Patellar and Quadriceps Tendon Tears: Overview

Patellar and Quadriceps Tendon Tears: Overview

This video will provide an overview of patellar and quadriceps tendon tears. The extensor mechanism of the knee is an important group of structures that allows the knee to straighten, which is needed for standing and walking. It includes the 4 quadriceps muscles of the thigh, the quadriceps tendon, the patella or kneecap, and the patellar tendon.

When the quadriceps muscles contract, they pull on the quadriceps tendon, which transfers force across the kneecap and patellar tendon to pull the shinbone and straighten the knee. Injury to either the quadriceps tendon or the patellar tendon disrupts this chain of events, which can make it very difficult or impossible to straighten the knee. The quadriceps tendon attaches the 4 quadriceps muscles to the top of the kneecap, while the patellar tendon attaches the bottom of the kneecap to the tibia, or shinbone.

Tears to these tendons are not that common, and usually result from a quick, forceful contraction of the quadriceps muscles when the knee is bent, which causes 1 of the tendons to tear. This often occurs with landing from jumping, slips, or falls, as the quadriceps muscles contract quickly to try to prevent losing balance. Both the quadriceps tendon and patellar tendon are very strong, so tears are more likely to happen when there are other risk factors involved that weaken the tendons over time.

These include medical conditions that involve inflammation throughout the body, like obesity, diabetes, rheumatoid arthritis, lupus, and chronic renal failure. Other risk factors include long-term use of corticosteroid medication and tendinitis, more commonly referred to as tendinopathy, which causes ongoing stress to the tendons. Both of these factors can lead to tendon weakening, which can increase the risk of a tear.

Tears occur more often in males, with patellar tendon tears more likely to occur in people under 40 years old, and quadriceps tendon tears more likely to occur in people over 40 years old. Symptoms of a quadriceps tendon or patellar tendon tear include pain at the front of the knee, swelling, and inability to straighten the knee, stand, or walk. A gap above or below the kneecap may also be felt after the injury if the tendon is completely torn off from the kneecap.

A health care provider will review a patient's symptoms and examine the knee. While x-rays may be taken to make sure there is not a broken bone, an MRI is the standard imaging technique used to see if the quadriceps tendon or patellar tendon is torn. A health care provider will use the results from imaging studies, along with the patient's symptoms, to determine the best treatment option.

In summary, the quadriceps tendon attaches the quadriceps muscles to the kneecap and the patellar tendon attaches the kneecap to the shinbone. Tears to these tendons result from quick, forceful contraction of the quadriceps muscles when the knee is bent. These injuries are more likely to occur in males and certain conditions increase the risk. Symptoms include pain, swelling, and inability to straighten the knee, stand, or walk. An MRI is used to make a diagnosis.