High-grade intramuscular tendon disruption in acute hamstring injury and return to play in Australian football players

Recent literature has reported intramuscular tendon (IT) disruption is associated with longer return to play (RTP) following acute hamstring injury.Investigate whether an increase in hamstring injury severity involving high-grade IT disruption and proximal injury location is associated with longer RTP times in elite Australian Rules Football (AFL) players.Hamstring injury records and RTP times from one professional AFL club were obtained over six seasons. MRI of injuries were retrospectively reviewed by a musculoskeletal radiologist blinded to RTP information. A simplified four-grade classification of acute hamstring injuries was developed based on IT disruption severity and proximodistal injury location. MR0 had no observable MRI tissue damage; MR1 involved muscle-tendon junction, myofascial and low-grade IT injuries; MR2 involved distal and/or single muscle high-grade IT injuries, MR3 involved high-grade IT injuries of the proximal biceps femoris (BF) IT with concomitant injury to BF + semitendinosus muscles.41 injuries were available for analysis. Median RTP times were: MR0, 14 days; MR1, 21 days; MR2, 35 days and MR3, 88 days. For MRI positive injuries (MR1, MR2, MR3), there was a significant difference in the distributions of RTP, with increased injury severity associated with increased RTP times (p < .001). The distributions of RTP were significantly different between MR1 vs MR2 (p=0.008), MR1 vs MR3 (p=0.002) and MR2 vs MR3 (p=0.012).In elite AFL players, acute hamstring injuries with high-grade IT disruption identified on MRI were associated with increased times to RTP compared to injuries with low-grade or no IT disruption