Comparative evaluation of novel hyper-supinated with standard radiographic views for thumb carpometacarpal and scaphotrapeziotrapezoid joints: An inter-rater analysis.

Introduction: Basal thumb osteoarthritis, encompasses degenerative arthropathy of the first carpometacarpal joint (CMCJ) and the scaphotrapezotrapezoidal joint (STTJ), is a prevalent condition that significantly impairs hand function. Complex orientation of these joints renders traditional radiographic assessments with anteroposterior (AP/True Robert's) and lateral views, prone to limitations in visualising peritrapezial joint spaces.The purpose of this study is to introduce a novel "hypersupinated view" and evaluates its efficacy in visualisation of peritrapezial joint spaces with implications in the clinical decision-making process. Patient and methods: A total of 26 patients with basal thumb pain underwent radiography of the thumb in three projections: AP, lateral and hypersupinated orientations. Two consultant orthopaedic hand surgeons independently evaluated the visual clarity of the CMCJ and STTJ on a 5-point Likert ordinal scale, with 1 being 'poor' and 5 being 'excellent' views. Inter-rater agreement was assessed using weighted Cohen's Kappa. Differences in ratings between views were analysed using Friedman and post-hoc Wilcoxon signed-rank tests. Results: For the first CMCJ, hypersupinated view ratings were highest (R1: 3.38, R2: 4.69), but inter-rater agreement was low (Kappa: 0.070). The AP view showed better agreement (Kappa: 0.160) despite slightly lower ratings (R1: 2.04, R2: 4.35). For the STTJ, the hypersupinated view again received the highest rating (R1: 2.38, R2: 4.62), while the AP view demonstrated the best agreement (Kappa: 0.460). Friedman tests showed significant differences for both raters for the first CMCJ and for rater 2 for the STTJ. Post-hoc tests confirmed that rater 1 preferred the hypersupinated view for first CMCJ, and rater 2 preferred hypersupinated and lateral views for STTJ. Conclusion: The hypersupinated view provides superior diagnostic detail for both joints though with reduced reproducibility between raters allowing better targeting to guide appropriate patient management.