Affiliations: [a] Department of Orthopaedic Surgery, Hannover Medical School, Hannover, Germany | [b] Institute of Forming Technology and Machines, Leibniz University Hannover, Hannover, Germany | [c] ATOS Clinic Heidelberg, Center for Hip, Knee and Foot Surgery, Heidelberg, Germany
Correspondence:
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Corresponding author: Dr. Matthias Lerch, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries Str. 1-7, 30625 Hannover, Germany. Tel.: +49 511 5354 576; Fax: +49 511 5354 682; E-mail: matthias.lerch@ddh-gruppe.de.
Abstract: Background:Numerous short stemmed total hip arthroplasty (THA) implants have been introduced over the last decades. It is questionable if little differences between the implant designs affect stress shielding and bone remodeling. The finite element analysis allows an evaluation of the design rationale of the implant without negative side effects for the patient. Objective:We investigated a relatively new short stemmed implant designed from clustered CT datasets of proximal femurs. How does the implant affect femoral bone remodeling? Can we see a positive effect on bone remodeling from the CT based design? Methods:We used a Finite Element Model that was validated by a prospective dual-energy-x-ray-absorptiometry study to calculate apparent bone density. Results:Apparent bone density (ABD) decreased by 2.3% in the entire femur. Bone mass loss was pronounced in the proximal calcar region. Little ABD increase was seen in the lateral aspect of the cortical ring, in the minor trochanter area and at the lateral aspect of the stem. Conclusions:ABD reduction occurs in the proximal regions of the femur. The overall bone mass loss was little after THA with the investigated implant. The specific design seems to have no major effect on stress shielding or load distribution.
Keywords: Total hip arthroplasty (THA), short stem, periprosthetic bone remodeling, finite element analysis (FEA)
