Long-term results of hemi-resurfacing and metal-on-metal hip resurfacing for osteonecrosis of the femoral head.

Purpose: Hemi-resurfacing arthroplasty (Hemi) and metal-on-metal hip resurfacing arthroplasty (HR) were proposed as alternatives to conventional total hip arthroplasty (THA) for patients with osteonecrosis of the femoral head (ONFH). Long-term results were evaluated.

Methods: Twenty-three hips with ONFH were treated, using Hemi in 12 and HR in 11. Mean follow-up was 15 years in the Hemi group and 10 years in the HR group. Long-term outcomes were reviewed retrospectively.

Results: In the Hemi group, 8 hips showed acetabular protrusion and were revised to THA. One of the 8 hips showed femoral loosening. In the HR group, pseudotumor was detected in 4 hips (36%), and 1 hip was revised due to symptomatic pseudotumor. No evidence of any femoral or acetabular loosening was seen in the HR group. Ten-year survival rates were 64.2% and 90.9% in the Hemi and HR groups, respectively. Survival rate in the Hemi group dropped to 22.9% at 15 years.

Conclusions: Long-term results of Hemi for patients with ONFH were very poor, and Hemi should not continue to be used. Although HR had a concern of pseudotumor, it could offer attractive indications for 10 years.