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Background/Objectives: After open-wedge high tibial osteotomy (OWHTO), the patella is displaced distally, causing patellofemoral joint degeneration. The objective of this study was to ascertain whether the combination of OWHTO and lateral retinacular release (LRR) can prevent articular cartilage degeneration of the patellofemoral joint using magnetic resonance imaging T2 mapping. Methods: This study included 37 patients (37 knees) who underwent OWHTO alone (OWHTO group) and 37 patients (37 knees) who underwent OWHTO with LRR (OWHTO + LRR group) with a correction angle of <10° for varus knee osteoarthritis. MRI was performed on all knees prior to and 6 months after surgery to assess the patellar cartilage in sagittal images for T2 mapping. Three regions of interest, (the medial facet, patellar ridge, and lateral facet), were established for the articular cartilage on the patellar side. The T2 values were subsequently quantified. Lower limb alignment, patellar height, patellar tilt angle, and lateral shift ratio were evaluated pre-and post-surgery. Results: Mean T2 values at 6 months post-surgery of the medial facet and patellar ridge of the OWHTO group showed a significant increase after surgery; no significant changes were observed in either region in the OWHTO + LRR group. In both groups, a significant decrease in patellar tilt angle was observed postoperatively; no change was noted in the lateral shift ratio or congruence angle. The change in patellar tilt angle was significantly lower in the OWHTO + LRR group than in the OWHTO group. Conclusions: LRR combined with OWHTO prevented patellofemoral joint cartilage degeneration after surgery in cases of varus knee osteoarthritis. [ABSTRACT FROM AUTHOR]

Purpose: Previous studies reported that anterior knee pain (AKP) occurs with an incidence of 32% after opening-wedge high tibial osteotomy (OWHTO). However, the biomechanical effects of this procedure on patellofemoral joints (PFJs) remain unclear. We aimed to quantify the changes in the kinematics and cartilage conditions of the PFJ during stair climbing before and after OWHTO. Methods: We recruited 15 patients who underwent unilateral OWHTO. All patients performed continuous stair climbing under the surveillance of a dual fluoroscopic imaging system to determine accurate 6-degree-of-freedom (6-DOF) PFJs and 3D hip-knee-ankle (HKA) angles before and 6 months after OWHTO. The volume penetration centres between the patellar and femoral cartilage models were defined as contact centres. Eleven of these patients underwent quantitative T2 relaxation MRI to determine whether and how PFJ cartilage degeneration progressed. Results: After OWHTO, patella valgus (mean − 3.73°, P = 0.02) and internal rotation (mean 3.14°, P = 0.03) increased compared with the preoperative conditions during the stair climbing motion. In addition, the patellae of OWTHO knees were located more laterally after surgery (1.56 ± 2.24 mm, P = 0.02) at knee flexion. Moreover, lateral shifts in the contact patterns of both the medial and lateral patellar facets together with increased T2 values (207.10 ± 21.84 ms, P = 0.04) of the lateral patella cartilage were found after surgery. Finally, the lateral patellar shift increased with decreasing varus 3D-HKA after surgery (R= -0.79, P < 0.001). Therefore, controlling 3D-HKA may be helpful in limiting lateral patellar shift. Conclusion: OWHTO changed the patellofemoral kinematics and contact patterns during stair climbing, especially the lateral patellar shift, which may lead to degeneration of the PFJ cartilage. Avoiding overcorrection of the HKA angle beyond 5 degrees of valgus reduces lateral patellar translation, which may help prevent AKP. Additional clinical studies are necessary to validate these biomechanical findings and clarify their impacts on patient outcomes. [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]

Background: Patellofemoral joint (PFJ) issues after total knee arthroplasty (TKA) are becoming a topic of interest once again. Due to the complex three-dimensional shape of the trochlea, various two-dimensional proxy measurements on plain X-rays have been described. One of these measurements is the anterior femoral offset (AFO). It is the distance between the anterior femoral cortex and the trochlea’s most anterior point (MAP) on a true lateral X-ray after TKA. Because the relationship between the trochlea’s MAP and its groove, which is the primary joint surface articulating with the patella, is unknown, the purpose of this study was to measure the distance between the MAP and the trochlear groove. Methods: After femoral component implantation, the surgeon identified the trochlea’s MAP and the trochlear groove in ten consecutive TKAs and measured their distance. Measurements were performed with a ruler on a true lateral photograph and with a radiographic marker on a lateral radiograph in four different knee flexion angles, according to a previously published protocol. Results: The trochlear groove had a mean distance from the MAP between 2.09 ± 0.15 and 5.50 ± 0.17 mm, depending on the position. In no case is the trochlear groove visible on a true lateral view. Conclusion: On a true lateral X-ray, the trochlea’s MAP omits the trochlear groove. Because the patella primarily articulates with the trochlear groove and because the relationship between the MAP and the trochlear groove is variable depending on the knee flexion angle, any conclusions regarding overstuffing based on a postoperative lateral knee X-ray are flawed. [ABSTRACT FROM AUTHOR]

