Runner’s Knee (Chondromalacia of the Patella)
The knee is a complex joint. It includes the articulation between the tibia and femur (leg and thigh) and the patella (knee cap). The most common knee problems in running relate to what is called the “patello-femoral complex”. This is the quadriceps, knee cap and patellar tendon. What is called runner’s knee is a condition known to the medical community as chondromalacia of the patella. This essentially means softening of the cartilage of the kneecap. Cartilage does not have the same blood supply that bone does. It relies on intermittent compression to squeeze out waste products and then allow nutrients to enter the cartilage from the synovial fluid of the joint.
During running certain mechanical conditions may predispose you to a mistracking knee cap. Portions of the cartilage may then be under either too much or too little pressure and the appropriate intermittent compression that is needed for waste removal and nutrition supply may not be present. This may result in cartilage deterioration, which at the knee usually occurs on the medial aspect or inner part of the kneecap.
The symptoms of runners knee include pain near the kneecap usually at the medial (inner) portion and below it. Pain is usually also felt after sitting for a long period of time with the knees bent. Running downhill and sometimes even walking down stairs can be followed by pain. The kneecap not tracking smoothly in its femoral groove causes the condition. When the knee is bent there is increased pressure between the joint surface of the kneecap and the femur (thigh bone). This stresses the injured area and leads to pain.
Factors that increase what is known as the “Q” (Quadriceps) angle increases the chance of having runners knee. The Q angle is an estimate of the effective angle at which the quadriceps averages its pull. It is determined by drawing a line from the Anterior Superior Iliac Spine (bump above and in front of your hip joint) to the centre of your kneecap and a second line from the centre of your kneecap to the insertion of the patellar tendon (where the tendon below your knee cap inserts). Normal is below 12 degrees; definitely abnormal is above 15 degrees. Many times adding to the strong lateral pull of the bulk of the quadriceps is a weak vastus medialis. This is the portion of the quadriceps that helps medially stabilize the patella. It runs along the inside portion of the thighbone to join at the kneecap with the other three muscles making up the quadriceps. Some of the mechanical conditions that may contribute to this include:
• Wide Hips (female runners)
• Knock Knees (Genu Valgum)
• Subluxating Patella
• Patella Alta (high patella)
• Small medial pole of patella or corresponding portion of femur
• Weak Vastus Medialis
• Pronation of the feet
Treatment of Runners Knee (Chondromalacia of the Patella)
At an early stage running should be decreased to lessen stress to this area and allow healing to begin. It is important to avoid downhill running which stresses the patello-femoral complex. Exercises performed with the knee bent should be avoided. When the knee is bent the forces under the kneecap are increased. Many people feel that the vastus medialis muscle works only during the final thirty degrees of extension of the knee. This is the muscle that helps stabilize the kneecap medially and prevents it from shifting laterally and tracking improperly at the patello-femoral joint. Straight leg lifts strengthen the vastus medialis and do not significantly stress the under surface of the knee cap. They should be done 10 times on each side. Start with 5 sets of 10 and work your way up to 10 sets of 10. Straight leg lifts are best performed lying on a cushioned but firm surface, with the exercising leg held straight and the non-exercising leg somewhat bent to take pressure off of the back.
Tight posterior muscles should be stretched. In many cases tight calf muscles or hamstrings lead to a “functional equinous” and make the foot pronate while running or walking. This pronation is accompanied by an internal rotation of the leg which increases the Q angle and contributes to the lateral subluxation of the knee cap. Running shoes that offer extra support should be used. If further control of pronation is needed orthotics should be considered. The late George Sheehan, M.D., sports medicine physician and philosopher, was the first to popularise the notion that it was important to look at the foot when runner’s knee occurs. It is also important to rule out other knee problems when knee pain occurs in runners and not just lump every pain as “runner’s knee”.
Iliotibial Band Syndrome
Symptoms of the iliotibial band syndrome are pain or aching on the outer side of the knee. This usually happens in the middle or at the end of a run. A concomitant problem may occur at the hip called greater trochanteric bursitis. During flexion and extension of the knee the iliotibial band rubs over the femoral condlyle that leads to irritation. Factors contributing to this syndrome are genu varum (bow legs), pronation of the foot (subtalar joint pronation), leg length discrepancy, and running on a crowned surface. Circular track running may also contribute to this problem, since it stresses the body in a manner similar to that of crowned surfaces and leg length differences. A tight iliotibial band aggravates all of these factors. Changes in training frequently contribute to this problem. It is always important to examine your training regimen and see what alterations have recently occurred.
Anatomy The iliotibial band is a thickening of the lateral (outer) soft tissue that envelopes the leg, which is called the fascia. In this area it is called the fascia lata. The thickened band is called the ilio-tibial band. The muscles that insert into the proximal (upper) portion of this band are the tensor fascia lata and a portion of the gluteus maximus. At its insertion into the tibia it blends with the Biceps femoris and the Vastus lateralis.
Self-treatment for this problem should include:
• Temporary decrease in training
• Side Stretching
• Avoid crowned surfaces or too much running around a track
• Shorten your stride
• Wear more motion control shoes to limit pronation
• Carefully examine your training regimen (& running diary)
The side stretching is well illustrated in Runners World, February 1995. It is performed while standing as follows: Place the injured leg behind the good one. If the left side is the sore side, cross your left leg behind your right one. Then lean away from the injured side towards your right side. There should be a table or chair that you can hold onto for balance on that side. This stretch is the best of several that exist for this area. Be careful not to overstretch. Hold for 7 to 10 seconds and repeat on each side 7 to 10 times.
If your self-treatment has not been completely successful than a trip to a sports medicine specialist may include the additional treatment of possible orthotics. Treatment is usually successful for this problem. So come in and see Jonathan Hagon at Shore Footed Podiatry Ltd, at 157 Kitchener Road, Milford. Phone for an appointment on (09) 489 1011 6 days a week.