Athletic Trainer- Elite Therapy Solutions; Athletic Trainer - Dallas Sidekicks Soccer Club
Memorize that word and throw it around at parties. It is a long title for what looks like a short muscle but that muscle can dictate the future health of your knees. Like many important areas of your body, we ignore, abuse, or otherwise try to wish our pain away. The VMO attaches to your kneecap (patella) at a 55 degree angle on the upper inside edge. The VMO is part of the powerful quadriceps muscle group commonly known as the quads. The VMO's main function is to pull the kneecap medially (inside). The other three longer quad muscles are either neutral or pull the kneecap laterally (outside).
Problems with the VMO can present itself in many ways. It can talk to you when you bend your knees as a snapping or popping sound. It can slap you in the knee when you go down stairs. It can yell at you as your knee mysteriously buckles beneath you. And it can scream at you on a long distance run like a stabbing sensation on the inside of your knee forcing you to drag your leg like a dead weight. All these symptoms can lead to pain and swelling around the knee which could lead to surgery and eventually a total knee. How can you save yourself from this growing menace? In order to address these problems, we first must understand the cause of the symptoms.
The kneecap is v-shaped where it rides in the valley formed by the condyles of your femur (upper leg bone). The popping sound is the kneecap dragging along one ridge of the valley. The knee collapsing is the kneecap catching of the outside ridge. The pain on the inside of your knee is the stretching and tearing of the connective tissue (medial retinaculum) as the kneecap pulled laterally. The swelling in the knee (supra patella bursa) is caused by the irritation of the patella femoral joint (kneecap on femur).
We need to examine how your knee got to this sad state. The causes are many. The abuse may be years in the making or it could be a single traumatic event. If you are a female, you have one strike against you. When the hips widen out after puberty, the whole mechanics of the knee changes. The Q-angle increases (the angle of the knee which dictates where the kneecaps rides). The kneecap rides high and to the outside. Females are more prone to subluxations and dislocations until the VMO stabilizes the kneecap. Trauma to the knee in the form of impact, twist, or surgery can leave the VMO defenseless. 20 cc's of swelling in the knee basically shuts down the VMO. It takes 80 cc's to shut down the vastus lateralis. Because of this difference, the vastus lateralis muscle pulls the kneecap to the outside, dragging the kneecap along the lateral femoral ridge. Unless VMO weakness is addressed, this will continue to happen until pain and degeneration of the kneecap makes it too painful to walk.
Another frequently overlooked reason for kneecap problems is leg length discrepancy. The longer leg will have a higher Q-angle and an externally rotated foot as the leg tries to shorten. The VMO is again under stress.
The perfect exercise for the VMO is kicking a soccer ball. Kicking the ball with the inside of your foot is a good warm up exercise. The adductor magnus (inside of thigh) is innervated by the same nerve as the VMO. After the warm up, start by dropping your toe and making short passes.(see picture) Increase the length of your passes as dictated by your comfort zone. Unfortunately, most people cannot tolerate kicking the ball right away. Exercises off the field should include the last 30 degrees of the knee extension to protect the underside of the kneecap. The "Parker Pinch"; can be accomplished with a foam pillow and a flat surface (see picture). Wall slides with a soccer ball between your knees help fire the VMO. You squeeze the ball and then bend your knees to 30¼ and raise back up (see picture). McConnell taping can help "re-align"; the kneecap until the VMO is strong enough to handle the load (see picture). A custom knee brace can be used if the skin becomes irritated. I have developed a custom knee brace with the help of New Options, a neoprene brace company in Dallas. You can order the K-15 with an inverted J and this can help simulate taping. (See picture) Orthotics can help decrease the Q-angle and the right shoes can give the foot a leg up on the competition.
A strong and healthy VMO can go a long way to helping correct faulty biomechanics of the knee joint.