Purpose: Registry data shows that less surgeons are resurfacing the patella during total knee arthroplasty (TKA). This tendency highlights the importance of matching trochlear and native patellar anatomy. Currently, there is a lack of consensus on implant design that best accommodates native patellae. The objective of this study was to compare the trochlear morphology of a large selection of contemporary TKA designs with the native trochlear anatomy. Methods: Three-dimensional models of 13 femoral component designs from seven manufacturers and 37 healthy human femora (average age: 31.2 ± 13.4 years) were reconstructed. The trochlear morphology, including trochlear length, sulcus angle, trochlear groove angle, and height and width of the medial and lateral facets, was measured along the trochlea at 15° increments. Results: The prosthetic trochlea was shorter and shallower compared to the native trochlea (p < 0.01). The native trochlea was bilinear and had a medial orientation proximally, whereas all asymmetrical TKA designs had a laterally oriented trochlea, resulting in opposite trochlear groove orientation (TKA, 5.8 ± 3.7°; native -3.1 ± 4.1°, p < 0.001). In addition, a strong correlation (R2 = 0.89) was found in TKA models between the heights of the medial and lateral facets, which was not observed for the native femora (R2 = 0.06). Conclusion: This study highlights that the lateral trochlear orientation in existing TKA models is not anatomical. Given the rising trend in patellar non-resurfacing during TKA, further studies are necessary to improve trochlear design that better accommodates the native patellar morphology. [ABSTRACT FROM AUTHOR]

Purpose: Trochlear dysplasia is found in 3.2% (95% confidence interval (CI) 1.2–6.7) of the general population and linked to patellar instability and anterior cruciate ligament (ACL) injuries. The purpose of this study was to evaluate the prevalence of radiographic trochlear dysplasia in patients with patellar fractures. Secondary outcome was to evaluate the prevalence of trochlear dysplasia in different type of patellar fracture. Methods: All consecutive 18-year-old or older patients treated in a level-1 trauma center for patellar fracture between 2003 and 2016 were retrospectively evaluated. Trochlear dysplasia was assessed according to Dejour's classification on a strict lateral knee x-ray. Patellar fractures were analyzed on AP, lateral and axial knee x-rays and classified on pattern and displacement. Patellar dislocation at time of injury was recorded. Results: Out of 482 patellar fractures, a strict lateral knee x-ray was found in 166 cases (50.6% women, mean age 56years +/-21, 51% right knee). Nineteen cases had trochlear dysplasia (11.5%, 95% CI 6.9–17.9): 10 high-grade trochlear dysplasia meaning type B, C and D (6.0%, 95% CI 2.4–9.7%); 15 without dislocation (9.3%, 95% CI 5.2–15.3). Patellar fracture distribution showed 17 transverse non-displaced (10.2%), 38 transverse displaced (22.9%), 15 avulsion (9%), 27 multifragmented non-displaced (16.3%), 56 multi-fragmented displaced (33.7%), 7 vertical (4.2%) and 6 osteochondral (3.6%) fractures. Four dislocations were recorded, all had osteochondral fractures and trochlear dysplasia. When considering patellar fractures with dislocation, the incidence of osteochondral lesions was significantly higher in patients with trochlear dysplasia (p < 0.001). This is not true for any other type of patellar fracture (p = 0.138). Conclusions: This study suggests that there is a significant prevalence of trochlear dysplasia in patients with patellar fractures. This study also suggests that the pattern of patellar fracture is not influenced by the presence of trochlear dysplasia, except for osteochondral fractures associated with patello-femoral dislocations. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence High‐grade femoral trochlear dysplasia is associated with anterior knee pain, patellar maltracking, instability and the development of osteoarthritis. Scientific studies have signified the importance of trochlear resection on the knee extensor mechanism, and dysplasia can be addressed by a groove‐deepening trochleoplasty. Alternatively, tibial tubercle anteriorisation has been proposed to reduce patellofemoral joint (PFJ) pressure and alleviate pain from osteoarthritis. However, the relative contributions of articular changes in the sagittal and axial planes remain unknown. This study aimed to better understand the effect of these different osteotomies, that alter the sagittal plane geometry, on PFJ biomechanics.Seven cadaveric knees were used to measure the following factors: (1) PFJ contact pressure; (2) Knee extension torque (KET); and (3) Patellar kinematics at 60°, 45°, 30°, 15° and 0° of knee flexion among four different osteotomy states: native, anteriorised trochlea, combined anteriorised trochlea and anteriorised tibial tubercle, and anteriorised tibial tubercle. Analysis was made using a two‐way repeated‐measures analysis of variance.Anteriorising the trochlea increased mean PFJ contact pressures ×2.9 at 0° (p = 0.024) and ×2.2 (p = 0.029) at 15° flexion compared to the native state. Peak pressures increased ×4.9 at 0° and ×3.3 at 15° (n.s.). Anteriorising the trochlea reduced KET 18% (p = 0.001) at 40° flexion and 19% (p = 0.009) at 50°. The patella was anteriorised 8 mm in the extended knee (p < 0.001) and flexed 8° at 45° knee flexion (p < 0.001) compared to the native state. Elevating the tibial tubercle, alone or combined with an anteriorised trochlea, did not have a significant effect on the respective outcome measurements.An anteriorised trochlea elevated PFJ contact pressure, reduced KET and altered patellar position during knee flexion/extension movement, while a tibial tubercle anteriorisation had a negligible opposite effect. These findings indicate that symptoms associated with high grade trochlear dysplasia may be addressed better at the trochlea, rather than at the tibial tubercle.Basic science. [ABSTRACT FROM AUTHOR]

