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[The hinged knee prosthesis: outdated design or valuable implant for difficult cases?].

There are excellent results after unconstraint or semiconstraint bi- or tricompartimental total knee arthroplasty in case of uncomplicated degenerative joint disease of the knee. In the Swedish knee study, cumulative survival of unconstraint or semiconstraint knee prostheses was about 90 % at 10 years. In studies of single institutions, survival rates of more than 90 % at 15 years are reported. However, there is a need of more constraint designs because of the increasing number of complex total knee arthroplasties with disrupted collateral ligaments, deformities with flexion extension gap imbalance, comminuted distal femur fracture, distal femoral non-union in elderly patients and revision with massive bone loss. Initial hinged total knee designs were associated with a high failure rate. More recent designs have improved the femorotibial articulation and reduced the polyethylene wear. The bone resection necessary in actual hinged designs is similar to the resection in modern condylar prostheses. Due to these improvements, long-term survival of the best hinged designs are similar to the best condylar designs. In our study of a consecutive series of 422 hinged Blauth prostheses, the cumulative survival of the prostheses was 94.4 % at 20 years. Therefore, the hinged knee prosthesis is a valuable implant in case of complex total knee arthroplasty.