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ABSTRACT Objective Methods Results Conclusion Pseudo‐patella baja (PPB) was one of the complications after total knee arthroplasty (TKA). This complication may be closely related to the occurrence of knee joint movement limitation and pain after TKA. This study aimed to investigate whether PPB affects clinical outcomes after TKA and to study the biomechanical effects of PPB after TKA.This study was a retrospective case series of 462 eligible patients (563 knees). Clinical evaluation was performed using the visual analogue scale (VAS), the Hospital for Special Surgery (HSS), the Western Ontario McMaster University Osteoarthritis Index (WOMAC) scoring systems, the 5‐Level EuroQol Generic Health Index (EQ‐5D‐5L), the Forgotten Joint Score‐12 (FJS‐12), and patient satisfaction. CT and MRI scans of two healthy left knees and TKA prostheses were taken; 3D models including PPB, True patella baja (TPB), normal patella, and patella alta (PA) were created in FEA and applied load along the direction of quadriceps femoris. T‐test, Mann–Whitney U‐test, chi‐squared (χ2) test, and analysis of variance (ANOVA) were performed using GraphPad Prism (Version 8, GraphPad Software, USA). A statistically significant difference was considered at p < 0.05 with bilateral α.The VAS, HSS, WOMAC, EQ‐5D‐5L, FJS‐12, and patient satisfaction scores in the PPB and TPB groups were significantly worse than those in the patella normal (PN) group (p < 0.05). The PPB group found a positive correlation between Blackburne–Peel index (BPI) and FJS‐12 score. PPB showed lower contact stress of patellofemoral joint compared to TPB when knee flexion was less than < 90° (p < 0.01), but no significant difference when flexion was more than > 90° (p > 0.05) in the finite element model with Patella baja (PB). The contact area of the patellofemoral joint tended to increase with the deepening of knee flexion, and decreased after reaching the peak value. The contact area of the patellofemoral joint tended to decrease with the increase in patellar height. There was no significant difference in the contact area of the patellofemoral joint among different patellar heights and different degrees of knee flexion (p > 0.05).PPB after TKA may increase patellofemoral joint stress and postoperative complications like anterior knee pain. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To explain the relationship between cartilage erosion and medial patellar luxation (MPL) and to identify risk factors in dogs. METHODS: A retrospective review was conducted on 90 dogs (103 stifles) surgically treated for MPL between January 2006 and March 2024. Data collected included signalment, side of operated stifle, patellar luxation grade, symptom duration, and lameness score. Cartilage erosion was evaluated for extent and location on the patella and femoral trochlea. Statistical analyses were conducted to identify risk factors. RESULTS: The prevalence of cartilage erosion of the patella and femoral trochlea was 47.6% (49/103) and 54.4% (56/103), respectively, increasing with a higher grade of patellar luxation. Lesions were most prevalent in the distolateral patella and proximomedial trochlea, with generalized lesions more prevalent in grade IV. The extent of both lesions was significantly associated with age, patellar luxation grade, and symptom duration, while body weight significantly correlated only with the cartilage erosion of the patella. No significant correlation was observed with sex, side of operated stifle, or lameness score. CONCLUSIONS: Many patients with MPL exhibited cartilage erosion in the patellofemoral joint, likely due to biomechanical mechanisms. Surgery can be indicated for patients with MPL, as it may prevent cartilage erosion while improving patellofemoral alignment and gait. When selecting surgical candidates, it is important to consider risk factors, such as patellar luxation grade, body weight, age, and symptom duration. CLINICAL RELEVANCE: Early surgical treatment is recommended, especially for dogs with higher body weight and higher grade of MPL, to prevent cartilage erosion and secondary osteoarthritis. [ABSTRACT FROM AUTHOR]

In designing femoral components, which restore native (i.e., healthy) knee kinematics, the flexion–extension (F-E) axis of the tibiofemoral joint should match that of the native knee. Because the F–E axis is governed by the curvature of the femoral condyles in the sagittal plane, the primary objective was to determine the variation in radii of curvature. Eleven high accuracy three-dimensional (3D) femur models were generated from ultrahigh resolution CT scans. The sagittal profile of each condyle was created. The radii of curvature at 15 deg increments of arc length were determined based on segment circles best-fit to ±15 deg of arc at each increment. Results were standardized to the radius of the best-fit overall circle to 15 deg–105 deg for the femoral condyle having a radius closest to the mean radius. Medial and lateral femoral condyles exhibited multiradius of curvature sagittal profiles where the radius decreased at 30 deg flexion by 10 mm and at 15 deg flexion by 8 mm, respectively. On either side of the decrease, radii of segment circles were relatively constant. Beyond the transition angles where the radii decreased, the anterior-posterior (A-P) positions of the centers of curvature varied 4.8 mm and 2.3 mm for the medial and lateral condyles, respectively. A two-radius of curvature profile approximates the radii of curvature of both native femoral condyles, but the transition angles differ with the transition angle of the medial femoral condyle occurring about 15 deg later in flexion. Owing to variation in A-P positions of centers of curvature, the F-E axis is not strictly fixed in the femur. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To identify baseline characteristics that modified the effect of a 12-week quadriceps-focused (QE) vs hip muscle-focused (HE) exercise program on symptoms and physical function, through changes at baseline in the Anterior Knee Pain Scale (AKPS) in patients with PFP. t DESIGN: A secondary analysis of a 26-week randomized trial involving 200 participants with patellofemoral pain. t METHODS: Participants were randomly assigned to a QE or HE program with a duration of 12 weeks. The primary outcome was change from baseline in the AKPS at week 12 and week 26. Subgroups were predefined and based on baseline information: presence of low back, hip, ankle, or bilateral knee pain; body mass index (BMI); sex; age; education; occupation; hypermobility; quadriceps strength; dynamic knee alignment; midfoot mobility; exercise self-efficacy; pain self-efficacy; pain catastrophizing; neuropathic pain; pain duration; and pain severity. RESULTS: Participants with pain catastroph-izing seemed to benefit from HE with a subgroup difference in treatment effect of 8.3 AKPS points at week 12 (95%CI 1.6 to 15.0). At week 26, participants with a baseline BMI above 25 seemed to benefit from HE with a subgroup difference in treatment effect of 11.1 (95%CI 4.8 to 17.4), and participants with severe knee pain at baseline seemed to benefit from QE with a subgroup difference of -9.1 (95% CI: -15.7, -2.6). t CONCLUSION: Hip-focused exercises may provide more benefits than quadriceps-focused exercises among patients with patellofemoral pain and pain catastrophizing or overweight. Quadriceps-focused exercises may provide more benefits than hip-focused exercises for patients with severe knee pain. [ABSTRACT FROM AUTHOR]

Patellofemoral osteoarthritis (OA) may be more common in females than males. Reasons for this are not fully understood, but sex differences in patellar morphology may help explain this phenomenon. We quantified differences in patellar morphology between males and females in healthy and patellofemoral OA populations. A total of 97 (50F, 47M) healthy and 67 (40F, 27M) OA knees were scanned via computed tomography. OA individuals were on a waitlist for total knee replacement. Patella 3D models were segmented and 2D measurements were recorded: patellar width and height, lateral and medial facet width, and surface area. Medial and lateral facet surface topography was mapped using 81 points to describe 3D articular surface shape. Sex and group differences were assessed using Procrustes analysis of variance (ANOVA). Data were ordinated using Principal Component Analysis. Differences in patellar 2D measurements between healthy and OA individuals were smaller than were differences between males and females from healthy and OA groups. Sex and healthy/OA differences were most pronounced for medial facet shape, which featured a posteriorly-curving facet and taller, narrower facet shape in males compared to females. Lateral facet shape variance was higher in OA cohorts compared to healthy groups. Medial and lateral facet shapes showed different patterning of variation by sex and healthy/OA status. Lateral facet shape may be of interest in future models of OA risk in the patellofemoral joint, here showing increased magnitudes of variance associated with increased severity of disease (patellofemoral Kellgren and Lawrence score). [ABSTRACT FROM AUTHOR]

Hip internal rotation has been reported to affect patellofemoral joint mechanics and contribute to patellofemoral pain (PFP). The SERF (S tability through E xternal R otation of the F emur) strap was designed to provide hip stability by pulling the thigh into external rotation during weight-bearing activities. What are the effects of the SERF strap on hip internal rotation and pain response in females with PFP who present with hip internal rotation during weight-bearing activities? Nineteen females between the ages of 18 and 45 with a diagnosis of PFP participated. Lower extremity kinematics were obtained during three tasks (drop-jump, unilateral step-down, over-ground running) under strap and no-strap conditions. A 10-cm visual analog scale (VAS) was used to assess pain response during each task and strap condition. Participants who exhibited at least 5 degrees of hip internal rotation during at least one of the 3 tasks were included in the final analysis. Peak hip internal rotation and mean VAS score were compared separately between strap conditions across tasks using 2 ×3 (strap condition x task) repeated-measures ANOVAs. Eighteen of the 19 females with PFP met the criteria for the presence of hip internal rotation. There was a significant reduction in peak hip internal rotation across tasks when wearing the SERF strap (mean ± sd = 7.4 ± 2.3, p<0.001). Additionally, the change in mean VAS pain score was significantly lower across tasks when wearing the SERF strap (1.0 ± 1.0, p=0.03). The SERF strap was effective in reducing hip internal rotation and PFP during dynamic weight-bearing activities in symptomatic females. The SERF strap may be a useful treatment adjunct for persons with PFP who present with poor transverse plane control of the hip. • SERF strap reduced hip internal rotation in females with patellofemoral pain. • SERF strap produced small absolute but large percent decreases in knee pain. • The reduced hip internal rotation suggests meaningful changes in joint loading. • Reduced hip internal rotation and knee pain are not necessarily causally related. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Methods Results Conclusions The risk factors for the degeneration of the patellofemoral joint (PFJ) have not been adequately and thoroughly studied. This study aimed to analyze the population distribution characteristics of patients with patellofemoral osteoarthritis (PFOA) and assess the correlation between PFOA and radiological parameters, including patella morphology, PFJ congruity, and patellar alignment. Moreover, the risk factors across various demographic groups were further analyzed.A retrospective analysis was conducted to examine the population distribution characteristics of PFOA patients from September 2020 to September 2023. Radiological parameters of the PFJ were measured from the anteroposterior and lateral views of knee joint as well as axial view of patella using X‐ray imaging and the PACS imaging system at the First Affiliated Hospital of Kunming Medical University. These parameters included patella morphology (patella type, width, thickness, and Wiberg index), PFJ congruity (patella height, Wiberg angle, sulcus angle, and lateral patella angle), and patellofemoral alignment (patella tilt angle, displacement, and lateral patellofemoral angle). PFOA severity was classified according to the Iwano PFJ radiological classification, and its correlation with the aforementioned parameters was examined. Additionally, risk factors for PFOA across different populations were further evaluated.The study included 1080 patients according to the inclusion and exclusion criteria. Age, female gender, overweight or obesity, and manual workers were significantly associated with PFOA. Moreover, type III patella (OR = 3.03, p < 0.05), greater patella width (OR = 1.12, p = 0.01), sulcus angle (OR = 1.04, p < 0.01), patella tilt angle (OR = 1.13, p < 0.01), and patella displacement (OR = 1.22, p < 0.01) as well as smaller patella thickness (OR = 0.87, p < 0.01), Insall–Salvati index (OR = 0.24, p = 0.04), and lateral patellofemoral angle (OR = 0.93, p = 0.02) were identified as risk factors for PFOA. Furthermore, greater patella thickness (OR = 1.17, p < 0.05) and smaller patella displacement (OR = 0.79, p < 0.01) correlated with higher Kujala patellofemoral scores. Discrepancies in risk factors across different populations were also observed.Older age, female gender, obesity, manual workers, and specific aberrations in patellofemoral parameters are predictive factors for PFOA. Additionally, greater patella thickness and smaller patella displacement were associated with increased severity of clinical symptoms. Thus, more attention should be paid to the discrepancies that exist in different populations. [ABSTRACT FROM AUTHOR]

