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Context: Poor knee biomechanics contribute to knee joint injuries. Neuromuscular control over knee position is partially derived from the hip. It is unknown whether isolated activation training of the gluteal muscles improves lower-extremity frontal plane mechanics. This study examined if a home-based hip muscle activation program improves performance on the Forward Step-Down Test as well as increases surface electromyography (sEMG) activation of the gluteal muscles. Design: The study utilized a single-group repeated-measures design. Methods: Thirty-five participants (24 females, mean age = 23.17 [SD 1.36] years) completed an 8-week hip muscle activation program. The Forward Step-Down Test score and sEMG of gluteus maximus and medius were assessed preintervention and postintervention. Results: Forward Step-Down Test scores improved significantly from preintervention (Mdn = 3.5) to postintervention (Mdn = 3.0, T = 109, P =.010, r =.31.), but this result did not meet clinical significance. sEMG analysis revealed a significant increase in mean gluteus maximus activation (P =.028, d = 1.19). No significant dose–response relationship existed between compliance and the Forward Step-Down Test scores or sEMG results. Conclusions: A home-based hip activation program increases gluteus maximus activation without clinically significant changes in frontal plane movement quality. Future studies may find clinical relevance by adding motor learning to the activation training program to improve functional muscle use. [ABSTRACT FROM AUTHOR]

The purpose was to examine (1) the effect of measurement position and sex on femoral cartilage outcomes, and (2) the association between gait biomechanics and cartilage outcomes. Fifty individuals participated (25 males and 25 females; age = 20.62 [1.80] y). Ultrasound measured femoral cartilage thickness and echo-intensity at 90°, 115°, and 140° of knee flexion. Gait outcomes included the external knee adduction and knee flexion moments. Cartilage outcomes were compared using 2 (sex) × 3 (position) repeated-measures analysis of variance. Gait and cartilage associations were assessed using stepwise regression. Medial cartilage was thicker when measured at 90° compared with 115° (P =.02) and 140° (P <.01), and 115° compared with 140°, (P <.01) in males but not in females. Cartilage was thicker at 90° compared with 140° across both sexes within all regions (P <.01). Males had thicker cartilage than females in all positions (P <.01). Echo-intensity was lower at 90° than 115° (P <.01) and 140° (P =.01) in the central and lower at 90° than at 115° (P <.01) and 140° (P =.03) in lateral regions. No association was found between gait and cartilage outcomes. Ultrasound imaging position effects cartilage features more in males compared with females. Imaging position and sex influence cartilage outcomes and should be considered in study designs and clinical evaluation. [ABSTRACT FROM AUTHOR]

Imbalanced joint load distribution across the tibiofemoral surface is a risk factor for osteoarthritic changes to this joint. Lateral wedge insoles, with and without arch support, are a form of biomechanical intervention that can redistribute tibiofemoral joint load, as estimated by external measures of knee load. The objective of this study was to examine the effect of these insoles on the internal joint contact characteristics of osteoarthritic knees during weightbearing. Fifteen adults with tibiofemoral osteoarthritis underwent magnetic resonance imaging of the affected knee, while standing under 3 insole conditions: flat control, lateral wedge alone, and lateral wedge with arch support. Images were processed, and the surface area and centroid location of joint contact were quantified separately for the medial and lateral tibiofemoral compartments. Medial contact surface area was increased with the 2 lateral wedge conditions compared with the control (P ≤.012). A more anterior contact centroid was observed in the medial compartment in the lateral wedge with arch support compared with the lateral wedge alone (P =.009). Significant changes in lateral compartment joint contact outcomes were not observed. These findings represent early insights into how loading at the tibiofemoral interface may be altered by lateral wedge insoles as a potential intervention for knee osteoarthritis. [ABSTRACT FROM AUTHOR]

We proposed an end-to-end deep learning convolutional neural network (DCNN) for region-of-interest based multi-parameter quantification (RMQ-Net) to accelerate quantitative ultrashort echo time (UTE) MRI of the knee joint with automatic multi-tissue segmentation and relaxometry mapping. The study involved UTE-based T1 (UTE-T1) and Adiabatic T1ρ (UTE-AdiabT1ρ) mapping of the knee joint of 65 human subjects, including 20 normal controls, 29 with doubtful-minimal osteoarthritis (OA), and 16 with moderate-severe OA. Comparison studies were performed on UTE-T1 and UTE-AdiabT1ρ measurements using 100%, 43%, 26%, and 18% UTE MRI data as the inputs and the effects on the prediction quality of the RMQ-Net. The RMQ-net was modified and retrained accordingly with different combinations of inputs. Both ROI-based and voxel-based Pearson correlation analyses were performed. High Pearson correlation coefficients were achieved between the RMQ-Net predicted UTE-T1 and UTE-AdiabT1ρ results and the ground truth for segmented cartilage with acceleration factors ranging from 2.3 to 5.7. With an acceleration factor of 5.7, the Pearson r-value achieved 0.908 (ROI-based) and 0.945 (voxel-based) for UTE-T1, and 0.733 (ROI-based) and 0.895 (voxel-based) for UTE-AdiabT1ρ, correspondingly. The results demonstrated that RMQ-net can significantly accelerate quantitative UTE imaging with automated segmentation of articular cartilage in the knee joint.

Excessive growth hormone (GH) has been shown to promote joint degeneration in both preclinical and clinical studies. Little is known about the effect of disrupted GH or GH receptor (GHR) on joint health. The goal of this study is to investigate joint pathology in mice with either germline (GHR-/-) or adult inducible (iGHR-/-) GHR deficiency. Knee joints from male and female GHR-/- and WT mice at 24 months of age were processed for histological analysis. Also, knee joints from male and female iGHR-/- and WT mice at 22 months of age were scanned by micro-CT (μCT) for subchondral bone changes and characterized via histology for cartilage degeneration. Joint sections were also stained for the chondrocyte hypertrophy marker, COLX, and the cartilage degeneration marker, ADAMTS-5, using immunohistochemistry. Compared to WT mice, GHR-/- mice had remarkably smooth articular joint surfaces and an even distribution of proteoglycan with no signs of degeneration. Quantitatively, GHR-/- mice had lower OARSI and Mankin scores compared to WT controls. By contrast, iGHR-/- mice were only moderately protected from developing aging-associated OA. iGHR-/- mice had a significantly lower Mankin score compared to WT. However, Mankin scores were not significantly different between iGHR-/- and WT when males and females were analyzed separately. OARSI scores did not differ significantly between WT and iGHR-/- in either individual or combined sex analyses. Both GHR-/- and iGHR-/- mice had fewer COLX+ hypertrophic chondrocytes compared to WT, while no significant difference was observed in ADAMTS-5 staining. Compared to WT, a significantly lower trabecular thickness in the subchondral bone was observed in the iGHR-/- male mice but not in the female mice. However, there were no significant differences between WT and iGHR-/- mice in the bone volume to total tissue volume (BV/TV), bone mineral density (BMD), and trabecular number in either sex. This study identified that both germline and adult-induced GHR deficiency protected mice from developing aging-associated OA with more effective protection in GHR-/- mice.

Context: The hamstrings are the most commonly injured muscle in sports and are especially injury prone in lengthened positions. Measuring knee muscle strength in such positions could be relevant to establish injury risk. Handheld dynamometry has been shown to be a valid, reliable, and practical tool to measure isometric muscle strength clinically. The aim of this study was to assess the validity and reliability of the assessment of isometric knee muscle strength with a handheld dynamometer (HHD) at various muscle lengths, by modifying the hip and knee angles during testing. Design: Concurrent validity and test--retest reliability. Methods: Thirty young healthy participants were recruited. Hamstring and quadriceps isometric strength was measured with a HHD and with an isokinetic dynamometer, over 2 testing sessions, in a randomized order. Isometric strength was measured on the right lower limb in 6 different positions, with the hip at either 0° or 80° of flexion and the knee at either 30°, 60°, or 90° of flexion. Pearson and Spearman correlations were used to assess the validity, and intraclass correlation coefficients were calculated to establish the test--retest reliability of the HHD. Results: Good to excellent reliability and moderate to high validity were found in all the tested muscle length positions, except for the hamstrings in a seated position with the knee extended at 30°. Conclusions: The use of a HHD is supported in the clinical setting to measure knee muscle strength at varying muscle lengths in healthy adults, but not for the hamstrings in a lengthened position (hip flexed and knee extended). These results will have to be confirmed in sport-specific populations. [ABSTRACT FROM AUTHOR]

Context: The purpose of the study was to develop normative ranges and standards for knee and shoulder isokinetic and anthropometric values. These standards can be qualitatively interpreted and allow practitioners to classify isokinetic and anthropometric values more objectively for university-level netball players. Design: Posttest only observational study design. All players were only evaluated once during the in-season to generate normative ranges. Methods: A total of 51 female players volunteered. Participants were evaluated on an isokinetic dynamometer at 60° per second to obtain knee-extensor and knee-flexor values as well as shoulder-flexor and shoulder-extensor values. A total of 16 anthropometric variables were collected including stature, body mass, 8 skinfolds, and 6 circumferences. Between-group differences were calculated to determine whether playing level was a differentiating factor in data. Results: Normative standards were developed for isokinetic parameters associated with the knee and shoulder joints as well as skinfolds and circumference measures. No statistically significant between-group differences were evident (χKruskal-Wallis²[2] = 3.96, P = .140). Conclusion: These standards can be used by coaches and practitioners to set attainable goals for individual players or those from secondary leagues, classify individual and team-based performances, and facilitate decision-making processes. [ABSTRACT FROM AUTHOR]

