Runner’s Knee


CHONDROMALACIA

Chondromalacia, refers to a condition in which there is damage to the joint surface of the patella (kneecap).  It is common in runners, cyclists, catchers –any athlete that is constantly bending their knees.  At a large runner’s clinic several years ago, knee problems predominated, and the most common cause of the pain was patella disease.

Runners with chondromalacia complain of a deep ache under the patella.  It is present during running and is aggravated by jogging up and down hills.  Frequently, the runner will complain of a noisy knee—a crackling sound is heard and felt.  Running through this injury only produces more pain and swelling.

CAUSE

The cause of the pain and the noise is a roughness on the underside of the patella.  Normally, the joint surface of the patella is very smooth—like a slick piece of ice.  Damage to the patella produces scratches and nicks so that eventually the surface becomes rough and irregular. Think of an ice skating rink after a hockey game.  As the knee bends, the patella is pressed tighter and deeper into the knee, and this causes pain, just as rubbing a skin wound would.  The knee becomes inflamed, and swelling can result.

Why does the damage occur?  Normally, the patella moves in a straight line as the knee bends and straightens. The patella is wedge-shaped and lies in a bony groove on the top of the femur (thigh bone).  This groove holds it in proper alignment.  If an abnormality is present to disrupt this alignment, the patella can slip out of the groove as it moves, and a shearing damage to its surface can occur.  This injury may be minor each time, but over the years the damage becomes extensive.  The most common abnormality is a combination of a “knocked knee” posture of the leg and tightness of the ligaments on the outer side of the knee.  A bowstring effect occurs and pulls the patella out of line.  Other causes include deformities of the patella or shallowness of the groove. Abnormalities of the foot, and even the hip can contribute. For example ,intoeing from the hip joint or pronation of the feet can lead to patella abnormalities and can influence proper patella alignment and tracking.

Any direct injury to the patella, such as a fall or fracture, can also produce this problem.  Athletes, such as baseball catchers or football linemen, who must constantly squat or kneel can also be susceptible.

TREATMENT

As one would imagine, treatment consists of rest from running and avoidance of excessive bending.  Since hill running produces constant knee flexion, changing to a flat surface, such as a track, is advisable.  Anti-inflammatory medication is useful for this condition and can be taken for the pain.  (It is best to consult your doctor before taking frequent doses.)

The most important factor in treatment, however, is a good exercise program.  To counter the tight bowstringing ligaments which pull on the outer side, the muscles on the inside of the knee must be developed and strengthened.  The best exercise is performed while lying flat with the knee completely straight.  The leg is lifted up and held to the count of ten.  During this time, an isomeric tightening of the knee muscles can also be done.  Lower the leg, rest for a few seconds, and raise it again.  One should gradually work up to 100-150 lifts per day (in intervals).  Ankle weights can also be used starting with two pounds and increasing to ten pounds over several weeks.  Bending exercises should generally be avoided because they increase the pressure on the patella and thereby aggravate the condition.

Later, when the pain subsides, running can be resumed with a graduated program.  Ice should be applied after the run.  Knee exercises should continue and hills avoided.

If the problem persists, various knee bands or braces can be prescribed.  The most common type of brace for chondromalacia has a hole over the kneecap to hold it in place and to prevent abnormal side displacement.  If the runner has pronated feet, a shoe orthotic may help to better position the heel and take pressure off of the knee.

In severe cases of chondromalacia, the patella may partially dislocate (sublux), producing further damage and disability.  Conservative medical measures already discussed should first be initiated; but if they fail, surgery is warranted.  Operative procedures can be performed with the arthroscope through small incisions.  The tight lateral ligaments can be cut ( lateral release), and the rough surfaces of the patella can be shaved and smoothed to some extent.  This operation is frequently successful.

I remember back to my training just prior to the advent of arthroscopic surgery. Operations on the patella for this conditions consisted of an open incision to re-align the patella. Tissues were cut on one side of the knee and others, on the other side were tightened. The results were frequently dismal. Now with arthroscopic surgery, the results are much better- achieved with minor surgery. This has been a great advance in medicine.

True dislocations of the patella can occasionally occur—usually as the result of trauma. They are usually treated with a brace to allow the torn ligaments to heal. Recurrent dislocations may require surgery. Sometimes, an open reconstruction: the results are not always uniform. Therefore conservative measures or even arthroscopic surgery should first be tried.

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