Sasaki T, Yagi T
Int Orthop. 1986;10(2):115-20.
Subluxation of the patella may produce pain and instability in young people. However its classification, diagnosis and treatment are controversial. We have used computerized tomography (CT) to measure the amount of lateral shift of the patella and the angle of tilt to the femur in patients with subluxation. The mean lateral shift was 31.4% and the angle of tilt 31.8 degrees. These values are significantly greater than those obtained from conventional axial radiographs or in arthrographic axial views. We have obtained interesting evidence that the rate of lateral shift apparently increased on voluntary contraction of the quadriceps muscle (Q-contracted). With the quadriceps contracted, the mean rate of the lateral shift in the affected knees showed a significant increase (+27.7%) compared to that in normal knees (+14.0%). We have reviewed 40 knees treated by operative realignment with a mean follow-up of 27 months. The mean rates of lateral shift measured from CT-image in the knees before operation improved significantly to the normal range at follow-up, both with the quadriceps relaxed and contracted. The results evaluated by Insall's criteria were "excellent" in 13 knees; "good" in 22; "fair" in 3 and "poor" in 2. The satisfactory group (those with excellent and good results) revealed an improvement in lateral shift when the quadriceps was contracted, while the unsatisfactory group (fair and poor results) did not.
髌骨半脱位在年轻人中可能会导致疼痛和不稳定。然而，其分类、诊断和治疗仍存在争议。我们使用计算机断层扫描（CT）来测量髌骨半脱位患者髌骨的外侧移位量以及髌骨相对于股骨的倾斜角度。平均外侧移位为31.4%，倾斜角度为31.8度。这些值显著高于传统轴位X线片或关节造影轴位视图所测得的值。我们获得了有趣的证据，即股四头肌自主收缩时（Q收缩），外侧移位率明显增加。股四头肌收缩时，患侧膝关节的平均外侧移位率与正常膝关节相比显著增加（+27.7%，正常膝关节为+14.0%）。我们回顾了40例接受手术复位治疗的膝关节，平均随访27个月。术前通过CT图像测量的膝关节外侧移位率在随访时，无论股四头肌放松还是收缩，均显著改善至正常范围。根据Insall标准评估的结果为：13例膝关节“优秀”；22例“良好”；3例“尚可”；2例“差”。满意组（结果为优秀和良好的患者）股四头肌收缩时外侧移位有所改善，而不满意组（结果为尚可和差的患者）则没有。
