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In Street Clothes

Covering sports injuries from the perspective of a certified athletic trainer and backed by analytics.

Understanding Rudy Gay’s Lateral Capsule Sprain

The Sacramento Kings have had a roller coaster of a season with their early season success and the stellar play of DeMarcus Cousins overshadowed by a surprise change in coaches and Cousins’ peculiar bout with viral meningitis. The team struggled without their best player, losing eight of the 10 games in which Cousins was sidelined. Now the team is preparing to manage another uncommon injury as forward Rudy Gay suffered a left knee injury early in the team’s overtime loss to the Dallas Mavericks.

Gay’s injury has been diagnosed as a left lateral joint capsule sprain. The joint capsule of the knee is a complex envelope that surrounds the knee joint. It encompasses the kneecap, menisci, bursa, and the multiple stabilizing ligaments of the knee. The joint capsule aids in both active and passive stabilization and is a key component of fluid motion. The capsule is divided into two layers, the outer fibrous layer compromised of connective tissue and the synovial membrane.

The lateral portion of the joint capsule of the knee sits on the outside portion of the leg. It is very complex and includes the iliotibial tract (IT band), lateral meniscus, as well as multiple tendons and ligaments. One of these tendons belongs to the popliteus, a muscle active in unlocking the knee and rotating the lower leg. Unfortunately by allowing the popliteus tendon to runs through this area, the lateral capsule sacrifices a bit of its integrity and can be susceptible to injury.

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Isolated injuries to the lateral aspect of the knee are much more infrequent than medial injuries. A majority of the lateral joint capsule injuries that have been reported occur in conjunction with a more serious problem. Way back during the 1996-97 season, Shaquille O’Neal hyperextended his left knee. In the process, he suffered partial tears of his lateral collateral ligament (LCL) and joint capsule and an avulsion fracture. O’Neal missed 28 games recovering. Current Mavericks center Greg Smith sprained his LCL last year while a member of the Rockets and yo-yoed in and out of the lineup with lingering pain and soreness before eventually undergoing surgery.

However it does appear Gay has avoided a significant injury. The extent of the damage was not revealed but it’s promising to see the Kings list him as day-to-day. The injury has been classified as a sprain, meaning a stabilizing structure of the area has been damaged, likely the outer layer of the capsule. Unfortunately, the specific area or ligament involved was not reported. However the Kings medical staff is well aware than any laxity in the area would dramatically alter the stability of the entire joint and make Gay susceptible to a more severe injury should he return prematurely. As a result Sacramento may opt to treat the injury conservatively and it wouldn’t be surprising to see Gay sidelined for a game or two.