Clinical Scenario: Hamstring extensibility plays a significant role in maintaining postural alignment essential for a functional musculoskeletal system. When hamstring extensibility is lacking, individuals are placed at a higher risk for developing various lumbar spine, pelvis, knee, and foot dysfunctions. Limited hamstring extensibility is common, occurring in as much as 40% of college students and 86% of the adult population. Therefore, it is essential to maintain hamstring extensibility, which can be aided by understanding intervention effectiveness for improving flexibility. Purpose: To critically appraise the literature on the effectiveness of Active Release Technique (ART) for the treatment of hamstring extensibility deficits. Clinical Question: What is the effect of ART in a healthy population with or without hamstring extensibility deficits? Summary of Key Findings: Three studies were included for critical appraisal. Two studies concluded a single treatment session of ART that individuals possessing limited straight leg raise range of motion experienced improved active knee extension, popliteal angle, and sit-and-reach test measures. In the third study, a single session of ART was effective at improving hamstring extensibility in males without hamstring extensibility dysfunction. Clinical Bottom Line: Based on the current level 1 and level 3 evidence, ART may be an effective treatment to produce acute increases in hamstring extensibility. Future research is still needed. Strength of Recommendation: Level B evidence exists to support the use of ART to improve hamstring extensibility in the healthy population. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Adipose tissue has been associated with knee osteoarthritis (KOA) pathogenesis, but the longitudinal changes in adipose tissue with KOA progression have not been carefully evaluated. This study aimed to determine if longitudinal changes of systemic and local adipose tissue is associated with radiographic progression of KOA. METHODS: This case-control study used data from the Osteoarthritis Initiative (OAI) and included 315 cases (all the right knees with a minimum of Kellgren-Lawrence score (KL) of 0 and an increase of ≥ 1 KL from baseline to 48 months) and 315 controls matched by age, sex, race, and baseline KL. Cross sectional area of IPFP (IPFP CSA) and subcutaneous adipose tissue around the distal thigh (SCATthigh) were measured using MRI images at baseline and 24 months. Conditional logistic regression models were fitted to estimate associations of obesity markers, IPFP CSA, and SCATthigh with radiographic KOA progression. Mediation analysis was used to assess whether IPFP CSA or SCATthigh mediates the relationships between baseline BMI and radiographic KOA progression. RESULTS: 24-month changes of IPFP CSA (ΔIPFP CSA) and SCATthigh (ΔSCATthigh) were significantly greater in cases compared to controls, whereas Δ BMI and Δ abdominal circumference were similar in both groups during follow-up. Adjusted ORs for radiographic KOA progression were 9.299, 95% CI (5.357-16.141) per 1 SD increase of Δ IPFP CSA and 1.646, 95% CI (1.288-2.103) per 1 SD increase of Δ SCATthigh. ΔIPFP CSA mediated the association between baseline BMI and radiographic KOA progression (87%). CONCLUSIONS: Subjects with radiographic progression of KOA, had significant increases in IPFP CSA and subcutaneous adipose tissue while BMI and abdominal circumference remained stable. Additional studies are needed to confirm these associations.

BACKGROUND: The polyarticular nature of Osteoarthritis (OA) tends to manifest in multi-joints. Associations between cartilage health in connected joints can help identify early degeneration and offer the potential for biomechanical intervention. Such associations between hip and knee cartilages remain understudied. PURPOSE: To investigate T1p associations between hip-femoral and acetabular-cartilage subregions with Intra-limb and Inter-limb patellar cartilage; whole and deep-medial (DM), deep-lateral (DL), superficial-medial (SM), superficial-lateral (SL) subregions. STUDY TYPE: Prospective. SUBJECTS: Twenty-eight subjects (age 55.1 ± 12.8 years, 15 females) with none-to-moderate hip-OA while no radiographic knee-OA. FIELD STRENGTH/SEQUENCE: 3-T, bilateral hip, and knee: 3D-proton-density-fat-saturated (PDFS) Cube and Magnetization-Prepared-Angle-Modulated-Partitioned-k-Space-Spoiled-Gradient-Echo-Snapshots (MAPSS). ASSESSMENT: Ages of subjects were categorized into Group-1 (≤40), Group-2 (41-50), Group-3 (51-60), Group-4 (61-70), Group-5 (71-80), and Group-6 (≥81). Hip T1p maps, co-registered to Cube, underwent an atlas-based algorithm to quantify femoral and acetabular subregional (R2-R7) cartilage T1p. For knee Cube, a combination of V-Net architectures was used to segment the patellar cartilage and subregions (DM, DL, SM, SL). T1p values were computed from co-registered MAPSS. STATISTICAL TESTS: For Intra-and-Inter-limb, 5 optimum predictors out of 13 (Hip subregional T1p, age group, gender) were selected by univariate linear-regression, to predict outcome (patellar T1p). The top five predictors were stepwise added to six linear mixed-effect (LME) models. In all LME models, we assume the data come from the same subject sharing the same random effect. The best-performing models (LME-modelbest) selected via ANOVA, were tested with DM, SM, SL, and DL subregional-mean T1p. LME assumptions were verified (normality of residuals, random-effects, and posterior-predictive-checks). RESULTS: LME-modelbest (Intra-limb) had significant negative and positive fixed-effects of femoral-R5 and acetabular-R2 T1p, respectively (conditional-R2 = 0.581). LME-modelbest (Inter-limb) had significant positive fixed-effects of femoral-R3 T1p (conditional-R2 = 0.26). DATA CONCLUSION: Significant positive and negative T1p associations were identified between load-bearing hip cartilage-subregions vs. ipsilateral and contralateral patellar cartilages respectively. The effects were localized on medial subregions of Inter-limb, in particular. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1.

Objective: To rate athletes' functional ability and return to sport (RTS) success at the end of their individual, formal, medically prescribed rehabilitation after anterior anterior cruciate ligament (ACL) reconstruction. Methods: In our prospective multicenter cohort study, 88 (42 females) adults aged 18-35 years after acute unilateral ACL rupture and subsequent hamstring grafting were included. All patients were prospectively monitored during their rehabilitation and RTS process until the end of their formal rehabilitation and RTS release. As outcome measures, functional hop and jump tests (front hop, balance hops, and drop jump screening test) and self-report outcomes (Knee Injury and Osteoarthritis Outcome Score, ACL-RTS after injury) were assessed. Literature-based cut-off values were selected to rate each performance as fulfilled or not. Results: At 7.5 months (SD 2.3 months) after surgery, the percentage of participants meeting the functional thresholds ranged from 4% (Knee Injury and Osteoarthritis Outcome Score SPORT) and over 44% (ACL-RTS after injury sum score) to 59% (Knee Injury and Osteoarthritis Outcome Score activities of all daily living) in the self-report and from 29% (Balance side hop) to 69% (normalized knee separation distance) in performance testing. Only 4% fulfilled all the cut-offs, while 45% returned to the same type and level of sport. Participants who successfully returned to their previous sport (type and level) were more likely to be "over-cut-off-performers." Conclusions: The low share of the athletes who fulfilled the functional RTS criteria highlights the importance of continuing the rehabilitation measures after the formal completion to assess the need for and success of, inter alia, secondary-preventive therapies. [ABSTRACT FROM AUTHOR]

Context: The purpose of this study was to compare short-term clinical outcomes between meniscus procedures performed with anterior cruciate ligament reconstruction (ACLR), ACLR (ACLR-only), ACLR with meniscectomy/resection (ACLR-resect), and ACLR with meniscal repair (ACLR-repair) for bone patellar tendon bone grafts (BPTB) and hamstring tendon grafts, separately. Design: This was a cross-sectional study conducted in a controlled laboratory setting as part of a large point-of-care collaborative research program. Methods: This study included 314 participants (168 females; mean [SD]: age, 19.7 [4.8]) with primary unilateral ACLR with a BPTB or hamstring tendon. Patients were divided into 3 groups depending on meniscal procedure (ACLR-only, ACLR-resect, and ACLR-repair). Postsurgical testing included: isokinetic assessment of knee extension and flexion, single-leg hop tests, and patient-reported outcomes. Multivariate analysis of covariance compared differences between meniscal procedures on the battery of tests, and for each statistically significant variable an analysis of covariance assessed the effect of meniscal procedure within each graft type. Chi-square analysis assessed the influence of meniscal procedure on tests' pass rates defined as 90% of limb symmetry index. Results: BPTB: ACLR-only had greater hamstring strength than ACLR-resect (P = .05) and ACLR-repair (P = .005). ACLR-only had the highest proportion of participants to pass the hamstring strength test (P=.02). amstring tendon: ACLR-only (P=.03) and ACLR-resect (P=.003) had higher International Knee Documentation Committee scale scores than ACLR-repair. There was a significant difference in the proportion of participants who scored >90% limb symmetry index on the timed hop test (P = .05). Conclusions: The influence of meniscal repair on clinical outcomes is dependent on the graft choice. Following an ACLR with BPTB and a meniscal procedure, hamstring function should be more closely monitored for optimal short-term recovery. [ABSTRACT FROM AUTHOR]

Prior studies have explored the relationship between knee valgus and musculoskeletal variables to formulate injury prevention programs, primarily for females. Nonetheless, there is insufficient evidence pertaining to professional male soccer players. Here, the aim was to test the correlation of lateral trunk inclination, hip adduction, hip internal rotation, ankle dorsiflexion range of motion, and hip isometric strength with knee valgus during the single-leg vertical jump test. Twenty-four professional male soccer players performed a single-leg vertical hop test, hip strength assessments, and an ankle dorsiflexion range of motion test. A motion analysis system was employed for kinematic analysis. Maximal isometric hip strength and ankle dorsiflexion range of motion were tested using a handheld dynamometer and a digital inclinometer, respectively. The correlation of peak knee valgus with peak lateral trunk inclination was.43 during the landing phase (P =.04) and with peak hip internal rotation was −.68 (P <.001). For knee valgus angular displacement, only peak lateral trunk inclination presented a moderate positive correlation (r =.40, P =.05). This study showed that trunk and hip kinematics are associated with knee valgus, which could consequently lead to increased knee overload in male professional soccer players following a unilateral vertical landing test. [ABSTRACT FROM AUTHOR]

