Anatomical evaluation of the modified posterolateral approach for posterolateral tibial plateau fracture

Objective The study was undertaken to evaluate the efficacy and safety of a posterolateral reversed L-shaped knee joint incision for treating the posterolateral tibial plateau fracture. Methods Knee specimens from eight fresh, frozen adult corpses were dissected bilaterally using a posterolateral reversed L-shaped approach. During the dissection, the exposure range was observed, and important parameters of anatomical structure were measured, including the parameters of common peroneal nerve (CPN) to ameliorate the incision and the distances between bifurcation of main vessels and the tibial articular surface to clear risk awareness. Results The posterolateral aspect of the tibial plateau from the proximal tibiofibular joint to the tibial insertion of the posterior cruciate ligament was exposed completely. There was no additional damage to other vital structures and no evidence of fibular osteotomy or posterolateral corner complex injury. The mean length of the exposed CPN was 56.48 mm. The CPN sloped at a mean angle of 14.7° toward the axis of the fibula. It surrounded the neck of the fibula an average of 42.18 mm from the joint line. The mean distance between the opening of the interosseous membrane and the joint line was 48.78 mm. The divergence of the fibular artery from the posterior tibial artery was on average 76.46 mm from articular surface. Conclusions This study confirmed that posterolateral reversed L-shaped approach could meet the requirements of anatomical reduction and buttress fixation for posterolateral tibial plateau fracture. Exposure of the CPN can be minimized or even avoided by modifying the skin incision. Care is needed to dissect distally and deep through the approach as vital vascular bifurcations are concentrated in this region. Placement of a posterior buttressing plate carries a high vascular risk when the plate is implanted beneath these vessels.