Surface replacement arthroplasty of the hip.

The principle of hip joint resurfacing is replacement of diseased joint surfaces and simultaneous restoration of the normal anatomy and biomechanical function to the maximal degree possible. This concept offers several theoretical advantages over conventional total hip joint replacement and the clinical results in this series of 426 cases appears to confirm the value of both the method and the concept. Successful joint resurfacing surgery with attention to detail. Most problems can be anticipated and handled appropriately. Complications are few. The operation should only be done in cases of severe hip disability, when the patient's level of suffering demands operative intervention and when the only reasonable alternatives are fusion, total joint replacement or head and neck resection. It is an operation designed and recommended as an "in-between" procedure to gain time against the progressive disease. Resurfacing should not be performed if conservative measures or classic hip osteotomies offer significant benefit. The principal advantages of this procedure relate directly to the prosthetic design. Only the joint surfaces are removed during surgery, most of the normal bone is preserved, the medullary canal is not opened, and the implants utilized are of small volume. As a result the risk of infection is low compared to other implant arthroplasty techniques and clinical statistics confirm this anticipated advantage. The operation is designed to interfere minimally with the normal joint mechanics so it is also anticipated that prosthesis longevity will be greater than when rigid stem prostheses are placed in elastic bone. As yet follow-up is too short to make valid judgments on this point. The technique is applicable to younger patients, however, because if it should, in time, fail and other surgical treatment becomes necessary the original alternatives of total hip replacement, arthrodesis, or head and neck resection remain available. Relief of pain is predictable and almost all patients have experienced significant improvement in function. The procedure has a broader indication in cases of prior bone or joint infection and is definitely a preferable procedure in young individuals with severe hip disability.