Magnetic Resonance Imaging Parameters for Assessing Risk of Recurrent Hamstring Injuries in Elite Athletes

¹ Department of Medical Imaging, Victoria House Hospital, Prahran, Melbourne, Victoria, Australia
² Department of Radiology, Royal National Orthopaedic Hospital, Stanmore, London, United Kingdom
³ Centre for Health, Exercise and Sports Medicine, University of Melbourne, Melbourne, Victoria, Australia
⁴ Dept of Medical Imaging, Victoria House Hospital, Melbourne, and Dept of Medical Imaging & Radiation Sciences, Monash University, Clayton, Victoria, Australia

^* To whom correspondence should be addressed. E-mail: drgeorgek{at}gmail.com.

	Abstract

Background: Magnetic resonance (MR) imaging has established its usefulness in diagnosing hamstring muscle strain and identifying features correlating with the duration of rehabilitation in athletes; however, data are currently lacking that may predict which imaging parameters may be predictive of a repeat strain.

Purpose: This study was conducted to identify whether any MR imaging-identifiable parameters are predictive of athletes at risk of sustaining a recurrent hamstring strain in the same playing season.

Study Design: Cohort study; Level of evidence, 3.

Methods: Forty-one players of the Australian Football League who sustained a hamstring injury underwent MR examination within 3 days of injury between February and August 2002. The imaging parameters measured were the length of injury, cross-sectional area, the specific muscle involved, and the location of the injury within the muscle-tendon unit. Players who suffered a repeat injury during the same season were reimaged, and baseline and repeat injury measurements were compared. Comparison was also made between this group and those who sustained a single strain.

Results: Forty-one players sustained hamstring strains that were positive on MR imaging, with 31 injured once and 10 suffering a second injury. The mean length of hamstring muscle injury for the isolated group was 83.4 mm, compared with 98.7 mm for the reinjury group (P =.35). In the reinjury group, the second strain was also of greater length than the original (mean, 107.5 mm; P =.07). Ninety percent of players sustaining a repeat injury demonstrated an injury length greater than 60 mm, compared with only 58% in the single strain group (P =.01). Only 7% of players (1 of 14) with a strain <60 mm suffered a repeat injury. Of the 27 players sustaining a hamstring strain >60 mm, 33% (9 of 27) suffered a repeat injury. Of all the parameters assessed, only a history of anterior cruciate ligament sprain was a statistically significant predictor for suffering a second strain during the same season of competition.

Conclusion: A history of anterior cruciate ligament injury was the only statistically significant risk factor for a recurrent hamstring strain in our study. Of the imaging parameters, the MR length of a strain had the strongest correlation association with a repeat hamstring strain and therefore may assist in identifying which athletes are more likely to suffer further reinjury.