Evaluation of a Schanz pin technique for posterior cruciate ligament tensioning during reconstruction

Maximum anterior positioning of the tibia relative to the femur during posterior cruciate ligament (PCL) reconstruction is essential for achieving a tight graft and stable joint. A Schanz pin inserted in the proximal tibia is sometimes used to pull the proximal tibia forward during tensioning of the graft in PCL reconstruction. This study was designed to evaluate whether this technique provides more anterior translation than the traditional anterior drawer technique. Eight fresh-frozen cadaveric knees were tested using both methods in randomized order: pulling anteriorly on a 5-mm Schanz pin in the proximal tibia or a leather strap behind the calf designed to simulate a surgeon's hand performing an anterior drawer maneuver. An anteriorly directed force was applied from 0 to 60 N, and the sagittal position of the tibia in relation to the femur was recorded using a mini C-arm. Tests were performed first on the intact knees, again after the PCL had been cut, and again following transection of the popliteal-fibular ligament. We found a statistically significant (p < 0.05) increase in tibial translation, ranging between 1 and 2 mm, when the tibia was pulled by the Schanz pin compared with the strap under every set of conditions. This greater anterior translation could improve the stability of the postreconstructed knee.