THE EFFECT OF KUROSAKA SCREW DIVERGENCE ON THE HOLDING STRENGTH OF BONE-TENDON-BONE GRAFTS

Fresh-frozen porcine knees were used to demonstrate the effects of div erging Kurosaka screw placement on linear load to failure in simulated anterior cruciate ligament reconstructions. Screws, placed anteromedi ally (rear-entry or tibial type) or intraarticulariy (endoscopic femor al type) into each tibia, were directed at 0 degrees, 15 degrees, or 3 0 degrees divergence angles relative to a guide wire. Grafts were axia lly loaded to failure to determine holding strength. Hierarchical anal ysis of variance was used to analyze differences between tibial side a nd endoscopic femoral type screw placement and the angles of divergenc e, Overall, the difference in pullout strength between rear-entry (or tibial side) and endoscopic femoral type fixation was shown to be stat istically significant (P < 0.001). Anteromedially placed screws showed a statistically significant decrease in holding strength at 15 degree s and 30 degrees compared with 0 degrees of divergence (P < 0.05). Int raarticular screw placement resulted in a statistically significant de crease in holding strength only al 30 degrees of divergence (P < 0.05) . This study supports the importance of accurate screw placement withi n the tibia to ensure optimal interference fixation and suggests that endoscopic screw placement may offer significant added security when t here are minor degrees of divergence.