Role of the Remaining Rotator Cuff Following Reverse Total Shoulder Arthroplasty

Abstract

Rotator cuff degeneration and cuff tear arthropathy result from chronic degeneration and wear, representing a significant clinical and financial burden in the elderly population. Reverse shoulder arthroplasty (RSA) has proven to be superior in restoring clinical and functional outcomes in patients not amendable to direct rotator cuff repair when compared with total shoulder arthroplasty. However, the design of the reverse shoulder prosthesis fails to restore external rotation in the setting of massive posterior rotator cuff tears with a dislocation rates as high as 9%. This necessitates a review of the role of the remaining posterior rotator cuff (infraspinatus and teres minor) and subscapularis on postoperative clinical and functional outcomes after RSA. On the basis of the available literature, the health of the posterior rotator cuff, reflected in the degree of fatty infiltration and tearing, is essential for maintenance and restoration of external rotation postoperatively, with the integrity of the teres minor being more critical. Proper tensioning of the posterior cuff using increased offset designs is necessary to achieve optimal outcomes. However, tendon transfers using the latissimus dorsi, with or without the teres major, make the contribution of the remaining posterior rotator cuff on postoperative outcomes negligible. Meanwhile, subscapularis repair and integrity are not critical to postoperative stability of the prosthesis or internal rotation. Further investigations are warranted to determine the amount of remaining rotator cuff and the extent of degeneration necessary to impact postoperative outcomes after RSA.Key Words: rotator cuff-RSA-infraspinatus-teres minor-subscapularis-reverse shoulder arthroplasty-postoperative outcomes. (Tech Orthop 2016;31: 114-119)R otator cuff disease represents a significant financial and clinical burden in the elderly population, with reported prevalence rates for full-thickness cuff tears approaching 30% for those aged >60 years, and 50% in those aged >70 years. 1,2 Breakdown of the rotator cuff primarily results from gradual degeneration and weakening of the tendons secondary to both extrinsic and intrinsic stresses. 3 Over time, chronic wear coupled with age-associated changes result in irreparable tearing of the rotator cuff. In the setting of massive rotator cuff degeneration with rotator cuff tear arthropathy (CTA), surgical intervention is necessary to restore shoulder function.In patients suffering from CTA and rotator cuff disease not amendable to direct repair, the inherent instability of the shoulder makes traditional total shoulder arthroplasty prostheses ill suited to meet the functional demands in rotator cuffdeficient shoulders. 4 As such, total shoulder arthroplasty designed prostheses function effectively only when viable rotator cuff function is present. 4,5 Alternative treatment methods initially investigated in the 1970s utilizing highly constrained and semiconstrained reverse ball and socket designs. 6,7 Early reverse designs however, demonstrated...