Background/Objectives: Abnormalities in patellar tracking, often overlooked in surgical planning, have been identified as a contributing factor to total knee arthroplasty (TKA) complications, including anterior knee pain, patellar subluxation, and dislocation. This study aims to evaluate the repeatability of a novel intraoperative setup for assessing patellofemoral kinematics and its interaction with prosthesis design and positioning during surgery. This setup may support personalized alignment techniques in TKA, potentially improving surgical outcomes. Methods: Kinematic data were collected under both native and post-TKA conditions, and the Repeatability Coefficient (RC), Intraclass Correlation Coefficient (ICC), and Limits of Agreement of the Mean were calculated to assess measurement reliability. Results: RC values indicated high repeatability, with patellar flexion averaging an RC of 1°. Rotation and tilt demonstrated an RC below 1° post-mid-flexion, while patellar shift maintained an RC of approximately 1.6 mm. ICC and the extended Bland and Altman analysis showed an excellent agreement (ICC > 0.9) and an expected mean difference of zero for all the measured parameters. Measurements were consistent across both flexion and extension, and between native and post-TKA conditions. Conclusions: The proposed setup for intraoperative patellofemoral kinematic assessment demonstrated high repeatability and practical utility. The approach was found to be non-intrusive to patellar motion tracking and can be robustly integrated into the intraoperative workflow. This method provides a reliable approach for real-time patellar tracking, which may contribute to more personalized and precise TKA procedures, potentially reducing post-surgical dissatisfaction and complications. [ABSTRACT FROM AUTHOR]

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]

