The effect of partial excision of the A2 and A4 pulleys on the biomechanics of finger flexion.

The purpose of this study was to investigate the effect of partial excision of the A2 and A4 pulleys on digital angular rotation and the energy required to flex the finger. Partial excision of A2 resulted in a statistically significant decrease in angular rotation of 3 and 5% after 50 and 75% excision, respectively. Partial excision of A4 failed to produce any significant differences in angular rotation. Combined partial excision of A2 and A4 resulted in a significant decrease of 5 and 8% after 50 and 75% excision, respectively. Significant differences in work of flexion occurred only after excision of 75% of the A2 pulley. Although optimal finger function relies on the integrity of the A2 and A4 pulleys which maintain the efficiency of the digital flexor system, these data suggest that 25% of the A2 pulley, up to 75% of the A4 and 25% of the A2 and A4 together can be excised without significant effects on angular rotation.