Retrospective Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Dec 18, 2018; 9(12): 285-291
Published online Dec 18, 2018. doi: 10.5312/wjo.v9.i12.285
Socio-demographic factors impact time to discharge following total knee arthroplasty
Ugonna N Ihekweazu, Garrett H Sohn, Mitzi S Laughlin, Robin N Goytia, Vasilios Mathews, Gregory W Stocks, Anay R Patel, Mark R Brinker
Ugonna N Ihekweazu, Robin N Goytia, Vasilios Mathews, Gregory W Stocks, Anay R Patel, Mark R Brinker, Fondren Orthopedic Group, Houston, TX 77030, United States
Ugonna N Ihekweazu, Mitzi S Laughlin, Robin N Goytia, Vasilios Mathews, Gregory W Stocks, Anay R Patel, Mark R Brinker, Fondren Orthopedic Research Institute, Fondren Orthopedic Group, Houston, TX 77030, United States
Garrett H Sohn, Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX 77030, United States
Author contributions: Ihekweazu UN, Goytia RN, Mathews V, Stocks GW, Patel AR and Brinker MR contributed to the study conception and design; Ihekweazu UN, Goytia RN, Mathews V, Stocks GW and Patel AR contributed to the data acquisition and data interpretation; Laughlin MS contributed the data analysis, data interpretation and preparation of the tables and figures; Ihekweazu UN, Sohn GH and Laughlin MS contributed to the literature review and the writing of the article; all authors have approved this manuscript prior to submission and believe that this manuscript represents honest work.
Institutional review board statement: This study was evaluated and an IRB exemption was given for this work by the Texas Orthopedic Hospital’s IRB (TOH203e).
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data and the study was given an IRB exemption.
Conflict-of-interest statement: All authors declare no conflicts-of-interest related to this article but the following authors have financial relationships to report in general: Robin Goytia reports personal fees from Innomed, outside the submitted work; Gregory Stocks reports stock ownership from Nimbic Systems, Inc., outside the submitted work; Mark Brinker reports personal fees from Zimmer Biomet, outside the submitted work.
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:
Corresponding author to: Mitzi S Laughlin, PhD, Senior Researcher, Chief Scientist, Fondren Orthopedic Research Institute, Fondren Orthopedic Group, 7401 S. Main, Houston, TX 77030, United States.
Telephone: +1-713-7943408
Received: October 4, 2018
Peer-review started: October 4, 2018
First decision: October 29, 2018
Revised: November 6, 2018
Accepted: December 10, 2018
Article in press: December 10, 2018
Published online: December 18, 2018

To determine social, logistical and demographic factors that influence time to discharge in a short stay pathway (SSP) by following total knee arthroplasty (TKA).


The study included primary TKA’s performed in a high-volume arthroplasty center from January 2016 through December 2016. Potential variables associated with increased hospital length of stay (LOS) were obtained from patient medical records. These included age, gender, race, zip code, body mass index (BMI), number of pre-operative medications used, number of narcotic medications used, number of patient reported allergies (PRA), simultaneous bilateral surgery, tobacco use, marital status, living arrangements, distance traveled for surgery, employment history, surgical day of the week, procedure end time and whether the surgery was performed during a major holiday week. Multivariate step-wise regression determined the impact of social, logistical and demographic factors on LOS.


Eight hundred and six consecutive primary SSP TKA’s were included in this study. Patients were discharged at a median of 49 h (post-operative day two). The following factors increased LOS: Simultaneous bilateral TKA [46.1 h longer (P < 0.001)], female gender [4.3 h longer (P = 0.012)], age [3.5 h longer per ten-year increase in age (P < 0.001)], patient-reported allergies [1.1 h longer per allergy reported (P = 0.005)], later procedure end-times [0.8 h longer per hour increase in end-time (P = 0.004)] and Black or African American patients [6.1 h longer (P = 0.047)]. Decreased LOS was found in married patients [4.8 h shorter (P = 0.011)] and TKA’s performed during holiday weeks [9.4 h shorter (P = 0.011)]. Non-significant factors included: BMI, median income, patient’s living arrangement, smoking status, number of medications taken, use of pre-operative pain medications, distance traveled to hospital, and the day of surgery.


The cost of TKA is dependent upon LOS, which is affected by multiple factors. The clinical care team should acknowledge socio-demographic factors to optimize LOS.

Keywords: Total knee replacement, Total knee arthroplasty, Cost, Risk factors, Length of stay

Core tip: In an effort to decrease post-operative length of stay (LOS), many institutions continue to develop optimal discharge pathways. Since LOS is dependent upon many variables, we sought to define which socio-demographic factors influence LOS in total knee arthroplasty (TKA). Six factors were found to increase LOS: Age, gender, Black or African American race, simultaneous bilateral TKA, later procedure end times and number of PRA. Two factors decreased LOS, patient being married and surgery during a major public holiday week. While none of the patient specific factors are modifiable by the clinician, we do have the ability to optimize surgical schedule and allocation of resources.