INTRODUCTION: The incidence of periprosthetic distal femur fractures (PDFF) is increasing as the number of total knee replacements becomes more common. This study compared the demographics, fracture characteristics, treatment, and outcomes of periprosthetic versus native distal femur fractures (NDFF). MATERIALS AND METHODS: This was a retrospective cohort study of patients ≥ 18 who underwent surgical fixation of NDFF or PDFF from 2012 to 2020 at a level-1 trauma center. The main variables collected included demographics, AO/OTA fracture classification, fixation construct, concomitant fractures, polytrauma rates, bone density, and reduction quality. Primary outcomes were unexpected return to the operating room (UROR), hospital length of stay, and quality of reduction. T-tests, Fishers exact tests, and multivariate analyses were used for statistical analysis. RESULTS: 209 patients were identified, including 70 PDFF and 139 NDFF. PDFF patients were elderly females (81%) with isolated (80%) and comminuted (85%) 33 A.3 (71%) fractures. NDFF patients included 53% females, were commonly middle-aged, and displayed comminuted (92%) 33 C.2 fractures. 48% of NDFF patients had concomitant fractures. Intramedullary nailing was the primary fixation for both groups, followed by nail-plate combination (37%) for PDFF and lateral locking plates (21%) for NDFF. NDFF patients experienced significantly longer hospital stays, higher UROR rates, and worse quality of reduction (p

PURPOSE: Advancing age is one of the strongest risk factors for osteoarthritis (OA). DNA methylation-based measures of epigenetic age acceleration may provide insights into mechanisms underlying OA. METHODS: We analyzed data from the Multicenter Osteoarthritis Study in a subset of 671 participants ages 45-69 years with no or mild radiographic knee OA. DNA methylation was assessed with the Illumina Infinium MethylationEPIC 850K array. We calculated predicted epigenetic age according to Hannum, Horvath, PhenoAge, and GrimAge epigenetic clocks, then regressed epigenetic age on chronological age to obtain the residuals. Associations between the residuals and knee, hand, and multi-joint OA were assessed using logistic regression, adjusted for chronological age, sex, clinical site, smoking status, and race. RESULTS: Twenty-three percent met criteria for radiographic hand OA, 25% met criteria for radiographic knee OA, and 8% met criteria for multi-joint OA. Mean chronological age (SD) was 58.4 (6.7) years. Mean predicted epigenetic age (SD) according to Horvath, Hannum, PhenoAge, and GrimAge epigenetic clocks was 64.9 (6.4), 68.6 (5.9), 50.5 (7.7), and 67.0 (6.2), respectively. Horvath epigenetic age acceleration was not associated with an increased odds of hand OA, odds ratio (95% confidence intervals) = 1.03 (0.99-1.08), with similar findings for knee and multi-joint OA. We found similar magnitudes of associations for Hannum epigenetic age, PhenoAge, and GrimAge acceleration compared to Horvath epigenetic age acceleration. CONCLUSIONS: Epigenetic age acceleration as measured by various well-validated epigenetic clocks based on DNA methylation was not associated with increased risk of knee, hand, or multi-joint OA independent of chronological age.

PURPOSE: Hip osteoarthritis (OA) is a major cause of pain and disability worldwide. Lack of effective therapies may reflect poor knowledge on its aetiology and risk factors, and result in the management of end-stage hip OA with costly joint replacement. The Worldwide Collaboration on OsteoArthritis prediCtion for the Hip (World COACH) consortium was established to pool and harmonise individual participant data from prospective cohort studies. The consortium aims to better understand determinants and risk factors for the development and progression of hip OA, to optimise and automate methods for (imaging) analysis, and to develop a personalised prediction model for hip OA. PARTICIPANTS: World COACH aimed to include participants of prospective cohort studies with ≥200 participants, that have hip imaging data available from at least 2 time points at least 4 years apart. All individual participant data, including clinical data, imaging (data), biochemical markers, questionnaires and genetic data, were collected and pooled into a single, individual-level database. FINDINGS TO DATE: World COACH currently consists of 9 cohorts, with 38 021 participants aged 18-80 years at baseline. Overall, 71% of the participants were women and mean baseline age was 65.3±8.6 years. Over 34 000 participants had baseline pelvic radiographs available, and over 22 000 had an additional pelvic radiograph after 8-12 years of follow-up. Even longer radiographic follow-up (15-25 years) is available for over 6000 of these participants. FUTURE PLANS: The World COACH consortium offers unique opportunities for studies on the relationship between determinants/risk factors and the development or progression of hip OA, by using harmonised data on clinical findings, imaging, biomarkers, genetics and lifestyle. This provides a unique opportunity to develop a personalised hip OA risk prediction model and to optimise methods for imaging analysis of the hip.

ObjectiveCartilage degeneration involves structural, compositional, and biomechanical alterations that may be detected non-invasively using quantitative MRI. The goal of this study was to determine if topographical variation in T1rho values correlates with indentation stiffness and biochemical contents of human patellar cartilage.DesignCadaveric patellae from unilateral knees of 5 donors with moderate degeneration were imaged at 3-Telsa with spiral chopped magnetization preparation T1rho sequence. Indentation testing was performed, followed by biochemical analyses to determine water and sulfated glycosaminoglycan contents. T1rho values were compared to indentation stiffness, using semi-circular regions of interest (ROIs) of varying sizes at each indentation site. ROIs matching the resected tissues were analyzed, and univariate and multivariate regression analyses were performed to compare T1rho values to biochemical contents.ResultsGrossly, superficial degenerative change of the cartilage (i.e., roughened texture and erosion) corresponded with regions of high T1rho values. High T1rho values correlated with low indentation stiffness, and the strength of correlation varied slightly with the ROI size. Spatial variations in T1rho values correlated positively with that of the water content (R2 = 0.10, p

Context: To assess the reliability of a remote 2D markerless motion tracking method (Kinovea) to quantify knee and hip angles during dynamic tasks. Methods: Fourteen healthy adults performed body weight squats and lateral lunges while video recording themselves at home. Knee and hip angles were quantified in the sagittal plane for the squats and in the frontal plane for the lateral lunges. Two students each performed the video analysis procedure twice, 2 weeks apart. Intraclass correlation coefficients were used to calculate the intrarater and interrater reliability for angles at maximum depth. The intrarater and interrater agreement over the joint angle-time signals were quantified using a validation metric; an acceptable agreement threshold was set at a validation metric of 0.803 or higher. Standard error of measurement (SEM) was also calculated. Results: Reliability was good to excellent (intraclass correlation coefficients = .80-.98) for all angle comparisons at maximum depth. The agreement over the entire joint angle-time signal was acceptable for all squat variables except for the interrater hip angle comparison (validation metric = 0.797). None of the lateral lunge variables met the threshold of acceptable agreement. The mean SEM across participants for all joint angle-time signal and for maximum depth was acceptable (<5°) for all measurements (SEM = 1.2°-4.9°). Conclusions: Overall, the reliability, agreement, and SEM quantified in this study support the integration of remote methods to quantify lower-extremity kinematics into research and clinical practice. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To determine i) pain phenotypes (PP) in people with early-stage knee osteoarthritis (EKOA); ii) the longitudinal association between the phenotypes and pain worsening at two years. DESIGN: We studied participants with EKOA from the Multicenter Osteoarthritis Study defined as pain intensity ≤3/10, Kellgren and Lawrence grade ≤2, intermittent pain none to sometimes, and no constant pain. Two models of PP were explored. Model A included pressure pain thresholds, temporal summation, conditioned pain modulation, pain catastrophizing, sleep quality, depression, and widespread pain (WSP). In Model B, gait characteristics, quadriceps strength, comorbidities, and magnetic resonance imaging features were added to Model A. Latent Class Analysis was used to create phenotypes, and logistic regression was used to determine their association with pain worsening. RESULTS: 750 individuals (60% females), mean age [standard deviation (SD)]: 60.3 (9.4) were included in Model A and 333 individuals (60% females), mean age (SD): 59.4 (8.1) in Model B. 3-class and 4-class solutions were chosen for Model A and Model B. In Model A, the most severe phenotype was dominated by psychosocial factors, WSP, and measures of nervous system sensitization. Similarly in Model B, the Model A phenotype plus gait variables, quadriceps strength, and comorbidities were dominant. Surprisingly, none of the phenotypes in either model had a significant relationship with pain worsening. CONCLUSION: Phenotypes based upon various factors thought to be important for the pain experience were identified in those with EKOA but were not significantly related to pain worsening. These phenotypes require validation with clinically relevant endpoints.

