[Ipsilateral THA after stemmed TKA: Risk of interprosthetic fracture?]

There is an increasing number of patients who have undergone stemmed total knee arthroplasty and total hip arthroplasty in the same leg. These patients may be at increased risk of periprosthetic and interprostethic fracture. Etiology and the potential therapy strategies are not well represented in the current literature.

Determination of the risk factors for interprosthetic fractures and possible prevention.

We performed a review of the literature and additionally a survey among experts (members of the German Association for Arthroplasty [AE]) to investigate the risk and the necessity for a preventive internal fixation.

There are only a few biomechanical studies. The interprosthetic distance seems to have little influence on the fracture risk, but the thickness of the cortex and the cortical area at the diaphysis seems to be important. The value of a bridging osteosynthesis remains uncertain. Ninety experts took part in the survey. The risk of fracture risk was estimated to be only slight to medium. Opinions regarding the necessity of preventive internal fixation were heterogeneous.

The indication for preventive internal fixation could be derived neither from the literature nor from the survey of experts. The thickness of the cortex and co-morbidities (osteoporosis, tendency to fall, and medication) seem to be more important than the interprosthetic distance.