Glenoid Loosening
In the absence of reliable evidence, it is the opinion of this work group that total shoulder arthroplasty not be performed in patients with glenohumeral osteoarthritis who have an irreparable rotator cuff tear.

Rationale
In the setting of an irreparable rotator cuff tear, glenoid component loosening is a potential complication of total shoulder arthroplasty due to the increased eccentric rim loading of the glenoid component that can occur.  This has been termed the rocking horse phenomenon.  Loosening and failure of the glenoid component can lead to pain and decreased function and may ultimately necessitate revision surgery.  Currently, no reliable studies exists comparing clinical or radiographic results of total shoulder arthroplasty in patients with and without irreparable rotator cuff tears.  Despite this, the current “best medical practice” is to perform total shoulder arthroplasty in patients with glenohumeral osteoarthritis who have intact or reparable rotator cuffs. No studies of sufficient quality have been identified which examine TSA in patients with glenohumeral osteoarthritis with and without an intact rotator cuff.