Short single-wedge stems have higher risk of periprosthetic fracture than other cementless stem designs in Dorr type A femurs: a finite element analysis. Issue 3 (May 2022)

• Record Type: Journal Article
• Authors: Nandi, Sumon; Shah, Anoli; Joukar, Amin; Becker, Kevin; Crutchfield, Cody; Goel, Vijay
• Is Part Of: Hip international. Volume 32:Issue 3(2022)
• Page Start: 298
• Page End: 303
• Publication Date: 2022-05
• Subjects: Femur -- finite element analysis -- periprosthetic fracture -- stem -- total hip arthroplasty; Hip joint -- Pathophysiology -- Periodicals; Hip joint -- Diseases -- Periodicals; Hip joint -- Surgery -- Periodicals; 617.581005
• DOI: 10.1177/1120700020949185
• Languages: English
• ISSNs: 1120-7000

Abstract

Background: The use of total hip arthroplasty (THA) femoral stems that transmit force in a favourable manner to the femur may minimise periprosthetic fractures. Finite element analysis (FEA) is a computerised method that analyses the effect of forces applied to a structure with complex shape. Our aim was to apply FEA to compare primary THA cementless stem designs and their association with periprosthetic fracture risk. Methods: 3-dimensional (3D) models of a Dorr Type A femur and 5 commonly used primary THA cementless stem designs (short single wedge, standard-length single wedge, modular, double-wedge metaphyseal filling, and cylindrical fully coated) were developed using computed tomography (CT) imaging. Implant insertion, single-leg stance, and twisting with a planted foot were simulated. FEA was performed, and maximum femoral strain along the implant-bone interface recorded. Results: Femoral strain was highest with short single-wedge stem design (0.3850) and lowest with standard-length single-wedge design (0.0520). Location of maximum femoral strain varied by stem design, but not with implant insertion, single-leg stance, or twisting with a planted foot. Strain was as high during implant insertion as with single-leg stance or twisting with a planted foot. Conclusions: Our results suggest the risk of intraoperative and postoperative periprosthetic fracture with THA in a Dorr A femur is highest with short single-wedge stems and lowest with standard-length single-wedge stems. Consideration may be given to minimising the use of short single-wedge stems in THA. Implant-specific sites of highest strain should be carefully inspected for fracture.