Related Experiment Video
Updated: Jul 15, 2026
07:43
In Vivo Quantification of Hip Arthrokinematics during Dynamic Weight-bearing Activities using Dual Fluoroscopy
Published on: July 2, 2021
Association between dislocation, impingement, and articular geometry in retrieved acetabular polyethylene cups
Hiromasa Tanino1, Melinda K Harman, Scott A Banks
1Orthopaedic Research Laboratory, The BioMotion Foundation, PO Box 248, Palm Beach, Florida 33480-0248, USA.
Summary
This study found no direct link between impingement damage and dislocation in retrieved polyethylene liners. However, deeper liner designs may reduce early dislocation rates, regardless of impingement.
Area of Science:
- Orthopedic Surgery
- Biomaterials Science
- Medical Device Analysis
Background:
- Dislocation is a common complication following hip arthroplasty.
- Polyethylene liner geometry and impingement are suspected contributors to dislocation.
- Understanding these relationships is crucial for improving implant design and patient outcomes.
Purpose of the Study:
- To investigate the relationship between impingement damage, dislocation history, and polyethylene liner geometry in retrieved acetabular liners.
- To characterize geometric parameters of liners associated with impingement and dislocation.
- To identify design features that may mitigate dislocation risk.
Main Methods:
- A novel analysis technique was applied to 48 retrieved acetabular polyethylene liners.
- Liners were assessed for peripheral rim damage indicative of impingement.
- Liner articular geometry was measured using a digital stylus, quantifying lip height, head center inset, and head penetration.
Main Results:
- Thirteen liners (27%) exhibited impingement damage, and 12 (25%) had a history of dislocation.
- No significant difference in impingement prevalence was found between dislocated and stable liners.
- Dislocated liners showed significantly less head center inset and head penetration, attributed to shorter functional duration.
Conclusions:
- Impingement damage was not significantly associated with dislocation history in this cohort.
- Polyethylene liner geometry parameters (lip height, head center inset, head penetration) did not differ significantly between impinged and non-impinged liners.
- Designing liners with a deeper articular surface (>0.95 mm) may reduce early dislocation prevalence, independent of impingement damage.