Quadriceps tendon tears can be either partial or complete.

Partial tears. Many tears do not completely disrupt the soft tissue. This is similar to a rope stretched so far that some of the fibers are torn, but the rope is still in one piece.

Complete tears. A complete tear will split the soft tissue into two pieces.

When the quadriceps tendon completely tears, the muscle is no longer anchored to the kneecap. Without this attachment, the knee cannot straighten when the quadriceps muscles contract.

Cause

Injury
A quadriceps tear often occurs when there is a heavy load on the leg with the foot planted and the knee partially bent. Think of an awkward landing from a jump while playing basketball. The force of the landing is too much for the tendon and it tears.

Tears can also be caused by falls, direct force to the front of the knee, and lacerations (cuts).

Tendon Weakness
A weakened quadriceps tendon is more likely to tear. Several things can lead to tendon weakness.

Tendonitis. Inflammation of the quadriceps tendon, called quadriceps tendonitis, weakens the tendon. It may also cause small tears. Quadriceps tendonitis is most common in people who run and participate in sports that involve jumping.

Chronic disease. Weakened tendons can also be caused by diseases that disrupt blood supply. Chronic diseases which may weaken the tendon include:

• Chronic renal failure
• Conditions associated with renal dialysis
• Hyperparathyroidism
• Gout
• Leukemia
• Rheumatoid arthritis
• Systemic lupus erythematosus (SLE)
• Diabetes mellitus
• Infection
• Metabolic disease

Steroid use. Using corticosteroids has been linked to increased muscle and tendon weakness.

Fluoroquinolones. This special type of antibiotic has been associated with quadriceps tendon tears.

Immobilization. When you are off your feet for a prolonged period of time, the muscles and tendons supporting your knees lose strength and flexibility.

Symptoms

When a quadriceps tendon tears, there is often a tearing or popping sensation. Pain and swelling typically follow. Additional symptoms include:

• An indentation at the top of your kneecap where the tendon tore
• Bruising
• Tenderness
• Cramping
• Your kneecap may sag or droop because the tendon is torn
• You are unable to straighten your knee
• Difficulty walking due to the knee buckling or giving way

Diagnosis

Medical History
Your doctor will discuss your medical history. Questions you might be asked include:

• Have you had a previous injury to the front of your knee?
• Have you ever injured a quadriceps muscle?
• Do you have quadriceps tendonitis?
• Do you have any medical conditions that might predispose you to a quadriceps injury?
• Knee Extension

To determine the exact cause of your symptoms, Dr. Backe will test how well you can extend, or straighten, your knee. While this part of the examination can be painful, it is important to identify a quadriceps tendon tear.

Imaging Tests
To confirm the diagnosis, Dr. Backe may order some imaging tests, such as an X-ray or magnetic resonance imaging (MRI) scan.

X-rays. The kneecap moves out of place when the quadriceps tendon tears. This is often very obvious on a “sideways” X-ray view of the knee. Complete tears can often be identified with these X-rays alone.

MRI. This scan creates better images of soft tissues like the quadriceps tendon. The MRI can show the amount of tendon torn and the location of the tear. Sometimes, an MRI is required to rule out a different injury that has similar symptoms.

Treatment

If you have been diagnosed with a quadriceps tendon tear, you should go to an orthopaedic surgeon for treatment.

The type of treatment you require will depend on several things:

• The type and size of tear you have
• Your activity level
• Your age

Nonsurgical Treatment

Most small, partial tears respond well to nonsurgical treatment.

Immobilization. Your doctor may recommend you wear a knee immobilizer or brace. This will keep your knee straight to help it heal. You will most likely need crutches to help you avoid putting all of your weight on your leg. You can expect to be in a knee immobilizer or brace for 3 to 6 weeks.

Physical therapy. Once the initial pain and swelling has settled down, physical therapy can begin. Specific exercises can restore strength and range of motion.

Exercises will gradually be added to your program. Straight leg raises to strengthen your quadriceps are often central to a physical therapy plan. As time goes on, Dr. Backe or therapist will unlock your brace. This will allow you to move more freely with a greater range of motion. You will be prescribed more strengthening exercises as you heal.

Your doctor will discuss with you when it is safe to return to sports activity.

Depending on your age, your activities, and your previous level of function, Dr. Backe may recommend surgery for a large partial tear or a partial tear with associated tendon degeneration. Your surgeon will go over all the information and discuss an individualized plan for you.

Surgical Treatment

Most people with complete tears will require urgent surgery to repair the torn tendon. Surgery is also an option for people with partial tears who also have tendon weakness and degeneration.

Surgical repair reattaches the torn tendon to the top of the kneecap. People who require surgery do better if the repair is performed early after the injury. Early repair may prevent the tendon from scarring and tightening in a shortened position.