Total hip arthroplasty, one of the most successful orthopedic procedures of this century, can provide relief of pain and improved function in a wide variety of hip conditions. Long-term follow-up has shown, however, that problems can occur, especially with the femoral prosthesis. As a result of this, surface-replacement total hip arthroplasty was developed, and at present it appears to be a very useful procedure for younger patients with concentric hip disease. Both procedures are discussed along with restrictions and complications inherent in their use.