A specially designed tensiometer was employed to compare the mechanical efficiency of normal and reconstructed pulley systems in the thumb and the fingers. The "belt loop" technique for reconstruction was used in five fresh cadavers. A total of 10 thumbs and 40 fingers were dissected, and after a measured pull on the proximal tendon the yielded power output at the tip was compared with the normal and reconstructed systems. A mean of 10% loss of power in the reconstructed system in the thumb and 40% of power in the fingers, with excellent range of motion and no bow stringing was recorded.