Background The optimal timing of MRI following acute hamstring injury is not known and is mainly based on expert opinions.
Aims To describe the day-to-day changes in the extent of oedema and investigate the optimal timing for detection of fibre disruption on MRI following acute hamstring injuries.
Study design Prospective, descriptive study.
Methods We performed standardised MRI (1.5T) ≤1 day after injury in male athletes with acute hamstring injury. If initial MRI revealed positive signs of injury (increased signal intensity on fluid sensitive sequences), consecutive MRIs were obtained daily throughout the subsequent week (ie, 7 times). The MRI parameters (day 1–7) were scored by a single radiologist using a standardised scoring form. The day-to-day changes in the extent of oedema (distance from tuber, craniocaudal length, mediolateral width and anteroposterior depth) and the presence and extent of fibre disruption (tear) were assessed with descriptive statistics and repeated measures using analysis of variance of log-transformed data. The overall main effect for time was reported with a significance level set at p<0.05.
Results 13 out of 132 male athletes assessed for eligibility between January 2014 and December 2015 were included. 1 dropped out, while 12 (31 years, range 20–49) completed the study; 11 had 7 MRI scans each and one had 5 MRI scans performed. There were no significant day-to-day changes for any of the extent of oedema measures (p values ranging from 0.12 to 0.81). Fibre disruption (tear), present in 5 of the athletes, was detectable from day 1, with small and insignificant day-to-day changes (p values ranging from 0.45 to 0.95).
Conclusions We observed insignificant day-to-day changes in the extent of oedema throughout the first week following acute hamstring injury. Fibre disruption (tear) was detectable from the first day after injury. These findings indicate that MRI can be performed on any day during the first week following an acute (hamstring) muscle injury.
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Contributors AW designed the study, monitored data collection, analysed and interpreted data and drafted the article. JLT and RB designed the study, interpreted the data, revised the article and approved the final revision of the article. EA analysed the MRIs, interpreted the data, revised the article and approved the final revision of the article. EW and RW interpreted the data, revised the article and approved the final revision of the article.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Ethics Committee of Aspetar Orthopaedic and Sports Medicine Hospital, the Shafallah Medical Genetics Centre Ethics Committee and the Anti-Doping Lab Qatar (ADLQ) Institutional Review Board (IRB) Committee.
Provenance and peer review Not commissioned; externally peer reviewed.