OBJECTIVETo investigate the failure of internal fixation on displaced femoral neck fractures in adults under fifty-five years old retrospectively inorder to pay more attention to the treatment of these fractures.

METHODSFrom Junary 2007 to June 2010,18 failed cases of internal fixation on displaced femoral neck fractures in adults under fifty-five years old were treated,there were 13 males and 5 females with an average age of (48.0 +/- 6.0) years old ranging from 27 to 55. Among them, 17 patients were treated with cannulated screws and 1 patient was treated with intramedullary nail; 16 patients were diagnosed as osteonecrosis and 2 patients as osteonecrosis associated with nonunion.

RESULTSThe average time from internal fixation to failure was 23 months (ranged, 8 to 32 months). The quality of fracture reduction in Garden index was poor. The Harris Hip Score was (56.0 +/- 12.5) (ranged,33 to 80). Eight cases of osteonecrosis and 2 cases of nonunion combinated osteonecrosis were received total hip arthroplasty. Hip resurfacing arthroplasty were performed for other 5 osteonecrosis. Because of no evident clinical symptoms,the other 3 cases received conservative treatment. The patients with total hip arthroplasty and hip resurfacing arthroplasty were followed-up for 34 months ranging from 12 to 53 months. After operation,the Harris score was (94.0 +/- 3.0) ranged 89 to 96.

CONCLUSIONOsteonecrosis is a common complication after internal fixation on displaced femoral neck fracture in adults under fifty-five years old. More attention should be paid to the treatment of displaced femoral neck fracture in those patients.