The acromiohumeral distance and the subacromial clearance are correlated to the glenoid version

Abstract

BACKGROUND: The acromiohumeral distance (ACHD) is a radiographic parameter for evaluating the presence of a rotator cuff rupture. Previous investigations have demonstrated that several factors may influence the magnitude of the acromiohumeral distance, but glenoid version has not yet been considered.
HYPOTHESIS: Our hypothesis was that there is a direct correlation between glenoid version and acromiohumeral distance as well as subacromial clearance.
METHODS: Four right glenohumeral joints from adult fresh cadavers were anatomically dissected to the level of the rotator cuff. After fixation to a board and positioning of the humeral head in neutral position, an osteotomy of the glenoid neck was carried out and the version was altered in steps of 5°. The ACHD as well as the subacromial clearance (SAC) were measured for every degree of glenoid version.
RESULTS: The ACHD increased with increased anteversion and consistently decreased with increased retroversion of the glenoid. The SAC also depended on glenoid version. Neutral version was associated with a minimal clearance under the anterior third of the acromion, retroversion transferred the minimal SAC posteriorly and anteversion transferred minimal SAC under the coracoacromial ligament.
CONCLUSION: Our results indicate that glenoid version correlates directly with the magnitude of ACHD and SAC. Therefore, variations of glenoid version can lead to false interpretations of cuff integrity.
TYPE OF STUDY: Biomechanical investigation.
LEVEL OF EVIDENCE: Not possible to define.