 |
Anterior knee pain is common among athletes.
Etiology
There are many causes, particularly in runners. Causes include subluxation of the patella (when bending the knee) during running; chondromalacia of the patella (softening of the knee cap cartilage—see Bone and Connective Tissue Disorders in Children: Chondromalacia Patellae), which is one of the more common causes among younger running athletes; intra-articular pathology, such as meniscal tears and plicae (infolding of the normal synovial lining of the knee); fat pad inflammation; patellar tendinitis; stress fractures of the tibia; and malalignment of the lower extremities. Knee pain may represent referred pain from the lumbar spine or hip or result from foot problems (eg, overpronation—see
Fig. 1: Exercise and Sports Injury: Overpronation and patellofemoral syndrome. ).
|
Fig. 1
|
| | |
|
Overpronation and patellofemoral syndrome.
|
 |
|
Overpronation of the foot causes the lower leg to twist inward, pulling the kneecap inward, while the quadriceps pulls the kneecap outward. As a result, the patella subluxates laterally and rubs against the lateral condyle of the femur, resulting in pain.
|
|
Evaluation
Diagnosis requires a thorough review of the injured athlete's training program, including a history of symptom onset and aggravating factors, and a complete lower-extremity examination (for knee examination, see Fractures, Dislocations, and Sprains: Knee Sprains and Meniscal Injuries).
Chondromalacia is suggested by pain in the knee after running, especially on hills, and pain and stiffness after sitting for any length of time (positive movie sign). On examination, pain is typically reproduced by compression of the patella against the femur.
Treatment
Treatment of chondromalacia includes quadriceps strengthening exerciseswith balanced strengthening exercises for the hamstrings, use of arch supports if excessive pronation is a possible contributor, and use of NSAIDs.
| | |
| Exercises to Strengthen the Vastus Medialis |
|
1. Stand with both knees straight (the quadriceps should be contracted and the patella raised). Hold this position for 10 sec and then relax the muscles. Repeat this exercise frequently throughout the day.
|
|
2. Sit on the floor with both knees straight and legs far apart. Point the toes as far laterally as possible, then slowly raise the injured leg and lower it at the hip. Keep the knee straight. Perform 3 sets of 10 every other night.
|
|
3. Sit on the floor with 2 pillows under the knee so that it is flexed at 135°. Place a 5-lb (2.3-kg) weight on the ankle, raise the foot slowly, straighten the knee, and lower the foot slowly. Perform 3 sets of 10. Progress is made by increasing the weight, not the number of repetitions.
|
|
4. As an injury rehabilitates and strength increases, more intense methods of exercise, such as using a leg extension, leg press, or squat machine, may be warranted. As intensity of effort and loads increase, decrease the rate of frequency to once every 7–10 days.
|
|
Adapted from Mirkin G, Shangold M: The Complete Sports Medicine Book for Women. New York, Simon & Schuster, 1985, p. 101; used by permission of The Miller Press.
|
|
For patellar subluxation, use of patella-stabilizing pads or braces may be necessary, especially in sports that require rapid, agile movements in various planes (eg, basketball, tennis).
Last full review/revision November 2005
Content last modified November 2005
| |
