Are Some Neutral Liners More Neutral Than Others? An Ex Vivo Morphological Analysis of Acetabular Liners Classified As "neutral"

Overview

Journal Acta Orthop

Specialty Orthopedics

Date 2024 Oct 11

PMID 39392408

Authors

Jose A Ochoa

Perttu S Neuvonen

Jari Hyttinen

Jari Viik

Antti P Eskelinen

Affiliations

Soon will be listed here.

Abstract

Background And Purpose: In contemporary total hip replacement (THR), dislocation is one of the most common complications. At our institution, the cause of an increase in the dislocation rate was recently reported to be reduced head coverage of a newly introduced neutral liner. We therefore aimed to ascertain whether differences exist in articulating head coverage between the various neutral liners used in contemporary THR. A secondary aim was to utilize coverage measurements to develop a new liner coverage classification.

Methods: The articulating head coverage of 25 modular neutral polyethylene liners used in 6 uncemented cup designs from 4 major manufacturers was evaluated. The measurements were performed in a metrology laboratory and a mathematical model was developed to calculate coverage of the articulating surfaces. Further, 1 "elevated rim" liner and 1 "face changing liner" were included to develop a new liner coverage classification.

Results: The articulating head coverage among the studied liners ranged from 167.7° to 194.8°, corresponding to a variation of 27.1°. The variations with different cup and head sizes within each design were smaller (from 1.0° to 5.6°) than those between different designs. Each of the liner designs offered distinct coverage, even though they were all classified as neutral. Based on measurements, a set of descriptive parameters to discriminate different liners in terms of coverage was created.

Conclusion: We showed that all neutral liners are not equal - instead, they clearly varied in terms of their actual coverage design. We suggest our set of descriptive parameters called "hemispheric coverage index values" be used in discriminating the differences in liner coverage.

References

Ezquerra L, Quilez M, Perez M, Albareda J, Seral B . Range of Movement for Impingement and Dislocation Avoidance in Total Hip Replacement Predicted by Finite Element Model. J Med Biol Eng. 2017; 37(1):26-34. PMC: 5325855. DOI: 10.1007/s40846-016-0210-4. View

Lu Y, Xiao H, Xue F . Causes of and treatment options for dislocation following total hip arthroplasty. Exp Ther Med. 2019; 18(3):1715-1722. PMC: 6676097. DOI: 10.3892/etm.2019.7733. View

Goel A, Lau E, Ong K, Berry D, Malkani A . Dislocation rates following primary total hip arthroplasty have plateaued in the Medicare population. J Arthroplasty. 2015; 30(5):743-6. DOI: 10.1016/j.arth.2014.11.012. View

Scifert C, Brown T, Pedersen D, Callaghan J . A finite element analysis of factors influencing total hip dislocation. Clin Orthop Relat Res. 1999; (355):152-62. DOI: 10.1097/00003086-199810000-00016. View

Brien W, Salvati E, Wright T, Burstein A . Dislocation following THA: comparison of two acetabular component designs. Orthopedics. 1993; 16(8):869-72. DOI: 10.3928/0147-7447-19930801-04. View

Sariali E, Lazennec J, Khiami F, Catonne Y . Mathematical evaluation of jumping distance in total hip arthroplasty: influence of abduction angle, femoral head offset, and head diameter. Acta Orthop. 2009; 80(3):277-82. PMC: 2823207. DOI: 10.3109/17453670902988378. View

Tanino H, Harman M, Banks S, Hodge W . Association between dislocation, impingement, and articular geometry in retrieved acetabular polyethylene cups. J Orthop Res. 2007; 25(11):1401-7. DOI: 10.1002/jor.20410. View

Bozic K, Kurtz S, Lau E, Ong K, Vail T, Berry D . The epidemiology of revision total hip arthroplasty in the United States. J Bone Joint Surg Am. 2009; 91(1):128-33. DOI: 10.2106/JBJS.H.00155. View

Schairer W, Sing D, Vail T, Bozic K . Causes and frequency of unplanned hospital readmission after total hip arthroplasty. Clin Orthop Relat Res. 2013; 472(2):464-70. PMC: 3890213. DOI: 10.1007/s11999-013-3121-5. View

10.

Hermansen L, Iversen T, Iversen P, Viberg B, Overgaard S . The "true" 1-year incidence of dislocation after primary total hip arthroplasty: validation of an algorithm identifying dislocations in the Danish National Patient Register based on 5,415 patients from the Danish Hip Arthroplasty Register. Acta Orthop. 2024; 95:380-385. PMC: 11253031. DOI: 10.2340/17453674.2024.41064. View

11.

Griffin W, Nanson C, Springer B, Davies M, Fehring T . Reduced articular surface of one-piece cups: a cause of runaway wear and early failure. Clin Orthop Relat Res. 2010; 468(9):2328-32. PMC: 2919889. DOI: 10.1007/s11999-010-1383-8. View

12.

Behery O, Long W . The prevalence of elevated-rim polyethylene liner use in primary total hip arthroplasty in the New York State metropolitan area. Arthroplast Today. 2019; 5(4):486-488. PMC: 6921167. DOI: 10.1016/j.artd.2019.10.002. View

13.

Pakarinen O, Neuvonen P, Reito A, Eskelinen A . Increased risk for dislocation after introduction of the Continuum cup system: lessons learnt from a cohort of 1,381 THRs after 1-year follow-up. Acta Orthop. 2020; 91(3):279-285. PMC: 8023946. DOI: 10.1080/17453674.2020.1744981. View