Subacromial Decompression in the Shoulder
- Impingement symptoms refractory to at least 3 months of nonoperative management
- In conjunction with arthroscopic treatment of a rotator cuff tear
- Relative indication: type II or III acromion with clinical findings of impingement
- Assess the patient for
- Complete shoulder examination with range of motion and strength
- Tenderness with palpation over anterolateral acromion and supraspinatus
- Classic Neer sign with anterolateral shoulder pain on forward elevation above 90° when the greater tuberosity impacts the anterior acromion (and made worse with internal rotation)
- Positive Hawkins sign: pain with internal rotation, forward elevation to 90°, and adduction, which causes impingement against the coracoacromial ligament
- The impingement test is positive if the patient experiences pain relief with a subacromial injection of lidocaine.
- Be certain to evaluate for acromioclavicular (AC) joint pathology, and keep in mind that there are several causes of shoulder pain that can mimic impingement syndrome.
- Standard radiographs should be ordered, including anteroposterior (AP), lateral, and scapular Y views.
- Additional imaging that can aid in the evaluation of impingement syndrome includes supraspinatus outlet and AC joint views.
- AP view—glenohumeral anatomy and position of the humeral head
- Scapular Y view—acromial morphology (see curved acromion in Figure 1)
- Axillary view—os acromiale and anterior acromion
- Supraspinatus outlet view—complete acromial morphology
- Acromioclavicular view—AC joint pathology; osteophytes and degeneration PITFALLS • There are numerous possible causes of shoulder pain that can mimic impingement symptoms. All potential causes should be thoroughly evaluated prior to undertaking operative treatment of isolated impingement syndrome. Controversies
- Subacromial decompression in the treatment of rotator cuff pathology has been continually debated. Prospective studies have suggested that there is no difference in outcomes with and without subacromial decompression.
- Subacromial decompression performed in association with a superior labrum anteriorposterior (SLAP) repair can potentially increase postoperative stiffness.
- MRI is used to evaluate the integrity of the rotator cuff as well as the biceps and labrum.
- Ultrasound can be considered as an alternative method to evaluate the rotator cuff.
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