MSK case of the month Oct 2024 – Navigating the T-Junction: A Case of Distal Hamstring Injury in a Young Footballer 

Despite numerous injury prevention programs and an increase in research over the past decade, recent studies have shown the burden of hamstring injuries in sports such as football have increased significantly. ¹ 

Emerging evidence highlights that distal hamstring injuries, particularly involving the musculotendinous T-junction of the biceps femoris, may be particularly problematic, with increased reinjury rates and prolonged recovery times. ²   

Clinical History  

A 28-year male construction project manager presents with a 3-week history of left posterolateral thigh pain which occurred acutely during a football match.  

The patient sustained an injury while intercepting a ball during a match. He describes extending his left knee and looking over left shoulder the feeling a sudden “pop” and discomfort in the posterior-lateral thigh accompanied by acute pain. Immediate of the calf.  

He visited the Emergency Department bruising and swelling developed in the thigh, extending to distal third he was reassured that there was no bony injury and advised to follow relative rest, and undertake regular icing.  

Following this initial management, his symptoms settled within one week allowing him to return to daily activities and work without significant pain. However, he began experiencing recurring discomfort, particularly after prolonged periods of standing during his work.  

Additionally, he noted difficulty progressing to jogging and was unable to resume football due to ongoing discomfort in the injured leg. He denied any neurovascular symptoms, back pain, or noticeable weakness in knee flexion, ankle plantarflexion, or dorsiflexion. 

Past Medical History  

• Nil   

Drug History  

• Nil  

Exercise History 

Recreational footballer, primarily playing as a left winger in both 11-a-side and 7-a-side matches. He is left-leg dominant, with a weekly routine of one training session, and one 11-a-side game, and one 7-a-side match and occasional gym sessions. 

Clinical Examination 

• Gait: Unremarkable, with no observed abnormalities. 

• Visual Inspection: Normal appearance of the posterior thigh, with no visible bruising, swelling, or muscle atrophy. 

• Range of Motion: Full, pain-free knee range from -5 to 130 degrees, with unrestricted hip motion. 

• Strength Testing: Equal strength bilaterally on hamstring testing in both short and long lever positions, although there was mild discomfort localised to the distal biceps femoris tendon with a biceps femoris bias. 

• Palpation Findings: Notable tenderness and mild thickening were detected in the distal biceps femoris tendon and the short head of the biceps femoris muscle, approximately 5 cm proximal to the fibular head. No tenderness over the fibular head, popliteal fossa, or gastrocnemius insertion sites. 

• Joint Assessment: Normal and pain-free movement in the superior tibiofibular joint. 

• Gastrocnemius and Soleus: Pain-free, with preserved strength on testing. 

• Distal Neurovascular Exam: Intact, with no signs of neurovascular compromise. 

Bedside Diagnostic Ultrasound  

• There is a tear of the distal long head of bicep femoris tendon starting 10cm proximal to the head of the fibula and extending 4 cm. There is no loss of tension on dynamic assessment of the distal long head of bicep femoris tendon. 

• The short head of the bicep femoris shares the T junction but the muscle and the tendon attached to the short head is completely intact, seen inserting onto the head of the fibula distally.  

• The muscles of the semimembranosus and the semitendinosus speared normal. 

• No Baker’s cyst or other popliteal cyst.  

• No knee joint swelling or effusion. 

• Normal appearances of the popliteal artery and vein (no formal doppler scan performed at this stage). 

• MRI scan recommended. 

Diagnostic Imaging 

MRI   

Grade 2 tear of the long head component of the distal musculotendinous T junction of the biceps femoris. There is a partial-thickness tear of the long head component (L) of the T junction tendon structure (arrows) and peritendinous oedema and blood fluid. 

Image 1) Reproduced under Creative Commons Attribution-Noncommercial-NoDerivs 3.0 License   (http://www.creativecommons.org/licenses/by-nc-nd/3.0/)  

Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524253/figure/fig5-2325967117714998/  

Reference: Entwisle T, Ling Y, Splatt A, Brukner P, Connell D. Distal Musculotendinous T Junction Injuries of the Biceps Femoris: An MRI Case Review. Orthop J Sports Med. 2017 Jul 20;5(7):2325967117714998. doi: 10.1177/2325967117714998. PMID: 28795071; PMCID: PMC5524253.  

