Foot neuropathy in rheumatoid arthritis patients : clinical, electrophysiological, and ultrasound studies

Abstract EN

This study aimed to evaluate neuropathic foot pain in patients with rheumatoid arthritis (RA) using electrophysiological studies and musculoskeletal ultrasound (MSUS) to address the association between these findings and disease activity.

Evaluation of the usefulness of this combination was undertaken.

Design The present study was designed as a cross-sectional study.

Patients and methods A total of 50 RA patients underwent a complete history-taking and rheumatologic examination.

According to the cut-off point of Disease Activity Score in 28 joints, patients were divided into two equal groups (25 patients each): active and inactive.

In total, 25 healthy individuals were included as controls.

Routine tibial and peroneal nerve conduction studies, as well as electromyography of tibialis anterior and abductor hallucis muscles, were carried out.

MSUS assessment of the ankle joint and extra-articular portion of the foot complex was also performed.

Results Electrophysiological findings of foot neuropathy were observed in 78% of the patients, irrespective of the disease activity level.

In total, 48% of the patients had mononeuropathies of a demyelinating pattern (entrapment neuropathies), whereas the other 30% had symmetrical polyneuropathy with axonal degeneration.

Combined distal tibial and peroneal nerve entrapments were reported in 16% of the patients.

A positive power Doppler signal and joint erosions showed a highly statistical significant prevalence among the active group in comparison with patients in remission (P ≤ 0.001).

Conclusion Peripheral nerve affection is common in the rheumatoid foot, irrespective of the disease activity status.

The most common neuropathies were posterior tarsal tunnel syndrome, peroneal nerve entrapment at the fibular neck, and pure sensory axonal neuropathy.

A positive power Doppler signal and bone erosions of the ankle joint, detected by MSUS, were associated with RA disease activity.

Electrophysiology was superior to MSUS for the diagnosis of posterior tarsal tunnel syndrome.