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Background: Resilience is a psychometric parameter defined as one's ability to recover or bounce back from stressful events and has been shown to correlate with better outcomes following multiple orthopedic procedures. The purpose of this study was to analyze the correlation between resiliency, as measured using the Brief Resiliency Scale (BRS) and various knee outcome scores, including the International Knee Documentation Committee (IKDC), Lysholm, Single Assessment Numeric Evaluation (SANE), and Return to Work, following isolated partial meniscectomy., Methods: One hundred patients who had undergone an isolated partial meniscectomy during a 3-year period at a single institution were successfully recruited to participate in the study. The BRS and knee outcome scores (IKDC, Lysholm, SANE, Return to Work) were obtained via phone. Radiographs for each patient were obtained and graded for arthritis severity using the Kellgren-Lawrence classification system., Results: Brief Resiliency Scale scores ranged 15.0 to 23.0 with a mean of 18.2 ± 1.3. Mean knee outcome scores for IKDC, Lysholm, SANE, and Return to Work were 66.3, 77.1, 70.6, and 41.0, respectively. Outcome scores did not correlate with BRS scores. The severe arthritis group significantly correlated (p < 0.05) with worse IKDC, Lysholm, and Return to Work scores compared to mild arthritis scores. Additionally, analysis of the mild arthritis group revealed that resiliency significantly correlated with higher Return to Work scores compared to low resilience groups., Conclusion: This study suggests that there is no significant relationship between patient resiliency and outcomes following partial meniscectomy. However, those with poorer outcomes had more severe arthritis.

Venous thromboembolism (VTE), comprising pulmonary embolism and deep vein thrombosis, is one of the most common complications after knee arthroscopy. Sequelae of VTE include VTE recurrence, postthrombotic syndrome, and potential for loss of limb or life. Given the increasing volume of knee arthroscopy procedures worldwide and the considerable morbidity and mortality associated with VTE, it is important to prevent, diagnose, and treat VTEs efficiently and effectively. Risk factors such as history of VTE, family history of VTE, genetic coagulopathy, oral contraceptive use, cancer history, and old age increase the risk of postoperative VTE and warrant consideration of prophylaxis. Diagnosis and treatment should be initiated rapidly in the setting of concerning symptoms and positive imaging diagnosis, respectively. The purpose of this review was to provide a framework to individualized VTE risk, weigh prophylaxis options, expedite diagnostic pathways, and implement outpatient treatment algorithms., (Copyright © 2024 by the American Academy of Orthopaedic Surgeons.)

Purpose: This study aimed to identify factors influencing persistent muscle weakness in knee flexor strength after anterior cruciate ligament (ACL) reconstruction using the hamstring tendon and establish a clear cut-off value at 3 months postoperatively for the limb symmetry index (LSI) to exceed 90% at 6 months postoperatively., Methods: One hundred forty-eight patients undergoing ACL reconstruction were included and categorised into two groups based on knee flexor strength at 6 months postoperatively: patients with LSI of 90% or greater (achieved group: n = 114) and patients with LSI less than 85% (nonachieved group: n = 34). Items with significant differences between the two groups (preoperative waiting period, LSI to body weight ratio of knee flexor and extensor strength at 3 months postoperatively and peak torque angle of knee flexor muscle) were included in the multiple logistic regression analysis. Additionally, a receiver operating characteristic curve was used to calculate the cut-off value of the LSI at 3 months postoperatively, which was required to achieve the LSI criteria for knee flexor strength 6 months postoperatively., Results: Multiple logistic regression analysis extracted the preoperative waiting period and LSI for knee flexor strength at 3 months postoperatively. The cut-off value at 3 months postoperatively was 76.9% (area under the curve value, 0.82; sensitivity, 0.76; and specificity, 0.81) of the LSI., Conclusion: The LSI of at least 76.9% for knee flexor strength at 3 months after ACL reconstruction was an indicator for achieving the 6 months postoperatively. This is a criterion to aim for, considering the stress on the graft and the regeneration process of the semitendinosus tendon., Level of Evidence: Level III., (© 2024 European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Purpose: Resecting the posterior cruciate ligament (PCL) increases posterior laxity and increases the flexion gap more than the extension gap in the native (i.e. healthy) knee. These two effects could lead to significant anterior displacement of the medial femoral condyle in kneeling following total knee arthroplasty even when using a tibial insert with a high degree of medial conformity. Using an insert with ball-in-socket medial conformity and a flat lateral articular surface, the primary purpose was to determine whether the medial femoral condyle remained stable with and without PCL retention during kneeling., Methods: Two groups of patients were studied, one with PCL retention (22 patients) and the other with PCL resection (25 patients), while kneeling at 90º flexion. Following 3D model-to-2D image registration, A-P displacements of both femoral condyles were determined relative to the dwell point of the medial socket., Results: With PCL resection versus PCL retention, the medial femoral condyle was 5.1 ± 3.7 mm versus 0.8 ± 2.1 mm anterior of the dwell point (p < 0.0001). Patient-reported function scores were comparable (p ≥ 0.1610) despite a significantly shorter follow-up of 7.8 ± 0.9 months with PCL retention than 19.6 ± 4.9 months with PCL resection (p < 0.0001). Range of motion was 126 ± 8° versus 122 ± 6° with and without PCL retention, respectively (p = 0.057)., Conclusion: Surgeons that use a highly conforming tibial insert design can stabilize the medial femoral condyle during kneeling by retaining the PCL. In patients with PCL resection, the 9 mm high anterior lip of the insert with ball-in-socket medial conformity was insufficient to prevent significant anterior displacement of the medial femoral condyle when weight-bearing on the anterior tibia., (© 2024. The Author(s) under exclusive licence to SICOT aisbl.)

Purpose: To compare the efficacy and safety of MAKO robot-assisted total knee arthroplasty (MA-TKA) with conventional manual total knee arthroplasty (CM-TKA) in patients with end-stage knee osteoarthritis (KOA) during the early postoperative period., Method: A retrospective analysis was conducted on 22 patients with KOA who underwent MA-TKA and 26 patients who underwent CM-TKA from April 2023 to July 2023. Hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), American Knee Society Score (AKSS), Forgotten Joint Score-12 (FJS-12), visual analogue scale (VAS), and postoperative complications were recorded and compared between the two groups., Result: Both groups successfully completed the surgeries. In terms of radiographic parameters, postoperative one month LDFA and HKA in the MA-TKA group were significantly lower than those in the CM-TKA group (P < 0.05). At the one month follow-up, 19 patients (86.4%) in the MA-TKA group had an HKA less than 3°, compared to 20 patients (76.9%) in the CM-TKA group. Clinically, VAS scores at 24 h, 48 h, and 72 h postoperatively were lower in the MA-TKA group both at rest and during activity. At one month and three months postoperatively, AKSS Function Scores and FJS-12 scores in the MA-TKA group were significantly higher than those in the CM-TKA group (P < 0.05). Regarding postoperative complications, no complications occurred in the MA-TKA group, while one patient in the CM-TKA group experienced postoperative knee stiffness, which resolved after physical therapy, with no statistically significant difference (P > 0.05)., Conclusion: Compared with conventional manual total knee arthroplasty, MAKO robot-assisted TKA demonstrates better short-term clinical efficacy, achieves better alignment planning, and maintains good safety., (© 2024. The Author(s).)

Background: Arthrofibrosis is a debilitating postoperative complication and a major cause of patient dissatisfaction following total knee arthroplasty (TKA). There is no consensus regarding the optimal treatment for stiffness after TKA. For cases not amenable to manipulation under anesthesia (MUA), one component or full revision are both suitable options. In a value-based healthcare era, maximizing cost-effectiveness with optimized clinical outcomes for patients remains the ultimate goal. As such, we compared (1) Knee Injury and Osteoarthritis Outcome Scores for Joint Replacement (KOOS, JR), (2) range of motion (ROM), as well as (3) complication rates, including MUA and lysis of adhesions (LOA), between polyethylene exchange and full component revision for TKA arthrofibrosis., Methods: Patients were queried from an institutional database who underwent revision TKA for arthrofibrosis between January 1, 2015, and April 31, 2021. There were 33 patients who underwent full revision and 16 patients who underwent polyethylene exchange. Demographics and baseline characteristics between the cohorts were analyzed. Postoperative outcomes included MUA, LOA, and re-revision rates as well as KOOS, JR, and extension and flexion ROM at a mean follow-up of 3.8 years. Baseline comorbidities, including age, body mass index, alcohol use, tobacco use, and diabetes, were comparable between the full revision and polyethylene exchange revision cohorts (P > .05). The one and full component revisions had similar preoperative KOOS, JR (43 versus 42, P = .85), and flexion (81 versus 82 degrees, P = .80) versus extension (11 versus 11 degrees, P = .87) ROM., Results: The full component revision had higher KOOS, JR (65 versus 55, P = .04), and flexion (102 versus 92 degrees, P = .02), but similar extension (3 versus 3 degrees, P = .80) ROM at final follow-up compared to the polyethylene exchange revision, respectively. The MUA (18.2 versus 18.8%, P = .96) and LOA (2.0 versus 0.0%, P = .32) rates were similar between full component and polyethylene exchange revisions. There was one re-revision (3.0%) for the cohort of patients who initially underwent full revision. There were four full re-revisions (25.0%) and two polyethylene exchange re-revisions (12.5%) performed in the cohort of patients who initially underwent a polyethylene exchange revision., Conclusions: The full component revision for stiffness after TKA showed favorable KOOS, JR, ROM, and outcomes in comparison to the polyethylene exchange revision. While the optimal treatment for stiffness after TKA is without consensus, this study supports the use of the full component revision when applied to the institutional population at hand. It is imperative that homogeneity exists in preoperative definitions, preoperative baseline patient demographics, ROM and function levels, outcome measures, and preoperative indications, as well as the inclusion of clinical data that assesses complete exchange, single exchange, and tibial insert exchange., (Copyright © 2024. Published by Elsevier Inc.)

