Unicompartmental ( Uni/Partial) Knee Replacement
Arthritis is inflammation of a joint causing pain, swelling (inflammation), and stiffness.
Osteoarthritis is the most common form of knee arthritis in which the joint cartilage gradually wears away. It most often affects older people. In a normal joint, articular cartilage allows for smooth movement within the joint, whereas in an arthritic knee the cartilage itself becomes thinner or completely absent. In addition, the bones become thicker around the edges of the joint and may form bony “spurs”. These factors can cause pain and restricted range of motion in the joint.
- Arthritis of the knees can cause knee pain, which may increase after activities such as walking, stair climbing, or kneeling.
- The joint may become stiff and swollen, limiting the range of motion. Knee deformities such as knock-knees and bow-legs may also occur.
What is a Partial Knee?
Unicompartmental knee replacement is a minimally invasive surgery in which only the damaged compartment of the knee is replaced with an implant. It is also called a partial knee replacement. The knee can be divided into three compartments: patellofemoral, the compartment in front of the knee between the knee cap and thigh bone, medial compartment, on the inside portion of the knee, and lateral compartment which is the area on the outside portion of the knee joint.
Traditionally, total knee replacement was commonly indicated for severe osteoarthritis of the knee. In a total knee replacement, all worn out or damaged surfaces of the knee joint are removed and replaced with new artificial parts. Partial knee replacement is a surgical option if your arthritis is confined to a single compartment of your knee.
The exact cause is unknown, however, there are several factors that are commonly associated with the onset of arthritis and may include:
- Injury or trauma to the joint
- Fractures of the knee joint
- Increased body weight
- Repetitive overuse
- Joint infection
- Inflammation of the joint
- Connective tissue disorders
Your doctor may recommend surgery if non-surgical treatment options such as medications, injections, and physical therapy have failed to relieve the symptoms.
During the surgery, a small incision is made over the knee to expose the knee joint. Your surgeon will remove only the damaged part of the meniscus and place the implant into the bone by slightly shaping the shinbone and the thigh bone. The plastic component is placed into the new prepared area and is secured with bone cement. Now the damaged part of the femur or thigh bone is removed to accommodate the new metal component which is fixed in place using bone cement. Once the femoral and tibial components are fixed in proper place the knee is taken through a range of movements. The muscles and tendons are then repaired and the incision is closed.
You may walk with the help of a walker or cane for the first 1-2 weeks after surgery. A physical therapist will advise you on an exercise program to follow for 4 to 6 months to help maintain your range of motion and restore your strength. You may perform exercises such as walking, swimming, and biking but high-impact activities such as jogging should be avoided.
After surgery, you will feel pain. This is completely normal and part of the healing process. Your doctor and nurses will work together to reduce your pain, this will help you recover faster.
Prior to you leaving the hospital your doctor will send a prescription to your pharmacy for some short-term pain relief after surgery. Your doctor may suggest multiple medications to help manage your pain, such as opioids, non-steroidal anti-inflammatory drugs (NSAIDs), and local anesthetics. Your doctor will discuss which options or combinations would be best for you.
At MD West One, your health is always a top priority, which is why we are very passionate about getting you back to full activity in a safe and timely manner. We understand every patient is unique when it comes to pain management. A key component of a successful pain treatment plan includes weighing all risks and benefits to find the pain treatment plan that best fits you.
A high risk of dependence and overdose is associated with the use of opioids. To avoid this from accruing our agreement with you:
- You should take all medications as ordered by your provider. If you take the medication in excess of what is prescribed and run out of the medication prior to the refill date, the refill will not be authorized early.
- If you are requiring a refill of your prescription please call during regular business hours. Our providers will not refill any pain medications over the weekend, holidays, or after clinic hours.
- Make sure to tell your physician or nurse which medications you are taking, including herbal remedies, since narcotic medications can interact with over-the-counter medications and other prescribed medications, especially cough syrups that contain alcohol, codeine, or hydrocodone.
- Alteration of any written prescription, sharing, trading, or selling your medication is a federal offense and will be reported.
- You are responsible for keeping your pain medication in a safe and secure place, such as a locked cabinet or safe. Stolen medications should be reported to the police and to your physician immediately.
- If your medications are lost, misplaced, or stolen, your physician may choose not to replace the medications or to taper and discontinue the medications.
Possible risks and complications associated with unicompartmental knee replacement include:
- Knee stiffness
- Blood clots (Deep vein thrombosis)
- Nerve and blood vessel damage
- Ligament injuries
- Patella (kneecap) dislocation
- Plastic liner wears out
- Loosening of the implant
The advantages of Unicompartmental Knee Replacement over Total Knee Replacement include:
- Smaller incision
- Less blood loss
- Quick recovery
- Less post-operative pain
- Better overall range of motion
- Feels more like a natural knee
Don't wait any longer to get relief. Make an appointment to see one of our orthopedic specialists.
AMERICAN ASSOCIATION OF HIP and KNEE SURGEONS
This article has been written and peer-reviewed by the AAHKS Patient and Public Relations Committee and the AAHKS Evidence-Based Medicine Committee.