Jumper's Knee (Patellar Tendonitis) Symptoms and Causes
Jumper's knee, medically known as patellar tendonitis, is inflammation of the patellar tendon which connects your kneecap to your shinbone (tibia). People who participate in activities that require running or jumping and sports like volleyball and basketball are more likely to get it, hence the nickname "jumper's knee." The patellar tendon works with the quadriceps muscles and quadriceps tendon in the front of your thigh to straighten your knee and leg. Inflammation of the patellar tendon weakens the tendon and may also cause small tears.
Although anyone can injure their patellar tendon, the American Academy of Orthopaedic Surgeons (AAOS) reports that partial or complete tendon tears are more common among middle-aged people who play running or jumping sports. A complete tear of the patellar tendon is a disabling injury that usually requires patellar stabilization surgery to regain full knee function.
Jumper's Knee Symptoms
Symptoms may come on slowly and not be associated with a specific injury. You may experience one or more of the following common symptoms of jumper's knee:
- Pain and tenderness around the patellar tendon
- Pain with jumping, running or walking
- Pain with bending or straightening the leg
- Tenderness behind the kneecap
Untreated, symptoms of jumper's knee worsen with time and activity and can be grouped in four progressive stages:
- Stage 1 – You experience pain only after an activity, and you don't have any functional impairment.
- Stage 2 – You experience pain during and after activity, although you can still perform satisfactorily in your sport or activity
- Stage 3 – You experience prolonged pain during and after activity, and it becomes increasingly difficult for you to perform satisfactorily.
- Stage 4 – Your inflammed patella tendon is completely torn and requires surgical repair.
The symptoms of jumper's knee may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
Jumper's Knee Causes
Patellar tendonitis may be caused by:
- Overuse of the knee joint – such as frequent jumping and running on hard surfaces.
- Steroid use – Medications such as corticosteroids and anabolic steroids have been linked to increased muscle and tendon weakness.
- Previous surgery around the tendon – Total knee replacement or anterior cruciate ligament (ACL) reconstruction might put you at greater risk for patellar tendonitis or a tear.
Weakened tendons that can lead to jumper's knee can also be caused by diseases that disrupt blood supply such as:
- Chronic renal failure – A serious condition in which the kidneys fail to rid the body of wastes. Kidney failure is the final stage of chronic kidney disease (CKD).
- Hyperbetalipoproteinemia – This genetic disorder is characterized by high levels of beta-lipoproteins and cholesterol and can lead to hardening of the arteries (atherosclerosis) at an early age.
- Rheumatoid arthritis – This type of arthritis is an autoimmune disease that can cause chronic inflammation of the joints as well as organs and other areas of the body.
- Systemic lupus erythematosus (SLE) – This autoimmune disease is characterized by the production of unusual antibodies in the blood.
- Diabetes mellitus – This chronic disease causes high levels of sugar glucose in the blood.
- Metabolic disease – A metabolic disorder occurs when abnormal chemical reactions in your body disrupt metabolism, the process your body uses to get or make energy from the food you eat. Diabetes is an example of metabolic disease.
Jumper's Knee Treatment
Like most patients with jumper's knee, your tendonitis may improve by modifying the activities that aggravate your injury, in addition to following a nonsurgical treatment regimen prescribed by your orthopaedist such as:
- Applying ice several times daily for 20-30 minutes
- Gentle stretching exercises
- Strengthening exercises
- Other sport-specific joint, muscle and tendon therapies
If nonsurgical treatments fail to provide improved function of your knee, your patellar tendon may need surgical repair.
The multidisciplinary team of orthopaedic experts at North Shore-LIJ Orthopaedic Institute's Joint Replacement Services in New York treats jumper's knee, (patellar tendonitis) as well as a broad range of conditions that affect the joints of the body.