Maintenance of pronation function after pronator teres to flexor pollicis longus tendon transfer: a cadaver study.

Study Design: Mechanistic cadaver study.

Objectives: Patients in groups 4 and 5 of the International Classification for Surgery of the Hand in Tetraplegia have a few options for tendon transfer donors, but in general the needs for reestablishing motor power exceed the donor options, such that any increase in the number of potential transfers can enhance function. Although transfer of brachioradialis (BR) in these patients is well-established, pronator teres (PT) may also be a suitable donor due to its strength and excursion. It has not been extensively studied in this role, possibly because of concerns about its expendability as the major agonist of forearm pronation. The purpose of this study is to quantify forearm pronation capability pre- and post-tendon transfer of PT to flexor pollicis longus (FPL) in a cadaver model.

Setting: Surgery center in Indianapolis, USA.

Methods: Five cadaver arms were evaluated for pronation capability against gravity before and after PT to FPL tendon transfer. In both stages, the arms were also assessed for the pronation forces produced at the wrist when pulling PT with 25, 50, and 75 N of force. With each force, the arms were tested in full supination and neutral position.

Results: All five arms were capable of pronating against gravity before and after the PT to FPL tendon transfer. Following the transfer, pronation force at the wrist decreased by 1-5 N, but the change was not statistically significant.

Conclusions: PT to FPL tendon transfer produces thumb flexion while retaining the forearm's ability to pronate and would likely retain good clinical function, freeing up BR to recreate active finger flexion or extension.