Increasing reaming depth enhances implant stability whilst minimizing bone strain
File(s)
Published version
Author(s)
Karia, Monil
Doyle, Ruben
Reynolds, Adam
Jeffers, Jonathan
Cobb, Justin
Type
Journal Article
Abstract
Aims
Increasing the interference fit of the acetabular component can increase primary stability, but it introduces excessive periacetabular strain during impaction, which can lead to fractures. An optimal outcome following cementless acetabular component impaction is maximal primary implant stability with minimal periacetabular bone strain. The aim of this study was to investigate whether a simple modification to a surgeon’s reaming technique can achieve this desirable outcome.
Methods
A custom drop rig simulated impaction strikes, seating acetabular components of either 1 mm or 2 mm interference fit into synthetic sawbones with cavities reamed to either a true hemisphere or a hemisphere with an enhanced reaming depth of 2 mm or 4 mm. Synthetic bone strain was recorded using strain gauges, and push-out tests were conducted to assess implant stability. Polar gaps were measured using optimal trackers.
Results
Compared to a true hemispherical cavity, enhancing the reaming depth significantly increased the primary stability of the implant (p < 0.001) while reducing both the periacetabular strain and strain deterioration for both 1 mm and 2 mm interference fit components. A 4 mm reaming depth enhanced the primary stability of 1 mm press-fit components to a level almost equivalent to a 2 mm press-fit, albeit reducing strain to the bone. Enhancing reaming depth did not significantly affect polar gap.
Conclusion
Enhancing cavity reaming depth is a simple technique to increase the implant primary stability of press-fit uncemented acetabular components, while avoiding any excess in periacetabular strain and the associated fracture risk.
Increasing the interference fit of the acetabular component can increase primary stability, but it introduces excessive periacetabular strain during impaction, which can lead to fractures. An optimal outcome following cementless acetabular component impaction is maximal primary implant stability with minimal periacetabular bone strain. The aim of this study was to investigate whether a simple modification to a surgeon’s reaming technique can achieve this desirable outcome.
Methods
A custom drop rig simulated impaction strikes, seating acetabular components of either 1 mm or 2 mm interference fit into synthetic sawbones with cavities reamed to either a true hemisphere or a hemisphere with an enhanced reaming depth of 2 mm or 4 mm. Synthetic bone strain was recorded using strain gauges, and push-out tests were conducted to assess implant stability. Polar gaps were measured using optimal trackers.
Results
Compared to a true hemispherical cavity, enhancing the reaming depth significantly increased the primary stability of the implant (p < 0.001) while reducing both the periacetabular strain and strain deterioration for both 1 mm and 2 mm interference fit components. A 4 mm reaming depth enhanced the primary stability of 1 mm press-fit components to a level almost equivalent to a 2 mm press-fit, albeit reducing strain to the bone. Enhancing reaming depth did not significantly affect polar gap.
Conclusion
Enhancing cavity reaming depth is a simple technique to increase the implant primary stability of press-fit uncemented acetabular components, while avoiding any excess in periacetabular strain and the associated fracture risk.
Date Issued
2025-06-19
Date Acceptance
2025-02-25
Citation
Bone & Joint Research, 2025, 14 (6), pp.551-559
ISSN
2046-3758
Publisher
The British Editorial Society of Bone & Joint Surgery
Start Page
551
End Page
559
Journal / Book Title
Bone & Joint Research
Volume
14
Issue
6
Copyright Statement
© 2025 Karia et al. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (CC BY-NC-ND 4.0) licence, which permits the copying and redistribution of the work only, and provided the original author and source are credited. See https://creativecommons.org/licenses/by-nc-nd/4.0/
Publication Status
Published
Date Publish Online
2025-06-19