Background: Knee osteoarthritis (KOA) was characterized by pain and limited joint function, which seriously affected the quality of life of patients. The vast majority of KOA was closely related to degeneration of the patellofemoral joint and abnormal patellar movement trajectory. Tissue-bone homeostasis manipulation (TBHM) could correct abnormal patellar movement trajectory on the basis of loosening soft tissue. However, there was little strong evidence to verify its efficacy on the patients with KOA. The study objective was to explore the efficacy of the TBHM on gait and knee function in the patients with KOA. Methods: Sixty KOA patients were randomly assigned to either the joint mobilization (n = 30) or TBHM (n = 30) group. The joint mobilization group received joint mobilization, while the TBHM group received TBHM. For two groups, the patients participated in 30 min rehabilitation sessions thrice per week for 12 weeks. The primary outcome was biomechanical gait outcomes during walking, including step length, step velocity, double support, knee range of motion (ROM), and knee adduction moment (KAM). The secondary outcomes were the Western Ontario and McMaster Index (WOMAC) and 36-Item short- form health survey (SF-36), which reflected improvements in knee function and quality of life, respectively. At baseline and 12 weeks, evaluations were conducted and compared between groups. Results: After a 12-week intervention, significant group differences were observed in KAM (p = 0.018), WOMAC-Pain (p = 0.043) and WOMAC-Stiffness (p = 0.026). A noteworthy finding was the presence of a significant interaction effect between group and time specifically observed in step velocity during gait (p = 0.046), WOMAC-Function (p = 0.013) and SF-36 (p = 0.027). Further analysis revealed a significant difference in step velocity (p = 0.034), WOMAC-Function (p = 0.025) and SF-36 (p = 0.042) during post-assessment between the two groups. Moreover, a significant time effect was observed across all outcomes of the two groups (p < 0.05). Conclusion: The TBHM intervention has better improved the gait, knee function, and quality of life in the patients with KOA. Trial registration: ITMCTR, ITMCTR2200005507. Registered 06/01/2022, http://itmctr.ccebtcm.org.cn/zh-CN/Home/ProjectView?pid=09cdadad-0aef-41ee-81bd-a8dceb63f7f5. [ABSTRACT FROM AUTHOR]

Background: Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain encountered in the outpatient setting. The purpose of this study was to compare the lower limb biomechanical differences during anticipated and unanticipated side-cutting in athletes with PFPS. Methods: Fifteen male basketball players diagnosed with PFPS were enrolled in the study. Participants executed both anticipated and unanticipated 45-degree side-cutting tasks. Motion analysis systems, force plates, and electromyography (EMG) were used to assess the lower limb joint angles, joint moments, joint stiffness, and patellofemoral joint contact forces. Analyzed biomechanical data were used to compare the differences between the two circumstances. Results: Unanticipated side-cutting resulted in significantly increased ankle plantarflexion and dorsiflexion angles, knee abduction and internal rotation angles, and hip abduction angles, as well as heightened knee adduction moments. Additionally, patellofemoral joint contact forces and stress increased, while contact area decreased during unanticipated tasks. Conclusions: Unanticipated movement raises the demands for joint stability and neuromuscular control, increasing injury risks in athletes with PFPS. These findings have practical implications for developing targeted rehabilitation programs and injury prevention strategies. [ABSTRACT FROM AUTHOR]

Purpose: To examine the frequency of patellofemoral joint (PFJ) osteoarthritis (OA) and its symptoms in the long-term course of open-wedge high tibial osteotomy (OWHTO). Methods: We analyzed 113 joints of 91 patients. OA and osteonecrosis (ON) developed in 91 and 22 joints, after an average postoperative period of 127.5 ± 19.5 months. For X-ray evaluation, the standing femorotibial angle (FTA), % mechanical axis (%MA), Caton–Deschamps index (CDI), patellar tilt angle (TA), lateral patellar shift (LPS), and PFJ space width (medial [MJS] and lateral [LJS]) were analyzed. PFJ-associated symptoms were evaluated using the hospital for special surgery patellar score (HSS-PS) and knee injury and osteoarthritis outcome score patellofemoral subscale (KOOS-PF). Statistical analysis was performed with paired and unpaired t tests, and a risk rate of less than 1% was significantly judged. Results: Preoperative FTA and CDI decreased from 180.8° to 170.0° and 0.88 to 0.70 at the final follow-up. Preoperative %MA lateralized from 20.8 to 66.0 at the final follow-up. TA and LPS values decreased significantly compared with before surgery until plate removal. The MJS and LJS significantly decreased, and OA with a joint space < 3 mm occurred in 14 cases. However, HSS-PS and KOOS-PF scores were not significantly different between the groups with and without OA. Conclusion: PFJ OA occurred in 12.4% cases in the long-term postoperative course of OWHTO; however, no symptomatic difference was found in the group with or without OA. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate a non‐resorbable implant for the focal repair of chondral defects in eight adult horses with 12‐month follow‐up. The bi‐layered construct composed of a polycarbonate‐urethane‐urea biomaterial which was printed in 3D fashion onto a bone anchor was implanted into surgically created osteochondral defects into the femoropatellar joints of eight horses. The analysis of post‐mortem outcomes were compared to defects treated with microfracture in the same animal on the contralateral femoropatellar jointfemoropatellar joint. The overall macroscopic scoring after 12 months yielded higher scores in the OCI‐treated stifles compared to MF treatment (p = 0.09) with better quality and filling of the defect. Histology revealed good anchorage of repair tissue growing into the 3D structure of the implant and histopathology scoring for adjacent native cartilage showed no difference between groups. MRI and micro‐CT showed overall less sclerotic reactions in the surrounding bone in the implant group and no foreign body reaction was detected. Biomechanical analysis of the repair tissue revealed a significantly higher peak modulus (p < 0.05) in the implant group (0.74 ± 0.45) compared to the microfracture control group (0.15 ± 0.11). Dynamic loading yielded higher values for the repair tissue overgrowing the implant group (0.23 ± 0.17) compared to the microfracture control (0.06 ± 0.06) (p < 0.05). The bi‐layered osteochondral implant provided a safe implant for focal repair of full‐thickness osteochondral defects, as no adverse reaction was seen within the joints and the level of degeneration of adjacent cartilage to the repair site was not different compared to that seen in defects treated with microfracture after 12 months. [ABSTRACT FROM AUTHOR]

Introduction: Osteoarthritis of the knee is a debilitating disease. In most cases, only the medial compartments are affected. High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are the two main procedures commonly used in the surgical treatment of unicompartmental knee osteoarthritis patients not responding to conservative treatment. The aim of our study was to compare UKA and biplanar medial open-wedge HTO in terms of patellofemoral changes and functional score in patients under 60 years of age with medial compartment arthrosis. Materials and methods: A retrospective study. A total of 79 patients (37 HTO, 42 UKA) who received one of the two treatments in a single center were examined preoperatively and at a single postoperative follow-up. Posterior tibial slope, lateral patellofemoral angle (LPFA), Q-angle, patellar height, Cincinnati Rating System and Knee Injury and Osteoarthritis Outcome Score (KOOS) functional scores were evaluated in all patients preoperatively and at the 6-month follow-up examination. Results: Insall-Salvati ratio remained stable in the HTO group, while there was a minor decrease in the UKA group and the changes between the groups were not statistically significant. Caton-Deschamps ratio increased in the UKA group and decreased in the HTO group, and this change was statistically significant (p < 0.001). LPFA did not change in the UKA group in the postoperative period, while it increased in the HTO group (p < 0.001). Changes in Q angle and Cincinnati Rating System scores were statistically similar between the UKA and HTO groups (p = 0.827 and p = 0.340). Conclusions: In our study, biplanar medial open-wedge HTO and UKA performed with appropriate surgical technique had no negative effect on patellofemoral joint. In patients under 60 years of age with medial compartment osteoarthritis of the knee, both surgical treatments can be performed with appropriate patient selection. [ABSTRACT FROM AUTHOR]

