Observational Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Oct 18, 2018; 9(10): 210-219
Published online Oct 18, 2018. doi: 10.5312/wjo.v9.i10.210
Long-term results of an anatomically implanted hip arthroplasty with a short stem prosthesis (MiniHipTM)
Lars V von Engelhardt, Andreas Breil-Wirth, Christian Kothny, Jörn Bengt Seeger, Christian Grasselli, Joerg Jerosch
Lars V von Engelhardt, Faculty of Health, University of Witten/Herdecke, Witten 58448, Germany
Lars V von Engelhardt, Department of Trauma Surgery Orthopedics and Sports Medicine, Katholisches Karl-Leisner Klinikum, Kleve 47533, Germany
Andreas Breil-Wirth, Christian Grasselli, Joerg Jerosch, Department of Orthopedics, Trauma Surgery and Sports Medicine, Johanna Etienne Hospital, Neuss 41462, Germany
Christian Kothny, Munich Ortho Center, Munich 80802, Germany
Jörn Bengt Seeger, Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg, Giessen 35392, Germany
Christian Grasselli, Department of Orthopaedics and Traumatology, Waldburg-Zeil Clinic Tettnang, Tettnang 88069, Germany
Author contributions: Jerosch J, Kothny C and Seeger JB contributed to the study conception and design; Seeger JB, Breil-Wirth A, Jerosch J and Grasselli C contributed to the data acquisition, analysis and data interpretation; von Engelhardt LV contributed to the data interpretation, the literature research, the preparation of the figures and the writing of the article which was approved by all authors.
Supported by A sponsorship from Corin (Corin Group, Cirencest, United Kingdom).
Institutional review board statement: The study was reviewed and approved by the local ethical committee of the Medical Association of North Rhine (Ärztekammer Nordrhein) in Düsseldorf (Study No. 2011379).
Informed consent statement: All persons involved in this study gave their informed consent prior to study inclusion. All details that might disclose the identity of the subjects under study were omitted or anonymized.
Conflict-of-interest statement: This paper’s publication fee is paid by a sponsorship from Corin (Corin Group, Cirencest, United Kingdom). Except for Jörn Bengt Seeger, all authors have a paid consultancy/speakers contract for Corin. All authors declare to have no further interests, commercial or otherwise, which represent a conflict of interest in relation to this study.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Lars V von Engelhardt, MD, PhD, Surgeon, Department of Trauma Surgery Orthopedics and Sports Medicine, Katholisches Karl-Leisner Klinikum, Alfred-Herrhausen-Straße 50, Kleve 47533, Germany. chirurgie.ahk@kkle.de
Telephone: +49-2821-4901151 Fax: +49-2821-4901080
Received: May 22, 2018
Peer-review started: May 23, 2018
First decision: June 5, 2018
Revised: June 17, 2018
Accepted: June 28, 2018
Article in press: June 28, 2018
Published online: October 18, 2018
Processing time: 149 Days and 12.1 Hours
Abstract
AIM

To evaluate the clinical and radiological outcome nine and ten years after short-stemmed, bone preserving and anatomical hip arthroplasty with the MiniHipTM system.

METHODS

In a prospective study, 186 patients underwent hip arthroplasty with a partial neck preserving short stem (MiniHipTM, Corin). Elderly patients were not excluded from this study, thus the mean age at the time of surgery was 59.3 years (range 32 to 82 years). Surgery and the follow-up assessments were performed at two Centers. Up until now, the mean follow-up was 112.5 ± 8.2 mo. The Oxford Hip Score (OHS) and the Hip Dysfunction Osteoarthritis and Outcome Score (HOOS) was assessed pre- and each year after surgery. The clinical follow-up was accompanied by standardized a.p. and axial radiological examinations. Periprosthetic lucencies, hypertrophies within the Gruen zones one to fourteen were assessed. A subsidence of the stem was investigated according to Morray and heterotopic ossifications were assessed according to Brooker.

RESULTS

The OHS and HOOS improved from 18 ± 3.3 to 46 ± 2.0 and from 30 ± 8.3 to 95 ± 4.6 points, P < 0.001 respectively. There were no differences regarding age, etiology, friction pairings, etc., (P > 0.05). Two stems were revised due to a symptomatic subsidence four and twelve months postoperatively. Thus, the survivorship for aseptic loosening at nine to ten years was 98.66%. Including one stem revision due to a symptomatic exostosis, bursitis and thigh pain as well as one revision because of a septic stem loosening, the overall survival for the stem with revision for any reason was 97.32%. Besides one asymptomatic patient, radiological signs of a proximal stress-shielding, such as bone resorptions within the proximal Gruen zones, were not noticed. Findings suggesting a distal loading, e.g., bony hypertrophies or bone appositions of more than 2 mm, were also not detected.

CONCLUSION

Regarding these first long-term results on the MiniHipTM, the implant performed exceedingly well with a high rate of survivorship for aseptic loosening. Our radiological results within the Gruen zones support the design rationale of the Minihip to provide a reliable metaphyseal anchoring with the expected proximal, more physiological load transfer. This might minimize or exclude a stress shielding which might be associated with thigh pain, proximal bone loss and an increased risk of aseptic loosening. The MiniHipTM is a reliable partial-neck retaining prosthesis with good a clinical long-term outcome in younger as well as elderly patients.

Keywords: Primary hip arthroplasty; Long-term results; Short stem endoprothesis; Prospective follow-up study; Stress-shielding

Core tip: An innovative aspect of the MiniHipTM short stem prosthesis is that the design provides the possibility to restore the joint geometry by using an individual femoral neck cut. In general, there is an increasing demand for long-term results of newer arthroplasty systems. In contrast to other studies on short stems for hip replacement, this study was explicitly not only conducted in young and active patients. Therefore, this clinical and radiological long-term follow-up study is of particular interest. This study revealed an excellent and lasting clinical outcome, a reliable metaphyseal anchoring with a physiological proximal load transfer and an excellent long-term stem survivorship which is at least comparable to standard prostheses and other short stem concepts.