Comparison of Fracture Resistance Using Two Different Major Cemented Stems in Osteoporotic Bone Models.

Background: Periprosthetic hip fractures (PPFs) are one of the major complications in total hip arthroplasty (THA). Therefore, it is important to identify a mechanism for fracture resistance in THA. This study aimed to clarify the differences in fracture torque and fracture type analysis between two different types of cemented stems. Methods: We conducted biomechanical testing of bone analogues using six cemented stems of two different types with osteoporotic bone models: Anterior minimally invasive surgery (AMIS)-K and Charnley-Marcel-Kerboull (CMK) stems. Experienced surgeons implanted each of these types of stems into six bone analogues, and the analogues were compressed and internally rotated until failure. Torque-to-fracture and fracture type were recorded. Results: There was no significant difference in fracture torque of AMIS-K stem, compared to the CMK stem (p = 0.94). The AMIS-K stem showed one comminuted oblique fracture of Vancouver type B2 and five fractures of type C at the tip of the stem. The CMK stem showed five comminuted oblique fracture of Vancouver type B2 and one of type C at the tip of the stem. Conclusion: The AMIS-K stem demonstrated comparable fracture resistance to the CMK stem in an osteoporotic model.