This study examined the effect of age and surface on patellofemoral joint (PFJ) stress magnitude and waveform during stair ascent and descent tasks. A total of 12 young and 12 older adults had knee biomechanics quantified while they ascended and descended stairs on normal, slick, and uneven surfaces. The peak of stance (0–100%) PFJ stress and associated components were submitted to a two-way repeated measures ANOVA, while the PFJ stress waveform was submitted to statistical parametric mapping two-way ANOVA. During stair ascent, older adults exhibited greater PFJ stress waveforms, from 55 to 59% and 74 to 84% of stance (p < 0.001) as well as greater PFJ stress–time integral across stance (p = 0.003), and later peak PFJ stress, than young adults (p = 0.002). When ascending on the uneven surface, participants exhibited smaller PFJ stress from 9 to 24% of stance compared to the normal surface, but greater PFJ stress from 75 to 88% and from 63 to 68% of stance (p < 0.001) as well as greater PFJ stress–time integrals compared to normal and slick surfaces (p < 0.032). During stair descent, older adults exhibited a smaller PFJ contact area range (p = 0.034) and peak knee flexion angle (p = 0.022) than young adults. When descending on the slick surface, participants exhibited smaller PFJ stress from 5 to 18% of stance, but greater stress, from 92 to 98% of stance (both: p < 0.001), compared to the normal surface. Negotiating slick and uneven stairs may produce knee biomechanics that increase PFJ stress, and the larger, later PFJ stress exhibited by older adults may further increase their risk of PFJ pain. [ABSTRACT FROM AUTHOR]

Femoral deformities are highly prevalent in children with cerebral palsy (CP) and can have a severe impact on patients' gait abilities. While the mechanical stress regime within the distal femoral growth plate remains underexplored, understanding it is crucial given bone's adaptive response to mechanical stimuli. We quantified stresses at the distal femoral growth plate to deepen our understanding of the relationship between healthy and pathological gait patterns, internal loading, and femoral growth patterns. This study included three-dimensional motion capture data and magnetic resonance images of 13 typically developing children and twelve participants with cerebral palsy. Employing a multi-scale mechanobiological approach, integrating musculoskeletal simulations and subject-specific finite element analysis, we investigated the orientation of the distal femoral growth plate and the stresses within it. Limbs of participants with CP were grouped depending on their knee flexion kinematics during stance phase as this potentially changes the stresses induced by knee and patellofemoral joint contact forces. Despite similar growth plate orientation across groups, significant differences were observed in the shape and distribution of growth values. Higher growth rates were noted in the anterior compartment in CP limbs with high knee flexion while CP limbs with normal knee flexion showed high similarity to the group of healthy participants. Results indicate that the knee flexion angle during the stance phase is of high relevance for typical bone growth at the distal femur. The evaluated growth rates reveal plausible results, as long-term promoted growth in the anterior compartment leads to anterior bending of the femur which was confirmed for the group with high knee flexion through analyses of the femoral geometry. The framework for these multi-scale simulations has been made accessible on GitHub, empowering peers to conduct similar mechanobiological studies. Advancing our understanding of femoral bone development could ultimately support clinical decision-making. • Distal femoral growth plate stresses quantified with subject-specific simulations. • Large dataset of 50 femurs – 26 healthy, 24 femurs of participants with cerebral palsy. • Knee flexion angle is of high relevance for typical bone growth at the distal femur. • Workflow reveals plausible growth results supported by geometrical analysis. • Multi-scale workflow based on free software published on GitHub. [ABSTRACT FROM AUTHOR]

Objectives: To develop and validate a deep learning–based approach to automatically measure the patellofemoral instability (PFI) indices related to patellar height and trochlear dysplasia in knee magnetic resonance imaging (MRI) scans. Methods: A total of 763 knee MRI slices from 95 patients were included in the study, and 3393 anatomical landmarks were annotated for measuring sulcus angle (SA), trochlear facet asymmetry (TFA), trochlear groove depth (TGD) and lateral trochlear inclination (LTI) to assess trochlear dysplasia, and Insall-Salvati index (ISI), modified Insall-Salvati index (MISI), Caton Deschamps index (CDI) and patellotrochlear index (PTI) to assess patellar height. A U-Net based network was implemented to predict the landmarks' locations. The successful detection rate (SDR) and the mean absolute error (MAE) evaluation metrics were used to evaluate the performance of the network. The intraclass correlation coefficient (ICC) was also used to evaluate the reliability of the proposed framework to measure the mentioned PFI indices. Results: The developed models achieved good accuracy in predicting the landmarks' locations, with a maximum value for the MAE of 1.38 ± 0.76 mm. The results show that LTI, TGD, ISI, CDI and PTI can be measured with excellent reliability (ICC > 0.9), and SA, TFA and MISI can be measured with good reliability (ICC > 0.75), with the proposed framework. Conclusions: This study proposes a reliable approach with promising applicability for automatic patellar height and trochlear dysplasia assessment, assisting the radiologists in their clinical practice. Clinical relevance statement: The objective knee landmarks detection on MRI images provided by artificial intelligence may improve the reproducibility and reliability of the imaging evaluation of trochlear anatomy and patellar height, assisting radiologists in their clinical practice in the patellofemoral instability assessment. Key Points: • Imaging evaluation of patellofemoral instability is subjective and vulnerable to substantial intra and interobserver variability. • Patellar height and trochlear dysplasia are reliably assessed in MRI by means of artificial intelligence (AI). • The developed AI framework provides an objective evaluation of patellar height and trochlear dysplasia enhancing the clinical practice of the radiologists. [ABSTRACT FROM AUTHOR]

ObjectiveTo determine the longitudinal changes of patellofemoral joint (PFJ) contact pressure following anterior cruciate ligament reconstruction (ACLR). To identify the associations between PFJ contact pressure and cartilage health.DesignForty-nine subjects with hamstring autograft ACLR (27 males; age 28.8 [standard deviation, 8.3] years) and 19 controls (12 males; 30.7 [4.6] years) participated. A sagittal plane musculoskeletal model was used to estimate PFJ contact pressure. A combined T1ρ/T2 magnetic resonance sequence was obtained. Assessments were performed preoperatively, at 6 months, 1, 2, and 3 years postoperatively in ACLR subjects and once for controls. Repeated Analysis of Variance (ANOVA) was used to compare peak PFJ contact pressure between ACLR and contralateral knees, and t-tests to compare with control knees. Statistical parametric mapping was used to evaluate the associations between PFJ contact pressure and cartilage relaxation concurrently and longitudinally.ResultsNo changes in peak PFJ contact pressure were found within ACLR knees over 3 years (preoperative to 3 years, 0.36 [CI, -0.08, 0.81] MPa), but decreased over time in the contralateral knees (0.75 [0.32, 1.18] MPa). When compared to the controls, ACLR knees exhibited lower PFJ contact pressure at all time points (at baseline, -0.64 [-1.25, -0.03] MPa). Within ACLR knees, lower PFJ contact pressure at 6 months was associated with elevated T2 times (r = -0.47 to -0.49, p = 0.021-0.025).ConclusionsUnderloading of the PFJ following ACLR persists for up to 3 years and has concurrent and future consequences in cartilage health. The non-surgical knees exhibited normal contact pressure initially but decreased over time achieving limb symmetry.

Changes in lower limb alignment after open‐wedge high tibial osteotomy (owHTO) influence joint kinematics. The aim of this study was to investigate the morphological and kinematic changes of the knee joint, in particular the patellofemoral joint, using a multibody simulation model. OwHTO with an open tibial wedge of 6–12 mm (1 mm intervals) was virtually performed on each of 13 three‐dimensional (3D) computer‐aided design models (CAD models) derived from computer tomography scans of full‐leg cadaver specimens. For each owHTO, an individual biomechanical simulation model was built and knee flexion from 5° to 100° was simulated using a multibody simulation model of the native knee. Morphologic and alignment parameters as well as tibiofemoral and patellofemoral kinematic parameters were evaluated. Almost linear changes in tibial tuberosity trochlea groove (TT‐TG) (0.42 mm/1 mm wedge height) were observed which led to pathological values (TT‐TG > 20 mm) in 3 out of 13 knees. Furthermore, a 6 mm increase in osteotomy wedge height increased lateral patellofemoral rotation by 0.8° (range: 0.39° to 1.11°) and led to a lateral patellar translation of 0.8 mm (range: 0.37–3.11 mm) on average. Additionally, valgisation led to a medial translation of the tibia and a decrease in the degree of tibial internal rotation during knee flexion of approximately 0.3°/1 mm increase in osteotomy wedge height. The increase in TT‐TG and the biomechanical effects observed influence patellofemoral tracking, which may increase retropatellar pressure and are potential risk factors for the development of anterior knee pain. [ABSTRACT FROM AUTHOR]

Abstract Objective To analyze the influencing factors for patellofemoral joint (PFJ) overstuffing following total knee arthroplasty (TKA) without patella resurfacing, and explore the effect of PFJ overstuffing on clinical efficacy. Methods A retrospective analysis was conducted on 168 patients with end-stage knee osteoarthritis who underwent TKA without patella resurfacing at our hospital between Match 2019 and September 2021. The clinical data of these patients were retrospectively analyzed. In this study, PFJ overstuffing was defined as a postoperative PFJ distance greater than 1 mm compared to the preoperative measurement. The occurrence of postoperative PFJ overstuffing was counted. The patients were divided into the overstuffing group (n = 109) and the non-overstuffing group (n = 59) to count the patellar thickness and thickness of femoral anterior condyle in all patients before and after surgery, and analyze the influencing factors for postoperative PFJ overstuffing in such patients. Patients were followed up for 2 years to compare the recovery time of postoperative pain, score of visual analogue scale (VAS) and flexion activity between the two groups. Results There was no significant difference in patellar thickness between preoperative and postoperative measurements of the patients (P > 0.05). However, the thickness of the femoral anterior condyle and the PFJ distance after surgery increased significantly compared with those before surgery (P 0.05). Spearman rank correlation analysis indicated females tend to have a lower preoperative thickness of the femoral anterior condyle (r=-0.424, P

