Periprosthetic supracondylar femoral fractures following knee arthroplasty: a biomechanical comparison of four methods of fixation
Mäkinen, T.J., Dhotar, H.S., Fichman, S.G. et al.Knee
Purpose
The aim of this study was to determine the biomechanical properties of four fixation options for periprosthetic supracondylar femoral fractures.
Methods
Fourth-generation composite femurs were implanted with a posterior-stabilizing femoral component of total knee arthroplasty. All femurs were osteotomized to produce a AO/OTA 33-A3 fracture pattern and four different constructs were tested: (1) non-locking plate; (2) polyaxial locking plate; (3) intramedullary fibular strut allograft with polyaxial locking plate; (4) retrograde intramedullary nail. The composite femurs underwent non-destructive tests to determine construct stiffness in axial and torsional cyclic loading. The final testing consisted of quasi-static axial loading until failure.
Results
Under cyclic torsional loading, the retrograde intramedullary nail was less stiff than non-locking plate, polyaxial locking plate and intramedullary fibular strut allograft with polyaxial locking plate (p = 0.046). No differences were detected in cyclic axial loading between the different constructs. During quasi-static axial loading to failure, the intramedullary nail achieved the highest axial stiffness while the non-locking plate showed the lowest (p = 0.036).
Conclusions
The intramedullary fibular strut allograft with polyaxial locking plate did not prove to be significantly better to the polyaxial locking plate only in a periprosthetic distal femur fracture model.
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