A New Anatomical Approach to T-Junction Hamstring Injuries

Hamstring injuries are the most common muscle injuries in sport, particularly in football. Among these, injuries to the distal musculotendinous T-junction (DMTJ) of the biceps femoris remain poorly characterized and are frequently associated with prolonged recovery and high reinjury rates. The DMTJ is a complex, anatomically variable structure formed by the confluence of the long and short heads of the biceps femoris.

To assess whether the anatomical configuration of the DMTJ-specifically the extent of its deep connective tissue limb-is associated with return-to-play (RTP) time and reinjury rate following acute injury.

A retrospective cohort study was conducted involving 32 male professional football players (aged 18-35 years) with first-time, magnetic resonance imaging (MRI)-confirmed DMTJ injuries. Based on axial MRI, injuries were classified as "long T-junction" (> 30% aponeurotic coverage of the anterior long head surface) or "short T-junction" (≤ 30%). RTP time and reinjury rates at 6 months were compared. In addition, 10 cadaveric specimens were analyzed to examine the depth and morphology of the T-junction connective tissue.

A total of 16 injuries were classified as long T-junctions and 16 as short. The long T‑junction group showed significantly longer RTP times (mean 42.6 ± 6.2 versus 28.9 ± 5.1 days; p < 0.001) and a higher reinjury rate (37.5% versus 6.3%; p = 0.083 by two-sided Fisher's exact test). This difference did not reach statistical significance (RR 6.0, 95% CI 0.79-45.7). Anatomical dissections confirmed substantial variability in the depth and structure of the connective tissue extension.

Greater deep extension of the DMTJ is associated with delayed recovery and increased reinjury risk. Recognizing the anatomical variability of this region may improve injury classification, prognosis, and management. Further prospective, multicenter studies are needed to validate these findings.