Purpose Methods Results Conclusions Level of Evidence Trochlear dysplasia is a major risk factor for recurrent patellar instability, reduced quality of life and osteoarthritis of the patellofemoral joint. Patellar instability in patients with trochlear dysplasia can be treated by trochleoplasty, usually in combination with medial patellofemoral ligament reconstruction (MPFL‐R). An á la carte treatment algorithm, which also addresses patella alta, lateralisation of the tibial tuberosity and valgus or torsional malalignment when present has been standard in one clinic for treatment of patellar instability patients since 2009, based on the hypothesis that it results in optimal subjective and clinical outcome, normalisation of the lateral trochlea inclination (LTI) angle and a low rate of patellar redislocation.This prospective study reports the 5‐year results for consecutive patients with high‐grade trochlea dysplasia operated according to the algorithm 2010–2017, evaluated preoperatively and 1, 2 and 5 years postoperatively. Clinical information on previous surgery and postoperative patellar stability, range‐of‐motion (ROM) and subsequent surgery were registered. Subjective outcome was evaluated by four patient‐reported outcome measures (PROMs): Kujala, Lysholm, International Knee Documentation Committee and Knee injury and Osteoarthritis Outcome Score. The LTI angle was measured pre‐ and postoperatively on magnetic resonance imaging scans.There were 131 patients (87 females) with a median age of 22 years (range: 14–38). All had a trochleoplasty and an MPFL‐R. Additional procedures (tibial tuberosity medialisation/distalisation and/or femoral/tibial osteotomy) were performed in 52%. All PROM scores improved from preoperatively to 1‐year follow‐up with further improvement at 2 and 5 years after surgery (p < 0.05). Three patients (2%) had a traumatic patellar dislocation 9, 12 and 24 months postoperatively and 38% underwent subsequent surgery (hardware removal, arthroscopically assisted brisement force, knee arthroscopy). A normalisation of the LTI angle (≥11°) was achieved in 76%.Treatment according to the à la carte algorithm for patients with patellar instability and high‐grade trochlear dysplasia resulted in significant clinical and subjective improvement in all PROM scores and a very low redislocation rate (2%) 5 years after surgery.Level II. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence Patellofemoral pain, maltracking and instability remain common and challenging complications after total knee arthroplasty. Controversy exists regarding the effect of kinematic alignment on the patellofemoral joint, as it generally leads to more femoral component valgus and internal rotation compared to mechanical alignment. The aim of this systematic review is to thoroughly examine the influence of kinematic alignment on the third space.A systematic search of the Pubmed, Cochrane and Web of Science databases was performed to screen for relevant articles published before 7 April 2024. This led to the final inclusion of 42 articles: 2 cadaveric, 9 radiographic, 12 computer simulation and 19 clinical studies. The risk of bias was evaluated with the risk of bias in non‐randomised studies ‐ of interventions tool as the lowest level of evidence of the included clinical studies was IV. The effects of kinematic alignment on patellar kinematics and kinetics, trochlear anatomy reconstruction and patellofemoral complication rate were investigated.Kinematic alignment closely restores native patellar kinematics and kinetics, better reproduces native trochlear anatomy than mechanical alignment and leads to a 0%–11.4% incidence of patellofemoral complications. A more valgus joint line of the distal femur can cause lateral trochlear undercoverage and a trochlear angle orientation medial to the quadriceps vector when applying kinematic alignment, both of which can be solved by using an adjusted design with a 20.5° valgus trochlea.Kinematic alignment appears to be a safe strategy for the patellofemoral joint in most knees, provided that certain precautions are taken to minimize the risk of complications.Level IV clinical studies, in vitro research. [ABSTRACT FROM AUTHOR]

Background: Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of knee cartilage defects, although limited research is available on its longer term (≥10 years) sustainability in the patellofemoral joint. Purpose: To report the clinical and radiological outcomes at ≥10 years in a prospectively recruited cohort of patients undergoing MACI in the patellofemoral joint and compare outcomes in patients undergoing MACI on the patella versus the trochlea. Study Design: Case series; Level of evidence, 4. Methods: The current study prospectively enrolled 95 patients who underwent patellofemoral MACI, of whom 29 (13 patella, 16 trochlea) underwent concomitant tibial tubercle osteotomy. Patients were assessed preoperatively and at 2, 5, and ≥10 years using a range of patient-reported outcome measures (PROMs) including the Knee injury and Osteoarthritis Outcome Score, the 36-item Short Form Health Survey, and the frequency and severity of knee pain as well as patient satisfaction, full active knee flexion and extension, and peak isokinetic knee extensor and flexor torques. High-resolution magnetic resonance imaging (MRI) was performed to assess pertinent graft parameters, as well as determine an overall MRI composite score, per the Magnetic Resonance Observation of Cartilage Repair Tissue scoring system. Results were analyzed according to the graft location (patella or trochlea). Results: Of the 95 patients recruited, 82 patients (41 patella, 41 trochlea) were available for a clinical review at ≥10 years after surgery (mean follow-up, 11.9 years [range, 10-15 years]). For the whole patellofemoral MACI cohort, all PROMs significantly improved over time (P <.05), with no significant changes (P >.05) observed in any MRI-based score from 2 to ≥10 years after surgery. At ≥10 years, 90.2% (n = 74) were satisfied with MACI in relieving their knee pain, and 85.4% (n = 70) were satisfied with the improvement in their ability to participate in sports. No differences (P >.05) were observed in PROMs between those undergoing patellar MACI and those undergoing trochlear MACI, although a significant group effect was observed for limb symmetry indices of knee extensor (P =.009) and flexor (P =.041) strength, which were greater in those undergoing patellar (vs trochlear) MACI. No statistically significant differences (P >.05) were observed between patellar and trochlear grafts on any MRI-based measure. In the cohort assessed at ≥10 years after surgery, 4 patients (2 patella, 2 trochlea) demonstrated graft failure on MRI scans, although a further 3 patients (all trochlea) were omitted from the ≥10-year review for having already progressed to total knee arthroplasty. Conclusion: Good clinical scores, high levels of patient satisfaction, and adequate graft survivorship were observed at ≥10 years after MACI on the patella and trochlea. [ABSTRACT FROM AUTHOR]

Introduction: Knee Osteoarthritis (OA) is a significant cause of disability globally and is rapidly becoming a major health issue. The part of the knee most affected by OA is the patellofemoral joint. This type of arthritis poses challenges for both patients and healthcare providers in managing symptoms and improving the quality of life for those affected. However, there's a lack of data on specific therapies for the patellofemoral joint. Aim: To investigate if a varied frequency treadmill exercises protocol involving retro-walking has a greater impact on musculoskeletal responses, leading to better improvements in individuals with symptomatic Patellofemoral Joint Osteoarthritis (PFOA). Materials and Methods: The present study was an experimental research design i.e., between -subjects experimental design in which 60 participants with patellofemoral arthritis were enrolled based on the inclusion criteria. The study was conducted in the Department of Orthopaedics, SGT Medical College Hospital and Research Institute in Gurugram, Haryana, India for a duration of one year (May 2022- May 2023). Participants were randomly randomised to three distinct exercise program groups with varying intensity levels for retro-walking on a treadmill for six weeks, and all three groups received conventional treatment six days/week for six weeks. All participants were evaluated at three-time intervals of baseline, at the end of the third week, and after intervention (end of the sixth week) for the evaluation of several musculoskeletal parameters affecting patellofemoral arthritis. Statistical analysis was carried out using the IBM Statistical Package for the Social Sciences (SPSS) version 26.0. Comparison for within group differences between various outcome measures at various intervals of time was done using repeated measures of Analysis of Variance (ANOVA) and post-hoc analysis for mean values with Least Significant Difference (LSD) whereas for between group analysis One-way ANOVA and post-hoc Analysis for mean values was done with p-value set at <0.05. Result: Significant statistical and clinical differences were observed in musculoskeletal responses, Q-angle (p-value=0.001) and popliteal angle (p-value=0.001) in the high frequency group (group C) performing the protocol five times a week for six weeks leading to a better quality of life followed by group B and group A, respectively. Conclusion: The main finding of the present study suggested that the dosage for retro-walking on treadmill among patients with patellofemoral arthritis requires at least walking for five times/week for six weeks to get more clinical improvement in Musculoskeletal Disorders (MSD). [ABSTRACT FROM AUTHOR]

Introduction: Magnetic resonance imaging (MRI) scans are increasingly used for knee osteoarthritis evaluation and preoperative planning before unicompartmental knee arthroplasty (UKA), and often patients already have MRI scans before their initial surgeon consultation. This highlights the need for surgeons to understand anteromedial osteoarthritis (AMOA) patterns on MRI. Hence, we aim to describe MRI findings in patients with AMOA meeting current indications for medial UKA. Materials and methods: We analysed MRI scans from 100 knees evaluated for UKA between 2006 and 2013. Inclusion criteria comprised full-thickness medial compartment loss and intact lateral compartment joint space on preoperative radiographs. Assessment included cartilage lesions, osteophytes, meniscal damage, and anterior-cruciate ligament (ACL) status on tibial and femoral surfaces. Final decision to proceed with UKA relied on intraoperative findings, independent of MRI. Results: Complete anteromedial tibial and femoral cartilage loss preserved posterior cartilage rims was evident in all cases. Cartilage thinning occurred in the lateral compartment in 34% of cases. While 62% displayed lateral osteophytes, only 6 exhibited small areas of full-thickness cartilage loss. ACL abnormalities varied: 27% normal, 3% ruptured, and 70% had intrasubstance high signal. Larger osteophytes in the medial (p = 0.012) and lateral (p = 0.002) intercondylar notch correlated significantly with ACL damage. All underwent medial UKA, with no evidence of areas with full lateral compartment cartilage loss intraoperatively. Conclusions: The MRI findings confirmed the radiographic diagnosis of bone-on-bone medial disease but highlights a range of findings in the ACL, lateral compartment, and patellofemoral joint compartment for patients who met the current x-ray and intraoperative indication for UKA. Further research is required to understand if these MRI changes will affect long-term outcomes. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to report the approach of Greek surgeons regarding patellar management and provide the outcomes and the rate of the need for secondary patella resurfacing. Methods: Following the PRISMA guidelines, PubMed, Scopus, and The Cochrane Central Register of Controlled Trials (CENTRAL) databases were accessed in January 2024. Clinical studies evaluating the outcomes of patients undergoing primary TKA were considered eligible for this systematic review if the following predefined criteria were fulfilled: (1) published in English, (2) were conducted in Greece, and had a minimum of 2-year follow-up. The methodological quality and publication bias were assessed using the Modified Coleman Methodology Score (mCMS) and ROBIS tool, respectively. Data was presented in tables using absolute values from individual studies. Pooled data were presented as means, ranges, and percentages. Results: Six clinical studies with a total of 1084 TKAs were included. Four studies were retrospectives, and two studies were prospective. Patella was only resurfaced in 0.6% of total TKAs. TKA without patellar resurfaced, which resulted in an improvement in functional outcome. Among studies, the overall need for revision incidence was 7.6% (68 out of 892 TKAs). Additionally, Aseptic loosening (2.4%) was the most common reason for revision due to patellofemoral joint complications, followed by secondary patellar resurfacing (2.1%) and deep infection (1.3%). The mean mCMS demonstrated a fair methodological quality level, and the ROBIS toll a low risk of bias in all four domains. Conclusion: The available evidence supports that Greek surgeons mainly do not resurface the patella. However, patellar non-resurfacing yields good functional outcomes and presents relatively low revision rates for secondary patellar resurfacing. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

