Introduction  

Hamstring injuries to the intramuscular tendon (3c) have been associated with a higher re-injury rate  (21-57%) and longer return time to play time (84+/- 49.4 days) (Kerrin et al., 2023). Recently a  ramped isometric protocol has been shown to improve expected recovery rates following surgical  repair (Power et al., 2023). The purpose of this study was therefore to investigate a ramped  isometric rehabilitation program for accelerated return to play following Bicep Femoris  intramuscular tendon injury, in an elite Gaelic footballer. 

Methods 

A 29-year-old male Intercounty Gaelic football player sustained a running based sustained in a Inter  County game. Upon clinical examination 36 hours post-injury, the patient presented with 1) Pain on  walking (Visual Analog Scale (VAS) rating of 3/10) 2) Pain on palpation (mid-portion of the Biceps  Femoris) 3) Range of motion deficits (30° deficit in active straight leg raise; 30° deficit in active 90/90  test; 40° deficit in MFAKE 4) Both prone and supine single-leg long lever strength assessments were positive, with a VAS rating of 6/10 5) HRIG Isometric deficit (66% deficit, correlating with a Grade III  injury in the mid-portion of the Biceps Femoris 6) MRI taken 4 days post injury identified an injury to  the proximal biceps femoris intramuscular tendon demonstrating high signal >15cm in longitudinal  length and >5cm fibre disruption, consistent with BMAIC 3c injury (Figure 1). 

Early loading and ramping isometrics of the hamstring was conducted 3 days post injury, using the  HRIG device (Figure 2). The intensity of the isometric sessions were carefully controlled and  monitored, with predetermined targets for maximal voluntary isometric contraction (MVIC) and  force set for the player. 

Results

Relative torque improved consistently throughout the rehabilitation process. Muscle asymmetries
decreased from 0.34, to 0.8 and 0.99 on days 2, 18 and 40 respectively (Figure 3). Imaging showed
reduced high signal with evidence of ongoing scar maturation on coronal and axial views (Figure 4)
and final imaging with further reduced high signal and further scar maturation (Figure 5).

Discussion 

Early loading following acute muscle injury has been reported to accelerate RTP (Bayer et al., 2017).  The HRIG facilitated early load in a upright position specific to late swing and early stance. Return to  run, return to modified training and return to full training were achieved on days 19, 39 and 45  respectively. This study may impact future prognosis, rehabilitation and inform return to play  decision making and loading.  

References:

Bayer, ML., Magnusson, SP., Kjaer, M. 2017. Tendon Research Group B. Early versus Delayed  Rehabilitation after Acute Muscle Injury. New England Journal Medicine, 377(13):1300-1301.  doi:10.1056/nejmc170 8134  

Kerrin, F., O’ Flanagan, S., Coyle, J., Farrell, G., Curley, D., McCarthy Persson, U., De Vito, G.& Delahunt, E., 2023. Intramuscular tendon injuries of the hamstring muscles: a more severe variant?  A narrative review. Sports Medicine-Open, 9(1), p.75. 

Power, D., Haddad, F., Wallis, S., Baar, K. 2023. Ramping Isometrics for Accelerated Return to Play  following Hamstring Tendon Repair: A Case Study. Journal of Elite Sport Performance, Published  online June 1, 2023. doi:10.54080/MOMV6327 

Authors:

Dr Martin Mc Intyre, Dr Sean Moffat, Johnathan Doherty, Dr Joe Jordan