NIH Consensus Statement on total knee replacement

To provide health care providers, patients, and the general public with a responsible assessment of currently available data regarding total knee replacement.

A non-DHHS, non-advocate 11-member panel representing the fields of orthopaedics, rheumatology, internal medicine, nursing, physical therapy, rehabilitation, biostatistics, epidemiology, and health services research, as well as a TKR patient. In addition, 21 experts in related fields presented data to the panel and to the conference audience.

Presentations by experts; a systematic review of the medical literature provided by the Agency for Healthcare Research and Quality; and an extensive bibliography of total knee replacement research papers, prepared by the National Library of Medicine. Scientific evidence was given precedence over clinical anecdotal experience.

Answering pre-determined questions, the panel drafted its statement based on scientific evidence presented in open forum and on the published scientific literature. The draft statement was read in its entirety on the final day of the conference and circulated to the audience for comment. The panel then met in executive session to consider the comments received, and released a revised statement later that day at http://consensus.nih.gov. This statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government.

The success of primary TKR in most patients is strongly supported by more than 20 years of followup data. There appears to be rapid and substantial improvement in the patient's pain, functional status, and overall health-related quality of life in about 90 percent of patients; about 85 percent of patients are satisfied with the results of surgery. Short-term outcomes, as documented by functional outcome scales, are generally substantially improved after TKR. Functional outcome is improved after TKR for people across the spectrum of disability status. Technical factors in performing surgery may influence both the short- and long-term success rate. There is consensus regarding the following perioperative interventions that improve TKR outcomes: systemic antibiotic prophylaxis, aggressive postoperative pain management, perioperative risk assessment and management of medical conditions, and preoperative education. Revision TKR is done to alleviate pain and improve function. Contraindications for revision TKR include persistent infection, poor bone quality, highly limited quadriceps or extensor function, poor skin coverage, and poor vascular status. Results are not as good as with primary TKR; outcomes are better for aseptic loosening than for infections. Failed revisions require a salvage procedure (resection of arthroplasty, arthrodesis, or amputation), with inferior results compared with revision TKR. Factors related to a surgeon's case volume, technique, and choice of prosthesis may have important influences on surgical outcomes. One of the clearest associations with better outcomes appears to be the procedure volume of the individual surgeon and the hospital. Technical factors in performing surgery may influence both the short- and long-term success rate. Proper alignment of the prosthesis appears to be critical. Many design features, such as use of mobile bearings or designs sparing cruciate ligaments, have theoretical advantages, but durability and success rates appear roughly similar with most commonly used designs. There is clear evidence of racial/ethnic and gender disparities in the provision of TKR in the United States. The limited role of economic and other access factors in these racial or ethnic disparities can be demonstrated by significant differences in the rate of procedures in the VA system, where cost and access are assumed equivalent across race or ethnic groups.