Purpose: The purpose of this study was to compare postoperative patellar tilt at 4 months follow‐up in a consecutive series of randomised patients that received individualised or off‐the‐shelf (OTS) primary total knee arthroplasty (TKA). The hypothesis was that patellar tilt would be lower and less variable in patients who received individualised TKA compared to patients who received OTS TKA. Methods: A consecutive series of 385 patients randomised (1:1) to receive either OTS TKA or individualised TKA were analysed. Pre‐ and postoperative radiographs at 4 months were obtained of weight‐bearing long leg, anterior–posterior and lateral knee views and a skyline view at 30° of flexion. Postoperative patellar tilt was measured between the anterior femoral line and patellar resection surface (β) and the anterior femoral line and mediolateral patellar axis (σ). Postoperative patellar tilt (absolute value) was compared between the individualised and OTS TKA groups based on preoperative phenotypes of their femoral mechanical angle, tibial mechanical angle and hip–knee–ankle angle. Variability in postoperative patellar tilt was compared using the 95% confidence intervals (CIs). Results: Comparisons of baseline patient characteristics revealed no difference between the individualised and OTS TKA groups. Comparison of absolute postoperative patellar tilt revealed significant differences between individualised and OTS TKA (|β|, 1.0° ± 1.0° and 2.5° ± 2.2°, respectively, p < 0.001; |σ|, 1.7° ± 1.6° and 2.8° ± 2.3°, respectively, p < 0.001). The 95% CI of postoperative patellar tilt (|β|) was narrower in patients that received individualised compared to OTS TKA (0.0° to 3.8° and 0.1° to 8.3°, respectively), irrespective of their preoperative phenotype. Conclusion: Patients who underwent individualised TKA had lower and less variable postoperative patellar tilt than those with OTS TKA, irrespective of preoperative phenotype. Individualised TKA allows the decoupling of the tibiofemoral and patellofemoral joints, replicating anatomical trochlear orientation and improving patellar tilt, which could facilitate better clinical outcomes. Clinical Trial Registration: This study constitutes a part of a larger registered randomised controlled trial comparing patient satisfaction following OTS versus individualised TKA (NCT04460989). Level of Evidence: Level II. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of patellar morphology on functional outcomes and patellofemoral joint alignment after unicompartmental knee arthroplasty (UKA). Methods: This study retrospectively analyzed the clinical and imaging data of 207 patients with osteoarthritis of the unicompartment of the knee who underwent UKA between September 2020 and April 2023. Patients were divided into three groups according to the Wiberg classification: group W1 (I, n = 47), group W2 (II, n = 117), and group W3 (III, n = 43). Knee function was assessed using the Hospital for Specialty Surgery (HSS) knee score and Feller patellar score, and the incidence of anterior knee pain after surgery was recorded and compared. Imaging parameters such as patellar tilt angle (PTA), lateral patellofemoral angle (LPA) and Insall-Salvati ratio (ISR) were measured to assess patellofemoral joint alignment. Results: The HSS scores of the three groups were not statistically different; the postoperative Feller scores of the group W3 differed significantly from those of the other two groups. The incidence of early postoperative anterior knee pain was higher in the group W3 than in the other two groups. The difference between preoperative PTA, postoperative PTA and preoperative LPA in the group W3 and the other two groups was statistically significant. Conclusion: Patients with Wiberg III patellae exhibited worse patellar scores, as well as more anterior knee pain and patellar tilt postoperatively. This finding highlights the need for individualized treatment to the Wiberg III patella during UKA to enhance surgical outcomes. [ABSTRACT FROM AUTHOR]

Introduction: In November 2022, OpenAI launched ChatGPT for public use through a free online platform. ChatGPT is an artificial intelligence (AI) chatbot trained on a broad dataset encompassing a wide range of topics, including medical literature. The usability in the medical field and the quality of AI-generated responses are widely discussed and are the subject of current investigations. Patellofemoral pain is one of the most common conditions among young adults, often prompting patients to seek advice. This study examines the quality of ChatGPT as a source of information regarding patellofemoral conditions and surgery, hypothesizing that there will be differences in the evaluation of responses generated by ChatGPT between populations with different levels of expertise in patellofemoral disorders. Methods: A comparison was conducted between laymen, doctors (non-orthopedic), and experts in patellofemoral disorders based on a list of 12 questions. These questions were divided into descriptive and recommendatory categories, with each category further split into basic and advanced content. Questions were used to prompt ChatGPT in April 2024 using the ChatGPT 4.0 engine, and answers were evaluated using a custom tool inspired by the Ensuring Quality Information for Patients (EQIP) instrument. Evaluations were performed independently by laymen, non-orthopedic doctors, and experts, with the results statistically analyzed using a Mann–Whitney U Test. A p-value of less than 0.05 was considered statistically significant. Results: The study included data from seventeen participants: four experts in patellofemoral disorders, seven non-orthopedic doctors, and six laymen. Experts rated the answers lower on average compared to non-experts. Significant differences were observed in the ratings of descriptive answers with increasing complexity. The average score for experts was 29.3 ± 5.8, whereas non-experts averaged 35.3 ± 5.7. For recommendatory answers, experts also gave lower ratings, particularly for more complex questions. Conclusion: ChatGPT provides good quality answers to questions concerning patellofemoral disorders, although questions with higher complexity were rated lower by patellofemoral experts compared to non-experts. This study emphasizes the potential of ChatGPT as a complementary tool for patient information on patellofemoral disorders, although the quality of the answers fluctuates with the complexity of the questions, which might not be recognized by non-experts. The lack of personalized recommendations and the problem of "AI hallucinations" remain a challenge. Human expertise and judgement, especially from trained healthcare experts, remain irreplaceable. [ABSTRACT FROM AUTHOR]

Objective: 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. Methods: 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. Results: 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. Conclusions: 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]

ABSTRACT Objective 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. Methods 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 (χ 2) test, and analysis of variance (ANOVA) were performed using GraphPad Prism (Version 8, GraphPad Software, USA). A statistically significant difference was considered at p 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). Conclusion PPB after TKA may increase patellofemoral joint stress and postoperative complications like anterior knee pain.

