METHODS: Twelve fresh-frozen cadaveric knees were used. Five components of the quadriceps and the iliotibial band were loaded physiologically with 175N and 30N, respectively. The force required to displace the patella 10mm laterally and medially at 0°, 20°, 30°, 60° and 90° knee flexion was measured. Patellofemoral contact points at these knee flexion angles were marked. The trochlea cartilage geometry at these flexion angles was visualized by Computed Tomography imaging of the femora in air with no overlying tissue. The sulcus, medial and lateral facet angles were measured. The facet angles were measured relative to the posterior condylar datum.
RESULTS: The lateral facet slope decreased progressively with flexion from 23°±3° (mean±S.D.) at 0° to 17±5° at 90°. While the medial facet angle increased progressively from 8°±8° to 36°±9° between 0° and 90°. Patellar lateral stability varied from 96±22N at 0°, to 77±23N at 20°, then to 101±27N at 90° knee flexion. Medial stability varied from 74±20N at 0° to 170±21N at 90°. There were significant correlations between the sulcus angle and the medial facet angle with medial stability (r=0.78, p<0.0001).
CONCLUSIONS: These results provide objective evidence relating the changes of femoral profile geometry with knee flexion to patellofemoral stability.
METHODS: A total of 8 and 7 children who had gradual GGS and ACO correction, respectively, for angular deformities due to rickets from 2002 to 2022 were recalled for follow-up. Demographic data, types of rickets, data on pharmacological treatment, biochemical parameters, recurrence of angular deformity and postoperative complications were obtained from the medical records. A radiographic evaluation of the leg was performed to determine the tibiofemoral angle. For functional evaluation, the Active Scale for Kids (ASK) and Lower Extremity Functional Scale (LEFS) instruments were used for children below and above 15 years old, respectively.
RESULTS: In terms of the tibiofemoral angle, the GGS group documented greater angle changes compared to the ACO group, but the difference was not significant. In terms of functional outcomes, the overall score percentage of both groups was comparable with the GGS group showing a trend of higher score percentage compared to the ACO group. The GGS group presented no complication while 2 neurovascular injuries and 1 implant failure were recorded in the ACO group.
CONCLUSION: Both GGS and ACO procedures resulted in similar radiographic and functional outcomes for the treatment of rickets in children. GGS may be advantageous in terms of reducing complications of surgery. Nevertheless, the choice of surgical intervention should be made based on the patient's circumstances and the surgeon's preference.
METHODS: Three different cams (triangle, ellipse, and circle) and three different posts (straight, convex, concave) geometries were considered in this study and were analysed using kinematic analyses. Femoral rollback did not occur until reaching 50° of knee flexion. Beyond this angle, two of the nine combinations demonstrate poor knee flexion and were eliminated from the study.
RESULTS: The combination of circle cam with concave post, straight post and convex post showed 15.6, 15.9 and 16.1 mm posterior translation of the femur, respectively. The use of ellipse cam with convex post and straight post demonstrated a 15.3 and 14.9 mm femoral rollback, whilst the combination of triangle cam with convex post and straight post showed 16.1 and 15.8 mm femoral rollback, respectively.
CONCLUSION: The present study demonstrates that the use of circle cam and convex post created the best femoral rollback effect which in turn produces the highest amount of knee flexion. The findings of the study suggest that if the design is applied for knee implants, superior knee flexion may be possible for future patients.
LEVEL OF EVIDENCE: IV.