by Marcin Gornsiewicz, M.D.
“The load placed on the knees could be up to 7 times the body weight of a soccer player during kicking, and up to 11 times body weight when volleyball player lands after a jump.”
The knee is the largest joint in the body. It is essential for sitting, walking and running. The bones that make up the knee are the femur (thighbone), the tibia (shinbone) and the patella (knee cap). They give the knee strength needed to support the body’s weight. Ligaments are bands of tough fibers that hold these bones together.
There are two main groups of muscles, the quadriceps and the hamstrings. The quads are a group of four muscles and their primary role is to straighten the knee. The hamstrings are made up of three muscles in the back of the thigh. They are needed to bend the knee. Tendons are tough bands of fibrous connective tissue that connect muscles to bones. They are extremely strong but can be damaged if overstrained or improperly cared for.
The patella tendon (also known as patella ligament) is a continuation of the large quadricep muscle group. It covers the patella and attaches to the shin bone, it allows to straighten out the knee and provides strength for a kicking motion (figure 1).
Huge forces are transferred through the tendon. The load placed on the knees could be up to 7 times the body weight of a soccer player during kicking, and up to 11 times body weight when volleyball player lands after a jump. Therefore constant jumping, landing, kicking can lead to inflammation and irritation of patellar tendon, a condition called patellar tendonitis or “jumper’s knee.” It is believed to be caused by repetitive stress placed on the tendon, and is most common in sports such as basketball, soccer, volleyball, tennis, sports that require direction changing and jumping movement.
Symptoms include pain directly over the patellar tendon just below the knee cap. The bottom of the patella will be very tender when pressing. Movement of the knee may cause crunching sensation. Pain can be present when bending the knee, jumping, kneeling or climbing stairs.
Jumper’s knee can be categorized into stages. In stage one, the pain occurs only after activity. Kids have no symptoms before or during the activity. In stage two, pain is present at the beginning of the activity, goes away after warming up and then reappears after the activity. Play is usually not affected and kids often ignore these stage two symptoms. In stage three the pain is present during and after activity, and with stage four pain is constant with every day activities, and kids are unable to do any sports.
Treatment will depend on the grade of the injury, but the most important first step is to avoid activities that aggravate the problem. Resting for 2-4 weeks usually helps tremendously. Icing the knee and elevating when it hurts by placing a pillow under the leg reduces the pain and inflammation. Anti-inflammatory meds such as Ibuprofen or Naproxen and analgesics like Tylenol can be used. Exercises designed to strengthen the muscles are very important for treatment.
Depending on the severity of the condition, recovery could last from 2 weeks to several months. Children should stay away from sports that aggravate the knee pain and make condition worse, however that doesn’t mean they can’t participate in any sport. Low impact activities like swimming instead of running can be advised. It is important to go back to previous sport activities slowly, gently stretch before (warming up), and after exercise. Wearing a knee support or strap (intra-patellar strap or a Cho-Pat strap) may reduce strain on the patellar tendon by changing the angle that the tendon inserts into the patella, and the length of the tendon (figure 2).
Jumper’s knee may seem like a minor injury that is not that serious. Many athletes continue to train and compete. However, if left ignored and untreated, the injury can lead to chronic condition that may ultimately require surgery.
Dr. Marcin Gornisiewicz graduated with an MD degree from the Medical School of Warsaw in Warsaw, Poland. He completed residency training in internal medicine at Saint Barnabas Medical Center in Livingston, New Jersey. He completed fellowship training in rheumatology at the University of Alabama at Birmingham in Birmingham, Alabama. He joined Rheumatology Consultants, PLLC (rheumatologyconsultants.org) in 2002. He is board certified in Rheumatology.