Reproducibility of a new method for measuring lowering and medialisation of the humerus after reverse shoulder arthroplasty
Axel Marcoin, Antoine Ferrier, Laurent Blasco, Paul De Boissieu, Cécile Nerot, Xavier OhlShoulder
Background
Reverse shoulder arthroplasty (RSA) requires lowering the humerus and medialisation of the centre of rotation. Several techniques based on standard X-rays are available in the literature. The aim of this study was to expose and validate a new technique for measuring these parameters.
Materials and methods
Radiographic data of 20 patients were included. Three observers examined each X-rays three times to establish the inter- and intra-reproducibility of each technique (Jobin, Renaud and our method).
Results
Intra-observer reproducibility was between 0.10 and 0.94. The best intra-observer intraclass correlation coefficient (ICC) was obtained using Renaud’s and our techniques. The inter-observer reproducibility was between 0.37 and 0.74. The best inter-observer ICC was obtained with our technique.
Discussion
We describe a reliable and reproducible method to evaluate lowering and medialisation of the humerus after RSA. This technique may allow determine the optimal threshold of lengthening after RSA.
Link to article