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

Background: Recent literature has reported intramuscular tendon (IT) disruption is associated with longer return to play (RTP) following acute hamstring injury.
Objectives: 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.
Methods: Hamstring injury records and RTP times from one professional AFL club were obtained over six seasons. MRI of injuries was retrospectively reviewed by a musculo-skeletal 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, and MR3 involved high-grade IT injuries of the proximal biceps femoris (BF) IT with concomitant injury to BF+ semitendinosus muscles.
Results: Forty-one injuries were available for analysis. Median RTP times were as follows: 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 = .008), MR1 vs MR3 (P = .002), and MR2 vs MR3 (P = .012).
Conclusion: 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.
(© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)