Primary total knee replacement (TKR) is most commonly performed for knee joint failure caused by osteoarthritis (OA); other indications include rheumatoid arthritis (RA), juvenile rheumatoid arthritis, osteonecrosis, and other types of inflammatory arthritis. The aims of TKR are relief of pain and improvement in function. Candidates for elective TKR should have radiographic evidence of joint damage, moderate-to-severe persistent pain not adequately relieved by an extended course of nonsurgical management, and clinically significant functional limitation resulting in diminished quality of life.
The success of primary TKR in most patients is strongly supported by more than 20 years of follow-up 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. In general, prostheses are durable, but failure does occur.
Age younger than 55 at the time of TKR, male gender, diagnosis of osteoarthritis, obesity, and presence of comorbid conditions are risk factors for revision.
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 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.
The effectiveness of anticoagulation for the prevention of pulmonary emboli is unclear. There are insufficient data to support specific perioperative rehabilitation strategies, methods to reduce postoperative anemia, postoperative physical activity recommendations, and the site of post-acute care.
Revision TKR is done to alleviate pain and improve function. Fracture or dislocation of the patella, instability of the components or aseptic loosening, infection, and periprosthetic fractures are common reasons for total knee revision. A painful knee without an identifiable cause is a controversial indication. 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. When infection is involved, successful results occur with a two-stage revision. Failed revisions require a salvage procedure (resection of arthroplasty, arthrodesis, or amputation), with inferior results compared with revision TKR.
There is clear evidence of racial/ethnic and gender disparities in the provision of TKR in the United States. Racial or ethnic differences in the provision of care are not limited to joint replacements. 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 Veterans Administration (VA) system, where cost and access are assumed equivalent across race or ethnic groups.
Patients’ acceptance of physician recommendations varies greatly. Among persons with a potential need for TKR, only 12.7 percent of women and 8.8 percent of men were "definitely willing" to have the procedure. The interaction between the patient and physician affects the final recommendations and the patient’s acceptance of those recommendations. Physicians’ beliefs about their patients, the limited familiarity with these procedures in minority communities, patients’ mistrust of the health care system, and personal beliefs about the most effective treatment of joint problems may all have a role in these racial or ethnic disparities.
