What is a Patellar Tendon Rupture?

The patellar tendon is a strong band of tissue that connects the shin bone (tibia) to the bottom of knee cap (patella). It works with the muscles and tendon in your thigh to straighten and bend the leg at the knee. A tendon rupture is a complete tear. If the patellar tendon is completely torn, you won’t be able to straighten your knee. 

Symptoms

A rupture is usually signaled by a popping sound. Other symptoms include: 

Swelling

Inability to straighten the knee 

Swelling

Inability to straighten the knee 

Difficulty walking 

Pain or tenderness around and below the knee 

When to See a Doctor

Seek urgent treatment with on orthopedic surgeon (a healthcare provider who specializes in these types of injuries) if you have any of the symptoms listed above. A patellar tendon rupture heals best when treated immediately. 

Causes

A tendon rupture is usually caused by a forceful blow or collision. This often happens during sports activities. Other causes include:

  • Falls that result in cuts to the tendon
  • Weakness caused by:
    • Tendinitis (jumper’s knee)
    • Tendinopathy from repeated stress
    • A medical condition such as kidney failure, rheumatoid arthritis, or diabetes
    • Previous knee surgery
  • Long-term use of corticosteroids or use of anabolic steroids

Diagnosis and Tests 

Your healthcare provider will ask you about the injury and your medical history. The knee will be examined for common signs of injury, including:

  • Whether or not you can straighten your leg
  • Noticeable and painful changes in the tendon
  • Displaced kneecap

Imaging tests, such as X-ray, ultrasonography, and MRI can help your healthcare provider see any damage to your bones and soft tissue.

Treatments & Prevention

Treatments

Surgery is usually recommended to repair a ruptured patellar tendon. During surgery, the kneecap is positioned properly and the torn tendon is attached to the bottom of the kneecap with sutures (stitches) or with metal anchor screws. If the damaged tendon is too short, it may be necessary to graft extra tissue onto the tendon to perform the repair.

After surgery, you will need to rest the leg for a couple weeks. You’ll need to use crutches and may have either a full cast or a brace that keep the knee from moving.

Physical therapy is recommended after a few weeks. It is important to follow your exercise plan exactly as ordered to ensure that your tendon heals properly and to build strength gradually. You will likely wear a brace for several weeks to protect and support your knee as it heals.

It can take 6 to 12 months for a complete recovery. Athletes will need to have their strength tested and reviewed by the surgeon before returning to the field of play.