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Introduction

Knee Pain

Quadriceps Tendon Tear

Tendons are strong bands of tissue that attach muscles to bones. The quadriceps tendon is the most important tendon involved in straightening the knee from a bent position.

Small tears of this tendon cause pain or make it difficult to walk and participate in other daily activities. A complete tear of the quadriceps tendon is a disabling injury. It almost always requires surgery, followed by physical therapy to regain full knee motion and function.

Quadriceps tendon tears are not common. They most often occur among middle-aged people who play running or jumping sports.

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Causes

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. 

Tendinitis. Inflammation of the quadriceps tendon, called quadriceps tendinitis, weakens the tendon. It may also cause small tears. Quadriceps tendinitis 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 (kidney) failure

  • Other 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, and you may not be able to straighten your knee. 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

  • Difficulty walking due to the knee buckling or giving way

Diagnosis

A quadriceps tendon tear is easily diagnosable. A doctor will ask you about your medical history and what you were doing at the time of the injury. You may be asked to extend your leg from a bent position or try to move it around.  

Medical staff may then perform a physical examination and order some imaging tests to look inside the knee area and determine the extent of the injury. Imaging tests could include: 

  • An X-ray

  • An ultrasound

  • A magnetic resonance image (MRI)

These will help the doctor to determine the type of injury and may indicate possible complications. It will also show if the tendon tear is partial or complete. 

Non-surgical treatments

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, you can physical therapy. Specific exercises can restore the strength and range of motion in your leg.

Your thearpist will gradually add exercises to your program. Straight leg raises to strengthen your quadriceps are often central to a physical therapy plan. As time goes on, your doctor 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 or other physical activity.

Surgery