Background: In patients with a degenerative tear of the medial meniscus, recent meta-analyses and systematic reviews have shown no treatment benefit of arthroscopic partial meniscectomy (APM) over conservative treatment or placebo surgery. Yet, advocates of APM still argue that APM is cost effective. Giving advocates of APM their due, we note that there is evidence from the treatment of other musculoskeletal complaints to suggest that a treatment may prove cost effective even in the absence of improvements in efficacy outcomes, as it may lead to other benefits, such as diminished productivity loss and reduced costs, and so the question of cost effectiveness needs to be answered for APM., Questions/purposes: (1) Does APM result in lower postoperative costs compared with placebo surgery? (2) Is APM cost-effective compared with placebo surgery?, Methods: One hundred forty-six adults aged 35 to 65 years with knee symptoms consistent with a degenerative medial meniscus tear and no knee osteoarthritis according to the American College of Rheumatology clinical criteria were randomized to APM (n = 70) or placebo surgery (n = 76). In the APM and placebo surgery groups, mean age was 52 ± 7 years and 52 ± 7 years, and 60% (42 of 70) and 62% (47 of 76) of participants were men, respectively. There were no between-group differences in baseline characteristics. In both groups, a standard diagnostic arthroscopy was first performed. Thereafter, in the APM group, the torn meniscus was trimmed to solid meniscus tissue, whereas in the placebo surgery group, APM was carefully mimicked but no resection of meniscal tissue was performed; as such, surgical costs were the same in both arms and were not included in the analyses. All patients received identical postoperative care including a graduated home-based exercise program. At the 2-year follow-up, two patients were lost to follow-up, both in the placebo surgery group. Cost effectiveness over the 2-year trial period was computed as incremental net monetary benefit (INMB) for improvements in quality-adjusted life years (QALY), using both the societal (primary) and healthcare system (secondary) perspectives. To be able to consider APM cost effective, the CEA analysis should yield a positive INMB value. Nonparametric bootstrapping was used to assess uncertainty. Several one-way sensitivity analyses were also performed., Results: APM did not deliver lower postoperative costs, nor did it convincingly improve quality of life scores when compared with placebo surgery. From a societal perspective, APM was associated with € 971 (95% CI -2013 to 4017) higher costs and 0.015 (95% CI -0.011 to 0.041) improved QALYs over 2-year follow-up compared with placebo surgery. Both differences were statistically inconclusive (a wide 95% CI that crossed the line of no difference). Using the conventional willingness to pay (WTP) threshold of € 35,000 per QALY, APM resulted in a negative INMB of € -460 (95% CI -3757 to 2698). In our analysis, APM would result in a positive INMB only when the WTP threshold rises to about € 65,000 per QALY. The wide 95% CIs suggests uncertain cost effectiveness irrespective of chosen WTP threshold., Conclusion: The results of this study lend further support to clinical practice guidelines recommending against the use of APM in patients with a degenerative meniscus tear. Given the robustness of existing evidence demonstrating no benefit or cost effectiveness of APM over nonsurgical treatment or placebo surgery, future research is unlikely to alter this conclusion.Level of Evidence Level III, economic analysis., Competing Interests: Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research ® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Association of Bone and Joint Surgeons.)

Pathomechanics resulting from rotational deformities of the long bones in an idiopathic population have not been extensively studied, and are chiefly limited to level over ground walking. Thirty-five adolescents with excessive idiopathic outward tibial torsion (TT), femoral rotation, or both (pan genu) were studied both before and after corrective surgery. Data collected included computational motion analysis of a drop jump and patient-reported outcomes consisting of PODCI and Goal Attainment Scores. Results were compared to an age-matched typically developing cohort (n = 25). Subjects with femoral anteversion (FA) exhibited compensatory hip rotations to normalize knee progression angles at landing. Subjects with only TT did not compensate at the hip, landing with typical knee progression but excessive outward foot progression. These strategies resulted in elevated frontal plane knee moments for FA ( P  = 0.008), and elevated lateral knee forces in all groups compared to typical, with the TT group reaching significance ( P  < 0.001). Rotational osteotomies successfully restored elevated kinematics and kinetics to within or below typically developing ranges. Patient-reported outcomes generally improved after surgery across all domains studied. Drop jump testing elucidated compensation strategies employed by these cohorts. Compensation did not fully alleviate elevated forces at the knees. Surgical intervention normalized pathokinematics and pathokinetics, reduced pain, and improved patients' perception of their functional abilities. Greater improvements were found in individuals in the two groups with FA compared to the group with TT only., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Functional implant positioning (FIP) for total knee arthroplasty (TKA) is an evolution of kinematic alignment based on preoperative CT scan and robotic-assisted technology. This study aimed to assess the ligament balancing of image-based robotic-assisted TKA in extension, mid-flexion and flexion with an FIP using intraoperative sensor-guided technology. The hypothesis was that image-based robotic-assisted TKA performed by FIP would achieve ligament balancing all along the arc of knee flexion., Methods: This prospective monocentric study included 47 consecutive patients with varus knees undergoing image-based robotic-assisted TKA performed with FIP. After robotic-assisted bone cuts, trial components were inserted, and soft tissue balance was assessed using sensor-guided technology at 10°, 45° and 90° of knee flexion. A mediolateral balanced knee was defined by an intercompartmental pressure difference (ICPD) ≤ 15 lbf and medial and lateral compartment pressure ≤60 lbf. The mean age was 71.6 years old ±6.7, the mean BMI was 29.0 kg/m 2  ± 4.9 and the mean preoperative HKA was 174° ± 5 [159; 183]., Results: The mean postoperative knee alignment was 177.0° ± 2.2° [172; 181]. There were 93.6% of balanced knees (n = 44) at 10 and 90° of knee flexion versus 76.6% (n = 36) at 45° of knee flexion with a significant difference (p = 0.014). Median ICPD at 10, 45 and 90° of knee flexion were, respectively, 7.0 (interquartile range [IQR]: 9), 11.0 (IQR: 9.5) and 8.0 (IQR: 9.0). Pairwise analyses revealed differences for ICPD at 45° versus ICPD at 10° (p = 0.003) and ICPD at 90° versus ICPD at 45° (p = 0.007)., Conclusion: FIP with an image-based robotic-assisted system allowed the restoration of a well-balanced knee at 10° and 90° of flexion in varus knees. Nevertheless, some discrepancies occurred in midflexion, and more work is needed to understand ligament behaviour all along the arc of knee flexion., Level of Evidence: Level II., (© 2024 European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Background: The aim of this study was to compare the clinical results of kinematic alignment (KA) with those of mechanical alignment (MA) in single-stage bilateral total knee arthroplasty., Methods: In this double-blinded randomized controlled trial, 65 patients who had bilateral knee osteoarthritis underwent simultaneous bilateral total knee arthroplasty. One knee was randomly selected to be operated on with the calipered-KA technique and the other with MA. The participants were assessed via the Oxford Knee Score, Western Ontario and McMaster Universities Osteoarthritis Index questionnaire, and visual analog scale before the surgery and the same plus the Forgotten Joint Score at their last follow-up visit, 2 years postoperatively. Maximum knee flexion and the time reaching maximum knee flexion, named the recovery time, were also recorded. Hip-knee-ankle angle, medial proximal tibial angle, and lateral distal femoral angle were measured before and after the surgery using 3-joint-view radiographs., Results: At 2 years, there were significant differences between the KA and MA techniques in terms of duration of surgery, recovery time, and final Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten Joint Score, and maximum flexion range in favor of KA (P < .05), but no significant difference in visual analog scale score or Oxford Knee Score. In patients who have a preferred knee, the KA knee was preferred over the MA knee by most patients. No prosthetic failure or revision was reported in either group., Conclusions: The KA technique yields acceptable functional outcomes compared to the MA technique. The KA technique was associated with a shorter surgery time, a faster recovery time, and higher patient satisfaction in 2-year follow-ups. Larger multicenter studies with longer follow-ups are warranted to confirm these findings., Level of Evidence: I., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: The influence of tibial slope on tibial component migration following total knee arthroplasty has not been widely studied, although excessive posterior slope has been implicated in some failures. As implant micromotion measured with radiostereometric analysis can indicate successful fixation, the purpose of this study was to determine the associations between tibial slope, tibial component migration, and inducible displacement., Methods: Radiostereometric analyses at 6 visits over 2 years quantified implant migration for 200 cemented total knee arthroplasties. Longitudinal data analysis examined the influence of postoperative tibial slope on implant migration (overall maximum total point motion (MTPM) migration and anterior-posterior tilt migration), accounting for age, sex, and body mass index. The correlations of tibial slope with 1-year migration, continuous migration, and inducible displacements were also examined. Additionally, the amount of change in slope was compared to migration., Results: The mean posterior tibial slope was 8.0° (standard deviation [SD] 3.8°) preoperatively and 3.8° (SD 3.1°) postoperatively, with a mean reduction in slope of 4.2° (SD 4.7°). Postoperative tibial slope (range 14.0° posterior slope to 3.4° anterior slope) was not associated with longitudinal overall migration (P = .671) or anterior-posterior tilt migration (P = .704). There was no association between postoperative tibial slope and migration at 1 year postoperatively (P = .441 for MTPM migration, P = .570 for tilt migration), change in migration from 1 to 2 years (P = .951), or inducible displacement (P = .970 MTPM, P = .730 tilt). The amount of change in tibial slope was also not associated with migration or inducible displacement., Conclusions: Residual and change in postoperative tibial slope were not associated with implant migration into tilt or overall migration, or inducible displacement for a single implant design. These findings support positioning tibial implants in a range of slopes, which may support patient-specific approaches to implant alignment., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: Supply-demand mismatch of medial femoral condyle (MFC) osteochondral allografts (OCAs) remains a rate-limiting factor in the treatment of osteochondral defects of the femoral condyle. Surface contour mapping was used to determine whether a contralateral lateral femoral condyle (LFC) versus ipsilateral MFC OCA differs in the alignment of donor:native subchondral bone for large osteochondral defects of the MFC., Design: Thirty fresh-frozen human femoral condyles were matched by tibial width into 10 groups of 3 condyles (MFC recipient, MFC donor, and LFC donor) each for 3 cartilage surgeons (90 condyles). The recipient MFC was imaged using nano-computed tomography scan. Donor oval grafts were harvested from each matched condyle and transplanted into a 17 mm × 36 mm defect created in the recipient condyle. Following the first transplant, the recipient condyle was imaged and superimposed on the native condyle nano-CT scan. The donor plug was removed and the process repeated for the other donor. Surface height deviation and circumferential step-off height deviation were compared between native and donor subchondral bone surfaces for each transplant., Results: There was no statistically significant difference in mean subchondral bone surface deviation (LFC = 0.87 mm, MFC = 0.76 mm, P = 0.07) nor circumferential step-off height (LFC = 0.93 mm, MFC = 0.85 mm, P = 0.09) between the LFC and MFC plugs. There were no significant differences in outcomes between surgeons., Conclusions: There were no significant differences in subchondral bone circumferential step-off or surface deviation between ipsilateral MFC and contralateral LFC oval-shaped OCAs for 17 mm × 36 mm defects of the MFC., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Kelly M.R. Taylor: None declared; Conor S. Locke: None declared; Timothy S. Mologne: JRF Ortho, Arthrex; William D. Bugbee: JRF Ortho, Arthrex; John A. Grant: JRF Ortho, Arthrex, Vericel, Aesculap Biologics.

