RT Journal Article SR Electronic T1 Intramuscular tendon injury is not associated with an increased hamstring reinjury rate within 12 months after return to play JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 1261 OP 1266 DO 10.1136/bjsports-2017-098725 VO 52 IS 19 A1 Anne D van der Made A1 Emad Almusa A1 Gustaaf Reurink A1 Rod Whiteley A1 Adam Weir A1 Bruce Hamilton A1 Mario Maas A1 Aston S H Ngai A1 Maarten H Moen A1 Gert Jan Goudswaard A1 Johannes L Tol YR 2018 UL http://bjsm.bmj.com/content/52/19/1261.abstract AB Background Acute hamstring injury that includes intramuscular tendon injury has been suggested to be associated with increased reinjury risk. These observations were based on a relatively small number of retrospectively analysed cases.Objective To determine whether intramuscular tendon injury is associated with higher reinjury rates in acute hamstring injury.Methods MRIs of 165 athletes with an acute hamstring injury were obtained within 5 days of injury. Treatment consisted of a standardised criteria-based rehabilitation programme. Standardised MRI parameters and intramuscular tendon injury, the latter subdivided into tendon disruption and waviness, were scored. We prospectively recorded reinjuries, defined as acute onset of posterior thigh pain in the same leg within 12 months after return to play.Results Participants were predominantly football players (72%). Sixty-four of 165 (39%) participants had an index injury with intramuscular hamstring tendon disruption, and waviness was present in 37 (22%). In total, there were 32 (19%) reinjuries. There was no significant difference (HR: 1.05, 95% CI 0.52 to 2.12, P=0.898) in reinjury rate between index injuries with intramuscular tendon disruption (n=13, 20%) and without tendon disruption (n=19, 20%). There was no significant difference in reinjury rate (X²(1)=0.031, P=0.861) between index injuries with presence of waviness (n=7, 19%) and without presence of waviness (n=25, 20%).Conclusion In athletes with an acute hamstring injury, intramuscular tendon injury was not associated with an increased reinjury rate within 12 months after return to play.