Diagnosis: Grade 2 tear of the long head component of the distal musculotendinous T junction 

A distal biceps femoris injury was diagnosed, involving the T-junction, given the clinical presentation and location. Initial management included a structured physiotherapy-guided rehabilitation, focusing on gradual strength and conditioning. Given emerging evidence of high reinjury risk, a cautious approach to return-to-play is recommended​. 

Discussion And Key Points   

• Patients’ symptoms whilst dramatic initially settle quickly, often <1 week 

• Players struggle to return to high speed and pivoting movements 

• Whilst the principles of hamstring injury management apply to distal hamstring injuries there are a few key points to consider 

• Reinjury rates are high with some longitudinal studies reporting rates above 50% for higher grade injuries 

Anatomy 

The biceps femoris, has a complex structure and dual innervation which make it a unique and highly susceptible for injuries, especially at its distal T-junction, where the muscle’s long and short heads converge.  

This anatomical configuration poses unique challenges for clinicians due to the heightened potential for injury recurrence and extended rehabilitation needs associated with this region. 

The biceps femoris muscle consists of two distinct heads:  

• The long head, which originates from the ischial tuberosity and spans the hip and knee joints. 

• The short head, which originates from the femur and only crosses the knee joint.  

These heads converge distally at the musculotendinous junction (MTJ), commonly referred to as the T-junction due to its unique structural arrangement. This T-junction is a primary site of tension and force transmission, as the long head is innervated by the tibial portion of the sciatic nerve, while the short head is innervated by the common peroneal nerve. This dual innervation increases the complexity of neuromuscular control and motor unit recruitment in the biceps femoris, potentially leading to asynchronous contraction and higher susceptibility to strain injuries​. 

Schematic demonstrating the sequential axial anatomy of the distal musculotendinous T junction (DMTJ) of the biceps femoris. Proximally, the anterolateral epimysial surface of the long head (L) condenses to form the proximal portion of the DMTJ and appears L-, C-, or U-shaped (large arrow). In the midportion, the opposing epimysial condensations at the anterolateral aspect of the long head and the posterolateral aspect of the short head (S, small arrow) form the DMTJ that appears as a T-shaped structure. Distally, the posterolateral epimysial condensation of the short head forms the DMTJ and appears as a shallow convex structure. 

Image 2) Reproduced under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License   (http://www.creativecommons.org/licenses/by-nc-nd/3.0/)  

Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524253/  

Reference: Entwisle T, Ling Y, Splatt A, Brukner P, Connell D. Distal Musculotendinous T Junction Injuries of the Biceps Femoris: An MRI Case Review. Orthop J Sports Med. 2017 Jul 20;5(7):2325967117714998. doi: 10.1177/2325967117714998. PMID: 28795071; PMCID: PMC5524253.  

Axial proton density images demonstrating the anatomy of the distal musculotendinous T junction (DMTJ) of the biceps femoris. (A) The anterolateral epimysial surface of the long head (L) condenses to form the proximal portion of the DMTJ and appears L-, C-, or U-shaped (large arrow). (B) The opposing epimysial condensations at the anterolateral aspect of the long head (L, large arrow) and the posterolateral aspect of the short head (S, small arrow) form the midportion of the DMTJ that appears T-shaped. (C) The posterolateral epimysial condensation of the short head (S, small arrow) forms the distal portion of the DMTJ and appears as a shallow convex structure. 