Printed porous titanium metaphyseal cones have become a mainstay for managing bone loss in revision total knee arthroplasty (rTKA). A short or long stem is routinely used when implanting a cone to augment fixation and offload stresses. This retrospective analysis compared the short-term survivorships and functional outcomes for use of a short or long stem with a metaphyseal cone.A total of 179 cases using metaphyseal cones and stems with median follow-up of 1.95 years (interquartile range, 1.00-2.14) were compared based on stem type. There were 55 cases with long stem(s) and 124 cases with short stem(s). Cases with both long and short stems were excluded. Demographics, Kaplan-Meier survivorships, and preoperative and 1-year postoperative patient-reported outcome measures (PROMs; 2011 Knee Society Score [KSS] objective knee score, function, and satisfaction scores; EuroQol five-dimension scale; and Short Form Survey Physical Component Summary and Mental Component Summary scores) were compared using t -tests with a significance level of α = 0.05. There were no significant differences in body mass index (mean ± standard deviation) or sex (men [%]) between the short and long stem cohorts (32.3 ± 5.3, 36.3% and 31.5 ± 5.5, 38.2%, respectively; p  > 0.05). Patients who had short stems were younger (65.9 ± 8.8 vs. 69.0 ± 9.4, p  = 0.0323).Revision-free survivorship for the femoral or tibial component was 100% for long stems and 98.2% for short stems at 1 and 2 years, respectively (log-rank p  = 0.6330). The two revisions in the short group were for infection, thus the survivorship for aseptic loosening was 100% at 2 years for both cohorts. There were no significant differences in preoperative or postoperative PROMs.This study demonstrated that highly porous printed metaphyseal cones provided rTKA with excellent early survivorship and similar PROMs whether a short or long stem was used. Additional studies will be needed to discern longer term differences., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Increasing deformity of the lower extremities, as measured by the hip-knee-ankle angle (HKAA), is associated with poor patient outcomes after total hip and knee arthroplasty (THA, TKA). Automated calculation of HKAA is imperative to reduce the burden on orthopaedic surgeons. We proposed a detection-based deep learning (DL) model to calculate HKAA in THA and TKA patients and assessed the agreement between DL-derived HKAAs and manual measurement., Methods: We retrospectively identified 1,379 long-leg radiographs (LLRs) from patients scheduled for THA or TKA within an academic medical center. There were 1,221 LLRs used to develop the model (randomly split into 70% training, 20% validation, and 10% held-out test sets); 158 LLRs were considered "difficult," as the femoral head was difficult to distinguish from surrounding tissue. There were 2 raters who annotated the HKAA of both lower extremities, and inter-rater reliability was calculated to compare the DL-derived HKAAs with manual measurement within the test set., Results: The DL model achieved a mean average precision of 0.985 on the test set. The average HKAA of the operative leg was 173.05 ± 4.54°; the nonoperative leg was 175.55 ± 3.56°. The inter-rater reliability between manual and DL-derived HKAA measurements on the operative leg and nonoperative leg indicated excellent reliability (intraclass correlation (2,k) = 0.987 [0.96, 0.99], intraclass correlation (2, k) = 0.987 [0.98, 0.99, respectively]). The standard error of measurement for the DL-derived HKAA for the operative and nonoperative legs was 0.515° and 0.403°, respectively., Conclusions: A detection-based DL algorithm can calculate the HKAA in LLRs and is comparable to that calculated by manual measurement. The algorithm can detect the bilateral femoral head, knee, and ankle joints with high precision, even in patients where the femoral head is difficult to visualize., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Identification of femoral component debonding in the work-up of painful total knee arthroplasty (TKA) often poses a diagnostic challenge. The purpose of this study was to compare the sensitivity and specificity of radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) for identifying femoral component loosening with debonding at the time of revision of a primary TKA with a recalled polyethylene insert., Methods: Using an institutional database, we identified all cases of revision TKA performed for this specific implant recall following a primary TKA between 2014 and 2022. Patients who had a preoperative radiograph, CT, and MRI were included (n = 77). Sensitivity, specificity, and positive and negative likelihood ratio (LR) for predicting loosening were compared among the imaging modalities, using the intraoperative evidence of implant loosening as the gold standard., Results: At the time of revision surgery, the femoral component was noted to have aseptic loosening with debonding in 46 of the 77 (60%) of the TKAs. There were no significant differences in demographics in the cohort with femoral debonding compared to those with well-fixed implants. The CT demonstrated a sensitivity of 28% and a specificity of 97%, while the MRI demonstrated a sensitivity of 37% and a specificity of 94% for detecting femoral loosening due to debonding. Both CT and MRI demonstrated poor negative LRs for femoral loosening (LR 0.7)., Conclusions: In this series of revision TKAs for a specific recalled component, neither CT nor MRI accurately diagnosed femoral component debonding. For patients who have this implant, it is imperative to interrogate the implant-cement interface intraoperatively and prepare for full revision surgery as well as marked bone loss secondary to osteolysis., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: There is an increasing number of different brands of robotic total knee arthroplasty (TKA) systems. Most robotic TKA systems share the same coronal alignment, while the definitions of sagittal alignment vary. The purpose of this study was to investigate whether these discrepancies impact the sagittal alignment of the lower extremity., Methods: A total of 72 lower extremity computed tomography scans were included in our study, and 3-dimensional models were obtained using software. A total of 7 brands of robotic TKA systems were included in the study. The lower extremity axes were defined based on the surgical guide for each implant. We also set the intramedullary axis as a reference to evaluate the discrepancies in sagittal alignment of each brand of robotic system., Results: On the femoral side, the axis definition was the same for all 7 robotic TKA systems. The robotic TKA axes showed a 2.41° (1.58°, 3.38°) deviation from the intramedullary axis. On the tibial side, the 7 robots had different axis definitions. The tibial mechanical axis of 6 of the TKA systems was more flexed than that of the intramedullary axis, which means the posterior tibial slope was decreased while the tibial mechanical axis of the remaining system was more extended., Conclusions: The sagittal alignment of the lower extremity for 7 different brands of robotic TKA systems differed from each other and all deviated from the intramedullary axis. Surgeons should be aware of this discrepancy when using different brands of robotic TKA systems to avoid unexpected sagittal alignment and corresponding adverse clinical outcomes., Level of Evidence: Level IV, Therapeutic Study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Knee collateral ligaments play a vital role in providing frontal-plane stability in post-total knee arthroplasty (TKA) knees. Finite element models can utilize computationally efficient one-dimensional springs or more physiologically accurate three-dimensional continuum elements like the Holzapfel-Gasser-Ogden (HGO) formulation. However, there is limited literature defining subject-specific mechanical properties, particularly for the HGO model. In this study, we propose a co-simulation framework to obtain subject-specific material parameters for an HGO-based finite element ligament model integrated into a rigid-body model of the post-TKA knee. Our approach achieves comparable accuracy to spring formulations while significantly reducing coefficient calibration time and demonstrating improved correlation with reference knee kinematics and ligament strains throughout the tested loading range.

