Dunlop D G, Woodnutt D J, Nutton R W
New Royal Infirmary of Edinburgh, Department of Orthopaedics, Old Dalkieth Road, Little France, Edinburgh EH16 4SU, UK.
Knee. 2004 Feb;11(1):19-24. doi: 10.1016/S0968-0160(02)00129-1.
In posterior cruciate ligament (PCL) reconstruction, the acute angle of the graft at the tibial tunnel ('the killer curve') has been implicated as a cause of graft failure. Similar acute angles also occur at the entrance to the femoral tunnel. We describe a method to determine the true graft angle, based on measurements taken from two orthogonal radiographs in a cadaveric model, analysed using three-dimensional geometry. The true angles for the tibial and femoral tunnels are presented for a variety of tunnel positions. The effect on these angles of knee flexion and extension is analysed. Resultant graft-tunnel forces at a constant ligament tension are described. Based on these results, drilling the femoral tunnel from outside-in and lateral placement of the tibial tunnel are theoretically advantageous.
