As an orthopedic Physician Assistant, I am often asked why swelling occurs. When I first started, I thought that this was an abnormal response to the injury, but now I understand that most swelling occurs as a protective mechanism.
When we break a bone in our arm, swelling straightens the bones. When we injure a joint, swelling allows us to run on that injured joint. A similar process happens in the hip, with some flexion and external rotation, and doesn’t require any muscle strength to be run upon.
After ligament injuries in the knee, the knee will swell and become limited in motion to “stabilize” the joint enough to move. A swollen knee will fuse itself at 30° – this allows the injured patient to run.
After a surgical procedure, the joint that was operated on becomes swollen as a protective measure. The body is uncertain if the surgery was an injury and it will protect the joint making the joint stiff. This is one of the reasons that we ice, elevate, and use anti-inflammatory medicine immediately after many surgeries. Although the swelling will allow the joint to function without moving, it often limits the ability to return to normal activity if left untreated.
At the Bone and Joint Center, especially in the sports medicine area, we use physical therapy to allow patient’s to regain that motion as soon as possible. We will start physical therapy before the patient can even start strengthening. This allows us to make sure that the joint has full range of motion when strengthening begins.