Purpose: To compare short-term patient-reported outcomes (PRO) of two contemporary matrix-associated autologous chondrocyte implantation (M-ACI) products for the treatment of large articular cartilage defects of the knee., Methods: A retrospective, registry-based, matched-pair analysis was performed, comparing PRO of patients undergoing isolated M-ACI with either Spherox™, a spheroid-based ACI (Sb-ACI), or NOVOCART™ Inject, a hydrogel-based ACI product (Hb-ACI), for a focal full-thickness cartilage defect of the knee ≥4 cm 2 . Matching parameters included age, sex, body mass index, defect size, defect localization, symptom duration and previous surgeries. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) score were obtained up to the 24-month follow-up. The total KOOS response rate and percentage of patients attaining a substantial clinical benefit (SCB) in KOOS subscores were calculated., Results: A total of 45 patients per group were matched. The response rate after 24 months was not significantly different between the groups (Sb-ACI 64.4% vs. Hb-ACI 82.2%, p = 0.057). The number of patients with a SCB at 24 months was not significantly different in any KOOS subscore, despite significantly higher improvement of the total KOOS (14.8 ± 16.2 vs. 21.5 ± 15.4, p = 0.047) and KOOS pain in the Hb-ACI group (12.2 ± 18.6 vs. 20.6 ± 19.1, p = 0.037). The IKDC score in the Hb-ACI group was significantly higher at the 12- and 24-month follow-up (60.7 ± 20.2 vs. 70.9 ± 18.0, p = 0.013)., Conclusion: The response rate and number of patients achieving an SCB were not significantly different between patients treated with Sb-ACI or Hb-ACI. Both procedures can achieve favourable 2-year PRO. Hb-ACI was associated with better PRO between 1 and 2 years postoperatively; however, the clinical relevance of this benefit is yet to be proven., Level of Evidence: III, Retrospective comparative study., (© 2024 The Authors. Knee Surgery, Sports Traumatology, Arthroscopy published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Osteophytes are routinely removed during total knee arthroplasty, yet the preoperative planning currently relies on preoperative computed tomography (CT) scans of the patient's osteoarthritic knee, typically including osteophytic features. This complicates the surgeon's ability to anticipate the exact biomechanical effects of osteophytes and the consequences of their removal before the operation. The aim of this study was to investigate the effect of osteophytes on ligament strains and kinematics, and ascertain whether the osteophyte volume and location determine the extent of this effect. We segmented preoperative CT scans of 21 patients, featuring different osteophyte severity, using image-based active appearance models trained to identify the osteophytic and preosteophytic bone geometries and estimate the cartilage thickness in the segmented surfaces. The patients' morphologies were used to scale a template musculoskeletal knee model. Osteophytes induced clinically relevant changes to the knee's functional behavior, but these were variable and patient-specific. Generally, severe osteophytic knees significantly strained the oblique popliteal ligament (OPL) and posterior capsule (PC) relative to the preosteophytic state. Furthermore, there was a marked effect on the lateral collateral ligament and anterolateral ligament (ALL) strains compared to mild and moderate osteophytic knees, and concurrent alterations in the tibial lateral-medial translation and external-internal rotation. We found a strong correlation between the OPL, PC, and ALL strains and posterolateral condylar and tibial osteophytes, respectively. Our findings may have implications for the preoperative planning in total knee arthroplasty, toward reproducing the physiological knee biomechanics as close as feasibly possible., (© 2024 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Patients with bone sarcomas increasingly choose limb salvage. This can lead to issues with limb length discrepancy (LLD) for the skeletally immature. We synthesize management options into an algorithm and report our results. Patients with bone sarcomas involving any location from the femoral diaphysis to the tibial diaphysis 12 years or younger were reviewed. Our clinical pathway prescribed patients with metadiaphyseal lesions to intercalary allograft reconstruction, epiphyseal lesions and less than 5 cm expected LLD to osteoarticular allograft and patients with more than 5 cm expected LLD to extendable prosthesis. Twenty patients met inclusion criteria: 11 with osteoarticular allografts, 5 with extendable prostheses and 4 with intercalary allografts; median age 11.5 years; median follow-up 8.2 years; and final median LLD 1.6 cm. Five patients had contralateral epiphysiodesis, two patients underwent contralateral femoral shortening and a median of 6 (range 4-8) lengthenings were performed for extendable prostheses. Four patients had residual LLD over 3 cm. There were 13 revisions in 8 patients and 2 amputations. Limb-salvage in paediatric bone sarcoma of the knee can be managed with multiple techniques producing satisfactory results in regards to LLD. Careful pre-operative planning and shared decision making is a requisite given the high rate of secondary procedures for both LLD and reconstructive failures. Level of evidence: Level III Retrospective Comparative Study., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Arthrofibrosis following primary total knee arthroplasty (TKA) can result in pain and limit postoperative range of motion (ROM), jeopardizing clinical outcomes and patient satisfaction. This study aims to identify preoperative risk factors associated with necessitating a manipulation under anesthesia (MUA) following primary TKA.We retrospectively reviewed 950 cases of consecutive primary TKAs performed at one institution by three arthroplasty surgeons between May 2017 and May 2019. Recorded preoperative variables included smoking status, race, preoperative ROM, presence of effusion or positive anterior drawer, and medical comorbidities. Demographic characteristics were compared with Student's t -tests or chi-square tests as appropriate. For each preoperative factor, we obtained an odds ratio (OR) for MUA risk using multivariate logistic regression.Twenty (2.3%) patients underwent MUA following their index primary TKA surgery. History of ipsilateral knee surgery (OR: 2.727, p  = 0.047) and diagnosed hypertension (OR: 4.764, p  = 0.016) were identified as risk factors associated with significantly increased risk of MUA. The greater the preoperative ROM, the higher likelihood needed of MUA (OR: 1.031, p  = 0.034).Patients who had diagnosed hypertension or a history of prior ipsilateral knee surgery were associated with increased risk of necessitating an MUA following primary TKA. Additionally, a greater total arc of motion preoperatively increased the odds of needing MUA.Level III of evidence was present., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: We report a rare case of posterior cruciate ligament (PCL) calcification, which has only been reported in two case studies on PubMed., Case Presentation: A 71-year-old man developed left popliteal pain in the morning without any history of trauma and the pain became severe that night. On the following day, he presented to our department. The patient could not flex his left knee at all due to pain and swelling. CT and MRI scans showed calcification behind the PCL with mild osteoarthritic changes and accumulation of synovial fluid in the joint. Synovial fluid analysis did not reveal any crystals. Blood tests at first admission showed inflammation, hyperglycemia, and low blood uric acid levels. Although the patient's knee joint was injected with steroids, his symptoms did not improve. Thus, we performed arthroscopic surgery two days after symptoms had appeared. Intraoperatively, we observed a white, soft tissue in the synovial membrane behind the PCL. Part of this tissue was collected for histological analysis, which revealed sparse fibers with calcium deposits. Immediately after surgery, the patient's symptoms were completely gone. Afterward, the patient remained asymptomatic one month after surgery., Conclusion: This is the first reported case of debridement of PCL calcification and ossification that was performed soon after symptoms appeared. In addition, we demonstrated that early debridement led to complete recovery., (© 2024. The Author(s).)

Background: Around 6,000 revision knee replacement procedures are performed in the United Kingdom each year. Three-quarters of procedures are for aseptic, elective reasons, such as progressive osteoarthritis, prosthesis loosening/wear, or instability. Our understanding of how we can best support these patients undergoing revision knee replacement procedures is limited. This study aimed to explore patients' experiences of having a problematic knee replacement and the impact of undergoing knee revision surgery for aseptic, elective reasons., Methods: Qualitative semi structured interviews with 15 patients (8 women, 7 men; mean age 70 years: range 54-81) who had undergone revision knee surgery for a range of aseptic, elective indications in the last 12 months at an NHS Major Revision Knee Centre. Interviews were audio-recorded, transcribed, de-identified and analysed using reflexive thematic analysis., Results: We developed six themes: Soldiering on; The challenge of navigating the health system; I am the expert in my own knee; Shift in what I expected from surgery; I am not the person I used to be; Lingering uncertainty., Conclusions: Living with a problematic knee replacement and undergoing knee revision surgery has significant impact on all aspects of patients' lives. Our findings highlight the need for patients with problematic knee replacements to be supported to access care and assessment, and for long-term psychological and rehabilitation support before and after revision surgery., (© 2024. The Author(s).)

Case: A 13-year-old adolescent boy with spastic diplegic cerebral palsy (CP) presented with crouch gait and bilateral knee flexion contractures (KFCs). After failure of conservative treatments, the patient was referred to orthopaedics for surgical intervention. Anterior distal femoral hemiepiphysiodesis (ADFH), using a retrograde approach, and Strayer gastrocnemius recession were performed bilaterally. No complications were reported during surgery/follow-up. Full-active knee extension and improved gait were achieved., Conclusion: KFC is prevalent in ambulatory patients with CP, reducing gait function. Retrograde ADFH is an effective surgical intervention to reduce KFC and improve gait, and offers simpler insertion/removal than the traditional antegrade technique., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/C425)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

This prospective bi-center study aimed to analyze the outcomes of primary total knee arthroplasty using the Stemmable Tibia Attune system. A total of 100 patients who underwent primary total knee arthroplasty with Stemmable Tibia from January 2019 to December 2021 were enrolled in the study. Radiological outcomes (hip-knee-ankle axis and medial proximal tibial angle) were assessed preoperatively and postoperatively. Clinical outcomes (visual analog scale score, Hospital for Special Surgery score, Knee Society function score, Knee Society knee score, flexion contracture, further flexion, and range of motion) were analyzed preoperatively and at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively. Complications (periprosthetic joint infection and aseptic loosening) were examined. The hip-knee-ankle axis decreased (preoperative: 9.5° ± 6.3°, postoperative: 1.1° ± 2.7°), whereas the medial proximal tibial angle increased (preoperative: 84.6° ± 4.1°, postoperative: 89.8° ± 1.9°). The visual analog scale score, Hospital for Special Surgery score, Knee Society knee score, and Knee Society function score increased postoperatively. The Knee Society knee score indicated above good outcomes (100.0% and 99.0% at 1 and 2 years postoperatively, respectively). The Knee Society function score also showed above good results (98.0% and 93.0% at 1 and 2 years postoperatively, respectively). The range of motion significantly improved (p < 0.001): flexion contracture decreased from 9.10° ± 7.23° to 2.15° ± 2.87°, whereas further flexion increased from 136.05° ± 14.78° to 139.80° ± 10.02°. One patient developed periprosthetic joint infection; no early loosening was observed. In conclusion, Attune primary total knee arthroplasty with Stemmable Tibia not only is safe and effective but also leads to radiological and clinical improvements., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Rhee et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Xanthoma typically occurs in the subcutaneous tissues, with rare cases of xanthoma in the joints. However, the case of knee joint osteonecrosis combined with xanthoma is even more uncommon. In this article, we described a 50-year-old female patient who suffered xanthoma in the knee joint on the basis of osteonecrosis of the knee joint. The primary clinical symptoms were knee joint pain and limited mobility. The patient initially received conventional treatment for osteonecrosis. However, there was no significant improvement. Later, we found a synovial xanthoma in the patient's knee. Finally, she underwent arthroscopic excision of the knee joint synovial xanthoma. Following the procedure, her VAS score decreased from 7 to 2, and knee joint mobility increased from 10-103° to 10-140°. Through our follow-up, the patient did not exhibit symptom recurrence. This case is valuable as it provides a feasible therapeutic approach for future clinical applications., (© 2024. The Author(s).)

