ACL Tears in the NBA and the NFL

While the anterior cruciate ligament (ACL) is a thin strip of tissue connecting the thigh bone to the shin bone, its role in knee stability cannot be stressed enough.

Pro athletes are most aware of its significance, as injuries to this part of the knee have the unfortunate potential of sidelining a player for an entire season.

This debilitating injury is present in many competitive sports; however, its prevalence in football and basketball indicates that a comparison may illustrate why this type of injury occurs in two disciplines with few commonalities between them.

Facts and Figures

Receiving an ACL tear diagnosis can be devastating to most players, as it usually takes an average of 9 to 10 months to recover and rehab. Depending on the degree of the injury, rated from 1 to 3, the afflicted ACL can be sprained, partially torn, or completely torn. The latter case is the most severe and almost always requires surgical intervention to reconstruct the torn ligament.

A recent study analyzing NBA player injuries between 2017 and 2021 notes that knee injuries (697) hold the highest incidence percentage, with damage to the ligaments and tendons likewise being disproportionately represented.

During the same period, NFL data shows that 282 ACL tears affected players during both practice sessions and games in the pre and regular season. Notably, MCL tears were likewise high, potentially aggravating an associated ACL injury.

Knee injuries and specifically ACL afflictions are common both on the field and on the court, however, what leads to them is different based on the particularities of each game.

Research from Stanford that followed NBA injuries since the 1980s illustrates that 97 players experienced ACL tears:

• Players with an increased drive tendency experienced ACL tears at a higher rate (5.2%)
• Players with low driving tendencies sustained fewer ACL tears (3.8)

This indicates that an aggressive charging style is most associated with ACL injuries in the NBA.

In the NFL the medium rate of ACL tears is 62 per year, most occurring during pre and regular-season games.

• The most impacted players are those with 3 or fewer years of experience (75%).
• Training camps account for 40% of ACL injuries in the first weeks of the preseason.
• Special teams are likewise impacted, and running backs were the most susceptible.

Similar Causes For Separate Sports

Whether it's football or basketball, the high intensity of professional league games and preparation is fertile ground for knee and ACL injuries.

NBA players are packing more mass and executing moves at rapid speeds with high contact with opponents and the court, leading to increased stress on the ligament. At the same time, longer seasons and off-season training, along with the tendency of notable pre-NBA competition activity, are demanding on the joints and contribute to early-career ACL injuries.

In the NFL, recent data notes that a high percentage of ACL injuries stem from non-contact mechanisms (72.5%), usually resulting from pivoting, twisting, and cutting. The quantity and rate of training during off-seasons can lead to fatigue and an increased load on the players at the start of the regular season, placing them at a higher risk of tearing their ACL.

Another factor that may influence the rate of this type of injury is the playing surface, as less than 5% occur on low-traction surfaces common to wet and damp conditions, as opposed to high-traction surfaces that are more typical during dry conditions such as the start of the pre-season.