Reverse Total Shoulder Arthroplasty

Overview

Grammont introduced the semiconstrained reverse total shoulder arthroplasty (RTSA) in the early 1990s: a metal glenosphere on the glenoid articulating with a polyethylene humeral bearing (Campbell). Without a functioning cuff, deltoid contraction pulls the humeral head anterosuperiorly; the reverse prosthesis moves the center of rotation medially and distally and restores a fixed fulcrum around which the deltoid can elevate the arm (Campbell). RTSA is the preferred option for most rotator cuff-deficient conditions and for severe glenoid bone loss (Campbell's Concepts).

Indications (Campbell)

The primary indication is a nonfunctional rotator cuff:

• Cuff tear arthropathy (pain, poor active but near-normal passive motion, crepitus; radiographs show humeral head elevation, acromiohumeral pseudoarticulation and joint space loss)

• Massive cuff tear with pseudoparalysis without arthritis; multiple failed cuff repairs with anterosuperior instability

• Severe inflammatory arthritis with a massive cuff tear

• Three- and four-part proximal humeral fractures in the elderly; proximal humeral nonunion; greater tuberosity malunion

• Failed arthroplasty with cuff or tuberosity insufficiency; instability; reimplantation after periprosthetic infection; reconstruction after tumor resection

Requirements: intact deltoid, adequate glenoid bone stock, no infection, no severe neurologic disorder (Parkinson disease, Charcot joint, syringomyelia) and no excessive demands.

Contraindications: deltoid loss or inactivity, glenoid bone loss that prevents secure baseplate fixation; surgeon inexperience is a relative contraindication (costs and length of stay are lower at high-volume centers). Use in patients younger than 70 is increasingly accepted for some end-stage disorders.

Design and Biomechanics (Campbell)

• The baseplate is subjected to high shear stress; fixation depends on baseplate orientation and screw position. The inferior screw sees the highest shear; place peripheral screws in the densest bone: coracoid base, scapular spine and inferior pillar.

• Lateralization (glenoid- or humerus-sided) improves remaining cuff torque and external rotation and reduces scapular notching; larger glenospheres improve motion and reduce notching; a 135-degree neck-shaft angle protects against notching. Avoid superior inclination of the glenoid component, which increases shear and loosening.

• Humeral version: neutral version minimizes impingement, 40 degrees allows the greatest motion in a simulator; most recommend 20-30 degrees of retroversion.

• Glenoid wear in cuff-deficient shoulders is common (37.5% abnormal: posterior 17.6%, superior 9.3%, global 6.5%, anterior 4.2%); these may need an alternative center line along the scapular spine, bone grafting, augmented components or larger glenospheres.

Technique 13.1 (Approach and Humeral Exposure) and Technique 13.3 (Reverse) (Campbell)

Positioning and approach

1. Beach-chair at the top and edge of the table with the medial scapular border free so the arm can be fully adducted and extended; pad bony prominences.

2. Secure the head without hyperextension or tilt (cervical root compression). Drape widely with occlusive dressings.

3. Make an anterior incision about one-third to halfway between the coracoid and the lateral acromion; raise flaps over the deltoid.

4. Open the deltopectoral interval, letting the cephalic vein fall medially (authors prefer this to a superior approach for its versatility).

5. Release the subdeltoid, subcoracoid and subacromial spaces. Locate the axillary nerve by sweeping the index finger down the anterior subscapularis; protect it, especially during inferior capsular release. Avoid plunging into the brachial plexus.

6. The authors tenodese the biceps to the pectoralis major tendon with a figure-eight stitch before dividing it.

7. Incise the subscapularis 1 cm medial to the lesser tuberosity with traction sutures (alternatives: lesser tuberosity osteotomy or release off bone).

8. Open the rotator interval toward the glenoid.

9. Release the anteroinferior capsule from the humerus staying on bone, to at least the 7 o'clock position, then deliver the head with a Darrach retractor by external rotation, adduction and extension.

Humeral preparation

1. Open the canal with a burr at the base of the cuff footprint and ream by hand (no power reaming; avoid overreaming and fracture).

2. A larger head cut is often needed because of superior subluxation. The authors cut and broach at 30 degrees of retroversion, which they consider preferable to 20 degrees to prevent the more common instability in adduction and extension. Cemented, uncemented and short stems have all been used successfully.

Glenoid preparation

1. Debride the glenoid until all four borders are visible; identify the center point and move the starting point 1-2 mm inferiorly so the baseplate sits flush with the inferior glenoid rim, to prevent scapular notching.

2. Insert the guide pin with 0-10 degrees of inferior tilt (the complications discussion cites about 10-15 degrees of inferior tilt with inferior placement as the key factors against notching).

3. Ream judiciously, avoiding exposure of subchondral bone where possible.

4. Impact the baseplate and fix it with screws in the coracoid base, inferior pillar and scapular spine; rotating a circular baseplate about 10 degrees internally helps direct fixed-angle locking screws into the coracoid base and inferior pillar.

5. Dry the Morse taper and impact the glenosphere.

Trialing and closure

1. Insert the humeral stem and trial components. Reduce with longitudinal traction and forward elevation; deltoid tension should be slightly greater than before relocation but do not overlengthen the deltoid (dehiscence, acromial fracture). A 2-3 mm gap on traction without instability is acceptable.

2. Dislocate with a dislocation instrument between bearing and glenosphere and extension of the humerus; select the final bearing, dry the taper, impact and reduce.

3. Subscapularis repair is controversial: no correlation with outcome in some studies, but repair improves stability with Grammont-style (medialized) designs and is less important with lateralized designs.

4. Close over a drain in the deltopectoral interval; place the arm in a sling before waking.

Postoperative Care (Campbell)

• Gentle home program: passive forward elevation to 90 degrees and external rotation to neutral; pillow behind the elbow when recumbent.

• Full-time sling for 6 weeks, then 6 weeks of sling use in unprotected environments.

• Full passive motion by 6-12 weeks; isometric strengthening at about 10 weeks.

Outcomes (Campbell)

• Good or excellent results in 67-82%, with forward elevation of 100-138 degrees; implant survival over 90% at 10 years and 87% at 15 years (glenoid loosening survivorship 84%).

• Cuff tear arthropathy: in one multicenter series, 96% had no or minimal pain and forward elevation improved from 73 to 138 degrees, though 64% had notching. Results are better for primary RTSA than for revision of failed arthroplasty.

• Proximal humeral fractures in the elderly: meta-analyses favor RTSA over hemiarthroplasty, with average elevation about 100 degrees.

• Worse results with posttraumatic and revision indications and with absent or fatty teres minor. Patients with more than 90 degrees of preoperative elevation risk losing elevation.

Complications (Campbell)

References

1. Throckmorton TW, Brolin TJ. Shoulder arthroplasty. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 13, Techniques 13.1 and 13.3.