The total length of bone-patella tendon-bone autografts can vary significantly between individuals. Grafts that are "too long" may protrude from the tibial tunnel site, precluding interference screw fixation. A simple calculation can be used to estimate the length of the tibial tunnel required to accommodate the graft. An intraoperative final check can be made with a calibrated drill. This distance should accommodate the total graft length. If necessary, minor adjustments that include trimming the bone plugs or deepening the femoral osseous tunnel can be made to prevent graft protrusion.