Distal Biceps Brachii Tendon Transfer for Re-establishing Extrinsic Finger Function: Feasibility Study in Cadavers

To determine the anatomic feasibility of transferring the biceps brachii tendon into either the extensor digitorum communis (EDC) or flexor digitorum profundus (FDP), determine the excursion imparted to EDC and FDP tendons after transfer, and compare the work capacity of the cadaver biceps to previously published data on the biceps as well as the recipient muscles by calculating the physiologic cross-sectional area (PCSA).

Four fresh-frozen cadaver shoulder-elbow-wrist specimens were used to measure tendon excursion that can be obtained with transfer of the distal biceps tendon into either the EDC or FDP. Two cadavers had distal biceps-to-EDC transfer performed, and the other 2 had distal biceps-to-FDP performed. Passive ranging of each elbow from flexion to extension and active loading at 90° of elbow flexion were then performed on each specimen to determine tendon excursion. An analysis of the PCSA of the biceps muscle was performed on each specimen.

Distal biceps-to-EDC transfer resulted in an average of 24 mm of tendon excursion with passive loading, and 24 mm of tendon excursion with active loading. Distal biceps-to-FDP transfer resulted in an average of 24 mm of tendon excursion with passive loading, and 24 mm of tendon excursion with active loading. The average PCSA was 3.6 cm².

Transfer of the distal biceps tendon into the EDC or FDP is anatomically feasible and provides roughly 24 mm of tendon excursion to the tendon units. The PCSA in the specimens used is slightly lower than other published data; it closely approximates the PCSA of the EDC, but is only half of the PCSA of the FDP in previously published data.

The findings suggest potentially novel transfer options for restoring finger flexion and extension in patients lacking FDP or EDC function.