A Multi-factor Analysis of Revision in Total Hip Replacement Using the Collarless-Polished-Tapered Stems with Different Cups

Abstract

Objective: Collarless-polished-tapered (CPT) stems have been widely used in total hip replacement (THR). Given that various types of cups are combined with CPT in clinical practice, however, what cup type performs the best for use with CPT is still unclear. This study aimed to investigate the effects of three types of commonly used cups with CPT on revision and survival life using multi-factor analysis.

Methods: This study is a cohort study using the data between October 1998 to September 2021. The data of THR patients with ZCA All-poly Acetabular Cup, Continuum Acetabular System, and Trilogy Acetabular System with CPT were collected from several hospitals in the UK. The patients aged from 20 to 97 (n = 5981, 2345 male and 3636 female). Age, gender, body mass index, diagnosis, surgeon grade, cup material, cup size, surgical approach, survival life, complications, and Harris hip scores (HHS) were analyzed in relation to revision status. SPSS statistical software was used to analyze the relationship among various factors. The main statistical methods included chi-square with cross tables, analysis of variance (ANOVA) and survival analysis.

Results: The results in relation to HHS shows that the continuum cup has the best outcome in the postoperative period of 1 and 5 years (1 year = 90.7, 5 years = 91.3; P < 0.001); the Trilogy cup was the second (1 year = 88.4, 5 years = 87.3; P < 0.001); and the ZCA cup was the third (1 year = 84.6, 5 years = 82.4; P < 0.001). However, the Trilogy cup performed the best regarding survival life on revision while the Continuum cup was the worst.

Conclusion: When the CPT stem is combined with different cups, the trilogy cup shows the best characteristics in terms of survival trends with revision ratios compared with the continuum and ZCA cups, and is therefore recommended by this study.

Keywords: Implant combination; Multi-factors; Revision; The CPT implant; The Trilogy implant; Total hip replacement.