Is the strain pattern of conventional stems negatively affected by a previously short stem THA? An experimental study in cadavaric bone

Article type: Research Article

Authors: Floerkemeier, Thilo^{a; c; *} | Arokiasamy, Romy^a | Budde, Stefan^a | Hurschler, Christof^b | Windhagen, Henning^a | von Lewinski, Gabriela^a | Gronewold, Jens^a

Affiliations: [a] Department of Orthopaedic Surgery, Hannover Medical School, Hannover, Germany | [b] Biomechanics and Biomaterials Laboratory, Hannover Medical School, Hannover, Germany | [c] go:h Gelenkchirurgie Orthopädie Hannover, Hannover, Germany

Correspondence: [*] Corresponding author: Thilo Floerkemeier, go:h Gelenkchirurgie Orthopädie Hannover, Bertastr. 10, Hannover, 30159, Germany. Tel.: +49 511 700 525 0; Fax: +49 511 700 525 99; E-mail: Thilo.Floerkemeier@g-o-hannover.de.

Abstract: BACKGROUND: A short stem hip arthroplasty can be revised in many cases using a conventional stem. Furthermore, in some cases the implantation of a short stem is intended, but intraoperatively reasons may lead to the decision to implant a conventional stem after previous preparation of a short stem. OBJECTIVE: In both cases it is questionable if the anchorage of a conventional stem is negatively affected by the previous preparation of a short stem. In clinical practice mid- or long-term follow up for these special cases hardly exist. METHODS: The strain patterns for the conventional Bicontact stem in primary implantation and after preparation of the proximal femur for a METHA short stem were tested biomechanically in three pairs of cadaveric femora. RESULTS: The strain patterns for the conventional Bicontact after preparation of the METHA short stem were similar to conditions after testing the conventional stem in primary conditions. CONCLUSIONS: These data lead to the consequence that in clinical practise the implantation of a conventional stem after preparation of a short stem and even after revision of a short stem is possible without increased risk of loosening or long-term stress-shielding.

Keywords: Short stem hip arthroplasty (METHA), standard stem hip arthroplasty (Bicontact), biomechanical testing, strain gauges, strain pattern

DOI: 10.3233/THC-191940

Journal: Technology and Health Care, vol. 29, no. 2, pp. 323-331, 2021