Distal Hamstring Injuries and Disorders

Abstract

Hamstring injuries are a common injury sustained by athletes with most injuries occurring as strain injuries within the muscle belly or at the proximal musculotendinous junction. Distal hamstring pathology is relatively uncommon but comprises a collection of both acute and chronic diagnoses that can manifest with symptoms either on the medial or lateral side of the knee based on which hamstring tendons are involved. Pes anserinus bursitis is the most common of these distal hamstring pathologies with other chronic diagnoses, including snapping medial hamstrings or snapping biceps femoris. Acute biceps femoris ruptures can occur in an isolated fashion but most often occur in the setting of concomitant posterolateral corner injury as a result of high-energy trauma. Isolated semitendinosus ruptures can occur with lower-energy acute events, commonly with track and field events. Most distal hamstring pathology can be treated without surgery and do well with conservative treatment. However, acute avulsion injuries often require surgical intervention, as can chronic problems that do not adequately respond to prolonged conservative treatment. Treatment algorithms for distal hamstring injuries are less well-developed than more proximal injuries owing to their lower incidence. This review focuses on distal hamstring injuries, the state of current literature, and treatment strategies.

Figure 1

Sagittal T2 PDW MRI slice (A) demonstrating a distal avulsion of the biceps femoris tendon with the fibular head and retracted tendon end circled in red. There is fluid/edema between the visible tendon end and the fibular head with some tendon stump remaining on the fibular head. Coronal T2 PDW MRI slice (B) demonstrating retracted biceps femoris tendon. Note the nonlinear appearance or buckling of the tendon farther proximal to the ruptured end.

Figure 2

Clinical photographs demonstrating isolated complete distal avulsion of biceps femoris tendon from the fibular head (A) and repair of the tendon back to the fibular head. Photograph (B) demonstrating placement of repair stitches through the biceps femoris tendon after anchor placement into the fibular head, and photograph (C) demonstrating completed repair after sutures were tied.

Figure 3

Sagittal T2 PDW MRI slice demonstrating a distal avulsion of the semitendinosus tendon with the tendon stump circled in red. The MRI was taken in the subacute phase such that there is minimal edema and/or fluid collection present.

Figure 4

Clinical photographs demonstrating marked incision of semitendinosus stump after distal avulsion with incision centered over palpable stump.

Figure 5

Clinical photographs demonstrating (A) excised semitendinosus tendon stump extending just into musculotendinous junction after an isolated distal avulsion of the semitendinosus tendon. Tendon stump excised through open posterior approach (B) excised semitendinosus (right) and gracilis (left) tendons for snapping medial hamstring syndrome. Tendons excised using an open hamstring harvester through a small anterior incision over the pes insertion on the proximal tibia.