Background: Knee instability in midflexion may contribute to patient dissatisfaction following total knee arthroplasty (TKA). Midflexion instability involves abnormal motions and tissue loading in multiple planes. Therefore, we quantified and compared the tensions carried by the medial and lateral collateral ligaments (MCL and LCL) following posterior-stabilized (PS) TKA through knee flexion, and then compared these tensions with those carried by the native knee. Finally, we examined the relationships between collateral ligament tensions and anterior tibial translation (ATT)., Methods: Eight cadaveric knees (from 5 male and 3 female donors with a mean age of 62.6 years and standard deviation of 10.9 years) underwent PS TKA. Each specimen was mounted to a robotic manipulator and flexed to 90°. ATT was quantified by applying 30 N of anterior force to the tibia. Tensions carried by the collateral ligaments were determined via serial sectioning. Robotic testing was also conducted on a cohort of 15 healthy native cadaveric knees (from 9 male and 6 female donors with a mean age of 36 years and standard deviation of 11 years). Relationships between collateral ligament tensions during passive flexion and ATT were assessed via linear and nonlinear regressions., Results: MCL tensions were greater following PS TKA than in the native knee at 15° and 30° of passive flexion, by a median of ≥27 N (p = 0.002), while the LCL tensions did not differ. Median tensions following PS TKA were greater in the MCL than in the LCL at 15°, 30°, and 90° of flexion, by ≥4 N (p ≤ 0.02). Median tensions in the MCL of the native knee were small (≤11 N) and did not exceed those in the LCL (p ≥ 0.25). A logarithmic relationship was identified between MCL tension and ATT following TKA., Conclusions: MCL tensions were greater following PS TKA with this typical nonconforming PS implant than in the native knee. Anterior laxity at 30° of flexion was highly sensitive to MCL tension during passive flexion following PS TKA but not in the native knee., Clinical Relevance: Surgeons face competing objectives when performing PS TKA: they can either impart supraphysiological MCL tension to reduce anterior-posterior laxity or maintain native MCL tensions that lead to heightened anterior-posterior laxity, as shown in this study., Competing Interests: Disclosure: This study was funded by the Clark Foundation and Kirby Foundation. Zimmer Biomet donated the implants used in this study. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/I61 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Objective: To compare the effectiveness of I.D.E.A.L technique and transtibial (TT) technique in anterior cruciate ligament (ACL) reconstruction., Methods: A clinical data of 60 patients with ACL injury, who were admitted and met the selection criteria between January 2020 and September 2022, was retrospectively analyzed. All patients underwent arthroscopic ACL reconstruction with autologous tendon. During operation, the femoral tunnel was prepared by using I.D.E.A.L technique in 30 cases (I.D.E.A.L group) and using TT technique in 30 cases (TT group). There was no significant difference in baseline data such as age, gender, body mass index, cause of injury, injured side, interval from injury to operation, constituent ratio of combined cartilage and meniscus injury, and preoperative Lysholm score, International Knee Documentation Committee (IKDC) score, visual analogue scale (VAS) score, anterior tibial translation difference, and Blumensaat angle between the two groups ( P >0.05). The length of hospital stay and the occurrence of early and late complications were recorded. During follow-up, the Lysholm score, IKDC score, and VAS score were used to evaluate knee joint function and pain degree, and the anterior tibial translation difference was measured. MRI reexamination was performed to observe the healing of the graft, and the signal to noise quotient (SNQ) values of the femoral end, middle section, and tibial end of the graft, as well as the Blumensaat angle of the knee joint were measured. The differences in tibial anterior translation difference and Blumensaat angle before and after operation (change values) were calculated and compared between the two groups., Results: The incisions in both groups healed by first intention after operation, and there was no significant difference in the length of hospital stay between the two groups ( P >0.05). All patients were followed up 12-18 months, with an average of 14.9 months. The Lysholm score and IKDC score of the knee joint in both groups after operation increased when compared with those before operation, and the VAS score decreased. Compared to preoperative scores, except for the VAS score of the TT group at 1 week after operation ( P >0.05), there were significant differences in all scores at different time points postoperatively in the two groups ( P <0.05). The above scores in both groups showed a further improvement trend with the prolongation of time after operation. There were significant differences in Lysholm score and VAS score among 1 week, 1 month, 3 months, 6 months, and 12 months after operation in the two groups ( P <0.05). The IKDC score of both groups at 1 month after operation was significantly different from that at 1 week after operation ( P <0.05). At 1 week after operation, the Lysholm score and IKDC score in the I.D.E.A.L group were significantly higher than those in the TT group ( P <0.05), and the VAS score was significantly lower ( P <0.05); there was no significant difference between the two groups at 1, 3, 6, and 12 months after operation ( P >0.05). At 12 months after operation, the anterior tibial translation differences in both groups were significantly lower than those before operation ( P <0.05); and the change value in the I.D.E.A.L group was significantly higher than that in the TT group ( P <0.05). The incidences of early and late complications in the I.D.E.A.L group were significantly lower than those in the TT group ( P <0.05). At 12 months after operation, MRI examination showed that the grafts of the knee joint in both groups survived well, and the Blumensaat angles of both groups were significantly smaller than those before operation ( P <0.05). The change value of the Blumensaat angle in the I.D.E.A.L group was significantly higher than that in the TT group ( P <0.05). The SNQ values of the femoral end, middle section, and tibial end of the graft in the I.D.E.A.L group were significantly higher than those in the TT group ( P <0.05)., Conclusion: The early effectiveness of ACL reconstruction by using the I.D.E.A.L technique is better, the knee joint is more stable, and the incidence of postoperative complication is lower. However, the maturity of the graft after reconstruction using the TT technique is higher.

Objectives: This study aimed to investigate the relationship between the severity of preoperative valgus deformity and clinical outcomes of neutrally aligned total knee arthroplasty (TKA)., Patients and Methods: A total of 376 knees with valgus deformity who underwent TKA from January 2006 to March 2014 were retrospectively screened, and 287 knees (242 patients; 32 males, 210 females; mean age: 64.5±8.8 years; range, 35 to 83 years) aligned neutrally after the operation were included. Patients were divided into four groups based on the preoperative hip-knee-ankle (HKA): mild (0°< HKA ≤5°, n=94), moderate (5°< HKA ≤10°, n=74), severe (10°< HKA ≤15°, n=75), and very severe (HKA >15°, n=44) groups. Range of motion (ROM), Knee Society Score (KSS), Visual Analog Scale (VAS) dynamic pain scores, and Forgotten Joint Score (FJS) were evaluated. Mechanical failures were recorded to assess prosthesis survival. A survival rate analysis was performed using Kaplan-Meier survival analysis., Results: The degree of preoperative valgus deformity did not have a significant impact on the postoperative ROM, KSS, VAS dynamic pain scores, or FJS at the last follow-up. There were no significant differences in cumulative survival rates of neutrally aligned TKAs at 10 years between the four groups (p=0.513)., Conclusion: The severity of preoperative valgus deformity did not affect the clinical outcomes of neutrally aligned TKAs in the minimum five-year follow-up. Additionally, it did not impact the survival rates of neutrally aligned TKAs over 10 years.

Background: Characterizing the condition of patients suffering from knee osteoarthritis is complex due to multiple associations between clinical, functional, and structural parameters. While significant variability exists within this population, especially in candidates for total knee arthroplasty, there is increasing interest in knee kinematics among orthopedic surgeons aiming for more personalized approaches to achieve better outcomes and satisfaction. The primary objective of this study was to identify distinct kinematic phenotypes in total knee arthroplasty candidates and to compare different methods for the identification of these phenotypes., Methods: Three-dimensional kinematic data obtained from a Knee Kinesiography exam during treadmill walking in the clinic were used. Various aspects of the clustering process were evaluated and compared to achieve optimal clustering, including data preparation, transformation, and representation methods., Results: A K-Means clustering algorithm, performed using Euclidean distance, combined with principal component analysis applied on data transformed by standardization, was the optimal approach. Two unique kinematic phenotypes were identified among 80 total knee arthroplasty candidates. The two distinct phenotypes divided patients who significantly differed both in terms of knee kinematic representation and clinical outcomes, including a notable variation in 63.3% of frontal plane features and 81.8% of transverse plane features across 77.33% of the gait cycle, as well as differences in the Pain Catastrophizing Scale, highlighting the impact of these kinematic variations on patient pain and function., Conclusion: Results from this study provide valuable insights for clinicians to develop personalized treatment approaches based on patients' phenotype affiliation, ultimately helping to improve total knee arthroplasty outcomes., (© 2024. The Author(s).)

