Reverse Shoulder Arthroplasty for Cuff Deficiency: Surgical Technique


Chapter 40

Reverse Shoulder Arthroplasty for Cuff Deficiency


Surgical Technique



Gregory L. Cvetanovich, Peter N. Chalmers, and Anthony A. Romeo

Introduction


Rotator cuff arthropathy is a cause of shoulder pain and dysfunction consisting of rotator cuff deficiency, superior humeral head migration, and glenohumeral arthritis. History and physical examination with radiographs are the cornerstone of diagnosis, with magnetic resonance imaging (MRI) in select cases. Nonoperative treatment is first-line, including therapy for scapular and rotator cuff strengthening, activity modification, nonsteroidal antiinflammatories, and subacromial steroid injections. If nonoperative treatment fails, reverse total shoulder arthroplasty (RTSA) is a reliable surgical treatment for rotator cuff deficiency and arthropathy, offering pain relief and improved function. Complications following RTSA are not infrequent, but knowledge of RTSA technique offers a chance to help improve pain and function for patients while minimizing complications.

Procedure


RTSA is performed using a deltopectoral approach with release of the subscapularis from the lesser tuberosity and circumferential release of the glenohumeral capsule and labrum. After humeral head osteotomy, the humeral canal is reamed and broached, the glenoid is exposed, and the center is carefully identified with a central guidewire and then reamed in preparation for the baseplate. The glenoid baseplate and glenosphere are implanted, followed by implantation of the humeral stem and humeral cup, and the shoulder is reduced.

Patient History



Patient Examination





  1. • A careful and complete shoulder examination is indicated, including inspection, palpation, active and passive range of motion, strength testing, distal neurovascular examination, and finally provocative testing.
  2. • Inspection and palpation may reveal atrophy of the rotator cuff musculature, particularly the supraspinatus and infraspinatus muscle bellies in their respective fossae of the posterior scapula.
  3. • The most critical aspect of the examination is to confirm that the deltoid is intact and active. Deltoid deficiency or deinnervation is a contraindication to RTSA.
  4. • The humeral head may be prominent anterosuperiorly in cases of humeral head elevation.
  5. • Weakness of the rotator cuff muscles is present, typically consistent with a massive rotator cuff tear.
  6. • Supraspinatus strength may be tested using resisted elevation in Jobe position and the drop-arm test.
  7. • Infraspinatus testing involves resisted external rotation with the arm at the side and the external rotation lag sign. The external rotation lag sign involves passively externally rotating the shoulder with elbow at 90 degrees. Patients with massive infraspinatus tear will not be able to maintain the passive external rotation.
  8. • Teres minor examination consists of resisted external rotation at 90 degrees of shoulder abduction and 90 degrees of external rotation. This is typically evaluated using the Hornblower sign, in which the patient cannot maintain this abducted, externally rotated shoulder position due to teres minor dysfunction.


  10. image
    FIG. 40.1 Preoperative radiographs (A–C) demonstrate findings of rotator cuff arthropathy with superimposed glenohumeral osteoarthritis, including glenohumeral joint space narrowing, superior humeral head migration, and acromial acetabulization. Anteroposterior (A), scapular-Y (B), and axillary (C) views are shown.

  11. • Subscapularis tear is suggested by internal rotation weakness with the arm in maximal internal rotation so that the pectoralis is mechanically disadvantaged. Special testing includes belly press, liftoff, bear hug, and internal rotation lag sign.
  12. • Range of motion is tested actively and passively. Patients with rotator cuff arthropathy will generally be unable to actively elevate their shoulder above 90 degrees.
  13. • Pseudo paralysis is defined as patient inability to actively abduct the shoulder due to rotator cuff arthropathy.

Imaging





  1. • Patients being evaluated for rotator cuff arthropathy are initially evaluated with a complete shoulder radiographic series including: anteroposterior, Grashey (true anteroposterior), scapular-Y lateral, and axillary lateral (Figs. 40.1, 40.2).
  2. • Degenerative changes are present, including glenohumeral joint narrowing, subchondral sclerosis, cystic changes, and osteophyte formation. Superior glenoid wear is often seen in contrast to posterior glenoid wear in primary glenohumeral osteoarthritis.
  3. • The humeral head migrates superiorly or is “high-riding.” In other words, the acromiohumeral distance is decreased due to rotator cuff deficiency.
  4. • In more advanced cases, the humeral head and acromial undersurface may undergo changes in morphology in which the greater tuberosity becomes round and the acromial undersurface undergoes “acetabulization” due to abnormal contact with the humeral head. As a result, in early rotator cuff tear arthropathy, the glenohumeral articulation may be relatively spared from degeneration.


  6. image
    FIG. 40.2 Postoperative radiographs (A–C) demonstrate normal postoperative appearance of reverse total shoulder arthroplasty. Anteroposterior (A), scapular-Y (B), and axillary (C) views are shown.

  7. • MRI is not necessary in most cases for the diagnosis of rotator cuff arthropathy, because plain radiographs provide the necessary diagnostic information.
  8. • In equivocal cases, MRI would show massive, irreparable rotator cuff tear due to retraction and fatty infiltration.

Treatment Options: Nonoperative and Operative



Surgical Anatomy



Surgical Indications



Surgical Technique Setup


Positioning



Possible Pearls


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Mar 28, 2020 | Posted by in ORTHOPEDIC | Comments Off on Reverse Shoulder Arthroplasty for Cuff Deficiency: Surgical Technique

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