Background:Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease of unknown cause that primarily
affects the peripheral joints in a symmetrical pattern. Rheumatoidneuropathy could result from entrapment as by
adjacent tenosynovitis, nerve ischemia due to vasculitis or drugs used to treat these conditions. Tarsal tunnel syndrome
is a condition that is caused by compression of the tibial nerve or its associated branchesas the nerve passes underneath
the flexor retinaculum at the level of the ankle ordistally.Musculoskeletalultrasoundhaslong been established asa
valuable tool inthe diagnosis of synovitis and tenosynovitis in addition to effusions in RA patientsand also proofed
valuable for diagnosis of TTS.
Objective: The aim of the current study was to diagnose and evaluate tarsal tunnelsyndromein patients withrheumatoid
arthritis by meansof ultrasonography and nerve conduction studies.
Patients and methods: This study included fifty patients with age ranged from (20 to 68) years.All patients were
classified as having RA according to ACR/EULAR 2010criteria for RA classification, and suspected clinically to have
TTS by complaining of burning pain or paresthesia onthe plantar aspect of their feet and toes.
Results:Of 50 patients (50 feet), 47 patients (94.0%) had abnormal Electrophysiologicalfindings; 28 patients (59.6%)
had prolonged distal latency in the motor Lateral planternerve (any variable). 12 patients (25.5%) had prolonged distal
latency in the motor medial planter nerve (any variable). 35 patients (74.5%) had prolonged distal latency in the sensory
Lateral planter nerve (any variable). Musculoskeletal Ultrasonographyshowed 86.0 % of patients had abnormal findings
including ankle effusion (34.8%), Doppler (synovitis) (32.6%),tenosynovitis (tendon girth) (28.3%) and plantar faciatis
Conclusion:Musculoskeletal ultrasound and nerve conduction study should be used concomitantly to confirm the
diagnosis of tarsal tunnel syndrome in patients with rheumatoid arthritis.
Key words: Tarsal tunnel syndrome, rheumatoid arthritis, musculoskeletal ultrasonography, nerve conduction