Chapter 41 Subacromial Decompression
Surgical Overview
• Anatomically, the subacromial space is considered an interstitial pseudo-articulation among the proximal humerus, coracromial arch, acromioclavicular joint, superficial surface of the rotator cuff, and the subacromial and subdeltoid bursa.
• The acromioclavicular joint lies in the anteromedial most aspect, and its anterior wall is composed of the coracoacromial ligament going from the anterior aspect of the acromion to the coracoid process.
• The normal subacromial space is 7 to 14 mm, and narrowing of this space has been associated with rotator cuff pathology.
• The indications for surgical management of impingement are pain or weakness that interferes with work, sports, or activities of daily living (ADL).
• The first reported arthroscopic SAD was performed by Ellman in 1983.
1 In the procedure, a mechanical suction shaver is used to initially perform a bursectomy to establish visualization within the subacromial space.
2 The coracoacromial ligament is released with a surgical electrode, and electrocautery is used to release adhesions.
Rehabilitation Overview
• Rehabilitation begins immediately after surgery, and the patient is typically released from the hospital on the same day.
• A sling is used based on patient comfort for the first 2 to 7 days, but early mobilization is encouraged.
• Treatment goals are to restore full ROM, strength, flexibility, neuromuscular control, and return to previous level of function.
• The patient is instructed in a series of range of motion (ROM) exercises to prevent stiffness and promote mobility.
• Patients are advanced when they meet the goals and criteria defined in each phase of rehabilitation. Individual progression is also based on the level of pain during activity.
• Exercise should emphasize forward flexion, internal/external rotation, posterior capsule flexibility, and scapular stability.
• As ROM improves, strengthening exercises can be incorporated, with an emphasis on muscular balance of the scapulohumeral and scapulothoracic muscles.
• The rehabilitation specialist must carefully assess flexibility, scapulohumeral rhythm, and posture.
• Poor posture during exercise can affect the congruency of the shoulder joint and place the musculature in a poor mechanical position. Correct positioning during exercise will permit the glenohumeral muscles to work within the ideal length-tension relationship.
• Proper scapulothoracic function is also important to allow a stable base for glenohumeral rotation.
1 The scapular muscles must work in unison to maximize congruency between the humeral head and the glenoid during movement.
• Impingement commonly occurs when rotator cuff strength is insufficient to stabilize the humeral head during elevation, causing insufficient space for the rotator cuff tendons.
• Superior translation of the humeral head of up to 1.5 mm occurs when the arm reaches 120 degrees of elevation. Abduction with insufficient rotator cuff strength can also result in sharp increases in this superior translation.
• All exercises should be initially kept below the horizontal until sufficient rotator cuff and scapular strength are established to prevent impingement.
• Patients progress to overhead activity when they demonstrate pain-free ROM in conjunction with adequate strength.
• Appropriate patients progress to sport-specific activities, depending on the requirements of the sport.
• It is important to emphasize activity modification throughout the course of rehabilitation to avoid causing inflammation and delayed recovery.
