Large versus small femoral heads in metal-on-metal total hip arthroplasty.

The recent resurgence of metal-on-metal total hip arthroplasty has afforded the surgeon new options in femoral head diameters that were not previously available. Reduction in the risk for dislocation and potential improvements in articular wear are the obvious advantages of large-diameter femoral heads. Total hips with larger-diameter femoral heads are more resistant to dislocation. The clinical experience with 616 38 mm diameter femoral heads showed no dislocations within the first 3 months after surgery, compared with 2.5% of 78 patients receiving 28 mm diameter femoral heads with otherwise identical components. Use of larger-diameter femoral heads appears to have the potential to substantially reduce the early risk of dislocation of the prosthetic hip arthroplasty.