In the orthopedic clinic I often encounter patients who have had a thigh, calf or knee fracture caused by a car accident or trauma, and the fracture has healed after surgery, but the range of motion of the knee joint cannot be restored to its preoperative level. So much so that it seriously affects their daily life and they cannot go up and down stairs or use the toilet normally. So how does this happen? What is the best way for us to solve it? How does knee stiffness occur? The knee joint is a complex joint consisting of three parts: the proximal end of the lower leg, the distal end of the thigh, and the patella (commonly known as the kneecap). The surface of the three parts in contact with each other is covered by an extremely smooth surface of articular cartilage. The knee joint is wrapped in a structure called the joint capsule, which forms a relatively closed cavity with joint fluid that lubricates the joint, making it extremely flexible. The knee joint is powered by the surrounding muscles, and when these muscles contract in a coordinated manner, they drive the joint to move accordingly. After trauma, the bony and soft tissue structures around the knee joint are damaged and bleeding, which often restricts the knee joint movement for a long time after surgery. When the knee is unfixed, patients often find it difficult to move the knee normally; even if they can move it, the degree of movement is not very satisfactory. What should I do if my knee is stiff? In the past, there were two conventional ways to deal with this type of patient: 1. Suggest that the patient perform rehabilitation exercises for the knee joint on his own. This type of exercise has a limited effect and each exercise is very painful and often difficult for the patient to maintain. 2. surgical release with a large incision. This type of surgical incision is relatively large, traumatic and bleeding, and despite extensive intraoperative release of the quadriceps muscle, the postoperative results are still unsatisfactory. Therefore, the problem of trauma and post-operative knee stiffness has always troubled patients and orthopedic surgeons. In recent years, with the increasing maturity of arthroscopic techniques and the change of philosophy. We have used a new technique of small incision combined with arthroscopic technique to manage knee stiffness with satisfactory results (Figure 1), which was published in 2006 in the leading American Orthopaedic Journal (JBJS). This procedure allows for extensive release of the knee joint by simply using a small incision approximately 2-4 cm long. Specifically, it is divided into 5 steps: 1. release the lateral patellar support band. 2. release the suprapatellar capsule, patellofemoral interval, and anterior septum. 3. release the medial patellar support band. 4. sever the medial femoral muscle at the muscle and tendon migration. 5. lengthen the quadriceps tendon. The intercondylar fossa and cruciate ligament were also examined comprehensively under arthroscopy, and the scar tissue in the joint was released. We have counted that after such surgical treatment, the average flexion level of the knee joint of the patient increased from 27° to 115° after surgery, which greatly improved the joint function.