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Objective: Patellofemoral kinematics and contact mechanics are important measurements for the assessment of patellofemoral joint (PFJ) problems. Simultaneously measuring PFJ contact pressures and kinematics is a challenging task. The purpose of this study was to simultaneously measure the kinematics and mean/peak contact pressures in the PFJs of cadaveric knees. Methods: This was a comparative study performed on fresh cadaveric knees. The kinematic data was acquired for nine cadaveric knees using an optical tracking system. Data about the contact pressure and contact area in the PFJ was obtained at knee flexion angles of 0°, 30°, 60°, 90°, and 120° using a pressure sensor. Intraclass correlation coefficients (ICCs) and minimal detectable differences (MDDs) of six degrees of freedom (6 DOF) in the PFJs were calculated. ICCs and the MDDs of contact pressure, peak pressure, and contact area in the PFJs were also analyzed. We also compared the kinematics of the cadaveric knees before and after the insertion of the pressure sensor. Results: All ICC values of 6 DOF in the PFJs were found to be greater than or equal to 0.924. Regarding medial–lateral rotation, the patellar showed a simplified movement pattern that demonstrated progressive lateral rotation of 4.8° ± 3.4° at 120° of knee flexion. While for patellar tilting, the patella showed medial tilting that peaked at 7.2 ± 2.5° at 30° of knee flexion. Whereas no significant differences in PFJ kinematics were found between with and without the placement of the pressure sensor at all knee flexions (P > 0.05). Most of the ICC values for contact pressure, peak contact pressure, and contact area ranged from 0.8 to 0.9. The MDDs for rotational displacement were 0.9° and 0.6 mm for translational displacement. No statistical differences in patellar kinematics were found before and after the insertion of the pressure sensor. Conclusions: The setup in the present study enables researchers to simultaneously and synchronously collect real‐time PFJ kinematics and tibiofemoral joint (TFJ) biomechanical kinematic data with high reliability. The low MDDs enabled the researchers to obtain an accurate interpretation of the kinematic and contact mechanics measurement using the experimental setting used in the present study. [ABSTRACT FROM AUTHOR]

Despite an increasing request for skin rejuvenation above the knee, very few treatment options have been reported in literature. To evaluate the efficacy and safety of 1:4 hyperdiluted calcium hydroxylapatite (CaHA) in the treatment of skin laxity and dimples of the skin above the knees. A retrospective evaluation of hyperdiluted CaHA treatment for skin laxity and dimples above the knee was performed. Efficacy was classified as blinded evaluation of pre (T0) and 3‐month post‐treatment (T1) photographs by three investigators according to the validated knee cellulite severity score (KCSS) and patient satisfaction. Safety was evaluated through pain scores and adverse events evaluation. A significant reduction of KCSS at T1, as compared to T0, mainly in subjects with lower KCSS at T0, was observed (P <.05). All blinded assessments resulted in a correct identification of T0 and T1 pictures and evaluations of all investigators were found to be consistent and reliable. All patients were satisfied. Only minor adverse events (swelling, erythema, bruising, and skin irregularities) were reported, lasting 2 to 3 weeks after treatment. Our preliminary results highlight the efficacy and safety of hyperdiluted CaHA in the treatment of skin laxity and cellulite above the knees. [ABSTRACT FROM AUTHOR]

Purpose: Our clinical understanding of the relationship between 3D bone morphology and knee osteoarthritis, as well as our ability to investigate potential causative factors of osteoarthritis, has been hampered by the time‐intensive nature of manually segmenting bone from MR images. Thus, we aim to develop and validate a fully automated deep learning framework for segmenting the patella and distal femur cortex, in both adults and actively growing adolescents. Methods: Data from 93 subjects, obtained from on institutional review board–approved protocol, formed the study database. 3D sagittal gradient recalled echo and gradient recalled echo with fat saturation images and manual models of the outer cortex were available for 86 femurs and 90 patellae. A deep‐learning–based 2D holistically nested network (HNN) architecture was developed to automatically segment the patella and distal femur using both single (sagittal, uniplanar) and 3 cardinal plane (triplanar) methodologies. Errors in the surface‐to‐surface distances and the Dice coefficient were the primary measures used to quantitatively evaluate segmentation accuracy using a 9‐fold cross‐validation. Results: Average absolute errors for segmenting both the patella and femur were 0.33 mm. The Dice coefficients were 97% and 94% for the femur and patella. The uniplanar, relative to the triplanar, methodology produced slightly superior segmentation. Neither the presence of active growth plates nor pathology influenced segmentation accuracy. Conclusion: The proposed HNN with multi‐feature architecture provides a fully automatic technique capable of delineating the often indistinct interfaces between the bone and other joint structures with an accuracy better than nearly all other techniques presented previously, even when active growth plates are present. [ABSTRACT FROM AUTHOR]

Introduction Osteoporosis is common in haemophilic arthropathy. Quantitative ultrasound ( QUS) can be a suitable alternative for dual-energy x-ray absorptiometry for diagnosing osteoporosis in haemophiliacs due to its lack of ionizing radiation, and ease to use. Aim We investigated the intra- and inter-operator reliability of QUS, its responsiveness to bone growth, its ability to differentiate bone adjacent to blood-injected vs. control joints, and the effect of soft tissues on the speed of sound ( SOS) QUS values in a juvenile white New Zealand rabbit model of blood-induced arthritis. Methods Eight of 16 rabbits were injected with autologous blood (0.1 mL kg−1) 8 times over a 17-week period, the remaining eight rabbits served as controls. SOS was measured at baseline, weeks 8 and 17 in vivo and after the bones were excised on week 17. Results Intra- and inter-operator coefficients of variation for QUS data were <5% and intraclass correlation coefficients were >60% for 22/27 (81.5%) of bones assessed. The level of interval increase in SOS values from baseline to week 17 was significantly different in tibiae of injected, contralateral to injected and non-injected knee groups by anova ( P = 0.01). In vivo (mean ± SD, 4147.17 ± 96.27 m s−1) and postmortem (4457.85 ± 104.00 m s−1) measurements on week 17 differed ( P < 0.01) indicating an effect of soft tissues on SOS. Conclusion In conclusion, QUS' acceptable reliability, its responsiveness to growth-related changes and its ability to discriminate injected and non-injected joints make this technique a plausible candidate as a diagnostic tool for osteoporosis in the paediatic haemophilic population if these results are confirmed upon animal-human translation. [ABSTRACT FROM AUTHOR]