An Overview of Patellar Tendon Tear

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.

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.

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.

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.

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.