An Overview of Patellar Tendon Tear

Tears Typically Require Surgical Repair

Patellar tendons are the structures that connect the kneecaps (patella) to the shinbones (tibia). They connect the quadriceps muscle to the shin bone and, less precisely, are sometimes called patellar ligaments.

The tendon plays an important role in your ability to extend the leg in order to walk, climb stairs, run, and play sports. When the patellar tendon is injured, whether in a partial or full tear, activities can become difficult to perform.

This article explains how the patellar tendon works and common injuries like a patellar tendon rupture (complete tear). It explains how they are diagnosed and treated, as well as how people recover from them.

Common signs of a patellar tendon tear

Verywell / JR Bee

Patellar Tendon Tear Symptoms

Patellar tendon symptoms depend on the severity of injury, but almost all of them are associated with sports-related overuse patterns. It's one reason these injuries are called "jumper's knee."

A patellar tendon rupture, for example, happens most often in middle-aged adults before age 40 but still can happen to a healthy teen.Athletes who sustain the injury may feel a snapping or popping sensation and will typically be unable to walk following the injury.

The typical signs of a torn patellar tendon include:

  • Pain directly under the kneecap
  • Swelling and bruising in the front of the knee
  • A defect, or soft spot, where the tendon should be tight
  • Difficulty walking or doing sports activities

Patellar tendinosis, a term that reflects the degenerative (wear-and-tear) nature of the damage, describes this progressive weakness associated with basketball, volleyball, running, and other sports that put excessive strain on the knees.

How Painful Is a Patellar Tendon Tear?

Each person experiences pain differently, and the tear can be partial or complete. But pain typically occurs immediately after you feel a snapping or popping at the knee. You may be unable to straighten the knee or bear weight on it because it gives way. The kneecap also may appear to slide up into the thigh if it's no longer anchored in place.

Patellar Tendon Rupture Causes

Nearly all people who experience a patellar tendon rupture have abnormal tendon tissue associated with a chronic tendinosis. A tear often occurs at the weakest spot.

Tendon tears don't always occur because of a sports injury. Usually, there is a reason for the patellar tendon to become weak, such as a systemic disease or recent knee surgery that led to a weakened tendon. Treatment is usually similar in athletes and non-athletes alike, however.

Diagnosing a Tear

Patellar tendon tears are usually obvious on clinical examination. People who tear the tendon will be unable to extend their knee against gravity, and unable to perform a straight leg raise test. The healthcare provider can usually feel the gap in the tendon, just below the kneecap.

An X-ray will help to differentiate between a patellar tendon tear and a patellar fracture, which can cause similar symptoms. On the X-ray, the patella is usually up higher when compared to the opposite knee because the quadriceps pulls up on the kneecap, and nothing is holding it down in its normal position.

Magnetic resonance imaging (MRI) may be used to confirm the diagnosis and inspect the knee for any other damage that may have occurred.

Who's at Risk for Patellar Tendon Tears?

Patellar tendon tears are more common in biological males, but research suggests that risk arises from the activities themselves. For example, playing on concrete appears to lead to more injuries than wood courts. More frequent training raises the risk, and there's some evidence that so does playing only one type of sport. One constant is that 45% of people with a patellar tendon injury already had tracking changes in the knee structure.

Treatment

Patellar tendon tears do not heal well on their own. Left untreated, they will lead to weakness of the quadriceps muscle and difficulty with routine activities, including walking. Surgery to repair the torn tendon is relatively straightforward in concept but can be difficult to perform.

The torn ends of the tendon need to be sewn together. The difficulty lies in the fact that it is important to restore proper tension to the tendon, not making it too tight or too loose.

Also, it can be difficult to get a good repair, especially if the tendon has torn directly off the bone. In some cases, the tear may actually take a piece of bone with it. It means the sutures used to repair the tendon may have to be attached directly through the bone.

While patellar tendon surgery isn't painful in and of itself due to anesthesia, the recovery itself may prove challenging.

Recovery and Prognosis

Recovering from a torn patellar tendon is difficult and takes time. One of the most important prognostic factors for recovery is the time to surgery, and surgery delayed beyond a few weeks can limit recovery ability.

Some factors can speed recovery. They include early return to mobility after surgery, strengthening therapies that protect the knee, and avoiding any excessive stress on the repair.

Even with these steps, there is a minimum of three months until the return of normal daily activities, and four to six months until sports should be resumed.

While most people heal completely from a patellar tendon surgery, there can be long-term weakness even with a successful repair.

Athletes who are attempting to return to competitive sports may take a year or longer to return to their pre-injury level of function. Performing guided physical therapy can be helpful to ensure athletes are able to resume their normal sports activities.

Frequently Asked Questions

  • Can you exercise with a torn patella tendon?

    Not right away. After the tear, you should rest the knee and let it heal for a few weeks. After some of the pain and swelling have eased, you can begin exercises to rebuild the knee’s strength and range of motion.

  • Can a patellar strap help my knees stop hurting when I run?

    For occasional pain, a patellar tendon strap may help you during exercise. The strap supports an aching knee by keeping it in alignment during physical activity. The strap isn’t a solution for a chronic knee problem, though. If you usually have pain when you run, see a healthcare provider to find the underlying cause.

  • How can I strengthen my knee tendons?

    Resistance exercises can build up tendons, but to help regain strength, stability, and range of motion, you need to do exercises for the quadriceps muscles. Exercises that improve hip flexibility may also improve how the patellar tendons work. 

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Academy of Orthopaedic Surgeons. Patellar tendon tear.

  3. Reinking MF. Current Concepts in the Treatment of Patellar Tendinopathy. Int J Sports Phys Ther. 2016 Dec;11(6):854-866. PMID: 27904789

  4. University of Michigan Health. Patellar tracking disorder: Exercises.

By Jonathan Cluett, MD
Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams.