length of the tibia, width of the tibial plateau, length of the lower limb (leg length), and location of the center of deformity (CD) were measured. Differences in the required correction angle at the hinge point between the two techniques (CAD) were compared, and correlation analysis was performed to reveal the influential factors. The mean difference in CAD between HBHTO and OWHTO was 0.78 ± 0.22 (0.4~1.5)°, and mean WBL position change per correction angle was 3.9 ± 0.3 (3.0~4.6)% in HBHTO and 4.1 ± 0.3 (3.1~4.7)% in OWHTO. Correlation analysis revealed a strong positive correlation between CAD and HKA. mLDFA, JLCA, MPTA, leg length, OWCD, HBCD, and HCD were also significantly correlated with CAD. HBHTO required a 5.6% larger correction angle at the hinge point to achieve the same amount of alignment correction as OWHTO. [ABSTRACT FROM AUTHOR]

Finite element studies of the tibiofemoral joint have increased use in research, with attention often placed on the material models. Few studies assess the effect of meniscus modelling assumptions in image-based models on contact mechanics outcomes. This work aimed to assess the effect of modelling assumptions of the meniscus on knee contact mechanics and meniscus kinematics. A sensitivity analysis was performed using three specimen-specific tibiofemoral models and one generic knee model. The assumptions in representing the meniscus attachment on the tibia (shape of the roots and position of the attachment), the material properties of the meniscus, the shape of the meniscus and the alignment of the joint were evaluated, creating 40 model instances. The values of material parameters for the meniscus and the position of the root attachment had a small influence on the total contact area but not on the meniscus displacement or the force balance between condyles. Using 3D shapes to represent the roots instead of springs had a large influence in meniscus displacement but not in knee contact area. Changes in meniscus shape and in knee alignment had a significantly larger influence on all outcomes of interest, with differences two to six times larger than those due to material properties. The sensitivity study demonstrated the importance of meniscus shape and knee alignment on meniscus kinematics and knee contact mechanics, both being more important than the material properties or the position of the roots. It also showed that differences between knees were large, suggesting that clinical interpretations of modelling studies using single geometries should be avoided. [ABSTRACT FROM AUTHOR]

Background: Socket-tunnel overlap during meniscal allograft transplantation (MAT) combined with anterior cruciate ligament reconstruction (ACLR) may compromise graft integrity and lead to impaired fixation and treatment failure. Purpose/Hypothesis: The purpose of this study was to determine optimal socket-tunnel drilling parameters for medial and lateral MAT with concurrent ACLR using artificial tibias and computed tomography (CT) scans for 3-dimensional (3D) modeling. It was hypothesized that clinically relevant socket tunnels could be created to allow for concurrent medial or lateral MAT and ACLR without significant risk for overlap at varying tunnel guide angles. Study Design: Descriptive laboratory study. Methods: A total of 27 artificial right tibias (3 per subgroup) were allocated to 9 experimental groups based on the inclination of the socket tunnels (55°, 60°, and 65°) created for simulating medial and lateral MAT and ACLR. Five standardized socket tunnels were created for each tibia using arthroscopic guides: one for the ACL tibial insertion and one for each meniscus root insertion. CT scans were performed for all specimens and sequentially processed using computer software to produce 3D models for quantitative assessment of socket-tunnel overlap risk. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests. Results: No subgroup consistently presented significantly safer distances than other subgroups for all distances measured. Three cases (11%) and 24 cases (~90%) of tunnel overlap occurred between the ACL tunnel and tunnels for medial and lateral MAT, respectively. Most socket-tunnel overlap (25 of 27; 92.6%) occurred between sockets at depths ranging between 6.3 and 10 mm from the articular surface. For ACLR and posterior root of the lateral meniscus setting, the guide set at 65° increased socket-tunnel distances. Conclusion: When combined ACLR and MAT using socket tunnels for graft fixation is performed, the highest risk for tibial socket-tunnel overlap involves the ACLR tibial socket and the lateral meniscus anterior root socket at a depth of 6 to 10 mm from the tibial articular surface. Clinical Relevance: Setting tibial guides at 65° to the tibial articular surface with the tunnel entry point anteromedial and socket aperture location within the designated anatomic "footprint" will minimize the risk for socket-tunnel overlap. [ABSTRACT FROM AUTHOR]

The article presents the discussion on new silk-based hydrogel bioadhesive that integrates silk fibroin, ionic liquid, and growth factor TGF-beta1 to enable effective reconstruction of torn meniscus tissue. Topics include the significance of the meniscus in knee function, the challenges in treating meniscal injuries due to poor vascularization and current clinical approaches like repair, meniscectomy, and allograft transplantation.