In a 10-year analysis of injury rate, return to play and performance metrics, Brian Forsythe, MD, and other researchers found that forwards demonstrated persistent performance deficits.
The Impact of ACL Injuries on Major League Soccer Players’ Performance
Research Profile
In Major League Soccer (MLS), anterior cruciate ligament (ACL) tears often require surgical reconstruction and a lengthy rehabilitation. To date, there has been limited research on how surgery for ACL injuries affects MLS players’ time away from the field, performance and reinjury risk.
The study’s aim and methodology
To understand the impact of ACL injuries on player performance, Brian Forsythe, MD and his co-authors (including Drs. Vahram Gamsarian and Vikranth Mirle, as well as Camden Bohn, Josh Chang, Daanish Khazi-Syed and Catherine Hand from Rush) queried the MLS Injury Surveillance database for ACL injuries between 2010 and 2021.
The researchers extracted performance metrics, including games played, minutes per season, goals, assists, scoring attempts and offsides, from the MLS statistics website. For each injured MLS player, they selected three matched uninjured controls based on age, position and seasons played.
Results
Dr. Forsythe’s team analyzed 132 players (43 defenders, 36 midfielders, 29 forwards and three goalkeepers) with 144 ACL injuries and compared them with 396 matched controls. Due to insufficient numbers, goalkeepers were excluded from the performance analysis.
The authors found that return-to-play time following ACL reconstruction decreased significantly over the past decade, from 269 days in 2010–2015 to 219 days in 2016–2021. “This may reflect accelerated rehab protocols and possibly improved surgical techniques, or at least awareness of how concurrent pathology, such as meniscal tears and cartilage injuries, affect player recovery,” Dr. Forsythe says.
Researchers also found that acute contact injuries led to more missed games (20.7 vs. 15.6) and required 30 more days of recovery time than noncontact injuries, which was likely due to the more traumatic nature of the injuries, he says.
By year 3, most players’ performance matched or exceeded that of controls — with a notable exception. “By year 2 following their ACL reconstruction, defenders had returned to their preinjury performance level, while midfielders scored more goals by year 3. However, forwards experienced a decline in goals scored, minutes played and scoring attempts in year 3 that persisted into year 4. This suggests we need to do something different with forwards to prevent this drop off in performance,” Dr. Forsythe says.
Forwards are particularly dependent on explosive movements like cutting, pivoting and sprinting, as well as rapid accelerations and decelerations, which could put greater demands on their knees. In addition to these physical demands, they also have the mental pressure to score goals, Dr. Forsythe explains.
Next steps
The team’s findings underscore the need for more research on the psychological component of return to play and the impact of kinesiophobia on players’ recovery. “These players could lack confidence in their knee, or there may be some neuromuscular deficit or cognitive ability that we haven’t identified or appropriately rehabbed,” Dr. Forsythe says.
“As we collect more granular data, we can look at workload training volume and biomechanical factors with motion analysis studies to determine what variables we might tweak to get those players back to where they need to be,” he adds.
Dr. Forsythe, who serves as the Tim and Keli Walbert Endowed Chair in Orthopedic Surgery at Rush, is currently studying a brain-computer interface for neuromuscular visualization training to expedite muscle activation and decrease arthrogenic muscle inhibition in patients following ACL surgery.