BackgroundObesity influences the development of osteoarthritis via low-grade inflammation. Progression of local inflammation (= synovitis) increased with weight gain in overweight and obese women compared to stable weight. Synovitis could be associated with subcutaneous fat (SCF) around the knee. Purpose of the study was to investigate the effect of weight loss on synovitis progression and to assess whether SCF around the knee mediates the relationship between weight loss and synovitis progression.MethodsWe included 234 overweight and obese participants (body mass index [BMI] ≥ 25 kg/m2) from the Osteoarthritis Initiative (OAI) with > 10% weight loss (n = 117) or stable overweight (

Background: Despite significant progress in orthopaedic surgery, the prevalence of periprosthetic joint infections (PJIs) remains persistent, and future increases are expected due to the increasing number of joint arthroplasties. PJIs are intricately connected to biofilm-producing bacteria, which encase infected prostheses, impairing the effectiveness of antibiotics and the immune system. Acute PJIs with immature biofilms are traditionally managed with debridement, antibiotics, and implant retention (DAIR). However, to date, there has not been a conclusive direct clinical comparison (in vivo) demonstrating the superiority of one irrigation solution over others. Recently, there has been a growing interest in irrigation solutions with antibiofilm properties demonstrated in in vitro studies, exemplified by the preformulated Bactisure® irrigation solution, which contains ethanol, acetic acid, sodium acetate, benzalkonium chloride, and sterile water. The main objective of this study was to evaluate the effectiveness (infection cure rate) of preformulated Bactisure® irrigation solution in vivo compared with saline solution in a control group of patients with acute knee and/or hip periprosthetic infections treated with DAIR. Methods: Prospective single-centre randomized controlled trial involving patients with acute haematogenous PJI who received standard DAIR surgery from December 2022 to December 2024. The type of irrigation solution used during surgery will include two groups allocated at a 1:1 ratio: a control group (n = 25) with saline solution and an experimental group (n = 25) receiving the Bactisure® preformulated solution. The sample size was calculated based on an expected reduction in reinfection rates from 45% in the control group to 10% in the experimental group. Data on baseline patient characteristics, clinical and radiological information, and healthcare questionnaires will be recorded. All patients will be followed for minimum of 12 months. The infection cure rate at 1 year will be the primary outcome. Discussion: This study is the first to compare the effectiveness of preformulated Bactisure® irrigation solution with that of saline solution in real clinical practice (in vivo) in patients with acute knee and/or hip periprosthetic infections treated with DAIR. Our main hypothesis is that, compared with saline solution, Bactisure® provides a better infection cure rate at 1 year post-DAIR. Trial registration: International Standard Randomized Controlled Trial Number (ISRCTN): https://doi.org/10.1186/ISRCTN10873696. Registered on December 19, 2023. [ABSTRACT FROM AUTHOR]

Background: As one of the most prevalent chronic degenerative diseases, knee osteoarthritis (KOA) is associated with the progressive degradation of articular cartilage, meniscus, synovium, ligaments, bone, muscles, and tendons. Knee osteoarthritis affects the quality of life and can cause chronic disability worldwide. Magnetic resonance imaging (MRI) is a crucial imaging modality for the morphological assessment of cartilage and all other joint tissues involved in osteoarthritis. The objective of this study was to evaluate the effectiveness of the three-dimensional (3D) turbo spin-echo (TSE) MRI and to compare its relevance to two-dimensional (2D) routine MRI in adding additional information and in the early detection of KOA. Results: Total agreement between the two techniques ranged between 82.7% (cartilage degeneration), 91.4% (osteophytes), 98.3% for bone marrow edema and periarticular cyst up to 100% of other several features regarding meniscal injury and ligamentous tear. Conclusions: When compared to standard 2D TSE MRI, 3D TSE MRI demonstrates substantial to almost complete agreement and high accuracy for semiquantitative assessment of knee osteoarthritis (OA). 3D TSE MRI also takes less time, which is important for large OA studies and can be used for the detection of early knee joint changes. [ABSTRACT FROM AUTHOR]

Optimal ligament balance is crucial for successful total knee arthroplasty (TKA), which is a standard procedure for managing end-stage knee osteoarthritis. However, the reported values of ligament balance vary due to different methodologies and population differences, which requires further studies. This study aimed to investigate the varus-valgus ligament balance in healthy knees of Japanese individuals and its relationship with lower limb alignment. The studyanalyzed64 knees from 33 healthy young adults using stress radiographs to measure varus-valgus laxity. The mechanical hip-knee-ankle angle, medial proximal tibial angle, and lateral distal femoral angles were determined using digital long-leg radiographs. Varus and valgus laxities were compared, and the relationship between ligament balance and alignment parameters was analyzed. Mean varus laxity (3.6°± 1.3°) was significantly greater than mean valgus laxity(2.9°± 1.0°) (p<0.0001). No significant association was observed between ligament balance and alignment parameters. Healthy knees of Japanese individuals exhibited slightly greater varus laxity (0.7°) than valgus laxity, with no correlation observed between ligament balance and lower limb alignment. The finding underscores the importance of recognizing alignment diversity while noting that alignment does not influence ligament balance; this is particularly relevant in modern TKA techniques focusing on patient-specific joint and ligament reconstructions. The study's findings could help formulate strategies benefiting knee osteoarthritis management. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the clinical outcomes, mechanical axis, component positioning, leg length discrepancy (LLD), and polyethylene liner thickness between robotic-assisted total knee arthroplasty (TKA) and conventional TKA in patients with failed high tibial osteotomy (HTO). Methods: A total of 30 patients (30 knees) with failed HTO who underwent TKA using a robot-assisted system between June 2020 and December 2023 were included in this study (robotic group). Additionally, 60 patients (60 knees) with failed HTO who underwent conventional TKA were included as controls (conventional group). Propensity score matching was performed using a 2:1 ratio between the matched participants. The mean follow-up period was 2.1 years in the robotic group and 2.2 years in the conventional group. Clinical evaluations were performed using the Knee Society Score (KSS) rating system. Mechanical axis, component coronal and sagittal positioning, and LLD were evaluated using postoperative radiographs. The thickness of the polyethylene liner was also determined. The mean error values and outliers were calculated and compared between the two groups to determine the accuracy of the mechanical axis, postoperative component positioning, and LLD. Results: The postoperative KSSs in the robotic and conventional groups were not statistically different. The robotic group achieved better accuracy than the conventional group in terms of postoperative mean mechanical axis (1.7° vs. 2.4°, p < 0.05), femur coronal inclination (90.0° vs. 91.6°, p < 0.05), tibial coronal inclination (90.3° vs. 91.3°, p < 0.05), tibial sagittal inclination (90.5° vs. 91.4°, p < 0.05), and LLD (2.2 vs. 7.0 mm, p < 0.05). A significant difference in polyethylene liner thickness was observed between the two groups (p < 0.05). Conclusions: Robotic-assisted TKA showed improved mechanical axis, higher accuracy of component positioning and polyethylene liner thickness, and reduced LLD compared with those of conventional TKA in patients with failed HTO. Further studies with a larger sample size and long-term follow-up are warranted to ascertain whether the accuracy of robotic-assisted TKA can translate into better clinical outcomes and patient satisfaction. [ABSTRACT FROM AUTHOR]

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AbstractPurposeMethodsResultsConclusions\nImplications for rehabilitationTo determine the prevalence of metabolic syndrome and explore its association with clinical outcomes (pain, quality of life, and physical function) in adults participating in an education and exercise program (GLA:D®).An observational study of adults with hip and/or knee osteoarthritis who participated in GLA:D® between 2019 and 2022. Metabolic syndrome status was determined through self-report. Differences in clinical outcomes among people with, at risk of (1–2 risk factors), or without metabolic syndrome were compared at baseline, 3-, and 12-months using linear mixed models (age, sex, and baseline outcomes as covariates).Of 6846 participants (aged 65(SD 9) years), 20% (n = 1337) had, and 68% (n = 4632) were at risk of metabolic syndrome. Adults with metabolic syndrome reported higher pain (0–100 VAS: 7.3, 95% CI 5.4–9.1), lower health-related quality of life (EQ5D 0–100, VAS: −8.6, 95% CI −10.2 to −7.0), and slower gait speed (−0.26 m/s, 95%CI -0.3 to −0.23) at baseline compared to those with no metabolic risk factors. Differences remained at 3- and 12-months for pain and quality of life.Metabolic syndrome risk factors were common in adults with osteoarthritis. Clinical outcomes remain impaired in people with metabolic syndrome compared to those without after education and exercise, suggesting further intervention may be required.Metabolic syndrome risk factors were prevalent in people with hip and/or knee osteoarthritis attending an education and exercise program.The presence of metabolic syndrome was associated with greater pain severity and disability, and poorer quality of life.People with metabolic syndrome participating in education and exercise programs for osteoarthritis may need additional specific physical activity and diet interventions to improve their outcomes.Metabolic syndrome risk factors were prevalent in people with hip and/or knee osteoarthritis attending an education and exercise program.The presence of metabolic syndrome was associated with greater pain severity and disability, and poorer quality of life.People with metabolic syndrome participating in education and exercise programs for osteoarthritis may need additional specific physical activity and diet interventions to improve their outcomes. [ABSTRACT FROM AUTHOR]

The purpose was to determine whether the benefits of a muscle strength and power training program are superior to those achieved with muscle strength training alone in people with patellofemoral pain (PFP). Thirty-seven individuals with PFP (25.86 ± 7.62 years) were randomly assigned to a strength and power training group (n = 18) or strength training group (n = 19). Primary outcomes were pain intensity and physical functioning. Secondary outcomes were kinesiophobia, quality of life, maximal isometric torque and rate of torque development of the hip and knee and self-perception of recovery. Primary outcomes were measured at baseline, after six weeks, after 12 weeks and at three, six- and 12-months follow-ups. Secondary outcomes were measured at baseline and after 12 weeks. The significance level was 0.05. After interventions, no significant differences were found between groups for primary or secondary outcomes. No difference between groups were found for pain or physical functioning at the other assessment times. Results of this study indicated that addition of power exercises to strength training for hip and knee muscles did not result in superior benefits compared to strength training alone. [ABSTRACT FROM AUTHOR]

