288 cases of posttraumatic deforming arthrosis of the knee-joint were examined. The further postoperative periodic examinations and checking of the late results of the treatment of 171 patients have proved that the symptoms of the disease are mainly due to the disorders in the knee-joint stability. The obtained data suggest the possibility of a secondary inflammatory origin of pain in deforming arthrosis and witness an important role played by the surgical prevention and correction of the joint instability in clinical remission of th disease.