Ankle extensor compartment injury

Ankle extensor compartment injuries are infrequently reported in the medical literature in contrast to the other ankle pathology. 

Epidemiology

The incidence of ankle extensor tendon abnormalities is unclear ^ref.

Pathology

The ankle extensor compartment contains (from medial to lateral) ^ref:

• tibialis anterior, extensor hallucis longus, and extensor digitorum longus tendons

• superior and inferior extensor retinaculum

The most common tendon injuries are to tibialis anterior followed by extensor hallucis longus and extensor digitorum longus tendons ⁴.

Radiographic features

MRI

Ankle extensor tendon tears may be visualized on MRI as intrasubstance signal abnormality on T2-weighted images, abnormal tendon diameter, or both.

Acute partial tears can be associated with edema and various form of tendon shape including increased tendon diameter, longitudinal tear along the long axis of the tendon and sometimes splitting the tendon into separate fiber bundles. In cases of chronic partial tears, the decreased diameter of the remaining tendon, and retraction and scarring of the torn fibers can also be seen ^5,6.

Treatment and prognosis

Almost all ankle extensor injuries compartment are underdiagnosed and prompt treatment is required for a good prognosis ^1-3. Conservative treatment is indicated for less severe cases of extensor tendinopathy. Early diagnosis followed by surgical repair of complete rupture of the tibialis anterior tendon significantly increased patients' function because this tendon provides 80% of dorsiflexion strength although some dorsiflexion deficit remains in most patients after anterior tibial tendon repair ^7-9.