Hemiarthroplasty in patients aged 50-65 years old: In-vitro assessment of prosthetic materials and rotator cuff status on glenoid wear
File(s)
Author(s)
Mahmud, Hazimah
Type
Thesis
Abstract
Hemiarthroplasty offers bone-sparing, minimally invasive surgery, advantageous for patients aged 65 years or younger who may require early revisions due to increased physical demands. Despite these advantages, the use of hemiarthroplasty is declining in favour of total shoulder arthroplasties, possibly due to its high revision rate, commonly caused by painful glenoid erosion. Thus, this thesis aimed to identify factors that could potentially reduce glenoid wear, a phenomenon that may be related to joint pain in shoulder hemiarthroplasty, specifically focusing on implant materials and subscapularis status resulting from surgery.
Glenoid wear in humeral hemiarthroplasty was assessed using a dedicated six-station shoulder wear simulator to simulate ‘washing the opposite axilla’ for 500,000 cycles. The wear tests conducted in this thesis did not find statistically significant evidence that a ceramic humeral head in shoulder hemiarthroplasty, bearing against healthy glenoid articular cartilage, causes less cartilage wear than a conventional metal humeral head. In contrast, total subscapularis dysfunction, which increased the posterior glenohumeral joint force by ~60% and reduced the force-related joint stability by ~30%, as investigated using a musculoskeletal shoulder model, resulted in more severe glenoid wear. This effect was particularly notable in female shoulders, which may be related to their smaller size and the associated lower joint stability.
Measurements of cartilage wear in hemiarthroplasty using Magnetic Resonance Imaging (MRI) have been challenging due to metal-related artefacts, which are not a concern for ceramic implants. Cartilage wear measurements using MRI with ceramic implants showed agreement within clinically useful limits with high-resolution micro-Computed Tomography (microCT), thus demonstrating the promising in-vivo application of MRI for monitoring cartilage wear rate with ceramic implants.
This thesis established in-vitro wear testing for shoulder hemiarthroplasty to assess the factors that influence glenoid wear. This methodology could also be applied to native joints and other hemiarthroplasties, such as hip joints.
Glenoid wear in humeral hemiarthroplasty was assessed using a dedicated six-station shoulder wear simulator to simulate ‘washing the opposite axilla’ for 500,000 cycles. The wear tests conducted in this thesis did not find statistically significant evidence that a ceramic humeral head in shoulder hemiarthroplasty, bearing against healthy glenoid articular cartilage, causes less cartilage wear than a conventional metal humeral head. In contrast, total subscapularis dysfunction, which increased the posterior glenohumeral joint force by ~60% and reduced the force-related joint stability by ~30%, as investigated using a musculoskeletal shoulder model, resulted in more severe glenoid wear. This effect was particularly notable in female shoulders, which may be related to their smaller size and the associated lower joint stability.
Measurements of cartilage wear in hemiarthroplasty using Magnetic Resonance Imaging (MRI) have been challenging due to metal-related artefacts, which are not a concern for ceramic implants. Cartilage wear measurements using MRI with ceramic implants showed agreement within clinically useful limits with high-resolution micro-Computed Tomography (microCT), thus demonstrating the promising in-vivo application of MRI for monitoring cartilage wear rate with ceramic implants.
This thesis established in-vitro wear testing for shoulder hemiarthroplasty to assess the factors that influence glenoid wear. This methodology could also be applied to native joints and other hemiarthroplasties, such as hip joints.
Version
Open Access
Date Issued
2024-04-01
Date Awarded
01/09/2024
Advisor
Ulrich, Hansen
Peter, Reilly
Sponsor
Orthopaedics Research (Charity)
Mathys Ltd (Firm)
Universiti Brunei Darussalam
Grant Number
Project 539
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)