Purpose: Abnormal patellar height has been identified as a source of aberrant mechanical functioning within the patellofemoral joint. The purpose of this study is to examine the statistical agreement among three commonly used classification methods: Blackburne‐Peel (BPI), Caton‐Deschamps (CDI) and Insall‐Salvati (ISR), by evaluating (1) the rates of patella alta identification and (2) the ability for one index to predict another. Methods: One hundred lateral knee radiographs were evaluated using BPI, CDI and ISR to classify each knee as patella normal, patella alta or patella baja. Linear regression analysis was performed to evaluate the relationship between each index. Conversion equations were then derived using the reported linear regression best‐fit line, comparing each pair of indices. Results: Patella alta was identified in 15 knees using BPI, 15 using CDI and 25 using ISR. A total of seven knees were classified as patella alta by all BPI, CDI and ISR. Statistical analysis revealed significant correlation (p ≤ 0.001) among BPI and CDI (R2 = 0.706), BPI and ISR (R2 = 0.328) and CDI and ISR (R2 = 0.288). Wilcoxon Signed‐Rank test between the three indices revealed no significant difference between the means of converted and original indices. Conclusion: Despite their significant correlations and adequate reproducibility, variability between common patellar height indices render predictions and conversions between BPI, CDI and ISR inequivalent. Users of these indices must be aware of their incongruent properties when considering application to patients in the clinical setting. Furthermore, it remains unclear which patellar height measurement technique is the correct index to use in a given knee. This study highlights the need for further investigation to create a reliable and standardised method for identifying patella height. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

This article provides information on myopathic Ehlers-Danlos syndrome (mEDS), a rare genetic disorder. It discusses the similarities and differences between mEDS and Ullrich congenital muscular dystrophy (UCMD). The study suggests that genetic analysis, muscle imaging, and muscle pathology can help distinguish between the two conditions. The article presents a case report of a 23-month-old girl with severe phenotypes of mEDS. It also includes a table with alphanumeric data about individuals with different conditions, but the purpose of the table is unclear without further information. Additionally, the article discusses muscle MRI data comparing a patient with mEDS to a patient with UCMD, highlighting differences in muscle involvement. The study also examines muscle biopsies and identifies a novel genetic variant associated with the most severe phenotype of mEDS. Overall, the article emphasizes the importance of various diagnostic tools in differentiating mEDS from UCMD/BM. [Extracted from the article]

Objective: To analyze the influencing factors for patellofemoral joint (PFJ) overstuffing following total knee arthroplasty (TKA) without patella resurfacing, and explore the effect of PFJ overstuffing on clinical efficacy. Methods: A retrospective analysis was conducted on 168 patients with end-stage knee osteoarthritis who underwent TKA without patella resurfacing at our hospital between Match 2019 and September 2021. The clinical data of these patients were retrospectively analyzed. In this study, PFJ overstuffing was defined as a postoperative PFJ distance greater than 1 mm compared to the preoperative measurement. The occurrence of postoperative PFJ overstuffing was counted. The patients were divided into the overstuffing group (n = 109) and the non-overstuffing group (n = 59) to count the patellar thickness and thickness of femoral anterior condyle in all patients before and after surgery, and analyze the influencing factors for postoperative PFJ overstuffing in such patients. Patients were followed up for 2 years to compare the recovery time of postoperative pain, score of visual analogue scale (VAS) and flexion activity between the two groups. Results: There was no significant difference in patellar thickness between preoperative and postoperative measurements of the patients (P > 0.05). However, the thickness of the femoral anterior condyle and the PFJ distance after surgery increased significantly compared with those before surgery (P < 0.05). Among the 168 patients, 109 cases (64.88%) experienced PFJ overstuffing. The risk of PFJ overstuffing was higher in female patients than in male (P < 0.05). The preoperative thickness of the femoral anterior condyle in the overstuffing group was significantly smaller compared to the non-overstuffing group (P < 0.001). Compared with the non-overstuffing group, the overstuffing group had longer recovery time of postoperative pain (P < 0.05), and had lower flexion activity at 2 years after surgery (P < 0.001). However, no significant difference was found in VAS score between the overstuffing group and the non-overstuffing group at 2 years after surgery (P > 0.05). Spearman rank correlation analysis indicated females tend to have a lower preoperative thickness of the femoral anterior condyle (r=-0.424, P < 0.001), as well as a positive postoperative PFJ overstuffing (r = 0.237, P < 0.05). Furthermore, there was a negative correlation between preoperative thickness of the femoral anterior condyle and postoperative PFJ overstuffing (r=-0.540, P < 0.001). Conclusion: Following TKA without patella resurfacing, there is a high risk of PFJ overstuffing, particularly among female patients and those with a small thickness of the femoral anterior condyle. Therefore, special attention should be given to these high-risk groups during clinical treatment. [ABSTRACT FROM AUTHOR]

Background: Marathons are the most challenging form of running, and amateur athletes may be more prone to injury due to a lack of professional knowledge and instruction in running. Purpose: To analyze the MRI manifestations of and factors related to knee injuries in amateur marathon runners. Subjects: Data were collected from a hospital database of 105 qualified amateur marathon athletes (65 males,40 females), between May 2018 and December 2021. Field strength/sequence: 1.5T MR: sagittal fs-PDWI, sagittal T1WI and sagittal 3D-DESS sequence. Assessment: The MRI manifestations of knee joint injury were analyzed and evaluated by two radiologists. Statistical tests: The inter-observer agreement on MRI readings was analyzed using the kappa coefficient, and binary logistic regression analysis was employed to identify factors associated with knee injuries. Results: The overall prevalence of knee cartilage lesions, meniscus lesions and bone marrow edema among amateur marathon runners was 45.7%, 72.4%, and 49.5% respectively. Our analysis revealed that older age (OR = 1.135, P<0.001), higher BMI (OR = 1.236, P = 0.044), and slower pace (OR = 2.305, P = 0.017) were associated with increased risk of articular cartilage disease. Furthermore, older age (OR = 1.425, P<0.001) was identified as a risk factor for meniscal lesions, while older age (OR = 1.088, P = 0.002) was bone marrow edema. Notably, no significant correlation was observed between knee joint injuries of amateur marathon athletes and gender or the monthly running distance (P>0.05). Conclusions: The occurrence of knee injuries among amateur marathon athletes was highly prevalent, with the patellofemoral joint cartilage and posterior horn of medial meniscus being frequently affected areas. Moreover, age, BMI, running years and pace were significant risk factors of knee joint injury. [ABSTRACT FROM AUTHOR]

Knee malalignment is a risk factor for patellar instability and patellofemoral osteoarthritis (PFOA), but etiologies remain unknown. We investigated the potential effects of decreased weight loading during growth on knee alignments and patellofemoral (PF) joint pathology. Hindlimb suspension (HS) was performed in 4‐week‐old female rats for 2, 4, and 8 weeks (HS groups). Age‐matched rats were used as controls. Three‐dimensional reconstructed images of the knee were obtained using X‐ray computed tomography. Tibial tubercle–trochlear groove (TT–TG) distance, patellar tilt angle, and bisect offset were measured as indices of knee alignment. Histological analysis was also performed to evaluate the changes in cartilage and synovium in the PF joints. At Week 8, TT–TG distance, patella tilt angle, and bisect offset were significantly larger in the HS group than in the control group, respectively, indicating tibial external rotation, outward patellar tilt, and external displacement of the patella. Lateral patellar dislocation was frequently found in the HS group at Week 8 (five of eight knee joints, p < 0.05). Degenerative changes in the cartilage of the trochlear groove were observed at Week 8, and synovial changes such as hypertrophy and synovitis were observed at Weeks 4 and 8. Correlation analyses revealed significant relationships between the Mankin score and bisect offset, and between the OARSI synovitis score and all knee alignments indices. These results suggest that decreased weight loading on the lower extremities in growing rats resulted in knee malalignments characterized by external rotation of tibia and high incidence of lateral patellar dislocation with concomitant PFOA. [ABSTRACT FROM AUTHOR]

Objective: Obtaining an optimal knee skyline view is challenging due to inaccuracies in beam projection angles (BPAs) and soft tissue obscuring bony landmarks. This study aimed to assess the impact of BPA deviations on patellofemoral index measurements and assessed the anterior border of the proximal tibia as an anatomic landmark for guiding BPAs. Materials and methods: This retrospective study consisted of three parts. The first was a simulation study using 52 CT scans of knees with a 20° flexion contracture to replicate the skyline (Laurin) view. Digitally reconstructed radiographs simulated neutral, 5° downward, and 5° upward tilt BPAs. Five patellofemoral indices (sulcus angle, congruence angle, patellar tilt angle, lateral facet angle, and bisect ratio) were measured and compared. The second part was a proof of concept study on 162 knees to examine patellar indices differences across these BPAs. Lastly, the alignment of the anterior border of the proximal tibia with the BPA tangential to the patellar articular surface was tested from the CT scans. Results: No significant differences in patellofemoral indices were found across various BPAs in both the simulation and proof of concept studies (all p > 0.05). The angle between the anterior border of the proximal tibia and the patellar articular surface was 1.5 ± 5.3°, a statistically significant (p = 0.037) yet clinically acceptable deviation. Conclusion: Patellofemoral indices in skyline view remained consistent regardless of BPA deviations. The anterior border of the proximal tibia proved to be an effective landmark for accurate beam projection. [ABSTRACT FROM AUTHOR]