Background: This study investigates the effectiveness of a self-developed intelligent monitoring system for home-based knee rehabilitation following total knee arthroplasty (TKA)., Methods: In this randomized controlled trial, 120 patients undergoing TKA were divided using random digit allocation. Preoperative and one-month postoperative assessments of knee function, quality of life, and isometric knee extension strength were conducted with the Intelligent Monitoring System. Patients received group-specific rehabilitation instructions pre-discharge and performed exercises for one month., Results: Changes in isometric knee extensor strength on the affected side within one month post-surgery for the brace-monitored rehabilitation group showed a significant decrease three days after surgery compared to one day before surgery. Subsequent measurements taken at postoperative days 5, 7, 14, and 21 indicated a gradual increase in strength, although these increases did not reach statistical significance when compared with previous measurements. One month post-surgery, all groups demonstrated significant improvements in knee joint function and mobility compared to pre-surgery levels. Notably, the brace-monitored group showed statistically significant improvements in 36-Item Short-Form Health Survey (SF-36) scores over the conventional rehabilitation group., Conclusions: The Intelligent Monitoring System provides effective real-time monitoring and guidance for home-based knee rehabilitation post-TKA. It significantly enhances knee joint function, isometric knee extension strength, and quality of life shortly after surgery compared to traditional rehabilitation methods. This system offers a promising approach for improving postoperative recovery in TKA patients., Trial Registration: This study was approved by the Medical Ethics Committee of Xiangya Hospital, Central South University (Ethics Approval Number 202209008-2). It was registered with the China Clinical Trial Registry, a primary registry of the World Health Organization's International Clinical Trials Registry Platform (Registration Number ChiCTR2300068852)., (© 2024. The Author(s).)

BACKGROUND This retrospective study from a single center in Turkey aimed to evaluate 2-year outcomes of 21 patients undergoing knee arthroscopic repair of extruded meniscus tears without root tear. MATERIAL AND METHODS The retrospective study comprised 21 individuals who underwent arthroscopic extruded meniscus repair and were followed up for at least 2 years. The study analyzed the meniscus extrusion amounts in preoperative and postoperative MRI scans, the Kellgren-Lawrence stages in knee radiographs, and the Lsyhom and The International Knee Documentation Committee (IKDC) scores of the included patients. RESULTS In this study, the repair operation extrusion levels were 3.30 mm from 4.01 mm preoperatively (P<0.001). After the repair, there was a significant increase in the Lsyhom and IKDC scores (P<0.001). According to the Kellgren-Lawrence scale, 12 patients were evaluated as stage 0, 6 patients as stage 1, and 3 patients as stage 2. According to the radiographs taken at the last follow-up, 2 patients progressed from stage 0 to stage 1, 2 patients progressed from stage 1 to stage 2, and 1 patient progressed from stage 2 to stage 3. CONCLUSIONS Arthroscopic treatment of extruded meniscus tears can enhance functional status and increase patients' functional status. Nevertheless, the absence of successful centralization extruded meniscus tears. This study discovered that radiological extrusion did not diminish beyond the critical threshold of 3 mm, which is associated with the development of osteoarthritis. This highlights the necessity of taking these elements into account when devising a treatment plan.

Background: Anterior cruciate ligament (ACL) graft failure is influenced by factors such as meniscal tears and tibial plateau slope. Combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction has reduced failure rates; however, its efficacy in high-risk patients remains unclear. This study hypothesized that combined ACL and ALL reconstruction would yield similar clinical outcomes in patients with varying risks of ACL failure., Patients and Methods: A total of 76 patients who underwent primary single-bundle ACL reconstruction combined with ALL reconstruction between June 2018 and June 2021 were included. The medial tibial slope (MTS), lateral tibial slope (LTS), and anterior tibial translation (ATT) were measured using magnetic resonance imaging and plain radiography of the knee joint. The meniscal lesions were assessed during surgery. Preoperative clinical assessments and final follow-up were conducted using patient-reported outcome measurements (PROMs), including the International Knee Documentation Committee (IKDC) evaluation, Lysholm knee scoring scale, and Tegner Activity scale. PROMs were collected at least two years postoperatively., Results: The average follow-up was 32.5 ± 7.4 months. There were no significant differences in postoperative IKDC score, Lysholm score, or Tegner activity score between patients with or without medial meniscus injury (p = 0.155, 0.914, and 0.042, respectively), with or without lateral meniscus injury (p = 0.737, 0.569, and 0.942, respectively), medial tibial slope > 12° or ≤ 12° (p = 0.290, 0.496, and 0.988, respectively), or lateral tibial slope > 7.4° or ≤ 7.4° (p = 0.213, 0.625, and 0.922, respectively). No significant correlations were found between anterior tibial translation and postoperative IKDC (R = -0.058, p = 0.365), Lysholm (R = -0.017, p = 0.459), or Tegner activity scores (R = -0.147, p = 0.189)., Conclusion: Our study demonstrates that single-bundle ACL reconstruction combined with ALL reconstruction provides reliable and comparable clinical outcomes in patients with high-risk factors for ACL graft failure, such as increased tibial slope or meniscal injury. Our results suggest that the indications for ALL reconstruction may be expanded to include patients with a high tibial slope or meniscal injury, because these factors have been shown to contribute to increased rotational instability and high rates of ACL graft failure. Future prospective randomized controlled trials with large patient cohorts and long follow-up periods are needed to validate these findings and establish clear guidelines for patient selection and surgical decision-making., Level of Evidence: Level 3., (© 2024. The Author(s).)

Wear of the ultra-high molecular-weight polyethylene (UHMWPE) component in total knee arthroplasty contributes to implant failure. It is often detected late, when patients experience pain or instability. Early monitoring could enable timely intervention, preventing implant failure and joint degeneration. This study investigates the accuracy and precision (repeatability) of model-based wear measurement (MBWM), a novel technique that can estimate inlay thickness and wear radiographically. Six inlays were milled from non-crosslinked UHMWPE and imaged via X-ray in anteroposterior view at flexion angles 0°, 30°, and 60° on a phantom knee model. MBWM measurements were compared with reference values from a coordinate measurement machine. Three inlays were subjected to accelerated wear generation and similarly evaluated. MBWM estimated inlay thickness with medial and lateral accuracies of 0.13 ± 0.09 and 0.14 ± 0.09 mm, respectively, and linear wear with an accuracy of 0.07 ± 0.06 mm. Thickness measurements revealed significant lateral differences at 0° and 30° (0.22 ± 0.08 mm vs. 0.06 ± 0.06 mm, respectively; t-test, p = 0.0002). Precision was high, with average medial and lateral differences of - 0.01 ± 0.04 mm between double experiments. MBWM using plain radiographs presents a practical and promising approach for the clinical detection of implant wear., (© 2024. The Author(s).)

Understanding alignment and gap balancing in Total Knee Arthroplasty (TKA) can be challenging for trainee and experienced orthopedic surgeons. Traditional learning methods may not effectively translate to real-life scenarios. The advent of advanced technologies like robotic surgery and navigation systems has revolutionized intraoperative understanding of gap balancing techniques. This trial aims to investigate the effectiveness of robotic TKA planning software in educating trainees about alignment and ligament balancing. We hypothesize that a single session with the software will significantly enhance trainees' understanding of these techniques. This UK-based single-center, two-arm, group parallel randomized controlled trial was conducted during a national robotic arthroplasty symposium. It aims to evaluate the effect of robotic knee arthroplasty software training on understanding TKA alignment and gap balancing principles using Multiple Choice Questions (MCQs). The MCQ test was crafted based on established guidelines from a different institution with expert consensus in the field. Our study revealed that baseline knowledge of gap balancing and alignment principles was generally low among all participants. However, the intervention group, which received comprehensive robotic software training, demonstrated a significant improvement in their MCQ scores compared to the control group, which did not undergo the training. In conclusion, our study demonstrates that robotic arthroplasty software training significantly improves the understanding of TKA alignment and balancing principles among orthopedic trainees. Level of Evidence II., (© 2024. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Despite total knee arthroplasty (TKA) being the gold standard for end-stage knee osteoarthritis, 20% of patients remain dissatisfied. Robotic-assisted arthroplasty promises unparalleled control of the accuracy of bone cuts, implant positioning, control of gap balance, and resultant hip-knee-ankle (HKA) axis. Patients underwent clinical and radiological assessments, including knee CT scans and patient-reported outcome measures (PROMs), preoperatively. Follow-up assessments were conducted at 2 weeks, 6 weeks, and 3 months post-operatively, with imaging repeated at 6 weeks. A total of 155 patients underwent robotic-assisted TKA and have completed 3 months of follow-up. Mean pre-operative HKA axis was 7.39 ± 5.52 degrees varus, improving to 1.34 ± 2.22 degrees varus post-operatively. Restoration of HKA axis was 0.76 ± 1.9 degrees from intra-operative planning (p < 0.0005). Implant placement accuracy in the coronal plane was 0.08 ± 1.36 degrees (p = 0.458) for the femoral component and 0.71 ± 1.3 degrees (p < 0.0005) for the tibial component. Rotational alignment mean deviation was 0.39 ± 1.49 degrees (p = 0.001). Most patients (98.1%) had ≤ 2 mm difference in extension-flexion gaps. PROM scores showed improvement and exceeded pre-operative scores by 6 weeks post-surgery. Robotic-assisted knee arthroplasty provides precise control over traditionally subjective factors, demonstrating excellent early post-operative outcomes.Level of evidence Prospective observational study-II., (© 2024. The Author(s).)