Background: Manipulation under anesthesia (MUA) has been recommended for refractory arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. However, the effectiveness of MUA to restore normal kinematics of the arthrofibrotic knee is still unclear. The objective of this study was to evaluate tibiofemoral and patellofemoral kinematics in six degrees-of-freedom (6DOF) in patients with arthrofibrosis before and after MUA. Methods: Computed tomography and dual fluoroscopic imaging system were used to assess in vivo knee kinematics. Ten patients (6 women and 4 men; 32.6 ± 6.5y, 168.4 ± 7.8 cm, 61.8 ± 13.2 kg) were included in this study. The tibiofemoral and patellofemoral kinematics in 6DOF were collected before and one year after MUA. A simple analysis of variance was used to evaluate kinematic data of preoperative arthrofibrotic knee, postoperative arthrofibrotic knee, and the contralateral knee. Results: The patella in the postoperative arthrofibrotic knee shifted significantly more inferiorly compared to the preoperative knee at 45° (P = 0.010), 60° (P = 0.008), and 75° (P = 0.049) of flexion. The patellar flexion in the postoperative arthrofibrotic knee significantly increased at 45° (P = 0.048), 60° (P = 0.037), and 75° (P = 0.006) of flexion compared to the preoperative arthrofibrotic knee. The patellar tilt was significantly decreased at 60° (P = 0.006) and at 75° (P = 0.037) of knee flexion in the postoperative arthrofibrotic knee compared to the contralateral knee. MUA significantly increased tibial internal rotation angle in the arthrofibrotic knee at 45° (P = 0.047), at 60° (P = 0.033), and at 75° (P = 0.021) of knee flexion. Conclusions: MUA could restore normal patellar inferior shift, flexion, and tibial rotation compared to the contralateral side. However, the MUA could not restore normal patellar tilt of the arthrofibrotic knee. This indicated that improvement of patellar tilt should be emphasized in postoperative rehabilitation. Highlights: The abnormal knee kinematics has been thought to be an important factor contributing to the associated joint degeneration in patients with arthrofibrosis after ACL reconstruction. Despite the effectiveness of MUA in the ROM gains for patients with knee arthrofibrosis, the effectiveness of MUA to restore normal knee kinematics in patients with arthrofibrosis after ACL reconstruction is still unclear. The MUA could restore normal patellar inferior shift, flexion, and tibial rotation. The MUA could not restore normal patellar tilt of the arthrofibrotic knee, indicating that improvement of patellar tilt should be emphasized in postoperative rehabilitation. [ABSTRACT FROM AUTHOR]

Non-invasive assessment of joint status using acoustic emissions (AE) is a growing research area that has the potential to translate into clinical practice. The purpose of this study is to investigate the correlation of the knee's AE with measures of proprioception, self-assessment, and performance, as it can be hypothesised that, AE parameters will correlate with joint function metrics due to AE being recorded during interaction of the articular surfaces. Threshold to detect passive motion (TTDPM), Knee Osteoarthritis Outcome Scores (KOOS) and 5 times sit-to-stand test (5STS) were collected from 51 participant. Knee AE were recorded during cycling with 30 and 60 rpm cadences using two sensors in different frequency ranges and three modes of AE event detection. Weak (0.297, p = 0.048) to moderate (0.475, p = 0.001) Spearman's correlations were observed between longer 5STS time and AE parameters (i.e. higher median absolute energy, signal strength, longer AE event rise time and duration). Similarly, AE parameters shown correlation with lower KOOS, especially in the "Function in Sports and Recreation" and "Activities of Daily Living" subscales with correlation coefficients for higher median amplitude up to 0.441, p = 0.001 and 0.403, p = 0.004, respectively. The correlation with the TTDPM was not detected for most of the AE parameters. Additionally, a lower frequency sensor and 60 rpm cadence AE recordings showed higher correlations. Considering that this study included subjects from the general population and the number of participants with KOOS <70 was relatively small, higher correlations might be expected for clinically confirmed OA cases. Additionally, different ICCs might be expected for alternative signal parameters and proprioception assessment methods. Overall, the study confirms that AE monitoring offers an additional modality of joint assessment that reflects interaction between cartilage surfaces and can complement orthopaedic diagnostics, especially in the context of remote monitoring, drug testing, and rehabilitation. [ABSTRACT FROM AUTHOR]

Background: Tenuous blood supply carries a risk of wound-healing problems and subsequent infection following total knee arthroplasty (TKA). This risk may be increased by the presence of previous incisions. Performing a sham incision procedure allows for detection of wound-healing problems prior to performing TKA. The purpose of this retrospective case series is to describe the indications for and technique of a sham incision procedure in patients with previous knee incisions who underwent TKA following this procedure and to report the clinical outcomes observed in these patients following further surgery. Methods: Patients who had prior knee incisions, had undergone a sham incision prior to TKA, and had a minimum follow-up of 2 years were identified, and their cases were retrospectively reviewed. The identified cases typically adhered to the surgeon's standard protocol, which consisted of making a midline incision adventitious to TKA, dissecting down to deep fascia, and closing the wound with suture. Incisions were then observed for at least 4 weeks to determine the viability of the skin flaps before TKA was performed via the same incision. Results: A total of 47 knees in 47 patients were included in the study cohort. TKA was performed at an average of 21.1 weeks (range, 4 to 163 weeks) following the sham incision. There were no cases of skin necrosis or periprosthetic joint infection at an average follow-up of 4.6 years (range, 2 to 12 years) after sham incision. A total of 11 patients (23.4%) required manipulation under anesthesia for stiffness. Conclusions: In our series, no patients developed skin necrosis or periprosthetic joint infection following TKA subsequent to a sham incision procedure, suggesting that healed sham incisions are safe to use for TKA and may be considered prior to TKA in cases in which local previous incisions increase the risk of wound-healing problems. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence To assess the incidence of ramp lesions in anterior cruciate ligament (ACL) injuries and to compare preoperative knee laxity between the patients with and without ramp lesions by using an electromagnetic measurement system (EMS).Two hundred six patients who underwent primary ACL reconstruction with preoperative EMS measurements were retrospectively enrolled in the present study. The diagnoses of the ramp lesions were made by arthroscopic inspections. The patients with ramp lesions and no other meniscal lesions were allocated to ‘ramp group’, and the patients without any meniscal lesions were allocated to ‘control group’. Before ACL reconstruction under general anaesthesia, the side‐to‐side difference (SSD) in anterior tibial translation (ATT) during Lachman test (mm) and tibial acceleration (m/s2) of posterior tibial reduction during the pivot‐shift test was measured using the EMS. The SSD in tibial internal/external rotation angle (°) at 30, 60 and 90 were further measured using the EMS. The SSD in ATT using KT‐2000 was also measured. Knee laxity measurements were compared between two groups using unpaired Student's t test.Ramp lesions were observed in 30 patients (14.7%). Subsequently, 17 patients were allocated to ‘ramp group’ and 77 patients to ‘control group’, and there were no statistical differences with regard to background demographics. ATT‐SSD during Lachman test was significantly greater in ‘ramp group’ (9.1 [95% confidence interval, CI: 5.7–12.5] mm vs. 6.2 [95% CI: 5.1–7.3] mm, p = 0.037). However, SSD in ATT with KT‐2000, tibial acceleration during pivot‐shift test, and SSD in tibial rotational angles were not significantly different between the two groups.Presence of ramp lesion was associated with increased anterior knee laxity during Lachman test, suggesting ramp lesions may need to be addressed at the time of ACL reconstruction.IV. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament (ACL) injury is a common sports injury, and ACL reconstruction is an effective surgery for this trauma. Most cases gain good recovery after surgery, while some patients may experience knee stiffness, which is characterized by joint fibrosis, leading to reduced joint mobility, pain, and dysfunction. Currently, various research studies have been conducted to unveil the mechanisms underlying this condition, identifying pre-, intra-, and post-operative risk factors, and testify the efficacy of different therapeutic methods against it. In this review, we summarize the current progress regarding the advancements in knee fibrosis after ACL reconstruction. The risk factors associated with knee fibrosis are systematically delineated, accompanied by an evaluation of the efficacy of various treatment modalities for both the prevention and mitigation of fibrosis. Furthermore, recommendations for future research directions are proposed, offering a foundational basis for subsequent investigations. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the comparative precision of the augmented reality (AR)-assisted navigation system and the accelerometer-based navigation system in total knee arthroplasty (TKA). We performed noninferiority analysis in a retrospective cohort. The coronal alignment of femoral prosthesis was compared between 109 TKAs performed using the AR-assisted navigation system and 118 TKAs performed using the accelerometer-based navigation system. All femoral prostheses were planned to be positioned perpendicular to the mechanical axis of the femur. The primary outcome was the success rate of coronal alignment of the femoral prosthesis defined as alignment error relative to neutral alignment <3°. We calculated the noninferiority margin as 7%-points using the 95%–95 % method and also confirmed the validity of the noninferiority margin using the fixed margin method. Noninferiority would be shown if the lower boundary of the 95 % confidence interval (CI) for the between-group difference in percentage of the success rate was not less than 0.93 (i.e., 1.00 − 0.07). Treatment success was achieved in 104 of 109 patients (95.4 %) in the AR-assisted navigation group and 110 of 118 (93.2 %) in the accelerometer-based navigation group. The risk ratio of success between the AR-assisted navigation group versus accelerometer-based navigation group was 1.02 (95 % CI, 0.96 to 1.09): the CIs did not include the noninferiority margin of 0.93. The AR-assisted navigation system was noninferior to the accelerometer-based navigation system in terms of coronal alignment of the femoral prosthesis in TKA. [ABSTRACT FROM AUTHOR]

