Knee Tendinitis

Patellofemoral Syndrome

(e.g., Knee Tendinitis, Runner's Knee, and Chondromalacia)

Knee pain is a very common problem experienced by people who are active in sports. Studies have shown that the patellofemoral syndrome accounts for up to 5% of the overuse injuries. This syndrome is caused by an irritation to the undersurface of the kneecap (patella), which is normally smooth. The irritation can lead to a roughing of the patella undersurface, a condition called chondromalacia. The irritation and roughening of the patella can lead to inflammation which causes pain. Patellofemoral syndrome and chondromalacia are not arthritis. Measures taken to reduce the inflammation can relieve the pain.

The Injury

The patella, a moving bone, glides up and down in a groove formed by the femur (the thigh bone). Repeated bending of the knee causes pressure between the patella and femur. As the pressure increases, the resulting tension can exceed what is normally tolerated, causing pain in the knee. Pain is associated with inflammation of the tissues of the knee.

Contributing Factors

When the patella is not centered in the groove of the femur, the imbalance that results leads to wear and tear. This problem with alignment (called patellar malalignment) can be identified by examination and X-rays of the knee.

  • Overuse and overload of the knee joint, especially with jogging, hiking, stair climbing, and downhill running
  • Knock knees
  • Abnormal rotation of the lower leg (called tibial torsion)
  • Flat (pronated) feet
  • Weak thigh (quadriceps) muscles
  • Previous injury to the knee
  • Family tendency
  • Sudden increase in activity or training level
  • Obesity or sudden weight increase


Treatment is based on two principles: reducing the inflammation and improving the alignment or tracking of the patella in the groove of the femur.


This stands for rest, ice, compression, and elevation.

Rest. The degree of rest will depend on the severity of the inflammation. The athlete may have to temporarily stop running, stair climbing, or playing his sport, to allow the injury to heal. Continuing the sport or activity often aggravates the injury, causing the athlete to experience pain, possibly more than initially. The athlete should use pain as his guide. To avoid pain, the athlete should keep his leg straight when sitting and refrain from squatting then standing and walking. Once the pain begins to subside, knee exercises can be started to improve flexibility and strength, allowing the athlete to resume his sport sometime in the future.

Ice. Ice can be applied to the knee for 20 – 30 minutes, 3 – 4 times per day initially, and then 2 times per day. Ice massage is a very effective form of ice application. Apply the ice for 15 minutes after any activity involving the knee to minimize additional inflammation caused by the activity.

Compression. This can be achieved by using an ACE wrap or a neoprene knee sleeve. A patellar stabilizer may be recommended to help support knee tendons, thereby reducing tension and pressure on these tendons and relieving the inflammation.


Stretching exercises of the knee and upper and lower legs are essential to help improve muscle tendon flexibility and strength. These exercises help reverse the muscle weakness which results from the inflammation and enable the tendons to resume the usual demands and workloads of the sport. When the thigh muscles are strengthened and balanced, they will be able to control the movement of the patella in the groove more accurately and with less pressure (see section on Exercises).

Physical Therapy: This may be necessary to help reduce the knee inflammation. The physical therapist may use such modalities as ultrasound, phonophoresis, iontophoresis, friction massage, electrogalvanic stimulation, and soft tissue mobilization to treat scar tissue in the muscle tendons caused by the chronic inflammation. The physical therapist may use the McConnell taping technique to improve tracking of the patella in the groove.

Medication. An oral anti-inflammatory medication may be prescribed or recommended. Such medication helps relieve the pain and reduce the inflammation.

Surgery. If all other forms of treatment fail to provide relief, then surgery should be considered. The surgeon would look inside the knee joint with an arthroscope to determine the nature and severity of the injury and the most appropriate repair. In some cases, repositioning of the patella is required. This procedure can be performed as an outpatient surgery, and the results are usually excellent.


Knee. A knee sleeve, stabilizer, strap, or brace may be recommended to help support the knee tendons, reduce tension and pressure caused by increased activity, and keep the patella in the groove for better tracking. See the patellar stabilizer and Cho-Pat strap below and other knee braces in the Sports Med Store.

Returning to Sports

Weight-Bearing vs. Non-Weight-Bearing Sports. Knee tendinitis can be aggravated by weight-bearing sports. Any sport where the foot lands and strikes the ground repeatedly, such as running and jogging, can aggravate the problem. Non-weight-bearing sports, such as swimming and cycling, are adequate temporary replacements and can help the athlete maintain cardiovascular fitness without irritating the knee.

Warming-Up. The athlete should move all major joints through their complete range of motion several times before starting play. Stretching and strengthening exercises help prevent injury.

Playing the Game. When resuming the sport of choice, play at a lower intensity. In running, run for shorter periods of time, at a slower speed, and less frequently. The athlete should choose flat, even surfaces on which to run. If the athlete experiences pain either during the run or the following morning, then he is doing too much. Resume competitive running or play once the injury has healed.

Pressure between the patella and femur is minimized when the leg is straight or only slightly bent. The best activities are the ones that limit the range of knee motion.

Sports that are easiest on the knees: swimming (flutter kick, knees straight), slow jogging, walking, skating, and cross-country skiing.

Sports that are questionable (may be alright for some people, but difficult for others): cycling (seat high and avoid hills), baseball, hockey, skiing (downhill), and tennis.

Sports that may aggravate knee problems (require deep knee bends and twists that stress the knee and are most likely to aggravate your condition): volleyball, basketball, soccer, running (sprints, downhill), football, racquetball, and squash.


The following exercises are designed to strengthen the muscles of the knee, stabilize the patella, and help support the injured area. If done regularly, they will help prevent re-injury. Do each prescribed exercise two times a day or more often if necessary.


When you stretch, always stretch slowly without bouncing until you feel your muscles stretch moderately. You should not feel pain.

Single Quadriceps Stretch. Standing with your back straight, pull your foot back until your thigh muscles stretch moderately. Push down and back with your knee. Hold 15 seconds. Repeat 2 times/day.

Hamstring Stretch. Either sit or stand.

Sitting. Sit on the floor as shown. With back straight, lean forward from the hip and reach down over your leg until you feel your muscles stretch. Hold ten seconds and relax.

Standing. Prop up injured leg, knee locked. Bend standing into leg slightly. Place hands on lower thigh just above the knee. With back straight, bend forward from the hip until you feel a stretch under your thigh. Hold ten seconds and relax. Repeat 15 times, 2 times/day.

Strengthening Exercises. Stay away from exercises that require you to bend your knee or otherwise aggravate your condition.

Static Quads. Sit on the floor with a pillow under your knee. Push your thigh into the floor; as your heel rises, bend your toes toward your body and hold five seconds. Change legs or do both at once.

"T" Exercise. With a two-pound weight around your lower leg, lock your knee and raise your leg 12 inches. Draw a "T" with your foot. Repeat with other leg. Gradually increase weight (up to five pounds) as each weight becomes easier. Repeat 10 times, 2 times/day.


Specialty Reference
Hip & Knee Center

I cannot give medical advice about how to treat a specific injury without evaluating the athlete first. While I may discuss general exercises to prevent and treat sports injuries, not all exercises are designed for all individuals or problems. A sports medicine physician should be consulted before starting any exercise program. If an athlete is experiencing any severe pain or discomfort, he should see such a physician and obtain a specific diagnosis and treatment plan. The exercises outlined here are general recommendations and are not intended as a substitute for professional medical advice.