Risk factors leading to total hip arthroplasty in patients with subchondral insufficiency fractures of the femoral head.

PURPOSE To retrospectively evaluate factors leading to total hip arthroplasty (THA) in patients with subchondral insufficiency fractures (SIF) of the femoral head. METHODS. 5 men and 22 women aged 51 to 85 (mean, 72) years with SIF of the femoral head initially underwent conservative treatment. THA was later performed for 13 patients, as the hip pain became worse secondary to joint space narrowing and/ or femoral head collapse. Patient demographics and radiological variables were retrieved. Risk factors leading to THA in patients with SIF of the femoral head were identified. Receiver operating characteristic curves were used to determine optimal cut-off values for the significant risk factors. RESULTS 2 men and 11 women aged 62 to 85 (mean, 74.9) years underwent THA and were followed up for 0.2 to 62 (mean, 13) months. The remaining 3 men and 11 women aged 51 to 81 (mean, 68) years underwent conservative treatment and were followed up for 9 to 93 (mean, 28) months. Patient age was the only risk factor for THA (p = 0.047, odds ratio = 1.13), the cutoff value being 71 years (sensitivity, 77%; specificity, 64%). The survival rate was significantly lower in patients aged 71 years or older than in those aged younger than 71 years (p < 0.05). CONCLUSION Elderly patients with SIF of the femoral head are at higher risk of undergoing THA.