Partial knee replacement surgery, which is also referred to as unicompartmental or unicondylar knee arthroplasty, is an operation in which damaged bones and cartilages on one side of the knee are excised and replaced with artificial implants.

The human knee joint is divided into three major compartments. The first one consists of a menisci (cartilage) and the joint formed by the femur (thigh bone) and tibia (shinbone) on the medial (inner) part of the knee. The second compartment is formed by the connection of these two bones and another menisci on the lateral (outer) part. The third compartment of the knee is formed by the patella (kneecap) and the femur.

Candidates for partial knee replacement surgery are those with arthritis that affects just one compartment. This arthritis is usually severe enough to keep them awake at night with pain that does not respond to medications taken by mouth.

Persons with minor deformities of the knee, who still have a good range of joint motion, are others who qualify to have this operation. Older patients with knee problems, who are relatively inactive but not morbidly obese, are other candidates for this knee surgery.

During a partial knee replacement, the patient is given anesthesia to block pain. This can be general anesthesia in which they are totally asleep, or it can be regional anesthesia in which they are numbed from the waist to the toes.

The orthopedic surgeon then makes an incision or cut on the skin over the joint which is around 4 inches long. They then remove the damaged tissues and replace them with a prosthetic joint made from metal and plastic. This implant is secured in position with bone cement and the wound is closed with sutures or stitches.

Patients who have had a partial knee replacement heal much faster than those who have had total knee replacement surgery. Most are discharged home one or two days after the operation with pain killers and medications to prevent blood clots. They are allowed to put their full weight on the knee and are encouraged to continue with physiotherapy as an outpatient to improve joint mobility.

Due to fewer complications associated with this knee operation, most patients are able to walk without a cane and resume their normal daily activities one month after the surgery.

Written by: Marian Kim, Rust Built, Marketing Services