Twenty-one patients with isolated avulsion fracture of the tibial attachment of the posterior cruciate ligament were treated in our hospital during the period 1965 to 1976. Twelve of the patients had fresh injuries and nine, injuries with delayed union or non-union. Twelve of the twenty-one patients were treated conservatively and nine, by surgical repair by means of staple fixation. Detachment of the posterior horn of the meniscus with an avulsed and displaced bone fragment was found in five of the nine patients operated on. All the patients were followed for an average of four years and eight months. Satisfactory results were obtained in every instance.