Primary total knee replacement (TKR) is most commonly performed for knee joint failure caused by osteoarthritis; other indications include rheumatoid arthritis, juvenile rheumatoid arthritis, osteonecrosis, and other types of inflammatory arthritis. The aims of TKR are relief of pain and improvement in function.
Symptoms:
- Pain in the knee joint
- Inflammation and swelling of the knee joint
- Restriction of motion
- Feeling of instability in the knee
Non-surgical treatment options:
- Non-steroidal, anti-inflammatory medications
- Cortisone injections
- Steroid injections
- Weight loss if applicable
- Physical therapy
- Knee brace or splint
In some patients the non-surgical treatment options may provide sufficient relief from discomfort and disability. However in patients who do not experience acceptable relief a total knee replacement may be appropriate.
Candidates for elective total knee replacement should have radiographic evidence of joint damage, moderate to severe persistent pain that is not adequately relieved by an extended course of non-surgical management, and clinically significant functional limitation resulting in diminished quality of life. In patients with rheumatoid arthritis and other inflammatory arthropathies, additional disease-specific therapies may be needed to achieve control of disease activity before proceeding with the surgical procedure.
During total knee replacement the bone and cartilage on the end of the femur and the top of the tibia are removed. They are replaced by a metal and plastic implant. Most knee replacement implants have four parts:
- Femoral component made of metal which fits on the end of the femur
- Tibial component made of metal which fits on top of the tibia
- Patellar component made of plastic which replaces the cartilage on the undersurface of the kneecap if condition of the cartilage dictates replacement
- Plastic insert which fits between the femoral and tibial components
There are two basic types of implants:
- Press-fit knee replacements have a rough surface that will allow bone to grow into it. The resulting bone growth holds the implant in position
- Cemented knee replacements are the most commonly used. They are cemented directly to the bone and hold the implant in position
Following surgery most patients remain in the hospital for 4 – 6 days. Patients will be discharged from the hospital once they are able to fully straighten the knee, bend the knee, walk with the assistance of a walker or crutches, and perform rehabilitation exercises. Rehabilitation exercises will need to be performed as directed by your physician to regain strength and motion in the knee joint. Most patients can return to work in 4 – 8 weeks depending upon their individual progress.
Knee replacements typically last approximately 20 years, however they can last as little as 10 years or as much as 30 years. Each patient will experience individual results. If wear dictates, a revision replacement may be performed.
