A Novel Modification of Anconeus Muscle Flap for Extensor Digitorum Communis-Selective Lateral Epicondylitis: Preliminary Clinical Study

Introduction: Lateral epicondylitis (LE) typically affects the extensor carpi radialis brevis (ECRB) tendon, while isolated degeneration of the extensor digitorum communis (EDC) origin is rare and poorly characterized. Surgical debridement of these lesions may result in capsular exposure requiring soft-tissue coverage, which can be achieved through a vascularized muscle flap to enhance tendon healing potential and reduce recurrence. This study aimed to describe a modification of the anconeus rotation flap as originally described by Almquist in 1998, and to evaluate its clinical and functional outcomes in patients with isolated EDC tendinopathy. The modified technique consists of a simpler muscle advancement (AMA) that preserves the distal vascular pedicle and reduces soft-tissue dissection. Methods: A retrospective study was conducted on 12 consecutive patients with lateral epicondylitis with isolated EDC tendon involvement (10.71% of all operative cases at our Institution between 2019 and 2022), who were surgically treated with the anconeus muscle advancement modification. Clinical outcomes, including the visual analog pain scale (VAS), grip strength and patient-reported outcome measures (PROMs), which include the QuickDASH score, the Mayo Elbow Performance Score (MEPS) and the Patient-Rated Tennis Elbow Evaluation (PRTEE) score were assessed. Paired statistical tests with 95% confidence intervals and minimal clinically important difference (MCID) thresholds were applied. Results: At a mean follow-up of 38 months, all outcomes demonstrated statistically significant and clinically meaningful improvements (p < 0.05). Reductions in pain/disability (VAS, QuickDASH, PRTEE scores) and functional gains (Grip strength, MEPS) far exceeded their respective MCID thresholds, with 100% attainment for each outcome. Conclusions: This modified anconeus muscle advancement appears to be a technically feasible option for managing isolated EDC-related lateral epicondylitis, preserving vascular integrity while limiting dissection. Although favorable results were obtained, the small retrospective cohort precludes definitive conclusions regarding efficacy. The findings support the technical feasibility of the proposed modification and warrant further prospective comparative investigations.