Is Extensor Indicis Proprius Tendon Transfer an Innocent Surgical Procedure for the Restoration of Extensor Pollicis Longus Function?

Abstract

Purpose of the study: The aim of this study to evaluate the subjective and objective results of Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) transfer with an emphasis on donor site morbidity.

Material and methods: 17 patients (59% men, 41% women) who underwent EIP-EPL transfer were retrospectively analyzed. The mean age was 43 (9-64) years, and the mean follow-up was 72 (19-124) months. The extensor strengths were measured according to the Medical Research Council (MRC) scoring system. Nail tip-table surface distance (NTD) was measured to evaluate extension loss, and pulp-palm distance (PPD) to evaluate thumb flexion-adduction limitation. Grip and key pinch strengths were measured and corrected regarding the dominance and compared with those of the non-operated side. Quick Disability of Arm, Shoulder, and Hand (QDASH) and satisfaction scores of the patients were evaluated.

Results: Donor site morbidity was detected in 6 patients (35%). The extension strength of the index finger was found to be significantly lower than the non-operative side (p<0.05). Thumb mean NTD and PPD values were 6.8 (0-50) and 2.9 (0-20) mm, respectively. The index finger mean NTD was 0.6 (0-10) mm. The grip strength was 86% (43%-100%) and the pinch strength was 82% (31-100%) of the expected strengths. Compared to the preoperative period, there was a significant decrease in the QDASH score (p <0.05). Postoperative QDASH scores of patients with donor site morbidity were significantly higher than those without (p <0.05).

Conclusions: Although patients are generally satisfied with the EIP-EPL transfer results, the permanent morbidity rate in the index finger is high. Therefore, alternatives other than EIP should be considered for transfer to EPL in individuals whose occupation requires complete and strong index finger extension.

Key words: extensor pollicis longus, neglected tendon laceration, extensor indicis proprius, tendon transfer, donor site morbidity.