1. What is unicondylar knee arthroplasty? A unicondylar knee replacement is a special type of artificial knee replacement that is limited to the unicondyle. The purpose of unicondylar knee replacement is to preserve as much of the normal joint structure as possible in order to achieve better functional recovery. The unicondylar knee replacement can be divided into medial and lateral compartments, but the medial side is still the primary one. 2. Why should I choose unicondylar? According to the shape and function of the knee joint, we divide the knee into two parts, the medial and lateral. The medial one consists of the medial femoral condyle, the medial meniscus and the lateral tibial plateau. Similarly, the lateral portion consists of the lateral femoral condyle and lateral meniscus and the lateral tibial plateau. The medial and lateral condyles of the knee are different in shape and do not function in exactly the same way. Generally the medial condyle is under more pressure and the lateral condyle has more rotational function. Therefore, as people get older, decades of wear and tear often damage the cartilage of the medial condyle of the knee first, exposing the bone and eventually causing the typical osteoarthritis, which is when the bones rub against each other, causing pain and swelling in the joint and making it difficult to walk. Since only the medial condyle of the knee joint is worn out and the lateral condyle is still intact, only the aging wear of the medial condyle needs to be treated, resulting in unicondylar replacement surgery. There are many unicondylar artificial joints abroad. This type of joint retains the structures of the lateral condyle, patella, and cruciate ligament, so the function of the patient’s knee is basically normal without the discomfort caused by total knee replacement. The trauma is small, the recovery is fast, and the cost is low. It is used more abroad, accounting for about 10% of all knee replacements (from 3% to 30% in different countries and stages). Domestic applications are less common, especially outside of Beijing. At present, almost all unicondylar replacements in Guangdong are done here at our joint center, and the results so far have been very good, with patients walking on the ground the next day. 3. Which patients need unicondylar arthroplasty? (1) unilateral interval narrowing of the knee, no contralateral interval lesion, no severe patellofemoral arthropathy; (2) knee inversion less than 10°, flexion deformity less than 10°; (3) structural integrity of the ligaments of the knee; (4) non-inflammatory arthritis, such as osteoarthritis, traumatic arthritis, etc. 4.How long after surgery can I get out of bed and walk? On the first day after surgery, start active contraction training of the quadriceps (isotonic contraction). On the second day, increase the passive activity of the knee joint, so that the knee joint extends and flexes 0-45°. 3-4 days after surgery, the passive activity of the knee joint should reach 0-90°, and one week after surgery, it should reach 0-100° (or 110°). Under normal circumstances, you can get out of bed on the second day after surgery to do partial weight-bearing and train walking. Full weight-bearing walking exercises can be done one week after surgery. Due to more passive exercises of the knee joint, the removal time is usually about 2 weeks after surgery. 5. Is unicondylar arthroplasty safe? With adequate preoperative preparation and careful intraoperative monitoring, unicondylar knee arthroplasty is generally a safe procedure with a very low complication rate. With improvements in prosthesis design and surgical techniques, as well as strict restrictions on the indications for history selection, unicondylar knee arthroplasty has a clear therapeutic benefit for patients with osteoarthritis in the medial compartment. 6. What are the benefits of unicondylar arthroplasty? Compared with total knee arthroplasty, the advantages of unicondylar arthroplasty are: (1) Only the diseased articular surface is removed, so less bone is removed than in total knee arthroplasty, eliminating overtreatment; (2) The anterior and posterior cruciate ligaments are preserved, preserving the anastomosis of the patellofemoral joint intact, maintaining normal anatomy, improving function and biomechanics, and increasing mobility; (3) Few foreign objects are implanted in the body (including (4) short operation time, less surgical trauma and complications, and fast postoperative recovery; (5) reduced costs and hospitalization days; (6) very fast postoperative recovery, allowing weight-bearing walking without crutches and restoring maximum knee function.