Background: In carefully selected patients with an arthritic valgus knee, distal femoral osteotomy (DFO) can improve symptoms at medium- to long-term follow-up, reducing osteoarthritis progression. To date, there is no clear evidence in the current literature regarding the role of postoperative joint line obliquity (JLO) in valgus deformity correction., Purpose: To assess the clinical and radiological outcomes of medial closing-wedge DFO (MCW-DFO) for the treatment of valgus knees, considering both tibial- and femoral-based deformities, as well as to verify the efficacy and safety of MCW-DFO according to JLO boundaries (≤4°)., Study Design: Cohort study; Level of evidence, 3., Methods: A retrospective analysis was conducted on a cohort of patients with valgus knees. Patients were divided into 2 groups: femoral-based valgus (FB-V) and tibial-based valgus (TB-V). Knee radiographs were collected before surgery and at the last follow-up. The clinical outcome was evaluated through several validated scores (International Knee Documentation Committee, Knee Society Score, Knee injury and Osteoarthritis Outcome Score, Tegner, Numeric Rating Scale, Crosby-Insall)., Results: A total of 30 patients (34 knees) with a mean age of 49.3 ± 9.1 years were included in the study. The overall mean follow-up was 9.4 ± 5.9 years. The mean preoperative hip-knee-ankle angle was 187.6°± 3.3° (range, 181.5°-191°) and the postoperative angle was 180°± 3.1° (range, 176°-185°). Most postoperative JLOs were within the safe zone of ≤4° in both groups (the postoperative JLO was >4° in 4 patients in the TB-V group and 1 patient in the FB-V group), although FB-V knees exhibited significant superior JLO correction (postoperative JLO in the TB-V group: mean, 4.0°± 2.5° [ P = .1]; postoperative JLO in the FB-V group: mean, 2.4°± 1.4° [ P = .5]). Significant improvements in all clinical scores were observed in both groups ( P < .01). Additionally, the severity of the osteoarthritis did not worsen at the last follow-up., Conclusion: MCW-DFO is an effective procedure for treating pathological valgus knees, regardless of the site of the deformity. Both FB-V and TB-V groups showed comparable improvements in the clinical scores, development of osteoarthritis, and the restoration of a neutral mechanical axis. Notably, FB-V knees achieved more JLO correction compared with the TB-V ones., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: Anterior cruciate ligament injury and anterior cruciate ligament reconstruction (ACLR) are risk factors for symptomatic posttraumatic osteoarthritis (PTOA). After ACLR, individuals demonstrate altered joint tissue metabolism indicative of increased inflammation and cartilage breakdown. Serum biomarker changes have been associated with tibiofemoral cartilage composition indicative of worse knee joint health but not with PTOA-related symptoms., Purpose/hypothesis: The purpose of this study was to determine associations between changes in serum biomarker profiles from the preoperative sample collection to 6 months after ACLR and clinically relevant knee PTOA symptoms at 12 months after ACLR. It was hypothesized that increases in biomarkers of inflammation, cartilage metabolism, and cartilage degradation would be associated with clinically relevant PTOA symptoms after ACLR., Study Design: Case-control study; Level of evidence, 3., Methods: Individuals undergoing primary ACLR were included (N = 30). Serum samples collected preoperatively and 6 months after ACLR were processed to measure markers indicative of changes in inflammation (ie, monocyte chemoattract protein 1 [MCP-1]) and cartilage breakdown (ie, cartilage oligomeric matrix protein [COMP], matrix metalloproteinase 3, ratio of type II collagen breakdown to type II collagen synthesis). Knee injury and Osteoarthritis Outcome Score surveys were completed at 12 months after ACLR and used to identify participants with and without clinically relevant PTOA-related symptoms. K-means cluster analyses were used to determine serum biomarker profiles. One-way analyses of variance and logistic regressions were used to assess differences in Knee injury and Osteoarthritis Outcome Score subscale scores and clinically relevant PTOA-related symptoms between biomarker profiles., Results: Two profiles were identified and characterized based on decreases (profile 1: 67% female; age, 21.4 ± 5.1 years; body mass index, 24.4 ± 2.4) and increases (profile 2: 33% female; age, 21.3 ± 3.2 years; body mass index, 23.4 ± 2.6) in sMCP-1 and sCOMP preoperatively to 6 months after ACLR. Participants with profile 2 did not demonstrate differences in knee pain, symptoms, activities of daily living, sports function, or quality of life at 12 months after ACLR compared to those with profile 1 ( P = .56-.81; η 2 = 0.002-0.012). No statistically significant associations were noted between biomarker profiles and clinically relevant PTOA-related symptoms (odds ratio, 1.30; 95% CI, 0.23-6.33)., Conclusion: Serum biomarker changes in MCP-1 and sCOMP within the first 6 months after ACLR were not associated with clinically relevant PTOA-related symptoms., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: Research reported in this manuscript was supported by funding from the University of North Carolina's Department of Orthopaedics Laurence E. Dahners Research Grant, the National Institute of Arthritis and Musculoskeletal and Skin Disease of the National Institutes of Health (1R03 AR066840-01A1 and P30 AR072580), the North Carolina Translational and Clinical Sciences (TraCS) Institute, and the National Athletic Trainers’ Association Research and Education Foundation (14NewINV001). R.A.C. has received consulting fees from Arthrex and support for education from SouthTech Orthopedics. G.K. has received compensation for services other than consulting from Arthrex. J.S. has received support for education from SouthTech Orthopedics. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: Osteochondral allograft (OCA) transplantation is an important surgical technique for full-thickness chondral defects in the knee. For patients undergoing this procedure, topography matching between the donor and recipient sites is essential to limit premature wear of the OCA. Currently, there is no standardized process of donor and recipient graft matching., Purpose: To evaluate a novel topography matching technique for distal femoral condyle OCA transplantation using 3-dimensional (3D) laser scanning to create 3D-printed patient-specific instrumentation in a human cadaveric model., Study Design: Descriptive laboratory study., Methods: Human cadaveric distal femoral condyles (n = 12) underwent 3D laser scanning. An 18-mm circular osteochondral recipient defect was virtually created on the medial femoral condyle (MFC), and the position and orientation of the best topography-matched osteochondral graft from a paired donor lateral femoral condyle (LFC) were determined using an in silico analysis algorithm minimizing articular step-off distances between the edges of the graft and recipient defect. Distances between the entire surface of the OCA graft and the underneath surface of the MFC were evaluated as surface mismatch. Donor (LFC) and recipient (MFC) 3D-printed patient-specific guides were created based on 3D reconstructions of the scanned condyles. Through use of the guides, OCAs were harvested from the LFC and transplanted to the reamed recipient defect site (MFC). The post-OCA recipient condyles were laser scanned. The 360° articular step-off and cartilage topography mismatch were measured., Results: The mean cartilage step-off and graft surface mismatch for the in silico OCA transplant were 0.073 ± 0.029 mm (range, 0.005-0.113 mm) and 0.166 ± 0.039 mm (range, 0.120-0.243 mm), respectively. Comparatively, the cadaveric specimens postimplant had significantly larger step-off differences (0.173 ± 0.085 mm; range, 0.082-0.399 mm; P = .001) but equivalent graft surface topography matching (0.181 ± 0.080 mm; range, 0.087-0.396 mm; P = .678). All 12 OCA transplants had mean circumferential step-off differences less than a clinically significant cutoff of 0.5 mm., Conclusion: These findings suggest that the use of 3D-printed patient-specific guides for OCA transplantation has the ability to reliably optimize cartilage topography matching for LFC to MFC transplantation. This study demonstrated substantially lower step-off values compared with previous orthopaedic literature when also evaluating LFC to MFC transplantation. Using this novel technique in a model performing MFC to MFC transplantation has the potential to yield further enhanced results due to improved radii of curvature matching., Clinical Relevance: Topography-matched graft implantation for focal chondral defects of the knee in patients improves surface matching and has the potential to improve long-term outcomes. Efficient selection of the allograft also allows improved availability of the limited allograft sources., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) funded this investigation. A.A.E.O. has received financial or material support from Stryker. M.H. has received consulting fees from DJO-Enovis, Moximed, and Vericel; honoraria from Encore Medical; support for education from Arthrex and Foundation Medical; and hospitality payments from Stryker and Medical Device Business Services. B.J.C. has received research support from Aesculap/B.Braun, Arthrex, and Regentis; consulting fees from Arthrex, DJO, and Samumed; royalties from Arthrex; financial or material support from Athletico, JRF Ortho, and Smith & Nephew; and holds stock and stock options in Bandgrip Inc, Ossio, and Regentis. A.B.Y. has received consulting fees from AlloSource, JRF Ortho, and Stryker; research support from Arthrex and Organogenesis; holds stock or stock options in Patient IQ, Sparta Biomedical, and Icarus; and is an unpaid consultant for Patient IQ and Sparta Biomedical. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: Increased load bearing across the patellofemoral and tibiofemoral articulations has been associated with total knee arthroplasty (TKA) complications. Therefore, the purpose of this study was to quantify the biomechanical characteristics of the patellofemoral and tibiofemoral joints and simulate varying weight-bearing demands after posterior cruciate ligament-retaining (CR) and posterior-stabilized (PS) TKAs., Methods: Eight fresh-frozen cadaveric knees (average age, 68.4 years; range, 40-86 years) were tested using a custom knee system with muscle-loading capabilities. The TKA knees were tested with a CR and then a PS TKA implant and were loaded at 6 different flexion angles from 15° to 90° with progressively increasing loads. The independent variables were the implant types (CR and PS TKA), progressively increased loading, and knee flexion angle (KFA). The dependent variables were the patellofemoral and tibiofemoral kinematics and contact characteristics., Results: The results showed that at higher KFAs, the position of the femur translated significantly more posterior in CR implants than in PS implants (36.6 ± 5.2 mm and 32.5 ± 5.7 mm, respectively). The patellofemoral contact force and contact area were significantly greater in PS than in CR implants at higher KFAs and loads (102.4 ± 12.5 N and 88.1 ± 10.9 N, respectively). Lastly, the tibiofemoral contact force was significantly greater in the CR than the PS implant at flexion angles of 45°, 60°, 75°, and 90° KFA, the average at these flexion angles for all loads tested being 246.1 ± 42.1 N and 192.8 ± 54.8 N for CR and PS implants, respectively., Conclusions: In this biomechanical study, CR TKAs showed less patellofemoral contact force, but more tibiofemoral contact force than PS TKAs. For higher loads across the joint and at increased flexion angles, there was significantly more posterior femur translation in the CR design with a preserved posterior cruciate ligament and therefore significantly less patellofemoral contact area and force than in the PS design. The different effects of loading on implants are an important consideration for physicians as patients with higher load demands should consider the significantly greater patellofemoral contact force and area of the PS over the CR design., Competing Interests: CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported., (Copyright © 2024 by The Korean Orthopaedic Association.)

