Distal Musculotendinous T Junction Injuries of the Biceps Femoris: An MRI Case Review

Abstract

Background:Injury to the distal musculotendinous T junction (DMTJ) of the biceps femoris is a distinct clinical entity that behaves differently from other hamstring injuries due to its complex, multicomponent anatomy and dual innervation. Injury in this region demonstrates a particularly high rate of recurrence, even with prolonged rehabilitation times.Purpose:To describe the anatomy of the DMTJ of the biceps femoris and analyze the injury patterns seen on magnetic resonance imaging (MRI) to aid prognosis and rehabilitation and minimize the risk of recurrence.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Acute injury to the DMTJ of the biceps femoris was identified in 106 MRI examinations from 55 patients at a single institution. Each injury was classified as involving the long head, the short head, or both components of the DMTJ, with each component individually graded. Injuries were classified as recurrent if there was a previous MRI demonstrating an acute injury to the DMTJ or if there was scarring present at the site of an acute injury.Results:Of the 106 acute injuries to the DMTJ of the biceps femoris, isolated injury to the long head component was the most common (51%), with both components involved in [round 42.5% to 43%] of cases. Isolated injury to the short head component accounted for 7% of cases. The recurrence rate for reinjury to the DMTJ was 54% in this series. The date of prior injury was known in 45 of 57 recurrent cases, with 34 of these reoccurring within 3 months (76%) and 40 reoccurring within 12 months (89%). The recurrent injury was of a higher grade than the prior injury in 22 of 44 instances (50%), the same grade in 16 instances (36%), and a lower grade in 6 instances (14%). Thus, 86% of recurrent injuries were of the same or higher grade than prior injury.Conclusion:These results suggest that high-risk muscle injuries, such as that to the DMTJ of the biceps femoris, should be evaluated using MRI to determine the structural components involved and to assess the extent and severity of injury.

Isolated Tearing and Avulsion of the Distal Biceps Femoris Tendon During Sporting Activities: A Systematic Review

“…Distally, the biceps femoris is a complex structure, arising from 2 separately innervated muscles (long head of biceps femoris and short head of biceps femoris), emerging from different origins proximally with dissimilar force vectors. 16 , 31 The short head component, originating from the linea aspera on the posterior aspect of the femoral diaphysis, converges and coalesces with the tendon of the long head of the biceps femoris (originating from the ischial tuberosity) in the posterolateral aspect of the distal half of the thigh. 6 , 31 In their study of 30 cadaveric knees, Terry and LaPrade 31 provided detailed anatomic descriptions of the tendinous insertions of the distal biceps femoris.…”

“…Meanwhile, the tendinous component of the short head’s direct arm inserts lateral to the fibular styloid and medial to the FCL, with the anterior arm inserting medial to the FCL and converging anteriorly with the anterior tibiofibular ligament, while also continuing laterally onto the tibia, 1 cm posterior to Gerdy’s tubercle. In a review of 106 MRIs from patients sustaining acute, indirect injuries to the distal biceps femoris, Entwisle et al 16 found that the majority of injuries were isolated to the long head of the biceps (51%, n = 54/106) and attributed this to the fact that the long head crosses both the hip and knee joint, while isolated injuries to the short head component were rare (6.6%, n = 7/106).…”

A Histoarchitectural Approach to Skeletal Muscle Injury: Searching for a Common Nomenclature

“…Injuries to the distal MTJ of the biceps femoris present a special clinical challenge due to its complex anatomic structure and dual innervation to the short and long head of the muscle. 11 As the long and short head of the biceps femoris merge together at the distal MTJ, they form a T-shaped aponeurosis. Injuries occurring in this region are demanding to treat; despite long rehabilitation times, the recurrence rates are the highest among skeletal muscle injuries reported to date, as more than 50% of patients sustain reinjury.…”

“…Injuries occurring in this region are demanding to treat; despite long rehabilitation times, the recurrence rates are the highest among skeletal muscle injuries reported to date, as more than 50% of patients sustain reinjury. 11 Because the maturation of scar tissue is a slow process, it has been recommended that MRI be used to determine proper scar maturation before RTP can be considered. 11 We can observe all 3 types of histoarchitectonic involvement in the common hamstring tendon in daily clinical practice: direct tendon involvement with gap ( Figure 6A), purely myotendinous injury without gap ( Figure 6B), and muscle injury produced by traction of the common tendon but without direct contact with it ( Figure 6C).…”

“…11 Because the maturation of scar tissue is a slow process, it has been recommended that MRI be used to determine proper scar maturation before RTP can be considered. 11 We can observe all 3 types of histoarchitectonic involvement in the common hamstring tendon in daily clinical practice: direct tendon involvement with gap ( Figure 6A), purely myotendinous injury without gap ( Figure 6B), and muscle injury produced by traction of the common tendon but without direct contact with it ( Figure 6C). Comin et al 8 used MRI to study gaps or fiber retractions in the central tendon and found these factors to be associated with significantly longer RTP times than injuries without these factors.…”