Abstract Background The patellofemoral joint (PFJ) stress as a primary mechanical stimulus in the patellofemoral pain (PFP) etiology is affected by plantar pressure symmetry. This study evaluated how pain exacerbation affects rear foot eversion and plantar pressure distribution symmetry. Method Sixty women with PFP participated in this study. Pain intensity, rear foot eversion, and plantar pressure were evaluated in the two conditions with and without pain exacerbation during double-leg squats. The MANOVA test was used to compare pain intensity, rear foot eversion, and plantar pressure symmetry between the two conditions. The Pearson correlation was used to evaluate the relationship between the pain intensity with the rear foot eversion and the plantar pressure symmetry. Results The comparison between the two conditions showed a significant difference in pain intensity (P

Most running biomechanics studies have focused on either the patellofemoral joint (PFJ) or Achilles tendon (AT) alone, generating fragmented understanding of how these structures interact as components of an integrated kinetic chain during running. This study was to investigate concurrent biomechanical changes in the PFJ and AT in recreational runners. The recreational runners who are accustomed to run with rearfoot strike (RFS, n = 15) and forefoot strike (FFS, n = 15) patterns were recruited. They were instructed to run at 10 km/h in cushion shoes with their habitual strike patterns on an instrumented split-belt treadmill. Kinematics of the ankle and knee joints in the sagittal plane and ground reaction forces were recorded simultaneously. The contact force and stress at the PFJ, as well as the force, loading rate, impulse, and stress of the AT, were calculated. The habitual RFS runners had significantly higher peak extension moment (p = 0.019, ES = 0.906), peak quadriceps force (p = 0.010, ES = 1.008), PFJ contact force (p = 0.007, ES = 1.056) and stress (p = 0.042, ES = 0.958) than habitual FFS runners. The peak plantar flexion moment (p < 0.001, ES = 2.692), peak AT force (p < 0.001, ES = −1.788), average (p < 0.001, ES = −2.337) and peak AT loading rate (p < 0.001, ES =-1.996), AT impulse (p = 0.002, ES = −1.246) and stress (p = 0.006, ES = −1.082) of the habitual RFS runners were significantly lower than those of the habitual FFS runners. The FFS pattern could decrease PFJ load but simultaneously increased the mechanical load on the AT. Conversely, the RFS pattern increased PFJ load, but imposed less load on the AT. • Forefoot strike reduces patellofemoral joint load but increases Achilles tendon stress. • Rearfoot strike increases patellofemoral joint load but reduces Achilles tendon stress. • Strike patterns in runners influence concurrent loading of patellofemoral joint and Achilles tendon. [ABSTRACT FROM AUTHOR]

Background: The ascending or descending extended biplanar tibial cut in open wedge high tibial osteotomy (owHTO) not only changes the lower limb anatomy in the coronal plane but also leads to different three-dimensional (3D) changes in the patellofemoral joint. This study aimed to perform a comprehensive analysis of the dynamic biomechanical changes in the knee joint using a multibody simulation model. Methods: Thirteen 3D computer models derived from lower limb computer tomography scans were used for owHTO. Osteotomies with ascending or descending biplanar cut were simulated for each wedge height from 6 to 12 mm (in 1-mm intervals). Multibody simulation was used to analyze differences in patellar shift, patellar tilt, mediolateral patellar rotation, and tibiofemoral rotation during a squat simulation from 5° to 100° knee flexion. Results: The main effects of an ascending compared with a descending extended biplanar cut in owHTO were characterized by an increase in lateralization of the patella and rotation, along with reduced tilt. Linear mixed models revealed statistically significant effects of both wedge height and cut variant on knee kinematics at 100° knee flexion, with the influence of the cut variant (ascending/descending) being higher on all analyzed kinematic parameters. Conclusions: Significant differences in the changes in patellofemoral shift, tilt, rotation, and tibiofemoral rotation were observed when performing owHTO with an ascending versus a descending biplanar cut. Apart from tibiofemoral rotation, the resulting kinematic changes were greater with an ascending cut. [ABSTRACT FROM AUTHOR]

Individuals who undergo anterior cruciate ligament reconstruction are at elevated risk for developing early‐onset patellofemoral joint osteoarthritis. Our objective was to use K‐means clustering to ascertain whether individuals at risk for patellofemoral joint osteoarthritis could be identified as determined by the presence of multiple co‐existing anatomical and patella alignment risk factors. Forty participants (20 after anterior cruciate ligament reconstruction, 20 healthy controls) underwent magnetic resonance imaging assessment of the patellofemoral joint. Measures of hypothesized risk factors for patellofemoral joint osteoarthritis were obtained including patella alignment (lateral patella displacement and tilt), trochlear morphology (sulcus angle, lateral inclination angle), patella height (Insall‐Salvati ratio and patella articulating overlap), and patellofemoral joint contact area. K‐means clustering (k = 2) was used to ascertain whether a high‐risk group could be identified. Following clustering, two distinct groups were detected. Participants assigned to cluster 1 exhibited features consistent with patellofemoral joint osteoarthritis including greater lateral patellar displacement and tilt, flatter trochlear grooves and lower lateral trochlear inclination, less patella articulating overlap, and reduced contact area. The proportion of females after anterior cruciate ligament reconstruction assigned to cluster 1 was 75% (N = 15) compared to 25% of healthy females (N = 5). K‐means clustering was capable of characterizing individuals at elevated risk for patellofemoral joint osteoarthritis based on the presence of multiple co‐existing anatomical and patella alignment risk factors. The fact that a significant percentage of females were assigned to the high‐risk cluster supports the clinical observation that these individuals may be at higher risk of early‐onset patellofemoral joint osteoarthritis. [ABSTRACT FROM AUTHOR]

