An Overview of Patellar Tendon Tear

Patellar tendon tears involve the partial or complete rupture of the band of connective tissue that attaches the bottom of the kneecap (patella) to the top of the shinbone (tibia).

A tendon is a cord of fibrous tissue that connects muscles to bones. The patellar tendon specifically works with the muscles in the front of your thigh (quadriceps) to straighten your leg.

A patellar tendon tear causes instability of the knee, making it difficult to walk or bear weight on the leg. Other symptoms include knee pain, swelling, and bruising.

This article describes the symptoms and causes of a patellar tendon tear, including how this orthopedic (bone-related) condition is diagnosed and treated.

Patellar Tendon Tear Symptoms

Patellar tendon tears can be partial or complete. The tear often occurs at the place where the tendon attaches to the kneecap, causing a piece of bone to break off with it.

The typical signs of a torn patellar tendon include:

• A snapping or popping sound at the time of the break
• Pain directly under the kneecap
• Swelling and bruising in front of the knee
• A divot or soft spot in front of the knee
  
• Difficulty walking or doing sports
• Inability to fully extend the leg

You can often tell if a tear is partial or complete by how much you can straighten your leg. If the rupture is complete, the lack of an attachment makes it impossible to straighten the knee. The kneecap may also appear to slide up into the thigh as you do.

How Do You Tear Your Patellar Tendon?

Patellar tendon tears are often called "jumper's knee" because they are commonly seen in sports that involve jumping and landing at different angles.

A patellar tendon tear can be caused by a traumatic knee injury; however, it is more often the result of repetitive stress placed on the knee over a period of time. Nearly everyone with a patellar rupture has a chronic (persistent) condition known as tendinosis caused by the overuse of a tendon. When the tear occurs, it happens at the weakest spot.

Jumper's knee is common in sports like basketball, volleyball, gymnastics, soccer, track and field, and long-distance running. It most often occurs before age 40 but can also affect healthy teens.

A patellar tendon tear is not always due to a sports injury. Certain medical conditions can directly or indirectly damage the tendon, causing it to weaken and tear.

Non-athletic causes include:

• Diabetes
  
• Lupus
• Obesity
• Overuse of oral corticosteroids (steroids)
• Previous knee surgery
• Rheumatoid arthritis
• Severe knee infection

Diagnosing a Patellar Tendon Tear

Patellar tendon tears are usually obvious. People who tear the tendon will be unable to extend their knee or perform a straight leg raise test. The healthcare provider can usually feel a 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 higher than the opposite knee as the quadricep pulls on the untethered kneecap.

Magnetic resonance imaging (MRI) may be used to confirm the diagnosis and inspect the knee for any other damage. MRIs create highly detailed images of soft tissues and can often spot tiny tears that an X-ray might miss.

Treatment Options

Patellar tendon tears may or may not need surgery depending on the extent of the rupture. Very small tears respond well to nonsurgical treatments. Complete tears almost invariably require surgery.

Non-Surgical Treatment

if the patellar tendon tear is small and there are no concerns that the tear will get worse, your orthopedic surgeon might recommend a conservative approach, involving:

• Immobilization: You would need to wear a knee immobilizer or brace for three to six weeks to keep your knee straight and help it heal. You will likely need crutches to avoid bearing any weight on the leg.
• Pain management: Applying an ice pack to the knee for 15 to 20 minutes several times a day can reduce swelling and pain. Elevating the leg also helps. Nonsteroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen) and Aleve (naproxen) can also ease pain and inflammation.
• Physical therapy: Once the initial pain and swelling have settled, you can begin physical therapy, starting with straight-leg raises in the knee brace. Later, you'll work in gentle range-of-motion exercises without a brace. Strengthening exercises would gradually be integrated into the rehabilitation plan along with other modalities like ultrasound, electrical stimulation, and kinesiology taping.

Surgical Treatment

Many partial patellar tendon tears do not heal well on their own. If left untreated, they will lead to the weakening of the quadriceps muscle and the loss of mobility.

Surgery used to repair the tear is relatively straightforward but difficult to perform. This is because the torn ends need to be sewn together so that the proper tension is maintained, ensuring that it is neither too tight nor too loose. This is especially difficult if the ruptured tendon has taken a piece of bone with it.

Most tendon repairs can be done on an outpatient basis, although some people may need to stay in the hospital overnight. The surgery may be performed with a spinal block which numbs the lower body, regional anesthesia which numbs only the leg, or general anesthesia which puts you to sleep.

The surgeon may directly stitch together the torn ends or use a device called a suture anchor to connect the tendon to the kneecap without having to drill holes. Wires or cables may be needed to help better support and stabilize the knee.

Recovery and Prognosis

Recovery from patellar tendon surgery can be difficult and take time. One of the most important factors influencing outcomes is the timing of surgery, Delaying surgery beyond a few weeks can cause significant retraction of the tendon, limiting your ability to fully recover.

Some factors can speed recovery. These involve a commitment to physical therapy along with taking appropriate measures to avoid overextending yourself. Rushing may cause reinjury, setting you back weeks or even months.

Even when taking the appropriate steps, you should expect a minimum of three months of rehabilitation before you can return to normal activities, and four to six months before sports can be resumed.

Athletes wanting to return to competitive sports may take a year or longer to return to their pre-injury level of performance.

Summary

A patellar tendon tear is the partial or complete rupture of the band of connective tissue that attaches the kneecap to the shin bone. When this happens, you may be unable to walk or fully straighten the leg. Knee pain, bruising, and swelling are common symptoms.

A patellar tendon tear is sometimes called "jumper's knee" because it commonly affects athletes who jump. It can also affect people with conditions that weaken the tendons, such as diabetes and previous knee surgery.

Depending on the extent of the tear, the treatment may involve immobilization with extensive physical therapy or surgery with extensive physical therapy.