We aimed to verify the feasibility of using shear wave elastography (SWE) to quantify knee scars and the elastic modulus of scar tissues. Overall, 16 participants underwent SWE assessments and range-of-motion measurement and completed the Knee Injury and Osteoarthritis Outcome Score. The inter-rater reliability for SWE in the suprapatellar bursa, below the patellar tendon, and in the medial and lateral trochlear groove remained within 0.861–0.907. The SWE values in the four regions increased with increasing knee angle, and significant differences were observed between the values for below the patellar tendon and the suprapatellar bursa at knee flexion angles of 60° and 90°. The SWE values of the medial and lateral trochlear groove at 30°, 60°, and 90° knee flexion were higher on the affected side. A negative correlation was observed between the SWE values for the lateral trochlear groove at 0°, 30°, and 60° and those for below the patellar tendon at 0° and the suprapatellar bursa at 30° with both active and passive knee extension. The suprapatellar bursa value at 60° exhibited a positive correlation with both knee flexion and passive knee flexion, whereas that of the suprapatellar bursa at 90° exhibited a positive correlation with both the range of motion and passive range of motion. SWE is a replicable and effective method for detecting scar strength in the knee joint. [ABSTRACT FROM AUTHOR]

Purpose: The European consensus was designed with the objective of combining science and expertise to produce recommendations that would educate and provide guidance in the treatment of the painful degenerative varus knee. Part I focused on indications and planning. Methods: Ninety‐four orthopaedic surgeons from 24 European countries were involved in the consensus, which focused on the most common indications for osteotomy around the knee. The consensus was performed according to an established ESSKA methodology. The questions and recommendations made were initially designed by the consensus steering group. And 'best possible' answers were provided based upon the scientific evidence available and the experience of the experts. The statements produced were further evaluated by ratings and peer review groups before a final consensus was reached. Results: There is no reliable evidence to exclude patients based on age, gender or body weight. An individualised approach is advised; however, cessation of smoking is recommended. The same applies to lesser degrees of patellofemoral and lateral compartment arthritis, which may be accepted in certain situations. Good‐quality limb alignment and knee radiographs are a mandatory requirement for planning of osteotomies, and Paley's angles and normal ranges are recommended when undertaking deformity analysis. Emphasis is placed upon the correct level at which correction of varus malalignment is performed, which may involve double‐level osteotomy. This includes recognition of the importance of individual bone morphology and the maintenance of a physiologically appropriate joint line orientation. Conclusion: The indications of knee osteotomies for painful degenerative varus knees are broad. Part I of the consensus highlights the versatility of the procedure to address multiple scenarios with bespoke planning for each case. Deformity analysis is mandatory for defining the bone morphology, the site of the deformity and planning the correct procedure. Level of Evidence: Level II, consensus. [ABSTRACT FROM AUTHOR]

Purpose: To explore the relationship between preoperative J‐sign grading and structural bone abnormalities in patients with recurrent patellar dislocation (RPD). Methods: A retrospective study was conducted on RPD patients over 5 years. Patients were categorised based on J‐sign grade into low (J‐ and J1+), moderate (J2+) and high groups (J3+). Trochlear dysplasia (TD) and osseous structures (femoral anteversion angle [FAA], knee torsion, tibial tuberosity‐trochlear groove [TT‐TG] distance, Caton–Deschamps index) were assessed and grouped according to risk factor thresholds. The χ2 test was used to compare composition ratio differences of structural bone abnormalities among the groups. Results: A total of 256 patients were included, with 206 (80.5%) females. The distribution of J‐sign grade was as follows: 89 knees (34.8%) of low grade, 86 moderate (33.6%) and 81 high (31.6%). Among the five structural bone abnormalities, TD was the most common with a prevalence of 78.5%, followed by increased TT‐TG at 47.4%. Excessive tibiofemoral rotation had the lowest occurrence at 28.9%. There were 173 (67.6%) patients who had two or more abnormalities, while 45 (17.6%) had four to five bony abnormalities. Among patients with any bony abnormality, the proportion of high‐grade J‐sign surpassed 40%. Patients with moderate and high‐grade J‐sign had more increased FAA and more pronounced patella alta (all p < 0.001). The proportion of excessive knee torsion and TD increased with increasing each J‐sign grade, with the more notable tendency in knee torsion (high vs. moderate vs. low‐grade: 61% vs. 22% vs 7%, p < 0.001). Furthermore, the higher J‐sign grade was also associated with more combined bony abnormalities (p < 0.001). In the high‐grade J‐sign group, 90.2% of the knees had two or more bony risk factors and 40.7% had four or more, which were significantly higher than the moderate and low‐grade J‐sign groups (40.7% vs. 11.6% vs. 2.2%, p < 0.001). Conclusion: In patients with a high‐grade J‐sign, over 90% of the lower limbs had two or more structural bone risk factors, and more than 40% had four or more. These proportions were significantly higher compared to knees with low‐grade and moderate J‐sign. In clinical practice, when treating high‐grade patellar mal‐tracking, it is important to focus on and correct these strongly correlated abnormal bone structures. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: When planning and delivering total knee arthroplasty (TKA), there are multiple coronal alignment strategies such as functional alignment (FA), kinematic alignment (KA), mechanical and adjusted mechanical alignment (MA, aMA). Recent three‐dimensional and robotic‐assisted surgery (RAS) studies have demonstrated that KA potentially better restores the trochlear anatomy than MA. The purpose of this study was to compare the restoration of the native trochlear orientation in patients undergoing RAS TKA using four different alignment strategies. It was hypothesised that FA would result in the lowest number of outliers. Methods: This is a prospective study of 200 patients undergoing RAS‐TKA with a single implant. All patients were analysed for MA and KA prebalancing, and 157 patients received aMA and 43 patients FA with intraoperative balancing. Preoperative transverse computed tomography scans were used to determine the posterior condylar axis (PCA), lateral trochlear inclination (LTI) angle, sulcus angle (SA) and anterior trochlear line (ATL) angle. Implant measurements were obtained using a photographic analysis. Intraoperative software data combined with implant data and preoperative measurements were used to calculate the differences. Outliers were defined as ≥3° of alteration. Trochlea dysplasia was defined as LTI < 12°. Results: Native transepicondylar PCA had a median of 2°, LTI 18°, SA 137°, ATL 4°. LTI outliers were observed in 47%–60% of cases, with KA < FA < aMA < MA. For ATL, the range of outliers was 40.5%–85%, KA < FA < aMA < MA. SA produced 81% of outliers. Of all median angle values, only LTI when using KA was not significantly altered compared to the native knee. Conclusion: There is a significant alteration of trochlear orientation after TKA, regardless of the alignment strategy used. KA produced the lowest, but a substantial, number of outliers. The uniform design of implants causes the surgeon to compromise on balance in flexion versus trochlear position. The clinical relevance of this compromise requires further clinical investigations. Level of Evidence: Level II, prospective cohort study. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive guide to the rehabilitation process after surgery for patellar instability (PI). PI is a condition that significantly impacts patients' lives and knee function, causing pain, activity limitations, and reduced quality of life. Surgery is recommended for patients with recurrent dislocations who are willing to undergo postoperative rehabilitation. The rehabilitation process is divided into several phases, each with specific goals and exercises. It focuses on restoring patellar stability, enabling normal everyday function, and allowing patients to participate in desired activities. Prehabilitation before surgery and a phase-based approach to rehabilitation are important for optimal outcomes. Psychological aspects of patellar instability should also be addressed. The overall goal of rehabilitation is to eliminate functional deficits and enable patients to regain confidence in their knee and return to their desired level of activity. [Extracted from the article]

Purpose: For primary total knee arthroplasty (TKA), there is an increasing trend towards patient‐specific alignment strategies such as kinematic alignment (KA) and inverse kinematic alignment (iKA), which by restoring native joint mechanics may yield higher patient satisfaction rates. Second, the most recent Australian joint registry report describes favourable revision rates for conventionally instrumented TKA compared to technology‐assisted techniques such as those using navigation, robotics or custom‐cutting blocks. The aim of this technique article is to describe in detail a surgical technique for TKA that: (1) utilises the principles of iKA and (2) uses conventionally instrumented guided resections thereby avoiding the use of navigation, robotics or custom blocks. Methods: A TKA technique is described, whereby inverse kinematic principles are utilised and patient‐specific alignment is achieved. Additionally, the patellofemoral compartment of the knee is restored to the native patellofemoral joint line. The sequenced technical note provided may be utilised for cemented or cementless components; cruciate retaining or sacrificing designs and for fixed or rotating platforms. Results: An uncomplicated, robust and reproducible technique for TKA is described. Discussion: Knee arthroplasty surgeons may wish to harness the emerging benefits of both a conventionally instrumented technique and a patient‐specific alignment strategy. Level of Evidence: Level V. [ABSTRACT FROM AUTHOR]

