This study is a prospective evaluation of the Less Invasive Stabilization System (LTSS) for the treatment of high-energy tibial plateau and proximal tibial fractures treated between November, 1998 and June, 2000. Thirty-two patients sustained thirty-five acute fractures of the tibial plateau (25) or proximal tibia (10). These patients were injured primarily in blunt trauma accidents, with eighteen having multiple fractures, fifteen having ipsilateral extremity fractures, and eleven having major knee ligament injuries. Seventeen patients had open fractures. Thirty-four patients healed their fractures, with one developing a nonunion. Two patients developed infections, both following Type III open fractures. Final range of motion averaged 2 to 116 degrees. Alignment was well maintained, with no patient losing the alignment that was obtained in the operating room. The tibial LISS system worked well at stabilizing difficult fractures of the tibial plateau and proximal tibia with a low incidence of complications in this preliminary study with short-term follow-up.