However, there are actions that may be performed to try to ameliorate the situation when stiffness arises. Early surgical therapy of knee stiffness is critical since prolonged treatment (of six months or more) is considerably less likely to produce satisfactory outcomes. In such circumstances, repeat surgery may be the only alternative. Physiotherapy can also help by treating any underlying causes (such as muscle weakness or imbalance) and performing exercises to maintain or improve range of motion and strength in the joint. Stiffness is when a joint becomes hard and inflexible due to damage or disease. The knee is a very important part of the body that connects your upper body to your lower body, and therefore plays an essential role in walking, running, and jumping. Therefore, it is not surprising that injuries to the knee joint are one of the most common problems in modern society. There are many ways the knee can be injured, but usually it is because someone falls down doing something they don't normally do- like stepping off a curb into traffic or being hit by a car. The two main parts of the knee are the femur (thigh bone) and the tibia (shin bone). Between these two bones is a large cavity called the knee joint. This joint allows for easy movement and provides flexibility; however, it also has some limitations. For example, the size of the femoral condyle limits how much weight a person can put on their leg when standing on one foot.