The neurogenic elbow disharmony loop: a pathophysiologic model for chronic elbow pain supported by one hundred and fifty seven radial tunnel decompressions

INTRODUCTION: Radial tunnel syndrome (RTS) remains an overlooked cause of chronic elbow pain. Clinical overlap with lateral epicondylitis, and the coexistence of other nerve entrapments contribute to diagnostic uncertainty. This study aimed to characterise the clinical presentation, and concomitant pain/nerve entrapment patterns following surgical decompression of posterior interosseous nerve (PIN) compression, and to explore the Neurogenic Elbow Disharmony Loop (NEDL) as a hypothesis-generating model for refractory elbow pain. METHODS: A retrospective review of 157 operated arms in 143 patients who underwent PIN decompression between 2012-2021 was performed. RTS was diagnosed clinically using a triad consisting of extensor carpi ulnaris (ECU) weakness, a positive sensory collapse test, and focal tenderness at the arcade of Frohse. Demographics, pain distribution, concomitant procedures, Quick/Work-DASH scores, postoperative visual analogue scale (VAS) scores, and patient satisfaction were analysed. RESULTS: The mean age was 45.9 years, and the majority (66.9%) had previously been diagnosed with lateral epicondylitis. Referred symptoms were common, involving the hand (45%), shoulder (38%), wrist (28%), and neck (14%). Concomitant lacertus syndrome requiring surgical release was identified in 72.6% of arms. Return of ECU power was confirmed in all operated arms intraoperatively or before discharge. Mean pre-/postoperative Quick-/Work-DASH scores improved from 43.4 to 11.0 (p < 0.001), and 56.2 to 11.2 (p < 0.001), respectively. Mean postoperative VAS scores were 1.8 (pain), 1.1 (numbness), and 8.5 (satisfaction), with 83% of patients reporting good/excellent outcomes. CONCLUSION: Surgery with PIN decompression resulted in significant functional improvement and high patient satisfaction. The high prevalence of concomitant lacertus syndrome and the bidirectional distribution of referred symptoms support a neurogenic-biomechanical interpretation of chronic elbow pain. The NEDL is proposed as a hypothesis-generating framework that may guide the evaluation and treatment of patients with refractory elbow pain.