Treatment results using high open corrective tibial osteotomy with tricalcium phosphate block (OTIS 50) and fixation by angle-stable mini plate (OTIS C PLUS) are presented for a 47 years old female patient with 3rd stage gonarthrosis. Evaluation of functional condition was performed by Joseph and Kaufman scale that made up 72 and 95 points before and 3 years after surgery, respectively. Control knee arthroscopy and histologic examination results showed partial restoration offibrous hyaline cartilage in the injured knee compartment.