Modified Extensor Indicis Proprius Opponensplasty

Abstract

Extensor indicis proprius (EIP) opponensplasty is one of the commonly used techniques to restore thumb abduction and opposition in patients with thenar muscle dysfunction from various causes of median nerve palsy. However, its subcutaneous route around the distal ulna may not represent a straight line of pull, and part of the extensor hood sometimes has to be harvested along with the EIP tendon to gain adequate length to reach the insertion. The purpose of the study is to present the alternative method of EIP opponensplasty and report the clinical outcomes. The modified EIP opponensplasty was performed on 16 patients with severe carpal tunnel syndrome. At the final follow-up examination, all patients were able to regain their desired level of activities. The Kapandji score, abduction angle, and the disabilities of the arm, shoulder, and hand score improved in all patients. There were no complications related to harvesting the EIP tendon. Two patients developed finger stiffness, which improved after rehabilitation. This technique is safe and effective for restoring thumb function and can solve the insufficient tendon length problem of the original EIP opponensplasty.