Rotator cuff status is critical for decision-making in shoulder arthroplasty (Neer, Co, Barrett, Sperling, Edwards, Waldt). A reliable physical examination of the rotator cuff in the setting of glenohumeral osteoarthritis (OA) can be difficult due to pain and stiffness (Dinnes, Gupta, Komaat, Roemer). Accurate imaging is therefore necessary to determine the integrity of the rotator cuff when choosing between standard total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty.
Magnetic resonance imaging (MRI) is commonly used to evaluate rotator cuff integrity, and it can also be used to evaluate glenoid morphology before shoulder arthroplasty (Karzel and Snyder 1993, Wang 1994, Wnorowski 1997, Seibold 1999). The sensitivity and specificity of MRI for detecting full-thickness rotator cuff tears exceeds 90% in non-arthritic shoulders (Iannotti 1991, Wang 1994, Balich 1997, Waldt 2007, DeJesus 2009). However, the sensitivity, specificity, and positive predictive value of this test may be different in the arthritic shoulder (Gupta 2004, Roemer 2009). In rheumatoid patients, one study found limited usefulness of MRI in preoperative evaluation of the rotator cuff in patients undergoing shoulder arthroplasty, with an accuracy of only 71% (Soini 2004). It has been our experience that radiologists’ interpretations of MRI in the setting of glenohumeral osteoarthritis frequently involve full-thickness rotator cuff tears not seen at the time of surgery. We retrospectively compared preoperative MRI evaluation of the rotator cuff to intraoperative findings in 100 consecutive patients. Our hypothesis was that MRI-based interpretation of full-thickness tears of the rotator cuff in osteoarthritic shoulders would have lower specificity and positive predictive value than in previously published reports.