Geometric and biomechanical perspectives on ulnar nerve compression in cubital tunnel syndrome: pathomechanics and surgical strategies

Cubital tunnel syndrome (CuTS) is the second most common upper extremity nerve entrapment disorder, characterized by compression of the ulnar nerve at the elbow. Traditional surgical classifications have emphasized anatomical depth or technical complexity, but they inadequately account for the geometric and biomechanical factors influencing nerve tension, strain, and recovery. This review introduces a geometric model that conceptualizes the ulnar nerve's trajectory during elbow flexion as a sharply angled triangle, where greater curvature correlates with higher mechanical stress and elongation. Surgical strategies are reclassified based on their degree of geometric correction: noncorrective, indirect corrective, and direct path reconfiguration. We critically analyze the biomechanical implications and clinical outcomes of each technique, supported by dynamic imaging, cadaveric data, and neurophysiological metrics such as motor conduction velocity and grip strength recovery. Submuscular transposition achieves the most complete path realignment and consistently demonstrates superior functional results. The review also highlights gaps in current literature, particularly the lack of quantifiable biomechanical outcome measures such as nerve curvature, strain, and excursion. We propose a new classification system and recommend incorporating geometric metrics into future surgical planning and comparative studies. By reframing surgical choices around path correction rather than procedural nomenclature, this model offers a more precise, individualized approach to CuTS management.