This condition is a tear of the tendon that connects the patella to the quadriceps muscles of the thigh. The quadriceps muscle is used to straighten the leg from the bent position. A complete rupture of the quadriceps tendon is a disabling injury.
This type of injury is often caused by trauma. It can result from an awkward landing after a jump or a fall. It can be caused by a direct blow, or by a laceration to the front of the knee. A person whose tendons are weakened is at an elevated risk for this type of injury. Tendon weakness can be caused by chronic conditions such as diabetes, kidney disease, lupus, rheumatoid arthritis and leukemia. Tendon weakness can also be caused by the use of corticosteroids, the use of certain antibiotics, and by long periods of immobilization.
A quadriceps tendon tear is a painful injury. It may result in swelling, bruising, tenderness and cramping. If the tendon ruptures completely, the person will often feel a popping sensation. The person will be unable to straighten the leg from a bent position. The person will have difficulty walking. The patella may slip downward, leaving an indentation at the top of the knee.
Treatment options depend on the severity of the tear. A partial tear may be treated with rest, immobilization of the knee, and (after a period of healing) physical therapy. A complete rupture requires surgery to reattach the quadriceps muscles to the patella. Surgery will be followed by physical therapy.