Total knee arthroplasty and persistent pain: a neuropathic perspective on peroneal and saphenous nerve compression

Total knee arthroplasty (TKA) is a common surgical procedure aimed at relieving pain and restoring function in patients with advanced knee osteoarthritis. However, up to 25% of patients report persistent postoperative pain, which remains a major clinical challenge. While mechanical and biological causes are well-documented, neuropathic pain due to dynamic nerve compression is often overlooked, particularly involving the common peroneal and saphenous nerves.

This study aims to highlight the role of dynamic nerve compressions in persistent post-TKA pain and propose an enhanced diagnostic approach by expanding Hagert's triad into a tetrad (pain, weakness, Scratch Collapse Test + , and orthogonal taping).

Dynamic nerve compression differs from static entrapment as it occurs intermittently, often escaping detection in standard electromyography (EMG) or imaging studies. The common peroneal nerve is commonly compressed in the peroneal tunnel, leading to lateral knee pain, ankle weakness, and gait instability. The saphenous nerve, entrapped in Hunter's canal, is associated with medial knee pain, fatigability in standing, and pain while climbing stairs. Incorporating orthogonal taping in the clinical assessment enhances diagnostic sensitivity by providing a reproducible mechanical relief test.

Dynamic nerve compression should be systematically considered in cases of persistent post-TKA pain. A thorough clinical examination, including Hagert's tetrad, helps improve early detection. When conservative management fails, surgical nerve release offers a valuable solution, with significant potential for pain relief and functional recovery. Further studies are needed to optimize treatment protocols and validate long-term outcomes.