What Happens With a Quadriceps Tendon Rupture

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The quadriceps tendon is a thick, strong tendon that can withstand tremendous force. In daily life, it acts as part of the extensor mechanism to straighten the knee.

People who injure the extensor mechanism may tear the quad tendon, tear the patellar tendon, or fracture the kneecap. All of these injuries have similar treatments and rehabilitation plans.

Man doing a leg lunge in a sports stadium
Cultura RM / Antonio Saba Cultura / Getty Images

The Quadriceps Tendon

The quadriceps tendon (quad tendon) is the large tendon just above your kneecap. The quad tendon is part of the extensor mechanism of the knee that includes the quadriceps muscle, the quad tendon, the kneecap (patella) and the patellar tendon.

A tendon is a structure that attaches a muscle to bone. The force of muscle contraction is transmitted through the tendon to move the bone.

It's the extensor mechanism that allows us to straighten our knee or perform a kicking motion.

When the quadriceps muscle (thigh muscle) contracts, force is transmitted through the quadriceps tendon, across the patella (kneecap), through the patellar tendon, and the knee is straightened.

Causes

Partial quad tendon injuries can occur in association with athletic activities or active lifestyles.

These symptoms may cause gradually increasing pain over the kneecap and may be misdiagnosed as a kneecap problem. An incomplete injury to the quadriceps tendon may be described as:

  • Tendinitis
  • Tendinosis
  • Partial tearing of the quadriceps

The key to differentiating this is whether or not the tendon is completely torn away from the kneecap.

Complete quadriceps tendon tears are unusual injuries. They most often occur in people over the age of 40, and often in people who have systemic medical conditions that can cause weakening of the tendon.

The quadriceps tendon ruptures typically occur during an eccentric contraction where the quadriceps muscle is contracting, but the knee is being straightened. When this occurs, the sudden, opposing forces can exceed the strength of the quadriceps tendon.

An eccentric contraction can occur with injuries such as a slip on wet ground or a sports injury.

Symptoms and Diagnosis

If the tendon is completely ruptured, you'll be unable to straighten the knee without help and you'll be unable to perform a straight leg raise.

Most people with a quadriceps tendon rupture will have​ a swelling of the knee and your healthcare provider will be able to feel the torn tendon just above the kneecap. If the swelling isn't too severe, you may be able to see a divot or gap where the tear in the tendon is located.

X-rays can help your practitioner determine if the kneecap was damaged. While an MRI is usually not necessary, your medical professional may order the test to evaluate for other damage within the knee joint.

Treatment

Partial tears of the quadriceps tendon can usually be managed with non-surgical treatments, which may include the use of:

Physical therapy can be especially beneficial by strengthening the quadriceps and surrounding muscles, and utilizing other modalities to stimulate healing of the tendon.

Complete tears of the quadriceps tendon require surgical intervention to regain strength in the extremity.

Surgery is usually done within a few weeks of the injury, as some reports have shown that delayed treatment may lead to less successful results. Surgery is performed to suture the torn tendon back to its attachment on the patella (kneecap).

In order to accomplish this, your surgeon will use a drill to make holes (tunnels) in the patella, and then loop sutures through these tunnels to pull the tendon to the bone.

Following surgery, most surgeons recommend a brace to protect the repair. You may also be put on crutches, although weight can be placed on the leg as long as the knee is kept straight.

Many surgeons allow early range of motion exercises, but this should be done under the supervision of a physical therapist or healthcare provider.

The brace can usually be discontinued after three months, and sports resumed in four to six months.

A Word From Verywell

A quadriceps tendon rupture is an uncommon injury that typically requires surgical treatment.

Without an intact quadriceps tendon, straightening the knee and walking normally can be difficult. During surgery, the tendon is reattached to the top of the kneecap bone.

Rehabilitation is lengthy following quadriceps tendon repair surgery, but most people recover normal activities.

5 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.
  1. Jolles BM, Garofalo R, Gillain L, Schizas C. A New Clinical Test in Diagnosing Quadriceps Tendon RuptureAnn R Coll Surg Engl. 2007;89(3):259-261. doi:10.1308/003588407X179044

  2. Nori S. Quadriceps tendon ruptureJ Family Med Prim Care. 2018;7(1):257-260. doi:10.4103/jfmpc.jfmpc_341_16

  3. Ennaciri B, Montbarbon E, Beaudouin E. Surgical management of acute quadriceps tendon rupture (a case report with literature review)Pan Afr Med J. 2015;22:243. doi:10.11604/pamj.2015.22.243.7533

  4. Hantes ME, Mathews R, Raoulis V, Varitimidis S, Karachalios T, Malizos KN. Better knee function after surgical repair of acute quadriceps tendon rupture in comparison to acute patellar tendon rupture. Orthop Traumatol Surg Res. 2019;105(1):119-123. doi:10.1016/j.otsr.2018.09.019

  5. Langenhan R, Baumann M, Ricart P, et al. Postoperative functional rehabilitation after repair of quadriceps tendon ruptures: a comparison of two different protocols. Knee Surg Sports Traumatol Arthrosc. 2012;20(11):2275-2278. doi:10.1007/s00167-012-1887-8

Additional Reading
Cluett

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.