Reduced revision rates with image-derived instrumentation in total shoulder arthroplasty : an analysis from the Australian Orthopaedic Association National Joint Replacement Registry.

Abstract

Image-derived instrumentation (IDI) can improve the accuracy of the positioning and alignment of the glenoid component in total shoulder arthroplasty (TSA), but it is unclear whether this technology has an effect on the clinical outcomes. The aim of this study was to compare the rates of revision TSA between procedures undertaken using IDI and those undertaken without technological assistance. Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) for two groups of primary TSA: TSA using IDI and those undertaken using standard instrumentation. The study period was between1 October 2013 (the date of the first use of IDI recorded in Australia) and 31 December 2022. Sub-group analyses were carried out for the type of primary TSA which was performed and for the glenoid morphology, using the Walch classification. Kaplan-Meier estimates of survival were used to report the time to revision. We compared rates of revision by Cox proportional hazard models adjusted for age and sex. A total of 7,424 IDIs and 44,896 primary TSAs without technological assistance were included. A total of 202 in the IDI group and 1,788 in the not technologically assisted (NTA) group were revised with a cumulative percent revision (CPR) of 4.2% (95% CI 3.6 to 5.0) and 5.2% (95% CI 5.0 to 5.5), respectively, at seven years postoperatively. The rate of revision was significantly lower in the IDI group compared with the NTA group (entire period hazard ratio 0.84, 95% CI 0.73 to 0.98; p = 0.023). The revision rate was lower for early (≤ three months) instability or dislocation, but not > three months, for loosening in reverse-stemmed TSAs. The use of IDI did not significantly change the rates of revision for anatomical stemmed and stemless TSAs, or with sub-group analysis by the grade of glenoid morphology. Primary TSA performed using IDI had a reduced mid-term revision rate compared with when undertaken without technological assistance. This difference was significant for reverse TSA, with a lower revision rate for all revisions and early revision for instability or dislocation, but not for anatomical TSA.