Sequential Release and Muscle Slide of Irreparable Rotator Cuff Tears Results in Linear Gains in Tendon Mobility

Abstract

The purposes of this study were to examine the technique of the supraspinatus and infraspinatus muscle slide for the treatment of rotator cuff tears and to quantify the amount of release and resultant tendon excursion at their insertion sites in cadavers. Twelve shoulders in 6 human cadavers were dissected. Their average age at time of death was 84 years. Though a large open posterior incision, artificial rotator cuff tears were created, if not already present. Standard arthroscopic release was completed. Muscle slide technique was then performed for the supraspinatus and infraspinatus muscles in quartiles, with tendon excursion measured at each interval. The average muscle length from its most medial border to the tendinous insertion was 130 mm and 145.8 mm for the supraspinatus and infraspinatus, respectively. Progressive release of the muscle origin from lateral to medial in 25% increments corresponded to a 6.47-mm lateral shift of the tendon to a maximum of 25.8 mm before complete release of the supraspinatus muscle was achieved. For the infraspinatus, it was an average of 5.38 mm at each 25% interval to a maximum of 21.5 mm. The only restraint to mobility were the motor branches attached to the undersurface of each muscle belly. An additional 25.8 mm (supraspinatus) and 21.5 mm (infraspinatus) of tendon excursion was produced when 100% of the muscle was released from its underlying fossa. At that juncture, tendon excursion was limited by tension placed on each muscle's respective neurovascular supply. Furthermore, sequential release of each muscle resulted in a predictable and consistent gain in tendon mobility, with an average of 6.47 mm and 5.38 mm for each quartile of muscle release in the supraspinatus and infraspinatus from lateral to medial. Tension at the repair site is a contributing factor to poor outcomes after arthroscopic rotator cuff repair of massive rotator cuff tears. This study quantifies the tendon mobility that may be gained following additional muscle slide techniques, and the addition of this technique may contribute to a tension-free repair.