OBJECTIVETo study the cause of X-ray misdiagnosis of the avascular femur head necrosis, so as to reduce the misdiagnosis rate and raise the early diagnosis level.

METHODSThe clinical and X-ray data of 99 patients(123 hips) with avascular femur head necrosis diagnosed by MRI were analyzed retrospectively. Among the patients, 56 patients were male and 43 patients were female,ranging in age from 21 to 84 years old,with an average of 53 years old. The patients had symptoms such as hip pain,functional restriction in flexion, adduction, abduction and internal rotation,and some patients had limping. The duration of the disease ranged from 1 week to 2 years.

RESULTSAmong 99 patients(123 hips),46 patients(52 hips) was misdiagnosed by the X-ray, the misdiagnosis rate was 42.27%, 100.00% in 0 stage, 100.00% in I stage, 83.67% in II stage, 18.18% in II stage, 0.00% in IV stage, 0.00% in V stage; the X-ray stage was negatively correlated with the rate of misdiagnosis. The careless film-reading and invigorating large enterprises while relaxing control over small ones was the main reason of misdiagnosis,then the lack of clinical histories and low-quality of X-ray projection.

CONCLUSIONThe relevant clinical history and comprehensive careful film-reading is the key to reduce the rate of misdiagnosis.