Partial knee replacement, also known as unicompartmental knee replacement, is a minimally invasive surgery in which only the damaged compartment of the knee is replaced with an implant, thereby sparing the other healthy portions of the joint from surgery. 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 used to treat patients with severe osteoarthritis of the knee. In 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 for when your arthritis is confined to just one part of your knee.
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. 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.
The exact cause is unknown, however there are several factors that are commonly associated with the onset of arthritis and may include:
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.
Your doctor will diagnose osteoarthritis based on the medical history, physical examination, and X-rays.
X-rays typically show a narrowing of joint space in the arthritic knee.
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 soft tissue and place the implant into the bone by slightly shaping the bones in your knee. The femoral and tibial components are placed into the new prepared area and is secured with bone cement. Once the femoral and tibial components are fixed in proper place the knee is taken through a range of movements. The soft tissues 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 the first few months after surgery to help maintain range of motion and restore your strength. When you recover, you may perform light exercises such as walking, swimming and biking but other high impact activities such as jogging should discussed with you surgeon prior to participation.
Possible risks and complications associated with partial knee replacement include:
The advantages of Partial Knee Replacement over Total Knee Replacement include:
