What Is a Medial Retinaculum?

The knee is where the femur, the thigh bone, comes together with the tibia, the bone of the lower leg. The medial retinaculum is located within the knee joint; it works with the patella tendon and the quadriceps muscles to help you perform the function of extending your knee.

Function

• The medial retinaculum plays a minor role -- along with the vastus medialis oblique and the medial patellofemoral ligament -- in providing medial stability in the knee, according to Dr. Stephen Pribut's running injuries website. "Medial" means "extending toward the middle."

  The knee has both dynamic and passive stabilizers; the medial retinaculum is a passive stabilizer of the knee joint. The two types of stabilizers work together to control patellar tracking -- the movement of the bone of the kneecap. While the medial retinaculum does help position and track the patella, its function in that regard is minor.

Problems

• The medial retinaculum is one of several parts of the knee now under suspicion as a cause of the painful injury called "runner's knee" -- also known as patellofemoral pain syndrome (PFPS) -- notes Dr. Stephen Pribut. In this condition, stress on the joint leads to pain, and joint pressure affects the ability of cartilage to effectively remove waste materials and receive nutrition; this can lead to deterioration, according to the doctor's website.

Causes and Symptoms

• Poor flexibility, overuse and trauma can lead to problems affecting the medial retinaculum, according to the American Academy of Family Physicians website. Overuse also leads to PFPS. People with PFPS describe pain and tenderness in the general area of the medial retinaculum -- underneath, behind and around the kneecap -- and pain when sitting for long periods of time, notes the website.

Treatment

• PFPS can be effectively treated with physical therapy, rest and a reduction in exercise or workload. Your physician may evaluate the way you stand, walk and squat to observe how your kneecap behaves, check the range of motion in your knees and hips, and palpate your knee to pinpoint painful areas and weakness and note flexibility in and around the joint, according to the American Academy of Family Physicians website. In cases of repetitive or severe injury, the medial retinaculum may be stretched and weakened or torn. Such damage may require surgery to repair or reconstruct the tissues, notes orthopedic surgeon Daniel C. Wnorowski, M.D.