Background: Isolated polyethylene insert exchange (IPIE) has not been established as a treatment option for hyperextension instability after primary total knee arthroplasty (TKA). The purpose of the study was to evaluate the survival rate and clinical outcomes of IPIE for the treatment of instability with or without hyperextension after TKA., Methods: This study retrospectively reviewed 46 patients who underwent IPIE for symptomatic prosthetic knee instability by dividing them into 2 groups based on the presence of hyperextension (without for group I and with for group IH). Patient demographics, clinical scores, radiographic data, range of motion (ROM), and surgical information were collected. Clinical failure was defined as a subsequent surgery following IPIE for any reason. The survival rate of IPIE and differences in demographics, clinical scores, and ROM were compared., Results: There were 46 patients (91% were women) with an average age of 70.1 years and a mean follow-up of 44.8 months. The average time between primary TKA and IPIE surgery was 6.5 ± 4.2 years, and during IPIE, 2 out of the 8 cruciate-retaining inserts were converted to "deep-dish" ultracongruent inserts while the insert thickness increased from 11.9 ± 1.8 mm to 17.1 ± 3.1 mm. After IPIE surgery, a significantly thicker tibial insert was used in the group with hyperextension (15.39 ± 2.4 mm for group I, 18.3 ± 2.9 mm for group IH; p < 0.001 by independent t -test), and no significant differences were observed in the ROM and clinical scores before and after IPIE between the 2 groups. The overall survival rate for IPIE was 83% at 5 years and 57% at 10 years, and there were no statistically significant differences between the groups using the Cox proportional hazards regression model., Conclusions: IPIE demonstrated an overall survival rate of 83% at 5 years with no difference in the recurrence of instability regardless of hyperextension. This study highlighted the effectiveness of using thicker inserts to resolve instability without significant differences in the ROM or clinical scores between the groups, suggesting its potential as a decision-making reference for surgeons., Competing Interests: CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported., (Copyright © 2024 by The Korean Orthopaedic Association.)

Background: The objective of this study was to compare the clinical outcomes of two internal fixation methods for high tibial osteotomy (HTO): double-triangle locking compression plate (DT-LCP) and T-shaped locking compression plate (T-LCP)., Methods: 202 adult patients in our hospital between January 2018 and December 2021 were included and followed up for at least one year: group 1(DT-LCP, 98 patients) and group 2 (T-LCP, 104 patients). Detailed information on demographics, preoperative and postoperative follow-up, surgical procedures, and complications were collected. The information of the International Knee Documentation Committee Knee Evaluation Form (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were collected before surgery and at the last follow-up., Results: A total of 202 patients were included in the per-protocol analysis. No significant difference was found in terms of demographic data between groups, except for age and BMI. Clinically relevant improvements in knee pain were reached up to last follow-up after the operation in both groups. The mean pain scores (KOOS, WOMAC) at the final follow-up were significantly higher among group 1 compared to group 2 (P = 0.040 and P = 0.023). Furthermore, the DT-LCP internal fixation exerted more excellent effects on other symptoms, function and quality of life than T-LCP internal fixation., Conclusions: Our study demonstrated that DT-LCP provided better clinical performance due to its implant irritant pain, compared with T-LCP. Thus, DT-LCP is a feasible alternative for the fixation of OW-HTO., (© 2024. The Author(s).)

Background: Medial tibial defects are common in patients who underwent primary total knee arthroplasty for varus deformity. Previous clinical studies have categorized tibial defects according to the depth of the defects and recommended different ways of addressing them. This study aimed to perform a biomechanical FE analysis to investigate the role of depth and surface area of the medial tibial plateau defects in the stability of the tibial component in primary TKA implants., Method: Forty posteromedial tibial defect models with eight different depths (including 2, 4, 6, 8, 11, 13, 16, and 18 mm) and five different surface areas (including 10, 20, 30, 40, and 50% medial surface involvement) were used to create the FE models. Loads were applied to ellipses on tibial tray with 70-30% mediolateral distribution. The resulting relative motion of the bone and implant was measured to evaluate the tibial tray instability., Results: For defects with less than 20% surface involvement, the amount of relative motion had a moderately increasing fashion; however, in more significant percentages of surface involvement of the medial tibial plateau, especially in 50%, the graphs revealed a nonlinear increasing pattern which means that the depth would affect the amount of relative motion only when defect area is large., Conclusion: In defects with less than 20% surface involvement approaches like graft and cement augmentation would suffice whereas it would be essential to consider a more appropriate method like stem or metal augments for defects with more than 20% of medial surface involvement as the instability increased nonlinearly., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Unicompartmental knee arthroplasty (UKA) is a viable option of treatment in case of osteoarthritis (OA) or avascular osteonecrosis (AVN) isolated to either the medial or the lateral compartment of the knee. The aim of this study was to retrospectively present clinical outcomes and survivorship at minimum 18 years follow up of a fixed bearing (FB) UKA comparing the results of conventional technique and navigation., Methods: Patients treated with a medial FB UKA between June 2003 and December 2006 were retrospectively evaluated. From March 2005 all UKAs were performed using a computer navigation system. Patients were divided into two groups: UKAs assisted by navigation (n-UKAs) versus standard UKAs (s-UKAs). For all patients, at final follow up, patient-reported outcome measures (PROMs) were collected: Western Ontario and McMaster Universities (WOMAC) score, Oxford Knee Score (OKS) and Forgotten Joint Score (FJS-12). Survival rate and outcomes were compared between groups., Results: Fifty-two patients were analyzed in this retrospective evaluation. All UKAs were medial and the tibial component was all polyethylene (AP) in 26 cases and metal backed (MB) in 26. Twenty-six UKAs were implanted with standard technique (AP 10, MB 16) and 26 assisted by a navigation system (AP 16, MB 10). Three patients (5.7%) underwent revision; the average time to revision was 140.7 months (standard deviation 81.2). Average follow up was 216.4 months (standard deviation 10.6). The survivorship of the implant was 94.4% at final follow up. Survivorship and PROMs were not different between groups., Conclusions: This study showed excellent survivorship and outcomes at long term follow up of the original fixed bearing Cartier designed implant in both groups with equivalent survivorship and PROMs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Accurate positioning of components in total knee arthroplasty (TKA) is essential to a satisfactory outcome. Significant malrotation may lead to chronic pain, stiffness, and dysfunction. This study aims to quantify improvements in functional outcomes following revision surgery for malrotation of either one or both components in TKA versus revision for aseptic loosening., Methods: This was a retrospective review of TKAs that matched and compared the two-year functional outcomes of the malrotation group to a functionally similar aseptic loosening group. Functional outcomes were compared between groups using Short Form (SF-12), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and Knee Society Functional Score (KSFS). Student t-tests and chi-squared or Fisher's tests were used for statistical analysis., Results: Of the patients revised, 24 had malrotation and 57 had aseptic loosening. A total of 16 femoral and 17 tibial components were revised for malrotation. All 16 femoral components were internally malrotated (mean -4.8 ± 4.1 degrees; range, -0.5 to -16.6). Of the tibial components, 15 were internally malrotated, (mean -9.5 ± 6.6 degrees; range, -2.2 to -23.5) and 2 were externally malrotated (mean 4.6 ± 2.1 degrees; range, 3.1 to 6.0). All functional outcome measures significantly improved comparably within both groups preoperatively to 24 months postoperatively. At 24 months, functional outcome measures were comparable between the groups and WOMAC function scores were significantly higher in the malrotation group., Conclusion: Revision TKA for malrotation can yield clinically and statistically significant functional improvements, similar in magnitude to those seen following revision TKA for aseptic loosening., Level of Evidence: Level III., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Patients with hallux valgus are known to alter lower limb joint kinematics during gait. However, little information is available about gait changes following hallux valgus surgery. We aimed to longitudinally investigate lower limb kinematic changes at the mid and terminal stances of gait after hallux valgus surgery., Methods: This prospective observational study included 11 female patients (17 feet), who underwent first metatarsal osteotomy. Gait analyses were performed preoperatively and 1- and 2-year postoperatively using a three-dimensional motion capture system. Toe-out angle, ankle, knee, and hip joint angles during gait were calculated from the recorded data. The spatiotemporal parameters and these angles at the mid and terminal stances of gait were statistically compared between preoperative and postoperative periods., Findings: All spatiotemporal parameters remained unchanged postoperatively. The toe-out angle was significantly greater at 1- and 2-year postoperatively. The ankle pronation angle, the knee abduction angle, and the hip adduction angle at the mid and terminal stances of gait were smaller postoperatively compared to the preoperative. These angular changes showed a similar trend at 1 and 2 years postoperatively. However, the postoperative changes of the sagittal joint angles were relatively small., Interpretation: Hallux valgus surgery can affect the toe-out angle and the lower limb coronal kinematics at the mid and terminal stances of gait in patients with hallux valgus. However, surgical correction of hallux valgus deformity did not directly improve the gait characteristics in patients with hallux valgus., Competing Interests: Declaration of competing interest The author(s) declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)