Subchondral insufficiency fracture of the femoral head in elderly people.

We evaluated the clinical course of subchondral insufficiency fracture of the femoral head (SIFFH) and its characteristic findings with special regard to joint space narrowing (JSN). Thirty-one cases of SIFFH of mean age 68.9 yr initially underwent limited weight-bearing conservative treatment. During the follow-up period, the patients with intractable pain underwent total hip arthroplasty (THA). For radiographic evaluation, lateral center-edge angle, JSN and femoral head collapse (FHC) were documented, and the extent of FHC was classified as mild (<2 mm), moderate (2-4 mm), and severe (>4 mm). The progression or new development of FHC more than 2 mm was evaluated on sequential plain radiographs. The relationship between radiographic parameters and clinical outcomes were evaluated. THAs were performed in 15 cases (48.4%). There was no significant correlation between clinical outcomes and the extent of initial FHC. However, a significantly larger proportion of patients that underwent THA showed JSN and FHC progression compared to the symptom improvement group. The risk factor significantly associated with failed conservative treatment was JSN (P=0.038; OR, 11.8; 95% CI, 1.15-122.26). Clinical results of conservative treatment for SIFFH in elderly patients are relatively poor. The patients with JSN are at higher risk of failed conservative treatment.