What is tarsal tunnel syndrome?
Surely you mean “carpal” tunnel syndrome?! Well not really, the more popular carpal tunnel syndrome is a condition affecting the wrist where the carpal bones are located, but in our foot & ankle clinics we also see and treat a similar condition affecting the foot called tarsal tunnel syndrome.
Both the carpal and tarsal tunnel syndromes are nerve entrapment syndromes. In the foot, the tibial nerve runs with other structures in an enclosed space called the tarsal tunnel, located just under the medial malleolus or the prominent bone at the inner aspect of the ankle. The tibialis posterior, the flexor digitorum and hallucis longus tendons are also in the same tunnel along with the posterior tibial artery and vein. Tom, Dick and Very Naughty Harry is the mnemonic!
Causes of tarsal tunnel syndrome
The causes for tarsal tunnel syndrome can be divided into intrinsic or extrinsic. In the first group we can find hypertrophic tenosynovitis or most commonly space-occupying lesions such as ganglion cysts, lipomas or varicose veins. Extrinsic causes can include anything that can compress the tunnel from the outside: post-trauma or post-surgery scarring, and poorly fitting shoes. Contrary to its wrist counterpart, this is a very rare condition but it can often be undiagnosed. It can be seen at any age and it is more common in females.
Tarsal tunnel syndrome symptoms
The symptoms are mainly those of heel pain, localised under the inner side of the ankle and radiating to the arch of the foot. Patients will frequently report a shooting pain with radiation to the sole of the foot and numbness or a tingling sensation in that same area. If quite advanced, the patient may feel weakness in the muscles of the foot.
Tarsal tunnel syndrome treatment
Treatment for tarsal tunnel syndrome is composed of a combination of strategies that initially include physiotherapy and orthotics to decrease the pressure at the tarsal tunnel. Depending on the specific cause the treatment will be tailored to addressing each problem individually. In those cases where a ganglion cyst is present, an aspiration with a needle guided with ultrasound can reduce the size of the ganglion and improve symptoms. If conservative management fails to improve symptoms surgery may be indicated and for patients with a space-occupying lesion this is an ideal solution. Surgery involves the release of the band overlying the tunnel (or retinaculum) and the decompression of any lesions found in the area surrounding the nerve. If the right treatment is not implemented early and the nerve has been compressed for a long time, some permanent damage may remain with long standing weakness and numbness or failure to achieve complete relief of symptoms. Early diagnosis and early treatment are key in this condition.