Summary

A epidemiological analysis of adductor injuries in MLS athletes over a 10 year period studying factors affecting return to sport time shows increased return to sport time overall and decreased re-injury rate.

Abstract

Purpose

To examine (1) the incidence of adductor muscle injuries in MLS athletes, (2) return-to-sport (RTP) following adductor injury, (3) investigate conditions that are associated with increased time to RTP.

Methodology

The MLS Injury Surveillance database was queried for athletes with adductor injuries from 2009 to 2021. An adductor injury was defined as an incident involving the adductor group that required medical attention. Demographic characteristics (i.e., age, height, weight, player position, seasons played) and injury characteristics (laterality, setting of injury, activity during onset, severity, management, RTP, and re-injury) were used for descriptive analysis.

Results

1501 total injuries were recorded between 2009 and 2021 in 859 MLS players. The median absence from sport per injury was 6.0 days (mean: 17.02 ± 51.7 days). ?RTP post injury significantly increased from 14.4 days in 2009-2015 to 19.7 in 2016-2021 (p=0.043). Of the 1501 total injuries, 437 (29.1%) were re-injuries. . Players who experienced re-injury had a decreased time to RTP after index injury compared to players without re-injury (16.6 days vs 20.6 days, p=0.18). Re-injury rate decreased from 40.4% in 2010-2015 to 33.2% in 2016-2021 (p = 0.0040). Players with acute contact injuries trended toward more missed time vs. chronic injuries (p=0.065). Other factors analyzed including age group, player position, weather conditions and field type, did not significantly affect RTP.

Conclusion

The median return to sport time after an adductor injury in the MLS between 2009-2021 was 6 days, and the re-injury rate was high (29.1%).? Comparing injuries between 2011-2015 and 2016-2021, there was a 36.8% increase in days missed for an adductor injury even with a similar proportion of injury severity in both groups. Analysis did not identify any player or injury characteristics including position, weather condition, or field type significantly associated with RTP. The current findings suggest that a high risk of re-injury has contributed to employment of a longer rehabilitation period before RTP to prevent re-injury. These lengthened timelines might be justified given the significant decrease in adductor re-injury rate between 2010-2015 and 2016-2021 seasons (p = 0.0040).