Background: Anterior knee pain is a prevalent issue post total knee arthroplasty, often necessitating revision surgery. Various factors contribute to this complication, including patellar maltracking and excessive patellofemoral load. Kinematic alignment has emerged as an alternative, showing promising outcomes in clinical studies. However, its impact on patellofemoral biomechanics needs to be more adequately understood. This study compared the effects of kinematically versus mechanically aligned total knee arthroplasty on patellofemoral joint biomechanics. Methods: Eight fresh-frozen human knee specimens underwent biomechanical testing in a knee rig setup, performing an active weight-loaded knee joint flexion of 30–130°. After the testing of native kinematics, kinematically and mechanically aligned total knee arthroplasty was performed using a medial pivot implant design without patellar resurfacing. Quadriceps force, retropatellar peak pressure and the retropatellar contact area were measured during knee flexion using a patellar pressure-sensitive film. Patella kinematics (shift and tilt) was tracked using an optoelectrical measurement system. Functional regressions were used to determine the influence of the alignment on the kinematics and loading of the knee joint. Results: Kinematically aligned total knee arthroplasty resulted in reduced quadriceps force during knee flexion compared to mechanically aligned total knee arthroplasty. Retropatellar peak pressure, retropatellar contact area and patella kinematics did not vary between the alignments. Conclusions: Kinematic alignment offers potential benefits in reducing quadriceps force during knee flexion, which may mitigate anterior knee pain risk. Further research is needed to elucidate its effects in varying anatomical conditions and alignment strategies. [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]

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]

There are some limitations to using the body condition score (BCS) for client education to prevent obesity, hyperlipidemia-related diseases, and orthopedic diseases in dogs because it is hard to quantify in detail. Especially in small dogs, patellar luxation is a common orthopedic disease that is related to obesity and the hind leg muscle. In this pilot study, the author evaluated the thorax/thigh circumference ratio as a prognostic evaluation index, along with the BCS, for assessing patellar dislocation and other hyperlipidemia-related diseases and states such as hypertriglyceridemia and obesity-related orthopedic disease in small dogs. Eleven client-owned dogs were selected randomly among patients that visited Bundang New York Animal Hospital, South Korea from June 2021 to August 2024. According to the results, triglycerides (TG) showed a negative correlation with thorax/thigh value (R = −0.585, p-value = 0.059) and a strong positive correlation with thigh circumference (R = 0.749, p-value = 0.008). Total cholesterol (TC) showed a strong positive correlation with thigh circumference (R = 0.776, p-value = 0.005), whereas the thorax/thigh value showed a negative correlation with the medial patella luxation (MPL) grade with low significance (R = −0.343, p-value = 0.302). These data indicate that thigh circumference can be an excellent negative indicator for hyperlipidemia and thorax/thigh value shows no correlation with medial patella luxation, which has many factors such as varus and trochlear groove. Despite the limitations of this study due to the small sample size, this pilot study is significant as it is the first trial to introduce a new indicator for monitoring hyperlipidemia at home by using a simple tape measure. Also, the author reviews molecular pathways including the ApoA-1, ApoE, and LPL genes, which are related to hyperlipidemia, to explain the results. [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. DESIGN: A secondary analysis of a 26-week randomized trial involving 200 participants with patellofemoral pain. 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 catastrophizing 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). 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]

