Observational Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Mar 18, 2020; 11(3): 167-176
Published online Mar 18, 2020. doi: 10.5312/wjo.v11.i3.167
Observational study of a new modular femoral revision system
Karen Dyreborg, Michael Mørk Petersen, Sidse Schwartz Balle, Anne Grete Kjersgaard, Søren Solgaard
Karen Dyreborg, Anne Grete Kjersgaard, Søren Solgaard, Department of Orthopaedic Surgery, Herlev-Gentofte Hospital, 2900 Hellerup, Denmark
Michael Mørk Petersen, Department of Orthopaedic Surgery, Rigshospitalet, 2100 København, Denmark
Sidse Schwartz Balle, Department of Diagnostic Radiology, Herlev-Gentofte Hospital, 2900 Hellerup, Denmark
Author contributions: Dyreborg K, Petersen MM, Kjersgaard AG, Solgaard S designed the research; Dyreborg K, Balle SS, Kjersgaard AG, Solgaard S performed the research; Dyreborg K, Petersen MM, Solgaard S analyzed the data; Dyreborg K, Petersen MM, Balle SS, Kjersgaard AG, Solgaard S wrote the paper.
Supported by the Zimmer Biomet, No. C004287.
Institutional review board statement: This study was reviewed and approwed by the National Patient Safety Authority of Denmark (Case number 3-3013-1695/1/) and by the Data Protection Agency of the Capital region in Denmark (number HGH-2016-021, I-Suite number.: 04437).
Informed consent statement: All study participants or their legal guardian provided informed written consent about personal and medical data collection prior to study enrolment.
Conflict-of-interest statement: Dr. Petersen reports grants from Zimmer Biomet during the conduct of the study. All other authors have no conflict of interests related to the manuscript.
Data sharing statement: No additional data are available since the research data is confidential according to Danish law when no consent for data sharing has been obtained.
STROBE statement: The authors have read the STROBE Statement-checklist, and the manuscript was prepared and revised accordingly.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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/
Corresponding author: Karen Dyreborg, MD, Research Scientist, Surgeon, Department of Orthopedic Surgery, Herlev-Gentofte Hospital, Kildegårdsvej 28, 2900 Hellerup, Denmark. karendyreborg@hotmail.com
Received: November 11, 2019
Peer-review started: November 11, 2019
First decision: November 22, 2019
Revised: December 2, 2019
Accepted: March 1, 2020
Article in press: March 1, 2020
Published online: March 18, 2020
Processing time: 126 Days and 18.4 Hours
Abstract
BACKGROUND

The uncemented ArcosTM Modular Femoral Revision System (ARCOS) is a new comprehensive, press-fit revision design. The modular design offers a wide range of possible combinations to accommodate different variations of anatomy and bone stock. The ARCOS is made by a proximal body and a distal stem. As probably the only ones worldwide we predominantly use a combination of body and stem which supports proximal fixation and load, since this mimics the concept of the primary total hip arthroplasty with proximal weight-bearing, leading to bone stock preservation and no stress shielding or thigh pain.

AIM

To evaluate the early results after femoral revision in a consecutive series of patients undergoing surgery over 3 years.

METHODS

We included 116 patients in the study. They were operated in the period August 2011 to December 2014 and we got a clinical mean observation time of 4 (0.5-6) years. Clinical and radiographical follow-up included present function of the hip assessed by Harris Hip Score, Oxford Hip Score, and EQ5D (measure of health outcome). Of the 116 patients, 17 died in the interim and were consequently included only in the implant survivorship analysis; 46 patients attended the follow-up control.

RESULTS

In total 6 (5%) hips were re-revised due to infection (n = 3), fracture (n = 2) or subsidence (n = 1). No patient was re-revised due to aseptic loosening. The 1-, 2- and 5-year probability of implant survival (95%CI) were 97% (93%-100%), 97% (93%-100%) and 96% (92%-99%), respectively. In this cohort 95 patients received a combination of a proximal broach and a distal curved and slotted stem (BS), aiming for proximal fixation and load bearing; 21 patients received a different combination. When comparing these two groups the BS-group had a 5-year implant survival probability (95%CI) of 97% (93%-100%) compared with the group of other combinations with a 5-year implant survival probability (95%CI) of 90% (78%-100%) (P = 0.3). Our regression analysis showed that periprosthetic fracture as an indication for the ARCOS operation was the only significant negative outcome predictor. The mean Harris Hip Score result (100 points being best) was 83 (range 5-98). The mean Oxford Hip Score result (48 points being best) was 40 (range 19-48).

CONCLUSION

The early results of the ARCOS are promising compared with similar studies. We encourage the use of the BS combination whenever the bone stock proximally is adequate.

Keywords: Hip prosthesis; Arthroplasty; Implantation; Replacement arthroplasty; Total hip replacements; Modular femoral stem

Core tip: The ArcosTM Modular Femoral Revision System is a new comprehensive, press-fit revision design. We have evaluated the early results after femoral revision in a consecutive series of 116 patients in a period of three years. This is a fairly large cohort when dealing with arthroplasty reoperations and the special feature of our cohort is that we use a combination of implant-modules which strives for proximal load bearing and fixation, mimicking the concept of the primary hip replacements.