The principle of internal ligament fixation : If we base the results of posterior cruciate ligament (PCL) reconstruction using autografts or allografts on accurate radiolaximetry, the mechanical efficiency is poor. Objective good mechanical results 12, +, 6, 10, 131 hardly attain 50% in the best of cases. Autogenous transplants require a postoperative period of rest, due to long periods of weaknessess related to collagen transformation and revascularisation. From the start, PCL reconstructions must resist gravity and permanent hamstring action.