Objective: To describe the main characteristics of subchondral fractures of the femoral head.
Case-reports: The seven patients, five women and two men, with a mean age of 50 years (37-76 years), presented with mechanical pain in the groin. Bone loss was the main risk factor. Two patients had postmenopausal osteoporosis (including one with a history of ovariectomy at 30 years of age), two had osteoporosis induced by glucocorticoid therapy given after transplantation (liver and allogeneic bone marrow, respectively), one had an ACTH-producing adenoma, and one had femoral osteopenia at a site of topical glucocorticoid therapy for atopic dermatitis. The remaining patient had osteopenia and a history of smoking. Phosphate and calcium levels were normal in five patients. One patient had isolated hypocalciuria and another had moderate proximal tubular disease with phosphate wasting and hypercalciuria. Magnetic resonance imaging (MRI) disclosed a subcapital line of low signal on T1- and T2-weighted sequences surrounded by an area of variable size generating low signal on T1 images and high signal on T2 images, with postgadolinium enhancement, denoting marrow edema. Complete elimination of weight bearing for 6 weeks, symptomatic agents, and treatment of the underlying causes of bone insufficiency were used in all seven patients. Mean follow-up was 2.4 years (range, 11-39 years). No cases of osteonecrosis were recorded.
Conclusion: Several cases of subchondral fracture have been reported in the literature. Bone insufficiency was the main risk factor in all the patients.