Purpose: Patellofemoral joint instability (PFJI) can surgically be treated with a multitude of approaches, depending on the underlying pathology. In the presence of increased femoral anteversion, some authors have reported good results with a derotational distal femoral osteotomy (DeDFO). The purpose of the study was to investigate the indications, outcomes and complication rate of DeDFO for PFJI. Methods: A systematic review was performed according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta‐analyses) by searching Medline, Embase, Web of Science and Cochrane Library databases through 1 December 2023. Included were levels 1–4 clinical studies of skeletally mature patients undergoing a DeDFO for PFJI irrespective of concomitant procedures. Study characteristics, indications, radiological and clinical outcomes, surgical technique and concomitant procedures, re‐dislocation and complication rate were all analysed, as was methodological quality. Results: A total of 12 studies including 310 patients (325 knees) were included. Three studies were cohort studies, all others were case series. The mean patient age across the studies was 22 years, and the mean follow‐up was 29.4 months. Femoral anteversion cut‐off was between 20° and 30°. Every study included at least one concurrent soft tissue, bony or combined procedure. Across all studies, one case of re‐dislocation was reported (0.3%) and four implant or osteotomy‐related complications (1.2%) were reported. All studies reported a statistically significant increase in clinical scores. Conclusion: This systematic review of DeDFO for patellofemoral instability in the presence of increased femoral anteversion demonstrates promising clinical results and an extremely low dislocation and complication rate. The heterogeneity of the cut‐off in anteversion and concomitant procedures, especially tibial tubercle osteotomy with seemingly identical results, indicates the need for high‐quality evidence for treating patellofemoral instability. Based upon this systematic review, we strongly recommend that DeDFO be added to the 'menu à la carte' of PFJI. Level of Evidence: Level III Systematic Review. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence This study aimed to investigate the development of patellofemoral joint (PFJ) cartilage lesions following anterior cruciate ligament reconstruction (ACLR) using hamstring tendon (HT) autograft through a systematic review.A comprehensive search was conducted in PubMed, Embase, Cochrane Library and Google Scholar databases to find articles published from database inception until 15 November 2023. The search terms were [(‘Anterior Cruciate Ligament’ [mesh] OR ‘anterior cruciate ligament’ OR ‘ACL’) AND ‘reconstruction’ AND ‘cartilage’ AND (‘second look arthroscopy’ OR ‘second‐look arthroscopy’ OR ‘MRI’ OR ‘magnetic resonance imaging’)]. Inclusion criteria were studies that reported on the occurrence of PFJ cartilage lesions following ACLR using HT autograft, as determined by second‐look arthroscopy or follow‐up magnetic resonance imaging (MRI).Fifteen studies (1084 patients) met the inclusion criteria, with follow‐up periods ranging from 1 to 5 years. In the results of second‐look arthroscopy, cartilage grade deterioration was observed, ranging from MDs of 0.1 to 2.0 in the patella and from 0 to 1.0 in the trochlea. Follow‐up MRI results reported the incidence of PFJ cartilage degeneration with rates ranging from 20% to 44%. Patient‐reported outcome measures often showed no significant association with PFJ cartilage lesions. The studies included in this review reported various risk factors for cartilage lesion development.Cartilage lesions in the PFJ, detected using second‐look arthroscopy or follow‐up MRI, frequently develop shortly after ACLR using HT autograft. At this stage, patients might not show specific symptoms; however, those with risk factors require careful observation and evaluation by clinicians during follow‐up.Level IV. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence The study aimed to determine the impact of intraoperative lateral laxity at extension on clinical and functional outcomes 1 year after posterior‐stabilised total knee arthroplasty (PS‐TKA).In total, 91 varus‐type osteoarthritic knees that underwent PS‐TKA using the medial preservation gap technique were included. After the femoral trial component placement and patellofemoral joint reduction, the soft‐tissue balance was assessed using an offset‐type tensor with a 40‐lb joint‐distraction force. Patients were divided into the following three groups according to the intraoperative lateral laxity at extension (i.e., varus ligament balance) using the mean ± 1 standard deviation: Groups A, ≤0°; B, 0–4°; and C, >4°. The 2011 Knee Society Score (KSS) and 3‐m timed up‐and‐go test (TUG) time 1‐year postoperatively, and their improvements were compared among the groups.While significant improvements were observed in all subscales of the 2011 KSS and TUG post‐TKA (p < 0.05), the improvement of functional activities and TUG time were significantly lower in Group C than in Group B (p < 0.05). However, no significant differences were observed in symptom improvement, patient satisfaction or patient expectation scores among the groups.An excessive lateral laxity (varus angle) >4° at extension was associated with lower improvement in functional ability 1‐year postoperatively. Therefore, excessive intraoperative lateral laxity should be avoided in PS‐TKA.Level IV. [ABSTRACT FROM AUTHOR]

Patellofemoral instability (PFI) is a common condition in children and adolescents, ranging from mild discomfort and mal-tracking to lateral patellar dislocation [1]. A number of anatomical risk factors have been described in the literature, such as trochlear dysplasia, patella alta, excessive tibial tuberosity to trochlear groove (TT-TG) distance, patellar tilt and soft tissue alterations [2]. Among them, TD has been identified as the main anatomical risk factor with the strongest association with PFI [1-2]. In the study by Dejour et al. [2] radiographically observed TD was identified in 96% of patients with a history of patellofemoral dislocation [1-2]. Patients with Dejour Type D dysplasia are characterized by a prominent and convex lateral facet with a vertical connection to a hypoplastic medial facet (Figure 1), which provides inadequate tracking of the patella in the trochlea during flexion leading to patella subluxation [2]. Non-operative treatment of lateral patellar dislocation presents a rate of re-dislocation up to 70% within 24 months of the first episode [3]. Sulcus deepening trochleoplasty is indicated for Type B and D dysplasia, in order to improve patella tracking, reduce the rate of re-dislocation and achieve good functional outcomes [2, 4]. Trochlea dysplasia is defined as a shallow or flattened groove with decreased resistance to lateral patellar translation. TD can be assessed on computed tomography (CT) and magnetic resonance imaging (MRI) with the use of overlapping axial images and are able to show perfectly the global shape of the femoral trochlea [2]. The thresholds for identifying trochlear dysplasia are established based on the sulcus angle ≥ 145°, medial/lateral trochlea facet asymmetry < 40%, trochlear depth < 3 mm and lateral trochlear inclination ≤ 11° and therefore it can be used in young adolescents [4-5]. A deep knowledge of anatomic variations and abnormalities of the patellofemoral joint, which may predispose to PFI, is crucial in order to choose the appropriate treatment for each patient. [ABSTRACT FROM AUTHOR]

Purpose: The aims of the present study were (1) to evaluate the survival of patellofemoral joint (PFJ) arthroplasty in a large cohort of patients using data obtained from an Italian regional arthroplasty registry and (2) to collect clinical outcomes of a subgroup of patients, with a minimum follow‐up of 4 years. The hypotheses were that PFJ arthroplasty is a procedure that had good survival and clinical outcomes, not inferior to those reported in the literature for primary total knee arthroplasty (TKA). Methods: The Register of Orthopaedic Prosthetic Implants (RIPO) of Emilia‐Romagna (ER) (Italy) database was searched for the inclusion of all PFJ arthroplasties implanted between 2003 and 2019. PFJ arthroplasties were excluded if they were implanted in patients who lived outside of the ER. The survival information was extrapolated from the RIPO considering the partial or total revision of the implant as failure; moreover, a subgroup of patients was contacted and interviewed by telephone to collect clinical outcomes. Descriptive statistics were used to summarise the data. The survival curve was calculated and plotted using the Kaplan–Meier method. Results: A total of 126 arthroplasties in 114 patients were included in the final analysis (mean age at surgery 60.1 ± 11.5 years old). The main causes of patellofemoral arthroplasty were primary osteoarthritis (88%) and posttraumatic arthritis (7%). The survival was 90.4 ± 30.6 and 78.8 ± 51.5 at 5 and 10 years of follow‐up, respectively. At the latest follow‐up, 23 implants failed (18.3%). The main cause of revision was osteoarthrosis progression (34.8%). A total of 44 patients were contacted by telephone to collect clinical outcomes: Western Ontario and McMaster Universities Osteoarthritis Index, functional Knee Society Score, Forgotten Joint Score and Oxford Knee Score. These patients reported good to excellent scores at a medium follow‐up of 10.3 ± 4.7 years. Conclusions: The PFJ showed good survival and clinical outcomes and could be considered a valuable option for patients affected by isolated patellofemoral osteoarthritis. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate patellar mobility in patients before and after knee arthroplasty (KA) and compare it with that of healthy subjects. It was hypothesised that patellar mobility is diminished in patients with osteoarthritis (OA) and remains unchanged after KA. Methods: A total of 101 patients (59 females and 42 males) with a mean age of 70.9 ± 9.9 years underwent KA and were compared with 25 healthy individuals (seven females and 18 males) with a mean age of 32.3 ± 9.3 years. Mediolateral patellar displacement was measured by applying a force of 10 N, and the medial and lateral patellar shifts were recorded separately using a validated novel patellostabilometer. Patients were examined preoperatively and at 3 months postoperatively, assessing the range of knee motion and the clinical and functional status based on the Oxford Knee Score (OKS), Kujala Score, subjective Knee Society Score (sKSS), Forgotten Joint Score (FJS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC). Results: Total patellar displacement was 42.1 ± 6 mm for healthy subjects, 31 ± 6 mm before surgery and 32.8 ± 7.8 mm after surgery in osteoarthritic patients (p < 0.01). The mean lateral patellar shift differed significantly between healthy individuals (17.9 ± 4 mm) and osteoarthritic patients (15.1 ± 6 mm) (p < 0.01). The mean medial patellar mobility of healthy individuals (24.2 ± 7 mm) was significantly greater than that of osteoarthritic patients (15.8 ± 4.8 mm) (p < 0.01). All scores improved significantly postoperatively. No correlation was found between patellar mobility and OKS, Kujala Score, sKSS, FJS and WOMAC (r = −0.11). Improvement in patellar mobility also showed no correlation with clinical outcomes according to OKS, Kujala Score, sKSS, FJS and WOMAC (r = 0.08). Conclusion: This study has demonstrated reduced patellar mobility in patients with OA. While patellar mobility significantly improved after KA, it may not hold clinical significance (p = 0.04). No impact on clinical outcome can be expected when the presurgical patella mobility is preserved in KA. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Purpose: Trochlear dysplasia is one of the main risk factors for recurrent patellar dislocation. The Dejour classification identifies four categories that can be used to classify trochlear dysplasia. The purpose of this study is to evaluate the inter‐ and intraobserver reliability of the Dejour classification for trochlear dysplasia. The hypothesis was that both intra‐ and interobserver reliability would be at least moderate. Methods: This is a cross‐sectional, reliability study. Twenty‐eight examiners from the International Patellofemoral Study Group 2022 meeting evaluated lateral radiographs of the knee and axial magnetic resonance images from 15 cases of patellofemoral instability with trochlear dysplasia. They classified each case according to Dejour's classification for trochlear dysplasia (A–D). There were three rounds: one with only computed radiograph (CR), one with only magnetic resonance imaging (MRI) and one with both. Inter‐ and intraobserver reliability were calculated using κ coefficient (0–1). Results: The mean age of patients was: 14.6 years; 60% were female and 53% had open physis. The interobserver reliability κ probabilities were 0.2 (CR), 0.13 (MRI) and 0.12 (CR and MRI). The intraobserver reliability κ probabilities were 0.45 (CR), 0.44 (MRI) and 0.65 (CR and MRI). Conclusion: The Dejour classification for trochlear dysplasia has slight interobserver reliability and substantial intraobserver reliability. Level of Evidence: Level I. [ABSTRACT FROM AUTHOR]

