Risk factors for postoperative femoral fracture in cementless hip arthroplasty

The objective of this study was to evaluate the incidence of and risk factors for femoral fracture in patients who underwent cementless hip arthroplasty during a 3-year period. Several predisposing factors have been reported; we tried to find another predictive indicator that could be recognized preoperatively. The records of all patients who underwent cementless hip arthroplasty from December 1993 to December 1996 were reviewed. The characteristics and clinical features (including age, gender, diagnosis, geometry of the proximal femur, and quality of bone) of the patients who had fractures were compared with those of patients who did not have fractures. During the 3-year study, 425 patients underwent a total of 454 cementless hip arthroplasties. There were 16 postoperative fractures (3.5%, 16 patients). Patients who suffered femoral fracture were significantly older than patients without fracture (65.6 +/- 10.9 yr vs 52.6 +/- 16.2 yr, p < 0.001). The fracture group had poorer preoperative bone quality compared with the nonfracture group (3.3 +/- 0.6 vs 3.8 +/- 0.7, Singh's Index of Osteoporosis, p < 0.01). The canal flare index of the proximal femur was significantly lower in the fracture group than in the nonfracture group (3.3 +/- 0.40 vs 3.8 +/- 0.7, p < 0.01). Our results indicate that old age and osteoporosis affect the likelihood of periprosthetic femoral fractures, and that a low flare index is a predictive indicator of femoral fracture. These factors should be taken into account during preoperative planning, and cemented arthroplasty should be considered for patients with these risk factors.