Metal-on-metal hip resurfacing: a skeptic's view

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Implant technology

Background:

• Metal-on-metal hip resurfacing aims to avoid diaphyseal femoral components.
• Previous hip arthroplasty designs with diaphyseal components show long-term success without adverse effects like stress shielding.
• The premise of hip resurfacing as a bone-conservative procedure is questioned.

Purpose of the Study:

• To critically evaluate the concept and clinical utility of contemporary metal-on-metal hip resurfacing.
• To compare hip resurfacing with conventional hip arthroplasty regarding surgical outcomes and patient selection.

Main Methods:

• Review of existing literature and clinical outcomes of metal-on-metal hip resurfacing.
• Analysis of potential complications, including metal ion release, hypersensitivity, and surgical difficulties.
• Comparison with established uncemented stemmed femoral components.

Main Results:

• Hip resurfacing may remove more acetabular bone than initially suggested.
• Computer simulations indicate a potentially reduced range of hip motion compared to conventional hip arthroplasty.
• High rates of femoral head unsuitability (40%) and increased risk of early complications and fractures are noted.

Conclusions:

• Metal-on-metal hip resurfacing has limited indications and presents significant risks, including adverse metal ion effects and hypersensitivity.
• The technical demands and complication rates suggest that hip resurfacing is not universally advantageous.
• The risks associated with metal-on-metal hip resurfacing appear to exceed any potential benefits, recommending cautious use by specialized surgeons.