Introduction: the two most used types of prosthesis are posterior cruciate ligament preserving (CR) and posterostabilized (PS). Proponents of CR TKA cited greater stability, greater range of motion, better proprioception, and greater kickback associated with the native posterior cruciate ligament. Objective: to assess the degree of pain, return of mobility and functionality of the joint of patients who had TKA, between the years January 2018 and December 2022 at the Juárez Centro Medical Surgical Unit, using their records as a study unit. Material and methods: observational, descriptive, retrospective and cross-sectional study in patients post-operative with total knee arthroplasty for the treatment of osteoarthritis. The universe studied included 87 patients, of these 22 corresponded to the Juárez Medical Surgical Unit of the Center, post-operated with posterostabilized total knee prosthesis, they were analyzed under the scale proposed by the KSS. Results: the degree of functionality was assessed by the KSS scale, 50% of the patients presented a good clinical assessment and physical examination at the end of rehabilitation, 23% of the patients presented an excellent clinical assessment and physical examination, 23% of the patients presented regular clinical evaluation and physical examination, 4% of patients presented poor clinical evaluation and physical examination. Conclusions: good functional results (73%) were obtained in patients operated by posterostabilized total knee arthroplasty in our Juárez del Centro Medical Surgical Unit. [ABSTRACT FROM AUTHOR]

Lateral meniscus posterior root tears (LMPRTs) are radial tears that occur within 10 mm of the posterior root tibial connection, also known as lateral meniscus posterior root avulsions. A common surgical approach for LMPRT (2) that contributes to positive biomechanical outcomes is independent transtibial pullout repair.(6,7,8) If this treatment is performed on people who need both LMPRT repair and ACL restoration, an extra tibial tunnel is required. The installation of a tibial tunnel increases surgical challenges and lengthens operation time, as well as the danger of iatrogenic damage to the normal architecture of the knee. To circumvent these drawbacks, we have developed a novel technique for intra-tunnel LMPRT repair using a knotless anchor construct at the upper posterior edge of the tibial tunnel. A stab incision is made to create the standard antero lateral portal and after introducing the trochar and the scope, a round of diagnostic arthroscopy is performed and the posterior root of lateral meniscus tear is identified. After creating an anteromedial portal, With help of 1 fiber tape, a loaded bite is taken with the help of a first pass mini device (Smith & Nephew), via the antero medial portal, deep into the posterior root (around 5 mm), using a self winching technique, and reduction of the LMPRT is checked. The position for the anchor entry is visualized in the superior edge of the tibial tunnel along its posterior wall, and the tapes are passed through the knotless anchor extra-articulately outside the AM portal. Thereafter, the anchor is shuttled in through the AM portal and punched in the footprint on the posterior-superior edge of the tibial tunnel with visualization of the reduction of the LMPR to the footprint. This technique offers a simple solution to a complex problem in the form of a simple procedure. This technique is a good choice when a tear of the posterior root of the LM occurs. [ABSTRACT FROM AUTHOR]

Background: Multi-ligament Knee Injuries (MLKI) are often caused by a high-energy impact resulting in dislocation of the knee joint. Given the higher degree of instability associated with these MLKIs, surgical fixation with adjunctive internal bracing and the use of suture augmentation have been proposed with the intention of better restoring knee stability and improving the long-term outcomes of surgery. This systematic review seeks to appraise the current literature in relation to the role of internal bracing in the management of MLKI. Methods: All randomised control trials, observational studies, cohort studies, and cross-sectional studies containing patients with multi-ligamentous knee injuries managed with the use of internal bracing or suture tape augmentation were included in this review. The primary outcomes of interest were re-operation and failure rates, with secondary outcomes focussed on patient-reported outcome measures (PROMs) and examination findings of knee stability. Results: 282 studies were identified for screening, 13 of which were suitable for inclusion and five of these had injuries with Schenck grade III or above. Of the studies identified, failure rates ranged from 0 to 13.6%. Lysholm score was the most commonly utilised PROM tool with scores ranging from 61.8 to 95. Stiffness requiring MUA ± adhesiolysis was a common complication identified across studies. Conclusions: The use of internal bracing in Multi-ligament Knee Injuries appears to be as effective as not using an internal bracing technique. The post-operative PROMs and relatively low failure rates reflect promising outcomes for the ongoing use of internal bracing in MLKI. However, further prospective studies directly comparing braced versus non-braced ligamentous repairs are required in order to definitively determine if the use of the internal brace does allow for increased joint stability and early rehabilitation. [ABSTRACT FROM AUTHOR]

Background: Gait and posture analysis plays a crucial role in understanding human movement, with significant applications in rehabilitation, sports science, and clinical settings. The GaitON® system, a 2D motion analysis tool, provides an accessible and cost-effective method for assessing gait and posture. However, its reliability in clinical practice, particularly for intra-rater consistency, remains to be evaluated. This study aims to assess the intra-rater reliability of the GaitON® system in a healthy population, focusing on gait and posture parameters. Methods: A total of 20 healthy participants (10 males and 10 females) aged 18 to 50 years were recruited for the study. Each participant underwent gait and posture assessments using the GaitON® system on two separate occasions, spaced one week apart. Video recordings from anterior and posterior views were used to analyze gait, while images from anterior, posterior, and lateral views were captured to assess posture with markers placed on key anatomical landmarks. The reliability of the measurements was analyzed using intraclass correlation coefficients (ICC), a standard error of measurement (SEM), and the smallest detectable difference (SDD) method. Results: The GaitON® system demonstrated excellent intra-rater reliability across a wide range of gait and posture parameters. ICC values for gait parameters, including hip, knee, and ankle joint angles, ranged from 0.90 to 0.979, indicating strong consistency in repeated measurements. Similarly, ICC values for posture parameters, such as the head alignment, shoulder position, and ASIS alignment, were above 0.90, reflecting excellent reliability. SEM values were low across all parameters, with the smallest SEM recorded for the hip joint angle (0.37°), and SDD values further confirmed the precision of the system. Conclusion: The GaitON® system provides reliable and consistent measurements for both gait and posture analysis in healthy individuals. Its high intra-rater reliability and low measurement error make it a promising tool for clinical and sports applications. Further research is needed to validate its use in clinical populations and compare its performance to more complex 3D motion analysis systems. [ABSTRACT FROM AUTHOR]

High-altitude landing maneuvers can pose a significant injury risk, particularly when performed with different landing techniques. This study aims to compare the biomechanical parameters and injury risks associated with two landing positions—staggered foot landing and simultaneous bilateral landing—using Xsens inertial units and electromyography (EMG) sensors. A total of 26 university students (13 males, 13 females) participated in this study. Kinematic data were collected using inertial measurement units (IMUs), muscle activity was recorded with EMG, and ground reaction forces were captured using 3D force plates. The data were processed and analyzed using the AnyBody modeling system to simulate joint forces, moments, and muscle activation. This study found that simultaneous bilateral landing exhibited greater hip flexion-extension, knee flexion-extension, and ankle inversion. Vertical joint forces were also significantly higher in the hip, knee, and ankle during simultaneous bilateral landing. Staggered foot landing showed higher muscle forces in the gluteus maximus, iliopsoas, and quadriceps femoris (p < 0.001). The EMG analysis revealed significant differences in the biceps femoris (p = 0.008) and quadriceps femoris (p < 0.001). These findings suggest that simultaneous bilateral landing increases joint load, while staggered foot landing increases muscle activation, which may lead to different injury risks between the two techniques. [ABSTRACT FROM AUTHOR]

A sport-related musculoskeletal injury carries substantial consequences. It is essential to individualize management of these injuries with a model optimizing goal-oriented rehabilitation. A major challenge is to link a patient's goal for returning to sport with the restoration of performance assessed through the rehabilitation process. Even more challenging is that the demanded movement competence is a moving target based on the type of sport and level of competition the athlete seeks to return to. Currently, no single standardized test battery can elucidate a patient's readiness to return to their desired sport at their desired level. We propose a clinical framework to link the assessed capacity (AC) of patients and the demanded competence (DC) of a sport/recreational activity to develop a readiness score (the AC-DC score). The AC-DC score provides a starting point for exploring the critical elements in the decision-making process surrounding the return-to-sport continuum. [ABSTRACT FROM AUTHOR]

Objective: Posterior condylar offset (PCO) and anterior condylar offset (ACO) exert an influence on the sagittal alignment in total knee arthroplasty (TKA). However, there is no common consensus that the variation range of posterior condylar offset (PCO) is associated with patient‐reported outcome measures (PROMs) and the optimum variation range of PCO. This study aims to investigate the correlation between PCO and the PROMs of primary TKA for osteoarthritis (OA) and find out the optimal variation range of the PCO. Methods: In this study, we performed a radiographic analysis of 106 patients (112 knees) with primary TKA. Patients were divided into two cohorts (A and B) according to the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC). Correlations between the sagittal parameter and WOMAC were investigated using univariate and multivariate analysis. The receiver operating characteristic (ROC) curve was used to establish the cut‐off value for the optimal variation range. We then further investigated how different variation range affects the WOMAC subscale score and forgotten‐joint‐score‐12 (FJS‐12). Results: Univariate analysis revealed a correlation between the variation range of PCO (p < 0.01), ACO (p < 0.01) and PROMs. Multivariate analysis showed that only PCO was associated with PROMs. In the ROC graph, the cut‐off value of the variation range of PCO is 2.85 mm (AUC = 0.66, Youden index = 0.26). The WOMAC functional ability score of the group outside the PCO variation range of 2.85 mm significantly increased compared to the group within the range. Conclusion: In this study, PCO variation was significantly associated with clinical outcomes in TKA and the optimal PCO variation range was within 2.85 mm. Maintaining the PCO variation within 2.85 mm could enhance functional recovery and patient satisfaction. [ABSTRACT FROM AUTHOR]

