Principles for the evaluation and management of shoulder instability.

During use of the normal shoulder, the humeral head is centered within the glenoid and the coracoacromial arch. When the shoulder cannot maintain this centered position during use, it is unstable. An unstable shoulder prevents normal function of the upper extremity. Shoulder instability is not the same as joint laxity. Joint laxity is a property of normal joints and allows the shoulder to attain its full range of functional positions. The concavity of the glenoid and the coracoacromial arch along with the passive and active forces that press the humeral head into the glenoid and the coracoacromial arch maintain the head in its centered position. This concavity-compression mechanism is dependent on the integrity of the glenoid and the coracoacromial arch, muscular compression, and restraining ligaments of the shoulder. Loss of any of these elements due to developmental, degenerative, traumatic, or iatrogenic factors may compromise the ability of the shoulder to center the humeral head in the glenoid.

Deltoidplasty: outcomes using orthobiologic augmentation.

Iatrogenic deltoid injury can result in severe shoulder dysfunction and pain. We used an augmentation patch (porcine submucosa) concomitantly to assist in deltoid repair. We prospectively studied 14 patients (mean age, 57.9 years). All underwent deltoidplasty for postoperative deltoid dehiscence with the orthobiologic patch placed around the detached deltoid and subsequent transosseous repair to the acromion (mean follow-up, 30 months [range, 24-62 months]). Ten patients underwent concomitant revision rotator cuff repair. All patients had undergone at least 1 previous operation. All improved postoperatively with regard to pain, function, or both. The mean pain level (out of 10) decreased (from 5.4 to 1.2); strength (out of 5) improved (from 3.2 to 4.4), forward elevation increased (from 93.1 degrees to 132.5 degrees), external rotation improved (from 30.8 degrees to 54.3 degrees), and internal rotation improved (from L1 to T9). Improvements were found for the mean Simple Shoulder Test score (out of 12) (from 3.6 to 7.1), Disabilities of the Arm, Shoulder and Hand score (from 68.8 to 28.8), and American Shoulder and Elbow Surgeons score (from 38.3 to 69.4). Recurrent deltoid dehiscence occurred in 2 patients (14%). Deltoid dehiscence remains an unsolved issue associated with shoulder reconstruction. Augmenting deltoid repair can improve function and diminishes pain after failed rotator cuff surgery. Careful revision surgical technique and rehabilitation might provide quality outcomes in this patient population.