[Medical Q&A] Can knee replacement be performed by replacing only half of the joint?

Planner: Chinese Medical Association

Reviewer: Han Liqiang, deputy chief physician, Tianjin University Central Hospital

Knee replacement is a conventional treatment for osteoarthritis of the knee. For some patients, when preparing for surgery after examination, doctors will recommend replacing only half of the knee. This surgical method can achieve good therapeutic effects while reducing surgical trauma.

Medically, this type of surgery is called "unicompartmental knee replacement". Compared with total knee replacement, it is a new type of minimally invasive surgery. It only targets the worn area and performs surface replacement on the medial or lateral compartment of the knee joint to replace the damaged cartilage surface of the femoral and tibial joints of the knee joint. It is also vividly called the "tooth filling" technology in knee replacement. This surgery does not require the removal of the anterior and posterior cruciate ligaments, which maximizes the retention of the patient's proprioception and joint function. Unicompartmental knee replacement has obvious advantages over total knee replacement. The surgical trauma is smaller, the postoperative wound pain is also lighter, and walking exercises can be carried out on the second day after surgery. However, this surgery has clear surgical indications and is suitable for the following patients: ① unilateral compartment lesions of the knee joint, especially anterior medial osteoarthritis, without severe joint lesions; ② knee varus <15°, flexion deformity <15°; ③ intact knee ligament function; ④ bone necrosis. Unicompartmental knee replacement performed in the early stage of knee disease when only a single compartment is affected can effectively relieve pain and prevent joint degeneration to the entire joint. It is a classic knee preservation option for the treatment of knee osteoarthritis. Because of its advantages such as less trauma and faster recovery, it can enable patients to return to normal life as soon as possible.