Real-time computer-assisted notch assessment in anterior cruciate ligament repair

Graft impingement can cause graft failure or movement restrictions. Intraoperative computer-assisted referencing of the tibial and femoral geometry, including precise mapping of the intercondylar notch, allows placement of the tunnels by real-time calculation balancing the impingement risks vs isometry. Biological fixation with bone cylinders locks the graft flush with the joint line and requires more accurate tunnel placement to avoid graft impingement. In 45 patients who underwent such navigation controlled tunnel placement 41 had no need for notchplasty. In two cases, the notchplasty was performed immediately for obvious osteophyte restriction. A notchplasty was added two times after the first referencing to obtain satisfactory isometry. At staged follow up to 18 months, we found no laxity, flexion contracture with a mean flexion arc over 130 degrees, or tunnel widening. With computer-navigated realtime assessment of notch geometry, full functional recovery and stability were obtained, and unnecessary notchplasties were avoided even with a less flexible biological graft fixation.