Iranpour Farhad, Merican Azhar M, Teo Seow Hui, Cobb Justin P, Amis Andrew A
Musculoskeletal Laboratory, Imperial College London, Charing Cross Hospital, London, United Kingdom.
Musculoskeletal Laboratory, Imperial College London, Charing Cross Hospital, London, United Kingdom; National Orthopaedic Centre of Excellence for Research and Learning (NOCERAL), Department of Orthopaedic Surgery, University of Malaya, Malaysia.
Knee. 2017 Jun;24(3):555-563. doi: 10.1016/j.knee.2017.01.011. Epub 2017 Mar 19.
Patellofemoral instability is a major cause of anterior knee pain. The aim of this study was to examine how the medial and lateral stability of the patellofemoral joint in the normal knee changes with knee flexion and measure its relationship to differences in femoral trochlear geometry.
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.
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).
These results provide objective evidence relating the changes of femoral profile geometry with knee flexion to patellofemoral stability.
髌股关节不稳是前膝痛的主要原因。本研究的目的是探讨正常膝关节中髌股关节的内侧和外侧稳定性如何随膝关节屈曲而变化，并测量其与股骨滑车几何形状差异的关系。
使用12个新鲜冷冻的尸体膝关节。分别以175N和30N的力对股四头肌的五个组成部分和髂胫束进行生理性加载。测量在膝关节屈曲0°、20°、30°、60°和90°时使髌骨向外侧和内侧移位10mm所需的力。标记这些膝关节屈曲角度下的髌股接触点。通过对无覆盖组织的空气中的股骨进行计算机断层扫描成像，观察这些屈曲角度下的滑车软骨几何形状。测量沟角、内侧和外侧小面角。小面角相对于后髁基准进行测量。
外侧小面斜率随屈曲从0°时的23°±3°（平均值±标准差）逐渐降低至90°时的17±5°。而内侧小面角在0°至90°之间从8°±8°逐渐增加至36°±9°。髌骨外侧稳定性从0°时的96±22N变化至20°时的77±23N，然后在膝关节屈曲90°时变化至101±27N。内侧稳定性从0°时的74±20N变化至90°时的170±21N。沟角和内侧小面角与内侧稳定性之间存在显著相关性（r = 0.78，p < 0.0001）。
这些结果提供了客观证据，将股骨轮廓几何形状随膝关节屈曲的变化与髌股稳定性联系起来。
