Wilson Nicole A, Press Joel M, Koh Jason L, Hendrix Ronald W, Zhang Li-Qun
Sensory Motor Performance Program, Rehabilitation Institute of Chicago, 345 East Superior Street, Chicago, IL 60611, USA.
J Bone Joint Surg Am. 2009 Mar 1;91(3):558-66. doi: 10.2106/JBJS.G.00572.
Patellofemoral pain syndrome is one of the most common knee problems and may be related to abnormal patellar tracking. Our purpose was to compare, in vivo and noninvasively, the patellar tracking patterns in symptomatic patients with patellofemoral pain and those in healthy subjects during squatting. We tested the hypothesis that patients with patellofemoral pain exhibit characteristic patterns of patellar tracking that are different from those of healthy subjects.
Three-dimensional patellar kinematics were recorded in vivo with use of a custom-molded patellar clamp and an optoelectronic motion capture system in ten healthy subjects and nine subjects with patellofemoral pain. The position of osseous knee landmarks was digitized while subjects stood upright, and then patellofemoral kinematics were recorded during squatting. The tracking technique was validated with use of both in vitro and in vivo methodologies, and the average absolute error was <1.2 degrees and <1.1 mm.
At 90 degrees of knee flexion, the patella showed lateral spin (the distal pole of the patella rotated laterally) in subjects with patellofemoral pain (mean and standard deviation, -10.13 degrees +/- 2.24 degrees) and medial spin in healthy subjects (mean, 4.71 degrees +/- 1.17 degrees) (p < 0.001). At 90 degrees of knee flexion, the patella demonstrated significantly more lateral translation in subjects with patellofemoral pain (mean, 5.05 +/- 3.73 mm) than in healthy subjects (mean, -4.93 +/- 3.93 mm) (p < 0.001).
Kinematic differences between healthy subjects and subjects with patellofemoral pain were demonstrated through a large, dynamic range of knee flexion angles. Increased lateral patellar translation and lateral patellar spin in subjects with patellofemoral pain suggest that the patella is not adequately balanced during functional activities in this group. Prospective studies are needed to identify when patellofemoral pain-related changes begin to occur and to determine the risk for the development of patellofemoral pain in individuals with abnormal kinematics.
髌股疼痛综合征是最常见的膝关节问题之一，可能与髌股轨迹异常有关。我们的目的是在有症状的髌股疼痛患者和健康受试者深蹲过程中，进行体内非侵入性髌股轨迹模式比较。我们检验了这样一个假设，即髌股疼痛患者表现出与健康受试者不同的特征性髌股轨迹模式。
使用定制的髌夹和光电运动捕捉系统，对10名健康受试者和9名髌股疼痛受试者进行体内三维髌股运动学记录。在受试者直立时，对骨性膝关节标志点的位置进行数字化处理，然后在深蹲过程中记录髌股运动学。通过体外和体内方法对跟踪技术进行了验证，平均绝对误差<1.2度和<1.1毫米。
在膝关节屈曲90度时，髌股疼痛受试者的髌骨出现外侧旋转（髌骨远端向外旋转）（均值和标准差，-10.13度±2.24度），而健康受试者的髌骨出现内侧旋转（均值，4.71度±1.17度）（p<0.001）。在膝关节屈曲90度时，髌股疼痛受试者的髌骨向外平移明显多于健康受试者（均值，5.05±3.73毫米）（均值，-4.93±3.93毫米）（p<0.001）。
通过大范围的动态膝关节屈曲角度，证明了健康受试者和髌股疼痛受试者之间的运动学差异。髌股疼痛受试者髌骨向外平移增加和外侧旋转表明，该组在功能活动期间髌骨没有得到充分平衡。需要进行前瞻性研究，以确定髌股疼痛相关变化何时开始出现，并确定运动学异常个体发生髌股疼痛的风险。
