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.
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.
Authors: Charles M Jobin; Gabriel D Brown; Maher J Bahu; Thomas R Gardner; Louis U Bigliani; William N Levine; Christopher S Ahmad Journal: J Shoulder Elbow Surg Date: 2011-11-06 Impact factor: 3.019