Hamstring Strain Grade on MRI and Return to Play in Elite Australian Cricket Players

Abstract

OBJECTIVE: The aims of this study were to (1) examine the relationship between magnetic resonance imaging (MRI)-confirmed hamstring strain grade and time to return to play; (2) examine this relationship specifically in pace bowlers; and (3) describe the incidence, prevalence, and grade of MRI-confirmed hamstring strains in elite Australian cricket players. DESIGN: This is a retrospective cohort study. SETTING: Elite Australian cricket teams over 13.5 seasons were analyzed. PARTICIPANTS: Four hundred seventy-eight male and 365 female contracted Australian cricketers participated in this study. INDEPENDENT VARIABLE: British Athletics Muscle Injury Classification system grading of hamstring strains, which had received MRI scan, was the independent variable. MAIN OUTCOME MEASURE: The main outcome was time to return to play (days). RESULTS: One hundred forty-one 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 (63%, 95% confidence interval: 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 22 (interquartile range: 15-38) days and missed 3 (1-6) matches. The number of days unavailable were higher for injuries that were graded 2 or 3, compared with grade 1 injuries (P = 0.004 and P = 0.007, respectively), and injuries that included the tendon compared with those which did not (P = 0.002). Pace bowlers has a higher number of days unavailable compared with players with other dominant skills for grade B and C injuries combined (P = 0.046). CONCLUSIONS: This 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 MRI findings may have informed management.