To date, no study has considered the impact of acromial morphology on shoulder range of movement (ROM). The purpose of our study was to evaluate the effects of lateralization of the centre of rotation (COR) and neck-shaft angle (NSA) on shoulder ROM after reverse shoulder arthroplasty (RSA) in patients with different scapular morphologies. 3D computer models were constructed from CT scans of 12 patients with a critical shoulder angle (CSA) of 25°, 30°, 35°, and 40°. For each model, shoulder ROM was evaluated at a NSA of 135° and 145°, and lateralization of 0 mm, 5 mm, and 10 mm for seven standardized movements: glenohumeral abduction, adduction, forward flexion, extension, internal rotation with the arm at 90° of abduction, as well as external rotation with the arm at 10° and 90° of abduction.Objectives
Methods
The indications for reverse shoulder arthroplasty
(RSA) continue to be expanded. Associated impairment of the deltoid
muscle has been considered a contraindication to its use, as function
of the RSA depends on the deltoid and impairment of the deltoid
may increase the risk of dislocation. The aim of this retrospective
study was to determine the functional outcome and risk of dislocation
following the use of an RSA in patients with impaired deltoid function.
Between 1999 and 2010, 49 patients (49 shoulders) with impairment
of the deltoid underwent RSA and were reviewed at a mean of 38 months
(12 to 142) post-operatively. There were nine post-operative complications (18%),
including two dislocations. The mean forward elevation improved
from 50° ( These results suggest that pre-operative deltoid impairment,
in certain circumstances, is not an absolute contraindication to
RSA. This form of treatment can yield reliable improvement in function
without excessive risk of post-operative dislocation. Cite this article:
