The aim of this work was to study semimembranosus musculotendinous injuries (SMMTI) and return to play (RTP). The hypothesis is that some related anatomic variables of the SM could contribute to the prognosis of RTP. The retrospective study was done with 19 athletes who suffered SMMTI from 2010 to 2013 and in whose cases a 3.0T MRI was performed. We evaluated the A, B, C SM regions damaged and calculated the relative length and percentage of cross-sectional area (CSA) affected. We found the correlation of these variables with RTP. The data was regrouped in those cases where the part C of the injury was of interest and those in which the C region was unscathed (pooled parts). We used the Mann-Whitney U test and there was a higher RTP when the injury involved the C part of SM (49.1 days; 95% CI [27.6– 70.6]) compared to non-C-part involvement (27.8 days; 95% CI [19.5–36.0]). The SMMTI with longer RTP typically involves the C part with or without participation of the B part. In daily practice, the appearance on MRI of an altered proximal tendon of the SM indicates that the injury affects the C region and therefore has a longer RTP.
Keywords: MRI; hamstring injuries; return to play; semimembranosus.