A quadriceps tendon rupture occurs relatively infrequently and usually occur in athletes older than 40 years. Injuries to the quadriceps tendon can be very disabling. They can cause significant loss of time from sport and work.
If not treated appropriately, these injuries can have many negative long-term sequelae, however if diagnosed quickly and treated appropriately, one can expect a full recovery from a quadriceps tendon rupture.
What is the quadriceps tendon and why is it important?
The quadriceps tendon is the strong tendon that inserts on the top of the patella
(knee cap). The quadriceps tendon is a confluence (coming together) of the four muscles that make up the muscles that extend the knee. These four muscles are: vastus medialis, vastus intermedius, vastus lateralis and rectus femoris. These muscles are the strong muscle on the anterior (front) side of the femur (thigh bone). Their main action is to extend the knee and leg. All four of these muscles come together just above the patella and form a strong, thick tendon.
The quadriceps tendon is important because it allows the knee to be extended. If the quadriceps tendon is injured then the patient will not be able to extend their knee.
How does one suffer quadriceps tendon rupture?
The quadriceps tendon is injured most commonly from a forced eccentric contraction (contracting while lengthening) against an outside force. This can happen during high-energy accidents such as motor vehicle crashes and during sporting activities, or during low energy injuries such as falls from a standing position.
What are some risk factors for a quadriceps tendon rupture?
Really there are very few risk factors. Most quadriceps tendon ruptures are the result of either direct or indirect trauma. There are some medical problems that can increase a person’s chance of having a quadriceps tendon rupture including renal (kidney) disease, rheumatoid arthritis, chronic steroid use and diabetes mellitus. However, even in patients with these disorders, the incidence of quadriceps tendon ruptures is still very low.
What are the signs and symptoms of a quadriceps tendon rupture?
Most people with a quadriceps tendon rupture will note the acute onset of pain and disability in the affected leg. Usually this is precipitated by a fall or other traumatic event. The pain will be located at the level of the knee or just above the knee joint. The patient with a complete rupture is unable to do a straight leg raise or extend their knee. These patients will have a difficult time walking on the affected leg.
On physical examination the patient will be acutely tender to palpation directly above the patella. There is oftentimes a palpable defect in this area when compared to the contralateral side (uninjured knee). The knee will have a large effusion (swelling in the knee). The patient will be unable to extend their knee. Some patients with a partial tear may still be able to extend their knee, but will have significant weakness when compared to the other leg.
What imaging studies are needed for a quadriceps tendon rupture?
Initially a patient who presents with pain and swelling in the knee should undergo plain radiographs (x-rays) of the affected knee. This will help to rule out a fracture as the cause of the problem. If these are negative, then a MRI scan can be obtained to evaluate the integrity of the quadriceps tendon.
The x-rays of a patient with a quadriceps tendon rupture may show patellar baja (a knee cap that is lower than normal). There may also be a small piece of bone that is torn off of the patella with the tendon that can be visualized on x-ray. The gold standard for diagnosis would be a MRI scan of the knee, which would evaluate all of the soft tissue structures in the knee including all of the cartilage and ligaments. This would also help to distinguish between a complete and partial tear.
What are some other injuries that can mimic a quadriceps tendon rupture?
There are many injuries to consider when a patient may have a quadriceps tendon rupture. These include: patellar (knee cap) fracture, patellar tendon rupture, fracture of the end of the femur (thigh bone) or top of the tibia (shin bone), ACL tear, and patellar dislocation. The diagnosis is confirmed by doing an appropriate physical examination and also through imaging studies.
What are the different types of quadriceps tendon ruptures and how are they treated?
Quadriceps tendon ruptures come in two main types: partial and complete tears. Distinguishing between the two is very important, as the treatment is vastly different.
Partial tears can sometimes be treated non-operatively. In order for a partial tear to be treated without surgery, the patient must be able to do a straight-leg raise and have good strength with this physical exam finding. If this is the case, treatment should commence immediately with immobilization of the leg in full extension (out straight) for a short period of time. Then range of motion exercises are started at between 3-6 weeks from the injury. After six weeks, quadriceps strengthening is begun. Typically, after 10-12 weeks the injury has healed. The patient may resume normal activities after they have full range of motion and quadriceps strength. This can be anywhere from 3-6 months after the injury. Return to sport is governed by the ability to pass functional tests specific to the sport (example: jumping for a basketball player).
Play video on Massaging the Quadriceps Muscles
Complete tears, as well as partial tears when the patient is unable to perform a straight-leg raise, are always treated with surgery. Without surgery, the patient will be unable to extend their knee and have significant long-term disability. Surgery is typically recommended within a few days to a week after the injury. If the patient’s other medical problems prohibit the opportunity to perform the surgery safely in the first week, it can be delayed until the patient is medically fit for surgery.
What does the surgery involve for repair of a quadriceps tendon rupture?
Typically surgery involves making an incision on the front of the knee. Then strong sutures are placed into the tendon and tied back down to the top of the patella. Surgery generally takes between one and two hours. The patient is then placed into a knee immobilizer keeping the knee straight after surgery.
What type of rehabilitation is needed after surgery?
After surgery, the patient will start with gentle passive range of motion with their physical therapist. The patient will be able to weight bear with all of their weight on their leg after a week or two, but will have to wear the brace they received after surgery locked straight for the first six weeks, except when doing their therapy. By six weeks post-op, the patient should have 90 degrees of flexion (bending) of the knee. After six weeks, progressive strengthening is started as well as increasing range of motion. Typically, the brace is discontinued at eight weeks from surgery. Light running is generally started at four months from surgery. Return to sport is governed by the ability to perform sport specific exercises and having adequate range of motion and strength. This is generally between 6-8 months from the day of surgery. It should be noted that rehabilitation protocols are often very specific to the type of injury and the type of repair that was achieved at the time of surgery. The above protocol is just an outline of “typical” rehabilitation.
Be sure to take a look at the following SportsMD video on strengthening the quadriceps muscle
What if I do not seek treatment for my quadriceps tendon rupture right away?
Quick Quad Strength
When quadriceps tendon ruptures are not identified early, it can be more difficult to fix with surgical repair. The quadriceps muscle is very powerful, therefore the tendon retracts proximally (up the thigh) and becomes harder to fix back to the patella with surgery. Surgical repair is still possible but may require special techniques to do so and an extended rehabilitation protocol.
What is the long-term prognosis for a quadriceps tendon rupture?
Most people who undergo treatment of a quadriceps tendon rupture will do well long-term. They will be able to return to work and sport after the appropriate rehabilitation. It is important to be very diligent with the appropriate prescribed physical therapy to ensure a good outcome. Re-tear of the tendon after surgical repair is rare unless something unexpected happens (ex: a fall during the early post-operative phase). The most common complication is loss of motion in the knee after surgical repair.
If you suspect that you have a quadriceps tendon rupture, it is critical to seek the urgent consultation of a local sports injuries doctor for appropriate care. To locate a top doctor or physical therapist in your area, please visit our Find a Sports Medicine Doctor or Physical Therapist Near You section.
Ilan D, Tejwani N, Keschner M and Liebman, M. Quadriceps Tendon Rupture. Journal of the American Academy of Orthopaedic Surgeons. 2003;11:192-200.
Rauh, M and Parker, R. Patellar and Quadriceps Tendinopathies and Ruptures. DeLee and Drez Orthopaedic Sports Medicine: Principles and Practice. 2010. Chapter 22 1513-1525.