What is the Purpose of Knee Replacement Surgery?
Orthopedic surgeons often recommend full or partial knee replacement surgery when a patient has extensive damage to all or parts of the knee and is experiencing pain and loss of mobility as a result. The purpose of knee replacement surgery is to replace the parts of the knee joint that have suffered damage, relieve the pain and restore a patient’s strength, stability, and activity levels.
What are the three parts of a knee?
To understand why knee surgery may be right for you, it is important to understand the anatomy of the knee and how it works.
A knee has three compartments:
- medial femoral-tibial compartment, found on the inside of the knee
- patellofemoral compartment, formed by the femur and kneecap
- lateral femoral-tibial compartment, found on the outside of the knee
Where these surfaces meet and move one on the other (articulate), the bone is covered with a thin layer (about 1/8 inch) of articular cartilage that is very smooth and slick. If this layer is disrupted for any reason and is no longer a low friction surface, the joint (arthro) becomes inflamed (itis), resulting in arthritis.
What causes the knee to deteriorate and need replacement surgery?
Cartilage destruction in a knee can be due to many different reasons: rheumatoid, gout, septic (infected), post-traumatic. Thus, one hears of rheumatoid arthritis, gouty arthritis, etc. The most common arthritis is the result of the progressive degeneration of the articular cartilage leading towards bone rubbing on bone and the associated deformity stiffness and pain seen with degenerative arthritis.
What is full knee replacement surgery?
The knee problem being corrected generally does not involve the bones, the ligaments, tendons, or other structures that make the totality of a knee. It is the cartilage that is damaged.
Surgery gets considered when all cartilage surfaces get compromised because the three knee compartments undergo damage. The cartilage is completely replaced in all three compartments with prosthetic devices that mimic the shape and function of the lost cartilage. Very little bone is removed with these artificial surfaces.
For many years, and still to a large extent, if one compartment was damaged, then all three were replaced. This typically made for an improved knee, but at the cost of a large operation that replaced the healthy parts of the knee and sacrificed the cruciate ligament function. The cruciate ligaments are essential to normal knee function. The ACL (anterior cruciate ligament) that injured athletes tear and have repaired is lost with a total knee.
What is partial knee replacement?
A partial knee replaces the portion of the knee’s cartilage that is damaged, leaving the healthy areas of the knee intact. A partial knee replacement is similar to a total knee replacement in that it uses the same materials to similar ends, the resurfacing of the bone where the cartilage is damaged or gone. However, the resurfaced area does not involve all three compartments, only one or two. Orthopedists refer to a single compartment replacement as a “uni” and a double compartment replacement as a “bi”.
What are the benefits of a partial knee surgery?
A partial knee replacement is considered minimal invasive surgery and is a good alternative for knees that have damage limited to one or two compartments. Because less of the knee is replaced, there are a number of benefits a partial replacement has versus a full replacement.
- Smaller incision
- Retains most of the knee tissue
- Lower risk of complications
- ACL is retained
- Quicker recovery
- End result is closer to a normal knee
- Better range of overall mobility
- Greater patient satisfaction with the outcome
Many studies show a large majority of “uni” knees to be functioning well at 15 or more years. With the improved designs, materials, and surgical techniques now available, the durability and long term results are expected to improve further.
If you are experiencing knee pain or would like more information on partial knee surgeries, Request an appointment online to Emerge Stronger. Healthier. Better.