Image 2) Reproduced under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License   (http://www.creativecommons.org/licenses/by-nc-nd/3.0/)  

Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524253/  

Reference: Entwisle T, Ling Y, Splatt A, Brukner P, Connell D. Distal Musculotendinous T Junction Injuries of the Biceps Femoris: An MRI Case Review. Orthop J Sports Med. 2017 Jul 20;5(7):2325967117714998. doi: 10.1177/2325967117714998. PMID: 28795071; PMCID: PMC5524253 

In addition to dual innervation, the distal T-junction’s structural properties contribute to its vulnerability. The T-junction forms through the convergence of myotendinous and myofascial tissues from both heads, resulting in a unique area of mixed tissue density. This combination of dense, tendinous fibers and less structured myofascial tissue may create uneven force distribution across the T-junction, heightening the risk of injury, particularly during high-stress activities like sprinting or sudden deceleration​. ³ 

Management and Return to Play 

It appears that traditional hamstring rehabilitation protocols, developed for more proximal injuries, may be insufficient for addressing the unique demands of distal T-junction injuries, necessitating extended rehabilitation and highly individualised approaches​.  

Many clinicians now take a more cautious approach in rehabilitation and return to play, with increased emphasis on eccentric strengthening, progressive load tolerance, and neuromuscular re-education.   

This involves gradual progression from pain-free, low-load exercises to isometric, isokinetic, and finally eccentric loading that focuses on restoring the muscle’s tensile strength. Emphasis on maintaining pain-free movement during each stage, even at the expense of prolonged recovery time.  

Regular strength and range-of-motion assessments guide progression, ensuring that each recovery milestone is achieved without exacerbating the injury. By focusing on neuromuscular coordination and progressive loading, clinicians can better support the injured muscle’s adaptation, which appears to be important in preventing recurrence.⁴ 

Return-to-play decisions for distal hamstring injuries are equally cautious.  There is a growing consensus on the importance of highly individualised criteria for T-junction injuries, as traditional return timelines and generalised functional benchmarks may inadequately account for the complexity of these injuries. Criteria such as eccentric strength thresholds, controlled introduction to sport-specific drills, and high-speed running assessments appear to be important components of the RTP decision-making process.  

Conclusion  

The high reinjury rates associated with T-junction injuries of the distal biceps femoris underscore the need for extended, tailored rehabilitation protocols and cautious return-to-play strategies.  

Recent studies reveal that standard rehabilitation timelines may be insufficient for addressing the unique challenges posed by T-junction injuries.  

By incorporating individualised recovery benchmarks, advanced imaging, and targeted neuromuscular re-education, clinicians can better support athletes in achieving a safer and more sustainable return to activity, ultimately reducing the risk of recurrent injuries in this vulnerable muscle region. 

Key Learning Points  

• T-junction injuries in the distal biceps femoris exhibit high reinjury rates suggesting the need for more conservative, prolonged rehabilitation than traditionally applied. 

• The structural complexity and dual innervation of the T-junction contribute to increased susceptibility to reinjury, especially under high athletic demands. 

• Individualized return-to-play criteria based on functional testing, neuromuscular control, and structural integrity can reduce reinjury risk and optimise long-term outcomes. 

References 

1. Ekstrand J, Bengtsson H, Waldén M, et al Hamstring injury rates have increased during recent seasons and now constitute 24% of all injuries in men’s professional football: the UEFA Elite Club Injury Study from 2001/02 to 2021/22 British Journal of Sports Medicine 2023;57:292-298. 

2. Shamji R, James SLJ, Botchu R, et al. Association of the British Athletic Muscle Injury Classification and anatomic location with return to full training and reinjury following hamstring injury in elite footballBMJ Open Sport & Exercise Medicine 2021;7:e001010. doi: 10.1136/bmjsem-2020-001010 

3. Kenneally-Dabrowski C, Serpell BG, Spratford W, Lai AKM, Field B, Brown NAT, Thomson M, Perriman D. A retrospective analysis of hamstring injuries in elite rugby athletes: More severe injuries are likely to occur at the distal myofascial junction. Phys Ther Sport. 2019 Jul;38:192-198. doi: 10.1016/j.ptsp.2019.05.009. Epub 2019 May 29. PMID: 31176259.  

4. Kerin F, O’Flanagan S, Coyle J, Curley D, Farrell G, Persson UM, De Vito G, Delahunt E. Are all hamstring injuries equal? A retrospective analysis of time to return to full training following BAMIC type ‘c’ and T-junction injuries in professional men’s rugby union. Scand J Med Sci Sports. 2024 Feb;34(2):e14586. doi: 10.1111/sms.14586. PMID: 38375584.