tarsal tunnel syndrome

definition

· entrapment of posterior tibial nerve behind flexor retinaculum

aetiology

· idiopathic

· most common

· posttraumatic

· scarring after sprain

· bony prominence after calcaneal fracture

· inflammatory

· rheumatoid arthritis

· tenosynovitis

· tumours

· ganglion

· lipoms

· neurilemmoma

pathogenesis

· entrapment of nerve in tarsal tunnel

· tarsal tunnel located behind and below medial malleolus

· roofed by flexor retinaculum

· other contents are

· TP, FHL and FDL tendons

· posterior tibial artery and vein

clinical features

History

· insidious onset

· burning pain under ball of foot

· aggravated by activity

Examination

· tenderness over tarsal tunnel

· positive Tinel’s sign over tarsal tunnel

· no localised tenderness in area of discomfort

· usually no neurological signs (weakness, sensory loss)

Investigations

Nerve conduction studies

· prolonged sensory conduction time in 75%

· prolonged motor latency in 50%

treatment

Nonoperative

· of little benefit

Operative

· surgical release by division of flexor retinaculum