Hamstring injuries remain a significant time loss injury. While intramuscular tendon injuries have been reported to be associated with a very poor prognosis they may not be as concerning as previously thought.
The intra-muscular (also known as the central) tendon refers to the part of the tendon to which muscle fibres attach. Injuries to this part of the hamstring are typically believed to have a worse prognosis, with a higher rate of recurrence and a more prolonged recovery, than those involving the muscle belly. This belief has been based on retrospective case series where there is a risk of bias. The largest of these studies suggested that central tendon injuries took about three times longer to recover and that a quarter of these injuries needed surgical treatment.1
The current study has been conducted prospectively with the clinician making the decisions about returning the player to full training and play having been blinded to the player’s MRI findings.2 To be included potential participants had to be athletes and had to have an MRI within five days of an acute hamstring injury. Players had a standardised treatment and rehabilitation programme.
The MRI findings of a full-thickness disruption or ‘waviness’ of the intramuscular tendon were associated with increased time to RTP. Compared with injuries without intramuscular tendon involvement, these injuries take slightly more than a week longer to RTP. However, the considerable overlap between groups with and without intramuscular tendon involvement substantially limits the predictive value of this radiological finding.
Based on the results of this study the time to RTP for hamstring injuries with intramuscular tendon involvement is considerably shorter than previously reported.
1 Comin J, Malliaras P, Baquie P, et al. Return to competitive play after hamstring injuries involving disruption of the central tendon. Am J Sports Med 2013;41:111–5.
2 Van der Made AD, Almusa E, Whiteley R et al. Intramuscular tendon involvement on MRI has limited value for predicting time to return to play following acute hamstring injury. Br J Sports Med 2017;0:1. doi:10.1136/bjsports-2017-097659.