Rheumatoid ahritis "Inflammation from rheumatoid ahritis results in a higher incidence of tarsal tunnel syndrome."- Current geriatric diagnosis,& treatment By C. Seth Landefeld, Robe Palmer, Mary Anne Johnson p459 "Carpal tunnel syndrome may be the presenting feature of rheumatoid ahritis."- Oxford textbook of rheumatology By David Alan Isenberg, Peter Maddison, Patricia Woo, David Glass, Ferdinand Breedveld 3/e p151 "Thus, compressive neuropathy of the branches of the posterior tibial nerve is a relatively frequent finding in patients with definite or classical RA."- Oxford Journals Medicine Rheumatology Volume 20, Number 3 Pp. 148-150 Tarsal tunnel syndrome Is entrapment neuropathy of the posterior tibial nerve (with or without involvement of the medial calcaneal nerve) within the fibro-osseous tunnel posterior and inferior to the medial malleolus. The tarsal tunnel is bounded superficially by the flexor retinaculum (laciniate ligament). The tibial nerve may be constricted by pressure from without or within this tunnel. Sources of constriction beneath and adjacent to the tarsal tunnel include bone fragments from displaced distal tibial, talar, or calcaneal fractures; tenosynovitis or ganglia of an adjacent tendon sheath; and bone and soft-tissue encroachment in rheumatoid ahritis or ankylosing spondylitis, varicosities, neural tumor (neurilemoma) or perineural fibrosis. Compression of the nerve leads to pain and sensory disturbances over the plantar surface of the foot. The pain may be precipitated by prolonged weight bearing. It is often worse at night and the patient may seek relief by walking around or stamping his or her foot. Paraesthesia and numbness can also be seen. Tinel's percussion test over the posterior tibial nerve may be positive. imaging Studies and Special Tests: Electromyography and nerve conduction studies should be performed but can be normal early in the entrapment. MRI provides excellent visualization of the tarsal tunnel and is indicated if there is suspicion of a space-occupying lesion within the tunnel. Treatment is conservative with ohotic modifications and measures to decrease the inflammation surrounding the involved nerve. A medial arch suppo can be fitted to hold the foot in slight varus. Surgical decompression is performed only in refractory cases