[Complications of hinged endoprostheses of the knee joint, endomodell link.]

The authors implanted in 1985-1992 25 hinged endoprostheses of the knee joint, type Endomodell Link. It is a type of endoprosthesis which belongs into the group of so-called modified hinged prostheses. In addition to flexion and extension the design of the implant permits also 15 degree axial rotation. Indication for operation were deformities of the knee joint in 21 cases, re-operation in two knee joints and bony ankylosis associated with rheumatoid arthritis in two knee joints. The mean age of the patients was 64 years. In two patients infectious complications developed and the implant had to be removed. The authors did not record in any of the patients aseptic loosening with migration of the components or formation of radiolucencies. In one female patient the movable portion of the endoprosthesis broke of and after reimplantation of the damaged part 1.5 years later mechanical failure occurred due to wear of the thin-walled polyethylene capsule which caused laxity of the joint in the varus - valgus sense. During clinical check-up of the patients the authors found a similar condition - laxity of the knee joint in another 10 patients. It may be assumed that in these patients mechanical failure and the necessity of re-operation is only a question of time. Based on this experience the authors ceased to use this type of endoprosthesis. Key words: hinged prosthesis of the knee joint, mechanical failure.