Background and Aims: Patellofemoral pain (PFP) is common in males, causing reduced physical activity and chronic pain. One proposed cause of PFP is aberrant biomechanics during tasks loading the patellofemoral joint. Consistent evidence exists for females with PFP, but it is uncertain if males with PFP have altered biomechanics. This study investigated the kinematics of males with PFP compared to pain‐free males during forward step‐down (StDn) and single‐leg squat (SLSq). Methods: A cross‐sectional study including 40 males aged 20–39 years (28.28 ± 5.46) was conducted (20 PFP, 20 pain‐free). Participants performed StDn and SLSq while motion was captured with a video‐based motion capture system (Motion Analysis Corporation). Triplanar peak angles and angular ranges of motion (ROM) of the trunk, pelvis, and weight‐bearing hip, knee, and ankle were dependent variables. Mixed‐model ANOVA tests were used to determine the presence of significant interactions and main effects of group and task. Results: Males with PFP had significantly lower peak knee adduction angles compared to pain‐free males (p = 0.01). Significant group x task interactions were found for hip and pelvis ROM (p < 0.05). PFP participants had increased hip and pelvis ROM during StDn in the frontal and transverse planes but reduced or nearly equal ROM for these variables during SLSq. Peak hip adduction, hip internal rotation, contralateral pelvic drop and anterior tilt, trunk flexion, and ankle dorsiflexion were greater during StDn compared to SLSq (p < 0.05). ROM of the hip, pelvis, trunk, and ankle were greater during StDn compared to SLSq (p < 0.05). Conclusion: Males with PFP had reduced peak knee adduction angles in StDn and SLSq. Males with PFP demonstrated increased hip and pelvis ROM during StDn versus SLSq, particularly in the frontal and transverse planes. Clinicians should consider StDn as a clinical test since aberrant movement may be easier to detect than in SLSq. Key points: Faulty kinematics are commonly reported in females with patellofemoral pain (PFP), but the kinematics of males with PFP are still uncertain.Males with PFP had reduced peak knee adduction angles during step‐down and single‐leg squatting. Compared to pain‐free males, the PFP group had greater hip and pelvis ranges of motion (ROM) during step‐down but reduced hip and pelvis ROM during squatting.The findings of this study indicate that males with PFP may have reduced knee adduction during weight‐bearing tasks. Excessive hip and pelvis ROM during step‐down may be present so may be a preferred clinical task to detect faulty kinematics. [ABSTRACT FROM AUTHOR]

Background Multicompartmental osteoarthritis (MOA) in both tibiofemoral and patellofemoral joints is a more commonly occurring, but neglected, clinical condition, and we examined the short-term safety and efficacy of autologous stromal vascular fractions (SVFs) for MOA using a single-blind, prospective, randomized, placebo-controlled trial. Methods Seventy MOA patients were recruited and randomly assigned to the SVF group and hyaluronic acid (HA) group (control group). The scores of visual analog scale, the Western Ontario and McMaster University Osteoarthritis Index, and the Samsung Medical Center patellofemoral scoring system were assessed and compared between the two groups 3, 6 and 12 months after treatment. Results The SVF group had significantly better visual analog scale scores than the HA group at 6 and 12 months after treatment and had better Western Ontario and McMaster University Osteoarthritis Index scores than the HA group only at 6 months after treatment. For Samsung Medical Center patellofemoral scoring system of the patellofemoral joint, the SVF group had significantly better scores than the control group at all postoperative time points. The proportion of patients whose visual analog scale and Western Ontario and McMaster University Osteoarthritis Index scores were above the minimal clinically important improvement was higher in the SVF group than in the HA group in the majority of assessments. The improvement of bone marrow by SVF treatment was significantly better than that of the HA group as observed by pre- and postoperative Magnetic resonance imaging (MRI). Conclusions Multiple intra-articular injection of autologous SVF reduces pain and improves function in the short term in patients with early or midstage MOA. However, there was heterogeneity in the improvement of overall knee and isolated patellofemoral joint after treatment.   What is already known on this topic   Knee osteoarthritis (KOA) is the most common type of degenerative joint disease in humans. Autologous stromal vascular fraction (SVF) has been gradually applied to the treatment of KOA due to its multidifferentiation and ease of access. However, most current studies have focused on the tibiofemoral (TF) joint, and we know little about the performance of SVF in multiple compartments of the knee, including the patellofemoral (PF) joint. What this study adds   Multiple intra-articular injections of SVF are safe and effective for MOA in short-term (within 12 months) follow-up. Patients with MOA appear to have different feedback on treatment in different compartments of the knee, including the PF and TF joints, after SVF treatment. How this study might affect research, practice, or policy   More research is needed to clarify the appropriate dosage and injection schedule of SVF to standardize its clinical use. The rational selection of the indications for SVF in the treatment of KOA needs to be done more carefully when OA affects multiple compartments of the knee joint. [ABSTRACT FROM AUTHOR]

Background: Torsional malalignment of the femur and/or tibia is associated with patellar maltracking, and torsional osteotomies have shown to improve clinical symptoms. In patients with severe torsional malalignment, a double-level torsional osteotomy may be necessary. Indications: Symptomatic torsional malalignment leading to patellofemoral maltracking associated with anterior knee pain and/or patellofemoral instability. Technique Description: A double-level torsional osteotomy correcting both increased internal femoral torsion and increased external tibial torsion, is described. Meticulous preoperative deformity analysis and planning of the osteotomy is mandatory. An arthroscopy of the knee is performed first to evaluate the patellofemoral joint and patellar tracking. Tibial torsional correction is performed by a lateral approach. A biplanar osteotomy is performed, and the amount of torsional correction is controlled by 2 Schanz screws. Osteosynthesis can be done via a bended 5-hole DC-Plate or an angle-stable plate. The femoral osteotomy is performed by a medial approach. A uniplanar osteotomy is performed perpendicular to the mechanical axis of the femur. The amount of torsional correction is controlled by 2 Schanz screws. Osteosynthesis is achieved by an angle-stable plate. Results: Double-level torsional osteotomy has been shown to be an effective treatment for patients with patellar dislocation or subluxation associated with severe torsional malalignment. In a series of 18 patients, double-level osteotomy led to improved patellofemoral stability, decreased pain, and increases subjective outcome scores. Discussion/Conclusion: In patients with patellofemoral problems caused by a combined increased tibial external torsion and increased femoral internal torsion, a double-level torsional osteotomy is able to correct torsional angles to normal. Available clinical data on this procedure are promising. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication. [ABSTRACT FROM AUTHOR]

To determine the cross-sectional and longitudinal associations of patella alignment with cartilage relaxation and patients self-reported symptoms. Thirty participants with isolated patellofemoral joint (PFJ) degeneration (six males, 53.7 ± 9.3 years) and 24 controls (12 males, 47.6 ± 10.7 years) were included. Magnetic resonance assessment was performed to provide grading of structural abnormalities, cartilage relaxation times, and patella alignment. Self-reported symptoms were assessed using the self-administrated knee injury and osteoarthritis outcome score (KOOS). All participants were examined at baseline and 3 years. Statistical parametric mapping and Pearson partial correlation were used to evaluate the associations between patella alignment with cartilage relaxation times and self-reported symptoms, respectively. The analyses were performed between baseline (cross-sectional) as well as the baseline against 3 years (longitudinal). Results indicated that patella height and patella flexion were associated with T1ρ and T2 relaxation times at baseline (percentages of voxels showing significant correlation [PSV] = 10.1%-24.8%; mean correlations [R] = 0.34-0.36; mean p = 0.015-0.026). Furthermore, greater patella lateral alignment, lateral tilt, and lateral spin were associated with longer T2 times at 3 years (PSV = 11.0%-14.4%, R = 0.39-0.44, p = 0.017-0.028). Last, a higher patella was associated with a lower KOOS at baseline and at 3 years (R = -0.33 to -0.35). The study suggests that patella malalignment is a risk factor for worsening cartilage health, informing clinicians of a better rehabilitation program that targets PFJ degeneration.

Abstract Background An isokinetic moment curve (IMC) pattern-damaged structure prediction model may be of considerable value in assisting the diagnosis of knee injuries in clinical scenarios. This study aimed to explore the association between irregular IMC patterns and specific structural damages in the knee, including anterior cruciate ligament (ACL) rupture, meniscus (MS) injury, and patellofemoral joint (PFJ) lesions, and to develop an IMC pattern-damaged structure prediction model. Methods A total of 94 subjects were enrolled in this study and underwent isokinetic testing of the knee joint (5 consecutive flexion-extension movements within the range of motion of 90°-10°, 60°/s). Qualitative analysis of the IMCs for all subjects was completed by two blinded examiners. A multinomial logistic regression analysis was used to investigate whether a specific abnormal curve pattern was associated with specific knee structural injuries and to test the predictive effectiveness of IMC patterns for specific structural damage in the knee. Results The results of the multinomial logistic regression revealed a significant association between the irregular IMC patterns of the knee extensors and specific structural damages (“Valley” - ACL, PFJ, and ACL + MS, “Drop” - ACL, and ACL + MS, “Shaking” - ACL, MS, PFJ, and ACL + MS). The accuracy and Macro-averaged F1 score of the predicting model were 56.1% and 0.426, respectively. Conclusion The associations between irregular IMC patterns and specific knee structural injuries were identified. However, the accuracy and Macro-averaged F1 score of the established predictive model indicated its relatively low predictive efficacy. For the development of a more accurate predictive model, it may be essential to incorporate angle-specific and/or speed-specific analyses of qualitative and quantitative data in isokinetic testing. Furthermore, the utilization of artificial intelligence image recognition technology may prove beneficial for analyzing large datasets in the future.