Left knee fall injury more than four months leg is still a little straight stiffness may be joint adhesion, muscle atrophy or deformity of healing and other factors, can be relieved and treated through joint movement training, muscle strength training and surgical treatment and so on. 1. Joint adhesion: active joint activities should be carried out, and the articular cartilage should be moderately pressurized and depressurized, so as to promote the exchange of cartilage matrix fluid and joint fluid, increase the mobility and stability of the joints, and prevent joint adhesion. 2. Muscle atrophy: daily isometric exercises and active contraction exercises can effectively prevent muscle atrophy, enhance muscle strength and increase joint stability. 3. Deformity healing: four months after the fall of the left knee leg is still not straight, stiffness can also be seen in the fracture deformity healing, should be promptly consulted to clarify the cause of the disease, the need for surgical treatment to correct the deformity if necessary. Left knee fall injury more than four months leg is still a little straight and stiff, we recommend that the patient timely hospital review, clear cause for targeted treatment.