Case Control Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Dec 18, 2017; 8(12): 895-901
Published online Dec 18, 2017. doi: 10.5312/wjo.v8.i12.895
Season of the year influences infection rates following total hip arthroplasty
Samuel Rosas, Alvin C Ong, Leonard T Buller, Karim G Sabeh, Tsun yee Law, Martin W Roche, Victor H Hernandez
Samuel Rosas, Department of Orthopedic Surgery, Wake Forest School of Medicine, Winston-Salem, NC 27101, United States
Samuel Rosas, Tsun yee Law, Holy Cross Orthopedic Institute, Fort Lauderdale, FL 33334, United States
Alvin C Ong, Orthopedic Surgery, Thomas Jefferson University Hospital, Egg Harbor Town, NJ 08234, United States
Leonard T Buller, Karim G Sabeh, Tsun yee Law, Victor H Hernandez, Department of Orthopedics Surgery, University of Miami, Miami, FL 33136, United States
Martin W Roche, Department of Orthopaedic Surgery, Holy Cross Hospital, Fort Lauderdale, FL 33316, United States
Author contributions: All of the authors contributed significantly to the data analysis and writing of this article.
Institutional review board statement: No IRB approval was required as this project utilized no patient identifying data as the data are extracted from a HIPAA compliant database.
Informed consent statement: This study was conducted by utilizing the PearlDiver Supercomputer. This allows the researchers to conduct research without requiring patient specific information and thus no informed consent was required.
Conflict-of-interest statement: None of the authors report any conflict of interest with this article.
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: Samuel Rosas, MD, Postdoctoral Fellow, Department of Orthopedic Surgery, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27101, United States. srosas@wakehealth.edu
Telephone: +1-336-7163950 Fax: +1-336-7167310
Received: August 17, 2017
Peer-review started: August 16, 2017
First decision: October 9, 2017
Revised: October 11, 2017
Accepted: November 22, 2017
Article in press: November 22, 2017
Published online: December 18, 2017
ARTICLE HIGHLIGHTS
Research background

Limited information is available in regard to the correlation between season of the year when a surgery is performed to the outcomes of the surgery. Weather variations may account for different bacterial patterns that may lead to infection. Thus, we studied the effects of season of the year on the infectious outcomes after total hip arthroplasty in the United States Medicare patient population.

Research motivation

Due to the large effect on morbidity, mortality and cost that infections can cause, it is important to study modifiable and non-modifiable risk factors for adverse outcomes after surgery. By identifying a seasonal variation in post-operative outcomes, one may ultimately use this information to delay elective surgery.

Research objectives

The purpose of this study was to determine if season of the year when a total hip arthroplasty is performed had an effect on 90-d post-operative superficial and deep infections among Medicare beneficiaries in the United States. The study identified certain seasonal differences that should promote research on this subject through prospective studies.

Research methods

The authors conducted a retrospective review of the entire Medicare files and stratified patients by region and season when the surgery was performed. The authors evaluated the 90-d post-operative period after the procedure to determine the incidence of these complications. The authors analyzed the entire Medicare records from 2005 to 2014. Comparative statistical analysis was used to compare the 90-d incidences reported by international classification of disease 9th edition code tracked in the patient file.

Research results

There was a significant difference in the incidence of acute postoperative infections by season in the West. The greatest incidence in this region (West) was following surgeries performed in the summer (1.59%), which was significantly greater than all other seasons (P < 0.001 for all). Our analysis demonstrated that season of the year had a significant effect on periprosthetic joint infections in two out of the four regions, Midwest and South. These results help demonstrate that variation exists in certain regions of the United States by season of the year and that more research is needed on this non-modifiable risk factor.

Research conclusions

There were no previous articles in the literature describing seasonal variation of outcomes after lower extremity arthroplasty. The new findings of this study is: Season of the year may influence post-operative outcomes after total hip arthroplasty. This study proposes the new theories that seasonal variation of these outcomes varies and that the seasonal variability between superficial infection and peri-prosthetic infection exists. This study offered the original insights into the current knowledge by providing evidence that there is regional and seasonal variation in outcomes. This study proposed the new hypotheses that temperature and weather variations may lead to different infectious complications after hip arthroplasty. The authos proposed the new methods that prospective trials to investigate the effect of not only season of the year when the surgery is performed affect the outcomes but also weather. We found the new phenomena that certain regions of the United States have different post-operative complication rates of infectious outcomes after THA when stratified by season of the year when the surgery was performed. Through experiments in this study, the authors confirmed the hypotheses that seasonal variation exists in infectious outcomes after THA in certain regions of the United States. In the future, non-modifiable risk factors may play a role in the outcome of THA such as season of the year when the surgery is performed.

Research perspectives

Season of the year when surgery is performed may have an effect on complication rates after THA. Future studies should create models that account for weather and seasonal variations in the study of outcomes after arthroplasty procedures.