Posterior Tarsal Tunnel Syndrome

This condition is caused by a compression of the posterior tibial nerve as it passes beneath the flexor retinaculum located at the posterior back side of the ankle. According to the Injury classification system, this syndrome usually develops because of a misalignment issue at the ankle joint complex considering a level 1 injury with associated nerve entrapment. In certain cases, the flexor tendons that run withing the same area may become inflamed and could compress the posterior tibial nerve classifying as a Level 2 injury with associated nerve entrapment.

Chronic injuries at the ankle may also narrow the nerve passage due to the scar/fibrotic tissue at the superficial fascia and by the osteophytic bone formation from the underlying bones.

This condition presents in a manner analogous to carpal tunnel. Patients complains of pain and numbness in the sole of the foot with intermittent weakness and instability of the foot according to the degree of never involvement

Mechanism of Dysfunction

The main predisposing factor for the development of this condition is a dysfunction misalignment of the calcaneus (heel bone) by either creating a direct nerve pressure or by narrowing the flexor retinaculum canal. Although the calcaneus is considered the main misaligned bone in this syndrome, the predisposing factor began at the level of the ankle joint (tibia – talus). A fixed ankle joint will trigger the adjoining bones (calcaneus) to become more flexible and hypermobile, eventually causing the heel bone to misalign and irritate the nerve.

Another important predisposing factor for the development of this condition is the impaired foot mechanics caused by a compromised of the arches (see Flat foot page for detailed information) particularly the inner arch, therefore allowing the weight bearing stress to migrate further down the foot altering pedal action forces resulting the calcaneus to misaligned laterally and initiating the pathological process of the posterior tarsal syndrome.

Assessment Protocol

The entire lower extremity biomechanical chain must be evaluated as part of the foot/Toe analyses as per the neurological and mechanical influences of the spine, hip, and knee. Lower back Disc lesions should be ruled out.

Clinical assessment of the key ankle/foot joints (tibia-talus, navicular, cuboid) with specific attention to the evaluation of the calcaneus.

Tinel Neurological sign

X-ray analysis

Depending on the level of arch compromised, X-rays may be indicated to allow proper alignment analysis of the key joints.

Lateral Xray view is essential to check the alignment of the calcaneus and the relationship of the tibia-talus joint (master bone of the ankle/foot)

Anterior – Posterior (AP) X-ray ankle view is essential for identifying the further misaligned patterns of the talus bone.

MRI analysis

Important exam to verify the level of narrowing of the nerve passage and the degree of nerve inflammation.

Treatment protocol

Restore the biomechanical alignment of the ankle and sub-talar joints

Neuromobilization techniques may be used once the direct compression of the nerve is reduced.

Specific therapeutic essential oils are applied to reduce nerve inflammation and enhance healing.

Depending on the level of nerve compromised and chronicity of the misalignment a minimum of 6 weeks up to 12 weeks of treatment care may be necessary to resolve this deformity.