Acute inferior dislocation of the patella is a rare presentation in trauma and orthopaedics. Type II is caused by direct upward force on the inferior pole of the patella when the knee is flexed impacting the superior pole osteophyte into the intercondylar notch. Impaction in the femoral trochlea is rarely reported. A 92-year-old lady presented with locked knee held in 85° of flexion with an abnormal knee contour. Radiographs demonstrated that the upper pole of the patella was impacted in the femoral trochlea with a fracture of a superior pole osteophyte. The extensor mechanism was intact. Closed reduction is achieved under strong opioid pain relief. The patient returned to her baseline knee function within 6 weeks. Closed reduction of an inferior patellar dislocation in elderly patients is aided by superior pole osteophyte fracture and facilitates early mobilization, and avoidance of general anaesthesia.
Case Rep Orthop Res 2021;4:89–92

中文翻译：

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下股骨滑车因Impact骨下脱位

trauma骨急性下脱位在创伤和骨科中很少见。II型是由于膝盖弯曲时，pole骨下极直接向上的力而导致上极骨赘进入into间切口。很少有人报道股骨滑车受累。一位92岁的女士，膝盖弯曲时被锁定，膝盖处于弯曲状态，弯曲角度为85度。放射线照片显示the骨上极受股极滑车影响，上极骨赘骨折。伸肌机制是完整的。在强烈的阿片类药物缓解疼痛的情况下，可实现封闭式复位。患者在6周内恢复了基线膝关节功能。
Case Rep Orthop Res 2021; 4：89–92