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Background: Anterior cruciate ligament (ACL) injuries frequently present with lateral meniscal injuries, and when irreparable, this may lead to meniscectomy, increasing the risk for osteoarthritis. Lateral meniscal allograft transplant (LMAT) can restore knee function and proper contact pressures. When combined with osteochondral allograft (OCA) for chondral defects, results are highly positive. Indications: LMAT is indicated in relatively young patients (<50 years of age) with a symptomatic, meniscus-deficient knee that has failed conservative treatment. The knee must be stable, without articular cartilage damage that cannot be repaired, and patients should be able to adhere to postoperative rehabilitation and future care. Indications for OCA include young, active patients with posttraumatic osteochondral defects, osteonecrosis, osteochondritis dissecans, large focal defects, previous cartilage repair failure, or patellofemoral joint cartilage lesions. Technique Description: After a diagnostic arthroscopy is performed and concomitant injuries are ruled out, the lateral meniscal tissue is debrided to a 1- to 2-mm rim for the recipient site preparation. Tibial sockets for root fixation are created using tibial guides and passing sutures are placed. A capsulodesis is performed to reduce meniscal extrusion by securing the lateral capsule through a transtibial tunnel to the anteromedial tibial cortex with high-strength sutures. A meniscal allograft, prepared with bone plugs, is introduced through an enlarged anterolateral portal. After it is accurately positioned, it is stabilized using Fast-Fix Flex devices and circumferential sutures. The bone plug sutures are then fixed through the tibial tunnels to the anteromedial tibial cortex with a button. The large cartilage defect is addressed with an OCA transplant, involving defect measurement, careful reaming, and press-fit insertion of a donor plug, ensuring congruent articulation. Results: Patients can expect improved clinical outcomes and high patient satisfaction with LMAT and concomitant OCA. The use of bone plugs minimizes soft tissue dissection while achieving solid osseous fixation. Discussion/Conclusions: LMAT with OCA leads to restored contact pressures to near-physiological levels, a high patient satisfaction of over 85%, and mean allograft survival of 16 years. 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]

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]

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]

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]

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: A previous study on osteoarthritic knees found that the average position of the centre of the proximal quadriceps tendon (PQT) was 9 mm lateral from the native trochlear groove. In patients with lateral patellar facet osteoarthritis, which indicates patellofemoral instability, the average location was 21 mm. The researchers suggested that a position more lateral than 20 mm might lead to poor outcomes after kinematically aligned total knee arthroplasty (KA TKA)—the current study aimed to test this hypothesis. Methods: The study involved all patients (n = 302) who underwent KA TKA (n = 313) in 2019, had a post‐operative long‐leg scanogram and knee computed tomography scan, and completed a 2‐year questionnaire. An evaluator measured the location of the PQT relative to the centre of the distal prosthetic trochlear groove. A Spearman's rank correlation coefficient analysis determined whether there was an association between the location of the PQT and the Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) at 2 years. Results: The mean location of the PQT was 11 ± 8 mm (range, −2 medial to 36 mm lateral), with 16% (N = 46) of the KA TKAs having a more lateral location than 20 mm. The location of the PQT was not associated with the FJS (r = −0.0349, p = 0.7281) and OKS (r = −0.0641, p = 0.9009)—no patient response indicated symptoms or operative treatment for patellofemoral instability. Conclusion: Even though 16% of patients with a KA TKA had a more lateral location than 20 mm, there is no reason to measure the centre of the PQT relative to the distal prosthetic groove. This is because the location did not show any association with the 2‐year FJS and OKS nor had any patient experienced patellofemoral instability. Level of Evidence: IV. [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]

Purpose: Though previous studies on surgical quadriceps tendon repair reported good to satisfactory results its impact on knee extensor strength and patellofemoral joint is unknown. The purpose of the study was to assess the clinical and functional outcome by quantifying subjective knee related outcome, isokinetic extensor strength complemented by magnetic resonance imaging (MRI). Methods: For this retrospective clinical trial twenty-one patients with a mean age of 59.1 (±14.9) years were carried out for follow-up evaluation. For clinical outcome numeric rating scale for pain (NRS), Kujala anterior knee pain score, Knee osteoarthritis outcome score (KOOS) with its subscores, Tegener Activity Score (TAS), Isokinetic extensor strength testing (ISO) and the Limb symmetry index (LSI) were utilized. Muscle volume (Vmqf), atrophy and cartilage status were assessed on MRI. Tendon integrity and implant loosening were evaluated. Statistical analysis was carried out using Student´s t-test, Pearson and Spearman correlation coefficient. Results: Mean follow–up was 56.2 (± 17.5) months. Clinical outcomes in mean were as follows: NRS 1.7 (±2.0), Kujala score 75.8 (± 15.8) points; KOOS 62.9 (±30.6) % (Subscores: (KOOSPain 84 (± 18.3)%, KOOSSymptoms 63.4 (± 15.3) %, KOOSADL 79.8% (± 19.4)%, KOOSSports&Rec 61.5 (± 28.8))%, TAS 3.7 (± 1.2). Mean ISO difference was 3.7 (±32.3) %). 41.2% of patients had an LSI < 90% and showed non-significantly (p > 0.05) better outcomes in NRS, Kujala score and KOOS than patients with LSI < 90%. ISO correlated with better subjective outcome (r > 0.5) but not with MRI findings. Vmqf asymmetry > 10% was seen in 41,2% of patients. Degenerative muscle and cartilage changes were few and low grade. One tendon showed partial retear. Patients showed no signs of implant loosening. Conclusion: Distal quadriceps tendon repair leads to satisfactory subjective outcome in patients with low to moderate activity levels. Tendon integrity was reliably restored. However, extensor strength deficits remain in more than 40% of patients. Atrophy signs of advanced fatty infiltration were recorded in 15% and patellofemoral cartilage defects in 20% of all patients, indicating that previous assessment tools do not display functional outcome adequately. [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]

