Retrospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Nov 18, 2021; 12(11): 859-866
Published online Nov 18, 2021. doi: 10.5312/wjo.v12.i11.859
Anthropometric method for estimating component sizes in total hip arthroplasty
Rajpreet Sahemey, Thomas S Moores, Hannah Meacher, Bishoy Youssef, Shehzaad Khan, Christopher R Evans
Rajpreet Sahemey, Department of Trauma and Orthopaedics, University Hospitals Coventry and Warwickshire, Coventry CV2 2DX, United Kingdom
Thomas S Moores, Department of Trauma and Orthopaedics, Walsall Manor Hospital, Walsall WS2 9PS, United Kingdom
Hannah Meacher, Bishoy Youssef, Department of Trauma and Orthopaedics, Royal Stoke University Hospital, Stoke-on-Trent ST4 6QG, United Kingdom
Shehzaad Khan, Department of Trauma and Orthopaedics, Royal National Orthopaedic Hospital, Stanmore HA7 4LP, United Kingdom
Christopher R Evans, Department of Orthopaedics, The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry SY10 7AG, United Kingdom
Author contributions: Sahemey R, Moores TS, Youssef B, Khan S and Evans CR designed and coordinated the study; Sahemey R, Moores TS, Meacher H and Khan S performed the experiments, acquired and analysed the data; Sahemey R and Moores TS wrote the manuscript; all authors approved the final version of this article.
Institutional review board statement: Institutional Review Board approval was not required in accordance with National Research Ethics Service (United Kingdom) guidance on the use of anonymised data collected retrospectively as part of routine clinical care.
Informed consent statement: Informed consent was waived. This retrospective study involves no more than minimal risk to the participants.
Conflict-of-interest statement: The authors declare that there are no conflicts of interest relevant to this article.
Data sharing statement: No additional data are available.
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: Rajpreet Sahemey, BSc, MBBS, Surgeon, Department of Trauma and Orthopaedics, University Hospitals Coventry and Warwickshire, UHCW, Clifford Bridge Road, Coventry CV2 2DX, United Kingdom. rajpreet.s@gmail.com
Received: May 26, 2021
Peer-review started: May 26, 2021
First decision: July 27, 2021
Revised: August 14, 2021
Accepted: September 15, 2021
Article in press: September 15, 2021
Published online: November 18, 2021
Abstract
BACKGROUND

Preoperative templating is essential in total hip arthroplasty (THA) as it not only helps to facilitate the correct implant type and size but also determines the post-operative biomechanics. Templating is also increasingly important from a medico-legal perspective and recommended in the British Orthopaedic Association Guide to Good Practice. Although templating has become increasingly digitised, there are no simple anthropometric models to predict implant sizes in the absence of digital methods.

AIM

To assess the accuracy of using an easily obtainable measurement (shoe size) to predict component sizes in THA compared with digital templating.

METHODS

Digital radiographs from a cohort of 102 patients (40 male, 62 female) who had undergone uncemented or hybrid THA at a single centre were retrospectively templated to desired cup and stem sizes using TraumaCad®. We compared the templated size to the actual size of the implant and assessed if there was any correlation with the patient’s shoe size.

RESULTS

Statistically significant positive correlations were observed between: shoe size and templated cup size (ρ = 0.92, P < 0.001); shoe size with implanted cup size (ρ = 0.71, P < 0.001); shoe size and templated stem size (ρ = 0.87, P < 0.001); and shoe size with implanted stem size (ρ = 0.57, P < 0.001). Templated and implanted acetabular cup sizes were positively correlated (ρ = 0.76, P < 0.001) and were exact in 43.1% cases; 80.4% of implanted cup sizes were within 1 size (+/- 2 mm) of the template and 100% within 2 sizes (+/- 4 mm). Positive correlation was also demonstrated between templated and implanted femoral stem sizes (ρ = 0.69, P < 0.001) and were exact in 52.6% cases; 92.6% were within 1 size of the template and 98% within 2 sizes.

CONCLUSION

This study has shown there to be a significant positive correlation between shoe size and templated size. Anthropometric measurements are easily obtainable and can be used to predict uncemented component sizes in the absence of digital methods.

Keywords: Anthropometric, Digital templating, Hip, Preoperative planning, Total hip arthroplasty

Core Tip: Templating for component size in total hip arthroplasty is becoming increasingly digitised, which can be limited by cost and availability of software. There are no anthropometric models to predict component sizes in the absence of digital methods. We demonstrated significant positive correlations between a patient’s shoe size and both their templated and implanted component sizes. Shoe size can reliably predict implant sizes in uncemented hip arthroplasty. In addition to helping the surgeon make a rapid estimation of implant size; this simple system can also assist purchasing departments to plan preoperative stock requirements without specialised software.