Intratendinous hamstring injuries: sequential MRIs as a tool to reduce the risk of reinjury in elite sport.

Hamstring injuries are the most common muscle injuries in elite football. Injuries involving the intramuscular tendon are considered more significant, with longer return to play (RTP) times and an increased risk of reinjury. MRI is the gold standard investigation for muscle injuries, but initial findings cannot accurately determine RTP times. The role of MRI in monitoring muscle and tendon healing is not well described. We present three cases of hamstring injuries with intramuscular tendon involvement, illustrating the changes seen on MRI during progressive tendon healing and describing how we utilised this information to inform safe rehabilitation progression. We conclude that intramuscular hamstring tendon healing can be accurately seen on sequential MRI scans and that this information, when combined with traditional rehabilitation markers in and elite sport environment, can be utilised by clinicians to determine the earliest but safe RTP.