[Hinge endoprosthesis of the knee joint. Long-term results based on the Blauth prosthesis]

Knee prostheses of the condylar or hinge type have constructional features that have both advantages and disadvantages. Both types are compromises as a result of different demands. Here we report long-term results with the Blauth prosthesis as an example of the efficiency of the hinge concept. The Blauth prosthesis is constructed according to the low-friction principle without a weight-bearing axis. Load transmission to the bone is accomplished by large interface areas. The sliding bearing of the patella is oriented perpendicular to the transverse axis of rotation. A prospective multicentric study reports on 511 prosthesis with a follow-up between 1 and 15 years. Aseptic loosenings were confirmed in 1.2% of the patients, deep infections in 3.3%. The survival analysis showed a probability of 89% that a prosthesis would not have a deep infection or loosen. A hinged knee prosthesis shows positive long-term results even compared with the condylar types if the relevant principles of construction are adequately considered.