Abstract
Introduction
The treatment of osteonecrosis of the femoral head (ONFH) in young and active patients remains a challenge. The purpose of this study was to determine and compare the clinical and radiographic results of the two different hip resurfacing systems; hemi-resurfacing and metal-on-metal total hip resurfacing in patients with ONFH.
Methods
This study was a retrospective review of 20 patients with 30 hips who had ONFH and underwent hemi-resurfacing or total hip resurfacing between November 2002 and February 2006. We mainly performed hemi-resurfacing for early stage ONFH, and total hip resurfacing for advanced stages. Fifteen hips in 11 patients had a hemi-resurfacing component (Conserve, Wright Medical Co) with a mean age at operation of 50 years and an average follow-up of 5.5 years. Fifteen hips in 10 patients had a metal-on-metal total hip resurfacing component (Birmingham hip resurfacing, Smith & Nephew Co.) with a mean age at operation of 40 years and an average follow-up years.
Results
The average postoperative Japanese Orthopaedic Association (JOA) hip scores were 86 points in hemi-resurfacing and 96 points in total hip resurfacing. The difference of pain score was a main factor to explain the difference of total JOA hip score in the two groups. Both implants were radiographically stable, but radiolucent lines around the metaphyseal stem were more frequent in total hip resurfacing. In hemi-resurfacing patients, ten of 15 hips had groin pain or groin discomfort and three hips were revised to total hip arthroplasties (THA) because of femoral neck fracture, acetabular protrusio, and osteoarthritic changes, respectively. In total hip resurfacing patients, there were no revisions and no groin pain observed.
Conclusion
In the prosthetic treatment of young active patients with ONFH, it is theoretically desirable to choose an implant with a conservative design in anticipation of the future revision surgery. Hemi-resurfacing hip arthroplasty is the most conservative implant for the treatment of ONFH. However, the results of hemi-resurfacing in this study have been disappointing due to high revision rates and insufficient pain relief despite of the good implant stability. However, the pain relief and implant survivorship after total hip resurfacing were superior to the results of hemi-resurfacing, although the usages of the total hip resurfacing were for more advanced cases. These results suggest that total hip resurfacing was a more valuable treatment option for active patients with ONFH than hemi-resurfacing.
