Magnetic resonance imaging parameters for assessing risk of recurrent hamstring injuries in elite athletes.
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.


OBJECTIVE
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.


METHODS
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.


CONCLUSIONS
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.
Koulouris
George
G
Department of Medical Imaging, Victoria House Hospital, Prahran, Australia. drgeorgek@gmail.com
Connell
David A
DA
Brukner
Peter
P
Schneider-Kolsky
Michal
M
D000328:Adult; D001265:Athletic Injuries / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation; D015331:Cohort Studies; D005538:Football / Q000293:injuries*; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries* / Q000503:physiopathology; D011237:Predictive Value of Tests; D020127:Recovery of Function; D012008:Recurrence; D012016:Reference Values; D018570:Risk Assessment / Q000379:methods