Axillary View: Arthritic Glenohumeral Anatomy and Changes After Ream and Run

Abstract

The technique and results of shoulder arthroplasty are influenced by glenohumeral pathoanatomy. Although some authors advocate a routine preoperative CT scan to define this anatomy, ordering a CT scan substantially increases the cost and the radiation exposure for the patient. We asked whether measurements of arthritic shoulders on a standardized axillary view are reliable; if postoperative radiographs can reliably show the changes in glenoid anatomy and glenohumeral relationships after shoulder arthroplasty, and if the axillary view can show differences in glenohumeral pathoanatomy in the different sexes and disease types. These questions were addressed using cross-sectional studies of 344 shoulders with different types of arthritis and of 128 osteoarthritic shoulders having a ream and run arthroplasty (a glenohumeral arthroplasty that combines a noncemented humeral hemiarthroplasty with concentric reaming of the glenoid bone without implantation of a prosthetic glenoid component). Measurements of glenoid type, glenoid version, and glenohumeral contact were made on standardized axillary radiographs. Interobserver reliability was calculated, preoperative and postoperative measurements were compared, and morphologic differences were compared as stratified by sex and disease type. The measurements on axillary views showed a high degree of interobserver reliability and sensitivity to the changes effected by arthroplasty. The ream and run substantially corrected the glenoid type and point of glenohumeral contact. Male shoulders and shoulders with osteoarthritis had more type B glenoids (ie, those with posterior erosion and biconcavity of the glenoid), more retroversion, and a greater degree of posterior displacement of the point of glenohumeral contact. The axillary view provides a practical method of characterizing glenohumeral anatomy before and after surgery that is less costly and exposes the patient to less radiation than a CT scan. Level IV, diagnostic study. See the Instructions for Authors for a complete description of levels of evidence.