Background: Distal femoral varus osteotomy (DFVO) is an established surgical procedure for addressing valgus malalignment across various knee conditions. However, the effect of DFVO on stress distribution within the femorotibial joint has not been explored through in vivo studies. Purpose: To (1) explore the distribution pattern of subchondral bone density across the proximal tibia in nonarthritic knees without arthritis and in those of patients with valgus knees, (2) assess changes in the pattern of bone density distribution in patients with valgus knees before and after medial closing-wedge (MCW) DFVO, and (3) determine the correlation between leg alignment and changes in bone density distribution. Study Design: Cohort study; Level of evidence, 3. Methods: The authors retrospectively analyzed clinical and radiographic data from 14 patients (14 knees; mean age, 44 years; 3 men, 11 women) treated with MCW-DFVO for lateral compartment osteoarthritis (OA) due to valgus malalignment, alongside a control group of 18 patients (18 knees; mean age, 21 years; 4 men, 14 women) without OA. The distribution patterns of subchondral bone density distribution on the femorotibial articular surface of the tibia were examined both preoperatively and >1 year postoperatively using computed tomography osteoabsorptiometry. Quantitative analyses were conducted on the locations and percentages of the high-density areas (HDAs) on the articular surface. The mean time between surgery and the postoperative radiograph and computed tomography absorptiometry imaging was 13.6 months (range, 11-19 months). The mean length of clinical follow-up was 28.7 months (range, 14-62 months) after surgery. Results: The mean proportion of HDA in the lateral compartment relative to the total HDA (lateral ratio) was significantly greater in the preoperative OA group (58.8%) compared with the control group (41.1%) (P <.001). After MCW-DFVO, the mean lateral ratio in the OA group notably declined to 45.3% (P <.001). The lateral ratio exhibited a significant correlation with the hip-knee-ankle angle in both the control (r = 0.630; P =.011) and OA (r = 0.537; P =.047) groups. Moreover, the alteration in the lateral ratio after MCW-DFVO showed a significant relationship with changes in the hip-knee-ankle angle (r = 0.742; P =.002) and the mechanical lateral distal femoral angle (r = −0.752; P =.002). Within the lateral compartment, HDAs in the 3 lateral regions of the 4 lateral subregions diminished after MCW-DFVO, whereas in the medial compartment, HDAs in the 3 lateral subregions saw an increase. Conclusion: The mean lateral ratio was significantly greater in the preoperative OA group compared with the control group. MCW-DFVO resulted in a redistribution of HDA from the lateral to the medial compartment of the proximal tibial articular surface. The extent of alignment correction after MCW-DFVO was closely linked to the shifts in HDA distribution, reflecting changes in stress distribution. [ABSTRACT FROM AUTHOR]

Background: Osteochondral allograft transplantation (OCAT) has become a standard-of-care treatment option for patients with large symptomatic articular defects. Recent advances in allograft science and OCAT protocols have been reported to result in consistently robust outcomes after OCAT in the knee. However, only short-term comparisons have been reported, and analyses are lacking for treatment failure risk factors that account for confounding variables. Hypothesis: Midterm functional graft survival rate would exceed 80% for all OCATs combined, with consideration of risk factors for lower survivorship including older patient age, higher body mass index (BMI), tibiofemoral bipolar OCAT, and nonadherence to prescribed postoperative rehabilitation protocols. Study Design: Case series; Level of evidence, 4. Methods: Patients with outcome data available at ≥5 years after primary OCAT using high chondrocyte–viability (HCV) osteochondral allografts were analyzed according to 2 clinically relevant definitions: (1) initial treatment failure, defined by revision or arthroplasty surgery performed for the primary OCAT at any time point during the study period; and (2) functional graft failure, defined by documented conversion to arthroplasty after primary or revision OCAT at any time point during the study period. Analyses were used to assess outcomes for each definition, separately for age group, sex, obesity status, tobacco use, type of OCAT surgery, osteotomy status, concurrent ligament surgery status, and adherence to postoperative protocols. Kaplan-Meier analyses were used to assess differences in survival rates, and Cox proportional hazards models were used to assess risk factors and multivariable relationships with survival. Patient-reported outcome measures for pain, function, mobility, and satisfaction were also analyzed. Results: Analysis included 137 primary knee OCATs performed in 134 patients with a mean follow-up of 66 months (59 female, 75 male; mean age, 37.8 years; mean BMI, 28.5). The midterm (5- to 8-year) functional graft survival rate for patients undergoing primary OCAT in the knee using HCV grafts was 82% for all cases combined, ranging from 69% for tibiofemoral bipolar HCV OCATs to 89% for patellofemoral bipolar, 94% for multisurface unipolar, and 97% for single-surface unipolar. Initial treatment failure rates (revision or arthroplasty after primary OCAT) and OCAT nonsurvival rates (arthroplasty after primary or revision OCAT) were greater for older patient age, concurrent ligament reconstruction, tibiofemoral bipolar OCAT, and nonadherence to the prescribed postoperative rehabilitation protocols. When adjusted for patients' age, BMI, and tobacco use status, different surgery types did not demonstrate an increased risk for failure, while concurrent ligament reconstruction and nonadherence did. Patients who experienced functional graft survival after primary OCAT reported significantly greater improvements in PROMIS Physical Function and Mobility (Patient-Reported Outcomes Measurement Information System), International Knee Documentation Committee questionnaire, and Single Assessment Numeric Evaluation scores such that they were significantly higher at final follow-up as compared with patients who required arthroplasty. Patient-reported improvements in pain, function, and mobility exceeded minimal clinically important differences for ≥5 years after primary OCAT. When asked if they were satisfied with primary OCAT surgery, 76.2% of patients were very satisfied or satisfied with their results, while 8.5% were neutral and 15.4% were unsatisfied or very unsatisfied. Conclusion: With use of HCV osteochondral allografts, midterm (5- to 8-year) functional graft survival rates for patients undergoing primary OCAT in the knee were notably higher than previously reported midterm rates for traditional OCATs. When adjusted for patient characteristics, risk factors for nonsurvival included concurrent ligament reconstruction for knee instability and nonadherence to the prescribed postoperative rehabilitation protocols. Patients who experienced functional graft survival for ≥5 years after primary OCAT reported statistically significant and clinically meaningful improvements in pain, function, and mobility. [ABSTRACT FROM AUTHOR]

Background: The long-term prognosis of jumper's knee and whether structural changes in the patellar tendon persist is unknown. Purpose: To investigate whether limitations in knee function and structural changes persisted beyond the athletic career of young elite volleyball players. Study Design: Cohort study; Level of evidence, 2. Methods: Volleyball players (mean ± SD age, 18 ± 0.8 years) enrolled in 2006-2011 in a prospective cohort study were invited in 2020-2022 to a follow-up study. Participants rated their knee function with the Victorian Institute of Sport Assessment–Patellar Tendon (VISA-P) score (baseline and follow-up) and the International Knee Documentation Committee (IKDC) score (follow-up) and reported if jumper's knee had influenced their decision to retire from sport. Tendon thickness and structural changes were assessed with ultrasound (baseline) and magnetic resonance imaging (MRI) (follow-up) of both patellar tendons. Results: We included 138 of 143 former athletes (97%) 11.4 ± 1.6 years after their baseline examination. At baseline, 37 persons (52 knees) had developed jumper's knee. At follow-up, participants reported lower knee function scores in knees diagnosed with jumper's knee at baseline than healthy knees (VISA-P scores: jumper's knee, 81 [95% CI, 70-92]; healthy, 90 [95% CI, 86-94]; P <.001; IKDC scores: jumper's knee, 82 [95% CI, 75-89]; healthy, 92 [95% CI, 91-95]; P <.001). Jumper's knee problems directly caused 7 of the 37 athletes (19%) with jumper's knee at baseline to retire from competitive volleyball. Of the 138 players included, 97 (70%) completed a bilateral MRI examination (194 knees). At follow-up, 38 of the 54 abnormal tendons (70%) had no structural changes (P <.001 vs baseline) while 22 of the 140 normal tendons (16%) had developed structural changes. Clinical symptoms were not correlated with tendon structure at follow-up (VISA-P scores for normal tendons: 85 [95% CI, 73-87]; abnormal: 89 [95% CI, 85-92]; P =.48). Conclusion: Jumper's knee is not a self-limiting condition; volleyball players who had developed jumper's knee during adolescence reported persistent reductions in knee function 11 years later, leading one-fifth to retire from competitive volleyball. Although approximately 70% of tendons with structural changes at baseline were normal at follow-up, there was no clear relationship between structure and function. [ABSTRACT FROM AUTHOR]

