Introduction: Osteonecrosis of the knee occurs with approximately 10% of the incidence of osteonecrosis of the hip. Core decompression is a minimally invasive technique which can potentially forestall bony collapse and thus avoid the need for joint arthroplasty. The purpose of this study was to evaluate the efficacy of a new minimally invasive approach using a small diameter Steinman pin to perform core decompression of the knee.

Materials and Methods: Between September 5, 2000 and May 30, 2003, the senior author performed 55 core decompressions of the knee in 39 patients with symptomatic osteonecrosis of the knee. All procedures were performed using the small-bit drilling technique. There were 32 women and 7 men who had a mean age of 43 years (range, 18 to 52 years). Radiographic and clinical outcomes were assessed during post-operative clinical visits, with persistent pain, loss of joint space, or progression to total knee replacement considered failures.

Results: There were excellent or good outcomes in 45 knees (82%) at a mean three year follow-up (range, 2 to 5 years). Four patients had symptomatic knees that led to total knee arthroplasty. There were no complications from the procedures which were all performed as out-patient surgery.

Discussion: The percutaneous drilling technique appears to be a low-morbidity method of relieving symptoms in patients with symptomatic knees from osteonecrosis. These short-term results are encouraging for this difficult to treat disease.

Introduction: The results of total hip arthroplasty in patients with avascular necrosis of the hip have been variable. This study analyzed the clinical and radiographic outcome of young patients (mean age of 39 years) treated with a proximally hydroxyapatite-coated tapered stem.

Materials and Methods: Sixty-seven patients (84 hips) treated with late-stage avascular necrosis of the hip with a proximally hydroxyapatite-coated tapered stem as part of their total hip arthroplasty was studied. There were 41 men and 26 women who had a mean age of 39 years (range, 18 to 80 years). Patients were followed both clinically and radiographically for a minimum of two years (mean of 3 years).

Results: Overall, there were good and excellent clinical outcomes in 78 hips (93%). Fair results were found in five patients with persistent pain. There was only one stem loosening (obese patient with SLE). Radiographic zonal analysis revealed no evidence of impending failure or progressive radiolucencies.

Discussion: Excellent short-term results were found with total hip arthroplasty in this difficult patient population. The proximally hydroxyapatite-coated tapered stem utilized in this study was useful in patients with avascular necrosis of the hip.