Q: I am a soccer player who plays rugby as a "weekend warrior." I don't want to trash my knees playing rugby because soccer is really my first choice of activities. Is there any benefit to wearing one of those hinge-braces?
A: Preventive or prophylactic bracing is becoming more popular now that there is some evidence that it can reduce the risk of knee injuries. This is especially true for protecting the medial structures of the knee. Medial refers to the side of the knee closest to the other leg.
It's the medical collateral ligament (MCL) with all its supportive structures that keeps the knee from rotating too much or sliding forward and back. The MCL aids and assists other ligaments inside the joint (e.g., the anterior cruciate ligament or ACL) with this function. This is especially important when force, load, or pressure is applied along the lateral (outside) of the knee toward the medial side.
Understanding the anatomy helps us see how a direct blow to the lateral side of the thigh or leg can disrupt the medial collateral ligament (MCL). Football and rugby players are at risk for this type of injury.
A second mechanism of injury occurs in skiers, basketball players, and soccer players. They plant the foot on the ground and rotate the leg above the foot when pivoting, cutting, or changing directions quickly. The force of that movement pattern can overpower the strength of this ligament. A strong enough force takes out the medial collateral ligament (MCL) along with the meniscus, the anterior cruciate ligament, and other bits and pieces of the soft tissues.
Here again, a protective brace that allows full function and all knee motions but prevents injury could be very helpful when playing either soccer or rugby.
Reference: Milford H. Marchant, Jr., et al. Management of Medial-Sided Knee Injuries, Part 1. Medial Collateral Ligament. In The American Journal of Sports Medicine. May 2011. Vol. 39. No. 5. Pp. 1102-1113.