Tibial plateau avulsion

I am having difficulty finding information on an injury that I recieved in September. I am scheduled for surgery in March to repair what the ortho is calling an avulsion fracture of the posteromedial tibial plateau. I asked him how many of these he had done or seen and he said none like mine. The semimembranosus tendon and a ligament avulsed away a piece of bone which has not healed back. I cannot find any information on this type of injury or type of repair done to fix it. Can anyone provide any information?