Knee pain can be caused by a sudden injury, an overuse injury, or by an underlying condition, such as arthritis. Treatment will vary depending on the cause. Symptoms of knee injury can include pain, swelling, and stiffness Knee pain is the most common musculoskeletal complaint that brings people to their doctor. With today?s increasingly active society, the number of knee problems is increasing. Knee pain has a wide variety of specific causes and treatments. The cause of ankylosing knee pain is unknown, but it is likely that both genes and factors in the environment play a role. The main gene associated with susceptibility to ankylosing knee pain is called HLA-B27. But while most people with ankylosing knee pain have this genetic marker, only a small percentage of people with the gene develop the disease. Physical therapy can provide a number of benefits, from pain relief to improved physical strength and flexibility. Your doctor may recommend that you meet with a physical therapist to provide you with specific exercises designed for your needs.