髌骨纵行骨折的机理及误诊原因探讨

报告髌骨纵行骨折20例，其中误诊12例，部分病例发生机理不能用三点挤压原理解释。作者对误诊原因和发生机理进行分析，认为对髌骨纵行骨折的认识不足，缺乏必要的体格检查，不摄髌骨轴位片是误诊的主要原因。当屈膝＜90°时，髌前方向外的暴力作用在髌骨上，先使内侧特别面与股骨内髁接触，外侧面悬起，暴力的继续作用和股外侧肌的强力收缩使髌骨外1／3纵行骨折。

Mechanism of Patellar Longitudinal Fracture and the Cause of Its Misdiagnosis

20 cases of longitudinal fracture of the patella were reported,among them 12 cases had been misdiagnosed and the fracture mechanism in some cases could not be explained with the principle of three- point stress. The causes of misdiagnosis and the mechanism of longitudinal fracture were analysed. It was considered that the insufficient knowledge about longitudinal fracture of patella,the lack of necessary physical examination and not taking the axial X-ray film of patella might be the major causes for misdiagnosis. As the knee flexes less than 90 degree,the force from anterolateral direction and acting on the patella can press the medial special surface of patella to contact with the medial condyle of femur and thus induce the suspension of the lateral surface of the patella. The further action of the force and the violent contraction of lateral femoral muscle can cause the patella to fracture at its lateral one third.