Tibiofemoral and patellofemoral mechanics are altered at small knee flexion angles in people with patellofemoral pain

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• 作者：Gretchen B. Salsich^a ; ^{salsichg@slu.edu} ; William H. Perman^b
• 关键词：Knee joint ; Biomechanics ; Magnetic resonance imaging ; Cartilage
• 刊名：Journal of Science and Medicine in Sport
• 出版年：2013
• 出版时间：January, 2013
• 年：2013
• 卷：16
• 期：1
• 页码：13-17
• 全文大小：266 K

文摘

Objectives

To test the hypothesis that, at 0¡ã and 20¡ã of knee flexion, patellofemoral contact area would be lower, while tibiofemoral rotation and patellofemoral malalignment would be higher in participants with patellofemoral pain (PFP) compared to pain-free participants. We hypothesized that no differences would be detected at 40¡ã due to increasing patellar stability.

Design

Cross-sectional, descriptive study.

Methods

Twenty-seven people with PFP and 29 pain-free people participated. Participants underwent magnetic resonance imaging at 0¡ã, 20¡ã, and 40¡ã knee flexion with the limb in a simulated weight-bearing position. Patellofemoral contact area, tibiofemoral rotation angle, patellofemoral alignment (bisect offset index and patellar tilt angle) were quantified and compared between groups at each angle using Student's t-tests. An a-posteriori comparison was made between the pain-free group and a subgroup of 15 participants with patellofemoral pain who demonstrated a faulty lower limb movement pattern (¡°medial collapse¡±).

Results

In the patellofemoral pain group, contact area was lower at 0¡ã (203.8 ¡À 45.5 mm² vs. 224.1 ¡À 46.6 mm², p = 0.05) and 20¡ã (276.8 ¡À 56.2 mm² vs. 316.7 ¡À 82.8 mm², p = 0.02), bisect offset index (BOS) and patellar tilt angle (PTA) were higher at 0¡ã (bisect offset index: 0.69 ¡À 0.13 vs. 0.64 ¡À 0.09, p = 0.04; patellar tilt angle: 12.5 ¡À 7.6¡ã vs. 9.2 ¡À 5.8¡ã, p = 0.04). In the patellofemoral pain subgroup, tibiofemoral rotation was higher at 0¡ã compared to pain-free participants (6.4 ¡À 5.9¡ã vs. 4.0 ¡À 4.6¡ã, p = 0.07).

Conclusions

While contact area and patellofemoral alignment were altered in people with patellofemoral pain, tibiofemoral rotation was altered in a subgroup of people who demonstrated medial collapse. Subgroup classification may help identify mechanisms of pain and assist in developing targeted interventions.