This is the first description of an arthroscopic-assisted intraosseous balloon-assisted repositioning and defect filling of a tibial plateau fracture. The bone defect was filled with calcium phosphate cement in a liquid/paste form. The described technique was therefore introduced in order to allow an arthroscopic control of reposition and intra-articular cement escape during defect filling. X-rays showed an exact reposition without cement escape and the clinical outcome was satisfactory.