The knee is a complex hinge joint. A unicompartmental knee replacement becomes necessary once all medical treatments have been exhausted. The diseased knee joint is usually isolated to the medial side (inside) of the knee and it becomes so badly damaged that, in spite of painkillers, it causes significant pain which interferes with your quality of life. The purpose of surgery is to relieve pain and therefore improve function and quality of life.

 

Unicompartmental knee replacement is normally considered when the joint cartilage is worn down to bone on the medial side of the knee, with relative preservation of the rest of the joint. It can also be performed on the lateral (outside) side of the joint. It is becoming an increasingly popular procedure and long term results are excellent. Surgery either takes place under a general anaesthetic or with an anaesthetic injection in the back (spinal anaesthetic) with or without sedation. The operation usually takes between one and one and a half hours. It usually involves resurfacing the end of the femur (thigh bone) and top of the tibia (shin) on the medial side of the knee joint with a cemented metal femoral components and a plastic fixed tibial component. The patella (kneecap) is left alone.

 

My unicompartmental knee replacement of choice is the Zimmer ZUK Uni knee replacement, which has an excellent track record. I normally inject the joint capsule with local anaesthetic and adrenaline, which enables post-operative rehabilitation to start on the day of surgery.

 

Hospital stay is usually 2 - 3 days and it usually takes 2 - 3 months to get over the procedure and return to normal activities, although this is variable upon individual circumstances. Rehabilitation starts on the day of surgery. The physiotherapist will advise you when to do this and will provide you with a programme of activities to perform in hospital and when you go home. Long term recovery and function is dependent upon not only the quality of the initial surgery but also the amount of work done by the patient in the rehabilitation phase.