Nontraumatic osteonecrosis of the femoral head: endoscopic visualization of its avascular burden.

The purpose of this study was to evaluate the intraosseous use of a flexible endoscope during core decompression in identifying avascular bone in the femoral head that did not meet magnetic resonance imaging diagnostic criteria for osteonecrosis. The flexible endoscope was used to visually examine and locate avascular bone in the entire core track. A high-speed burr was then used to debride the avascular bone. This debridement process was continued until a host bed of porous bleeding cancellous bone was observed, comprising thorough debridement of the femoral head. Autologous cancellous bone graft was then packed into the residual cavity and stabilized. Ten patients (13 hips total) with an average age of 49 years (range, 34-58 years) were included in the study. Eight patients were fully ambulatory at 3 weeks (range, 1-3 weeks). For all 13 hips, the mean preoperative Harris Hip Score was 43 (range, 30-75) and improved to a mean of 93 (range, 60-100) postoperatively. Eighty-five percent of patients (11 of 13 hips) demonstrated a good to excellent outcome at a minimum 2-year follow-up (range, 27-45 months). Flexible intraosseous endoscopy helped identify avascular bone that did not appear on the preoperative magnetic resonance imaging, safely widen the surgical margins of the core decompression track, and achieve thorough debridement of the femoral head using a minimally invasive technique.