Features of human autologous hamstring graft elongation after pre-tensioning in anterior cruciate ligament reconstruction

Precise pre-tensioning protocol of the graft has not been determined in anterior cruciate ligament (ACL) reconstruction. The aims of this study are to measure the human autologous graft elongation, and to reveal what portion of the graft elongated greater after pre-tensioning in ACL reconstruction. Twenty-four hamstring tendon grafts which were harvested from patients were included. A continuous load of 150 N was applied to the graft twice for 30 seconds each (150 N-1 minute), and the same loading was repeatedly applied (150 N-2 minute). The amount of elongation of the tendon portion (Length T) and the stitched portion (Length S) were measured after each pre-tensioning. Length S gradually increased by 1.57 +/- 0.67 mm after the 150 N-1 minute pre-tensioning and by 2.12 +/- 0.76 mm after the 150 N-2 minute pre-tensioning, respectively. Length T was not significantly elongated after 150 N-1 min (p = 0.66) and 150 N-2 min (p = 0.59). Graft elongation of the approximately 2 mm was observed, particularly in the stitched portion. It is necessary for a surgeon to focus on careful removal of slack from each stitch during suturing.