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Understanding Zion Williamson’s Lateral Meniscus Tear

The 2019-20 season is full of promise and intrigue with the league seemingly wide open for the first time in years. Sadly, some of the excitement was stifled Monday when it was announced a torn lateral meniscus would sideline Pelicans rookie Zion Williamson for multiple weeks. Early reports stated Williamson avoided significant damage but surgery was ultimately required.

Meniscus injuries aren’t uncommon in the NBA. The InStreetClothes.com/SMART NBA Injury Database has over 120 examples of meniscus-related injuries since the 2005-06 season, including five reported meniscus tears last season.  However, not all meniscus injuries are created equal. InStreetClothes.com has previously provided multiple breakdowns of these injuries but let’s once again examine the situation. 

The menisci of the knee serve as shock absorbers for the joint, similarly to the discs of the spine. The menisci are comprised of a specialized cartilage known as fibrocartilage that is able to withstand a high degree of stress while maintaining a degree of elasticity. Each knee has a medial and lateral meniscus with the latter playing a larger role in weight bearing. The lateral meniscus also plays a bigger role in joint motion and fluidity and as a result is designed to be more mobile. 

The medial meniscus, located on the inside of the knee is C-shaped while the outside or lateral meniscus is almost completely O-shaped. Unfortunately, their positioning between the femur and the lower leg bones leaves the discs susceptible to injury, especially in basketball. If the knee is forcibly twisted, the discs can become pinched between the bones of the leg, tearing the cartilage. Additionally, meniscus injuries often accompany other severe knee injuries like an anterior cruciate ligament (ACL) or medial collateral ligament (MCL) sprain.

Treatment for meniscus damage is a lot like real estate, location is key. Each meniscus is divided into zones based on the amount of blood supplied to the area. The peripheral portions of each disc are considered the red-red zone and receive a healthier amount of blood. The available blood supply decreases moving inward until the avascular white-white zone is reached. This is integral in recovery as a lack of blood negatively affects the body’s natural ability to heal. If a meniscus injury is small and located within the red-red zone of the disc then a quick recovery is very possible and surgery can be avoided. 

However, the vast majority of meniscus injuries result in a trip to the operating room. Meniscus surgeries can be broken down to two basic types, repairs and removals. Determining which route to takes depends on the location of the injury and the type of tear that has occurred. Tear classifications include flap, radial, longitudinal, and several other unique tears. Longitudinal tears occur around the outside of the disc and can be repaired if isolated to the outer portions of the meniscus.

A meniscectomy, or removal, is the more common of the two procedures and is often accompanied by a shorter recovery window. Following a meniscectomy, players can often return to activity within six weeks. Games lost due to meniscus injuries among NBA players is not dependent on which meniscus is damaged. However, the quick turnaround doesn’t come without consequences as removals do elevate the risk of long-term issues like osteoarthritis and other complications like cysts. 

In contrast, an arthroscopic meniscus repair has better long-term results though the recovery time following surgery is often much longer. Recovery following a repair is often measured in months not weeks.

Given that the initial estimated timeline is six-to-eight weeks and the term debridement was used, it seems as though Williamson underwent a meniscectomy rather than a true repair. However, Zion’s recovery will be influenced by several other factors. Concerns about his size and weight are warranted as a higher body weight does impact the cartilage of the knees. Studies have shown a higher body mass increases the load on the knee and negatively affects cartilage integrity and increases the risk of a potential meniscus injury. Furthermore, Williamson’s well-documented awkward movement pattern suggests there may be an underlying biomechanical influence. 

Fortunately, Williamson will be cared for by a Pelicans medical team now run by a staff that has historically been known for their work on preventative care and success in identifying potential issues along the kinetic chain. Aaron Nelson has long been on the forefront of sports medicine and will have an early opportunity to show why the team brought him onboard in in the offseason.