A Lädermann1, B V Stimec2, P J Denard3, G Cunningham4, P Collin5, J H D Fasel2. 1. Division of Orthopedics and Trauma Surgery, La Tour Hospital, 3, rue J.-D.-Maillard, 1217 Meyrin, Switzerland; Faculty of Medicine, University of Geneva, 1, rue Michel-Servet, 1211 Geneva 4, Switzerland; Division of Orthopedics and Trauma Surgery, Department of Surgery, Geneva University Hospitals, 4, rue Gabrielle-Perret-Gentil, 1211 Geneva 21, Switzerland. Electronic address: alexandre.laedermann@latour.ch. 2. Faculty of Medicine, Department of Cellular Physiology and Metabolism, Anatomy Sector, University of Geneva, 1, rue Michel-Servet, 1211 Geneva 4, Switzerland. 3. Southern Oregon Orthopedics, Medford, Oregon, USA; Department of Orthopedics and Rehabilitation, Oregon Health & Science University, Portland, Oregon, USA. 4. Division of Orthopedics and Trauma Surgery, Department of Surgery, Geneva University Hospitals, 4, rue Gabrielle-Perret-Gentil, 1211 Geneva 21, Switzerland. 5. Saint-Grégoire Private Hospital Center, 6, boulevard Boutière, 35768 Saint-Grégoire cedex, France.
Abstract
BACKGROUND: Subclinical neurological lesions after reverse shoulder arthroplasty are frequent, mainly those involving the axillary nerve. One of the major reported risk factors is postoperative lengthening of the arm. The purpose of this study was to evaluate the anatomical relationship between the axillary nerve and prosthetic components after reverse shoulder arthroplasty. The study hypothesis was that inferior overhang of the glenosphere relative to glenoid could put this nerve at risk. MATERIAL AND METHODS: Eleven fresh frozen shoulder specimens were dissected after having undergone reverse shoulder arthroplasty using a classic deltopectoral approach. RESULTS: The mean distance from the inferior border of the glenoid to the inferior edge of the glenosphere was 6.0±4.3mm (range, 1.0 to 16.2mm). The axillary nerve was never closer than 15mm to the glenosphere. The main anterior branch of the axillary nerve was in close contact with the posterior metaphysis or humeral prosthetic implant. The mean distance between the nerve and the humeral implants was 5.2±2.1mm (range, 2.0 to 8.1mm). CONCLUSIONS: The proximity of the axillary nerve to the posterior metaphysis or humeral implants may be a risk factor for axillary nerve injury after reverse shoulder arthroplasty. CLINICAL RELEVANCE: This study quantifies the proximity of the axillary nerve to the implant after reverse shoulder arthroplasty. LEVEL OF EVIDENCE: Basic science study, cadaver study.
BACKGROUND: Subclinical neurological lesions after reverse shoulder arthroplasty are frequent, mainly those involving the axillary nerve. One of the major reported risk factors is postoperative lengthening of the arm. The purpose of this study was to evaluate the anatomical relationship between the axillary nerve and prosthetic components after reverse shoulder arthroplasty. The study hypothesis was that inferior overhang of the glenosphere relative to glenoid could put this nerve at risk. MATERIAL AND METHODS: Eleven fresh frozen shoulder specimens were dissected after having undergone reverse shoulder arthroplasty using a classic deltopectoral approach. RESULTS: The mean distance from the inferior border of the glenoid to the inferior edge of the glenosphere was 6.0±4.3mm (range, 1.0 to 16.2mm). The axillary nerve was never closer than 15mm to the glenosphere. The main anterior branch of the axillary nerve was in close contact with the posterior metaphysis or humeral prosthetic implant. The mean distance between the nerve and the humeral implants was 5.2±2.1mm (range, 2.0 to 8.1mm). CONCLUSIONS: The proximity of the axillary nerve to the posterior metaphysis or humeral implants may be a risk factor for axillary nerve injury after reverse shoulder arthroplasty. CLINICAL RELEVANCE: This study quantifies the proximity of the axillary nerve to the implant after reverse shoulder arthroplasty. LEVEL OF EVIDENCE: Basic science study, cadaver study.
Authors: Michael E Hachadorian; Brendon C Mitchell; Matthew Y Siow; Wilbur Wang; Tracey Bastrom; T Barrett Sullivan; Brady K Huang; Eric W Edmonds; William T Kent Journal: JSES Int Date: 2020-07-25