Introduction: Anterior knee pain commonly affects young women resulting in the declination of the quality of life. One of the possible pathologies causing this symptom is chondromalacia patellae (CMP). Although CMP is used to describe the softening of patellar articular cartilage, it remains a general descriptive term as it cannot be associated with a specific pathophysiologic mechanism. The objective of this study is to investigate the effect of injectable PRP on patients with anterior knee pain in absence of altered patellofemoral joint anatomy. Methods: For this purpose, 43 patients of the affected population were recruited to participate in this non-randomized controlled trial, 28 patients in the injection group and 15 in the only-physiotherapy group. While patients in the experimental group received three PRP injections and one injection of hyaluronic acid (HA), comparators received the standard physical therapy regimen. The treatment choice was based on patients own decree. Patients between the ages of 18 to 50 years with anterior knee pain and positive Clarke´s sign were eligible for inclusion. Patients with evident anatomical abnormalities, chronic conditions affecting the knee and severe symptoms such as blocking, were excluded from the study. Patient related measures (PROMS) in the form of the VAS and the Kujala scores were the main outcome of interest. All outcomes were measured at baseline, and after 3 and 6 months after the treatment. Results: Although an improvement was seen in both groups, a statistically significant difference favoring the injection of PRP over the physiotherapy-only group was observed (p < 0.001). The superiority of the therapeutic modality under investigation was observed at 3 and 6 months after the initial diagnosis was made. Furthermore, the results of this study revealed a significant improvement at 3 and 6 months when compared to baseline measures. The analysis of the patients age showed a negative correlation when baseline values were compared to measures at 3 and 6 months, meaning younger patients had more benefit from the treatment. Discussion: The main results of this study affirm the positive effects of PRP and HA for the treatment of anterior knee pain described by previous research and the subsequent improvement of the quality of life. Relatively little information was found in the literature search regarding the therapeutic effects of PRP on anterior knee pain and chondropathies. While a previous radiologic study found no evidence regarding the effect of PRP, this study found a benefit when comparing PROMs between patient groups. [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]

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]

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. The functional status of the ankle joint is critical during dynamic movements in high‐intensity sports like basketball and volleyball, particularly when performing actions such as stopping jumps. Limited ankle dorsiflexion is associated with increased injury risk and biomechanical changes during stop‐jump tasks. Therefore, this study aims to investigate how restricting ankle dorsiflexion affects lower extremity biomechanics during the stop‐jump phase, with a focus on the adaptive changes that occur in response to this restriction. Initially, 18 participants during stop‐jumping with no wedge plate (NW), 10° wedge plate (10 W), and 20° wedge plate (20 W) using dominant leg data were collected to explore the relationship between limiting ankle mobility and lower extremity biomechanics. Following this, a musculoskeletal model was developed to simulate and calculate biomechanical data. Finally, one‐dimensional parametric statistical mapping (SPM1D) was utilized to evaluate between‐group variation in outcome variables using a one‐way repeated measures analysis of variance (ANOVA). Results. As the ankle restriction angle increased, knee external rotation angles, knee extension angular velocities, hip extension angle, and angular velocity increased and were significantly different at different ankle restriction angles (p < 0.001 and p = 0.001), coactivation of the peripatellar muscles (BF/RF and BF/VM) increased progressively, and patellofemoral joint contact force (PTF) increased progressively during the 3%–8% phase (p = 0.015). These results highlight the influence of ankle joint restriction on lower limb kinematics and patellofemoral joint loading during the stop‐jump maneuver. Conclusion. As the angle of ankle restriction increased, there was an increase in coactivation of the peripatellar muscles and an increase in PTF, possibly because a person is unable to adequately adjust their body for balance when the ankle valgus angle is restricted. The increased coactivation of the peripatellar muscles and increased patellofemoral contact force may be a compensatory response to the body's adaptation to balance adjustments. [ABSTRACT FROM AUTHOR]

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]

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]

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]