Background: Platelet-rich plasma (PRP) is increasingly used for the injection treatment of knee osteoarthritis (OA). However, the role of leukocytes contained in PRP is controversial, with some preclinical studies suggesting detrimental effects and others emphasizing their contribution in secreting bioactive molecules. Purpose: To compare the safety and effectiveness of leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) for the treatment of knee OA. Hypothesis: That leukocytes could influence results both in terms of adverse events and clinical outcomes. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: This double-blind randomized controlled trial included 132 patients with Kellgren-Lawrence grade 1-3 knee OA who were randomized to a 3-injection cycle of either LR-PRP or LP-PRP. Patients were prospectively assessed at baseline and at 2, 6, and 12 months with subjective evaluations comprising the International Knee Documentation Committee (IKDC) subjective score, the KOOS (Knee injury and Osteoarthritis Outcome Score), the WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), the visual analog scale for pain, the EuroQol–visual analog scale, the EuroQol–5 dimensions, and the Tegner activity scale. Objective evaluations consisted of the IKDC objective score, active/passive range of motion, and circumference of the index and contralateral knees. Patient judgment of the treatment was recorded as well as adverse reactions and failures. Results: An overall improvement in subjective and objective outcomes was documented, with no differences between the 2 groups, except for the improvement in the IKDC subjective score at 2 months, which was greater for the LR-PRP group compared with the LP-PRP group (14.8 ± 14.8 vs 8.6 ± 13.3, respectively; P =.046), as well as for active (P =.021) and passive (P =.040) ROM of the index knee at 6 months, showing statistically significant higher values in the LP-PRP group; and for quadriceps circumference of the index (P =.042) and contralateral (P =.045) knees at 12 months, which were significantly greater in the LR-PRP group. The IKDC subjective score improved from 42.5 ± 17.6 at baseline to 55.6 ± 21.4 at 12 months for the LR-PRP group (P <.0005) and from 45.7 ± 16.4 to 55.3 ± 20.4 for the LP-PRP group (P =.001). No differences in terms of patient treatment judgment were observed at all follow-up time points. No severe adverse events related to the treatment were reported, but some mild adverse events related to the treatment were observed: 16 in the LR-PRP group and 17 in the LP-PRP group. Treatment failed in 5 patients in the LR-PRP group and 2 in the LP-PRP group. Conclusion: This double-blind randomized controlled trial demonstrated that leukocytes did not affect the safety and efficacy of intra-articular PRP injections for the treatment of patients with knee OA. Both LR-PRP and LP-PRP demonstrated comparable clinical outcomes at all follow-up time points, without showing differences in subjective and objective outcomes or in adverse events and treatment failures. Registration: NCT04187183 (ClinicalTrials.gov). [ABSTRACT FROM AUTHOR]

Background: Platelet-rich plasma (PRP) is one of the most frequently used orthobiologic products for the injection treatment of patients affected by knee osteoarthritis (OA). Some preliminary evidence supports the influence of platelet concentration on patients' clinical outcomes. Purpose: To analyze if platelet concentration can influence the safety and clinical efficacy of PRP injections for the treatment of patients with knee OA. Study Design: Cohort study; Level of evidence, 3. Methods: This study consisted of 253 patients with knee OA (142 men, 111 women; mean ± SD age, 54.8 ± 11.4 years; Kellgren-Lawrence grades 1-3) who were treated with 3 intra-articular injections of 5 mL of autologous leukocyte-rich or leukocyte-poor PRP. All patients were prospectively evaluated at baseline and at 2, 6, and 12 months. Patients were clinically assessed thorough the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales and the International Knee Documentation Committee (IKDC) Subjective score. Platelet concentration was correlated with clinical outcome. Further analysis was performed by stratifying patients into 3 groups (homogeneous for OA severity) based on platelet concentration (high, medium, and low). All complications and adverse events were reported, as well as failures. Results: An overall statistically significant improvement in all clinical scores was documented from baseline to each follow-up evaluation. Platelet concentration positively correlated with clinical outcome. KOOS Pain improved more with higher platelet concentration at 2 months (P =.036; rho = 0.132), 6 months (P =.009; rho = 0.165), and 12 months (P =.014; rho = 0.155). The same trend was shown by the other KOOS subscales and by the IKDC Subjective score, as well as by the comparison of the groups of high-, medium-, and low-platelet PRP. The highest failure rate (15.0%) was found in the low-platelet group as compared with the medium-platelet group (3.3%) and the high-platelet group (3.3%). No differences were observed among the 3 groups in terms of adverse events. Conclusion: This study demonstrated that platelet concentration influences the clinical outcome of PRP injections in knee OA treatment. PRP with a higher platelet concentration provides a lower failure rate and higher clinical improvement as compared with PRP with a lower platelet concentration, with overall better results up to 12 months of follow-up in patients with knee OA. [ABSTRACT FROM AUTHOR]

Background: Arthroscopic meniscectomy is one of the most performed surgical procedures in orthopaedics. Different approaches have been proposed to improve patient recovery but with unsatisfactory results. Platelet-rich plasma (PRP) augmentation has been proposed as a strategy to improve the recovery after meniscectomy. Purpose: To investigate the clinical benefits of an intra-articular PRP injection after meniscectomy, in terms of faster and better patient recovery. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Ninety patients were randomized into a treatment group, with arthroscopic partial meniscectomy immediately followed by a 5-mL injection of autologous conditioned plasma, and a control group with partial meniscectomy alone. Patients were evaluated at baseline and at 15, 30, 60, and 180 days of follow-up with the visual analog scale (VAS) score for pain (primary outcome), as well as with International Knee Documentation Committee subjective score, Knee injury and Osteoarthritis Outcome Score subscales, Tegner score, and EuroQol-Visual Analog Scale score. Objective evaluation was performed analyzing knee range of motion and circumference and the International Knee Documentation Committee objective score. Complications, patient judgment, and satisfaction were documented as well. Results: No major complications and an overall significant improvement in the clinical scores were observed in both groups. Overall, the comparative analysis did not demonstrate significant between-group differences in absolute values or improvements of both subjective and objective scores, as well as activity level. The improvement in terms of VAS pain score for the treatment group was significant already at 15 days (from 4.3 ± 2.5 to 2.5 ± 2.5; P =.014), while in the control group it became significant at 30 days (from 3.7 ± 2.3 to 2.0 ± 2.4; P =.004). No significant differences were observed between the 2 groups in terms of judgment of treatment results and satisfaction. Conclusion: A single postoperative injection of PRP was not able to significantly improve patient recovery after arthroscopic partial meniscectomy. PRP augmentation did not provide overall benefits at a short-term follow-up (6 months) in terms of pain relief, function, objective parameters, and return-to-sport activities. Registration: NCT02872753 (ClinicalTrials.gov identifier). [ABSTRACT FROM AUTHOR]

In this paper, a novel method is proposed for the determination of the optimal subject-specific placement of knee implants based on predictive dynamic simulations of human movement following total knee arthroplasty (TKA). Two knee implant models are introduced. The first model is a comprehensive 12-degree-of-freedom (DoF) representation that incorporates volumetric contact between femoral and tibial implants, as well as patellofemoral contact. The second model employs a single-degree-of-freedom equivalent kinematic (SEK) approach for the knee joint. A cosimulation framework is proposed to leverage both knee models in our simulations. The knee model is calibrated and validated using patient-specific data, including knee kinematics and ground reaction forces. Additionally, quantitative indices are introduced to evaluate the optimality of implant positioning based on three criteria: balancing medial and lateral load distributions, ligament balancing, and varus/valgus alignment. The knee implant placement is optimized by minimizing the deviation of the indices from their user-defined desired values during predicted sit-to-stand motion. The method presented in this paper has the potential to enhance the results of knee arthroplasty and serve as a valuable instrument for surgeons when planning and performing this procedure. [ABSTRACT FROM AUTHOR]

Goals of knee replacement surgery are to restore function and maximize implant longevity. To determine how well these goals are satisfied, tibial femoral kinematics and tibial contact kinematics are of interest. Tibiofemoral kinematics, which characterize function, is movement between the tibia and femur whereas tibial contact kinematics, which is relevant to implant wear, is movement of the location of contact by the femoral implant on the tibial articular surface. The purposes of this review article are to describe and critique relevant methods to guide correct implementation. For tibiofemoral kinematics, methods are categorized as those which determine (1) relative planar motions and (2) relative three-dimensional (3D) motions. Planar motions are determined by first finding anterior–posterior (A–P) positions of each femoral condyle relative to the tibia and tracking these positions during flexion. Of the lowest point (LP) and flexion facet center (FFC) methods, which are common, the lowest point method is preferred and the reasoning is explained. 3D motions are determined using the joint coordinate system (JCS) of Grood and Suntay. Previous applications of this JCS have resulted in motions which are largely in error due to “kinematic crosstalk.” Requirements for minimizing kinematic crosstalk are outlined followed by an example, which demonstrates the method for identifying a JCS that minimizes kinematic crosstalk. Although kinematic crosstalk can be minimized, the need for a JCS to determine 3D motions is questionable based on anatomical constraints, which limit varus–valgus rotation and compression–distraction translation. Methods for analyzing tibial contact kinematics are summarized and validation of methods discussed. [ABSTRACT FROM AUTHOR]

Purpose: To analyse anterior cruciate ligament (ACL) rupture (ACLR) injury mechanisms in competitive judo using systematic video analysis, focusing on contact situations and biomechanics. Methods: Seventeen videos of judo competitions wherein athletes developed ACLRs were included and retrospectively evaluated by five analysts. In all videos, the moment of initial contact and the index frame were defined. The judo techniques leading to the injury; the occurrence of direct contact, indirect contact or noncontact mechanisms; the time interval between the initial contact and index frame; the positions of the hip, knee and foot in relation to the initial contact and index frame; and the balance status during the initial contact and index frame were recorded. Results: Eleven (65%) of ACLRs in judo involved direct contact. The mean time interval between initial contact and index frame was 15 ± 22 ms. Thirteen (77%) athletes were not balanced at initial contact. In the index frame, the hip was abducted in all cases and in combination with internal rotation in 12 (71%) cases. From initial contact to index frame, hip flexion increased in all cases; at index frame, the knee joint was internally rotated relative to the trunk in 12 (71%) cases, and the knee flexion angles increased from the initial contact. In the index frame, the foot was externally rotated relative to the knee in 12 (71%) cases, and severe valgus development of the knee with valgus collapse was observed in 14 (82%) cases. Conclusions: A direct attack on the knee was the most common injury mechanism observed. Valgus distortion appears to be the most important component of the mechanism of injury. With this knowledge, 'modified defence reactions' for specific judo techniques can be developed to reduce the injury risk. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]