Hamstring strain grade on MRI and return to play in elite Australian cricket players

Objectivei) determine whether the grade of hamstring strain confirmed by magnetic resonance imaging (MRI) is related to time to return to play, and ii) describe the incidence, prevalence and grade of hamstring strains confirmed by MRI in elite Australian cricket players. DesignRetrospective case series. MethodsHamstring strains from professional domestic and international cricket teams over 13.5 seasons which had received MRI scans were graded using British Athletics Muscle Injury Classification (BAMIC) system. The main outcome measure was time to return to play. Results141 hamstring strain injuries with available MRI imaging scans were recorded during the study period (average 3.2 per 100 players per season: male 4.5, female 1.2). The most commonly injured muscle was biceps femoris (64%, 95% CI 56-71%) and the most frequent category of injury was grade 2C (27%, 20-35%). Across all injury grades, players were unavailable for full participation for a median of 23 (IQR 15-38) days and missed 3 (1-6) matches. The number of days unavailable were higher for injuries which were graded 2 or 3, compared to grade 1 (p=0.018, p=0.002 respectively), and injuries which included the tendon compared to those which did not (p=0.002). ConclusionsThis study provides evidence that higher grade injuries and those involving the intramuscular tendon are associated with a more prolonged return to play. This finding should be viewed in context of the study limitation that clinicians treating players were not blinded to the MRI findings.