Reverse total shoulder arthroplasty

Radiopaedia • CC-by-nc-sa 3.0 • de

A reverse total shoulder arthroplasty (RTSA) (also known as a reverse total shoulder replacement (RTSR)) is a variant on the standard total shoulder replacement (TSR). It is often the preferred method when there has been advanced damage to the rotator cuff as seen in rotator cuff arthropathy.

Procedure

The reverse total shoulder arthroplasty flips the normal mechanical arrangement of the shoulder's ball-and-socket joint. Instead of the humeral head fitting into the glenoid, a rounded hemispheric glenoid prosthesis articulates with a socket on the humeral head prosthesis.

Advantages and disadvantages

Reversing the ball and socket arrangement, the point of rotation is moved more medially, aiding the deltoid muscle which, without an intact rotator cuff, will provide most of the early adduction for the upper extremity after the surgery. Internal and external rotation are more limited in this arrangement, however.

The indications for reverse total shoulder replacement are expanding and include

  • osteoarthritis in patients with a degenerate rotator cuff
  • irreparable massive cuff tear
  • replacement after tumor surgery
  • complex fractures in elderly patients where the greater and lesser tuberosity fragments are involved 
  • failed standard total shoulder replacement

Axillary nerve dysfunction is a contraindication for reverse total shoulder replacement.

The design is thought to have relatively good short and medium-term outcomes compared with other types of total shoulder replacements, with improved recovery time and pain scores . Long-term outcomes remain poorly defined.

Radiographic features

Plain radiograph
  • neutral AP view (Grashey view) and axillary views obtained
  • >2 mm of lucency around the prosthetic component is concerning for loosening
  • "scapular notching" (erosion of the inferior scapular neck) is suggestive of glenoid component failure
  • periprosthetic fractures at the base of the acromion at the scapular spine are more common
CT
  • better for evaluation if there is a suboptimal radiograph
  • as on conventional radiography, >2 mm of lucency around the prosthetic component is concerning for loosening
MRI
Ultrasound
  • useful for imaging the rotator cuff musculature, evaluating the prosthesis dynamically, and evaluating for joint effusion
  • cannot be used to evaluate for component loosening

Complications

The overall complication rate for all forms of total shoulder arthroplasty is ~15%. Complications include:

  • aseptic loosening of the glenoid component: most common complication (~30% of all shoulder replacements, but decreased with reverse total shoulder replacements )
  • aseptic loosening of the humeral component
  • dislocation
  • periprosthetic fractures
  • hardware failure
  • axillary nerve palsy
  • infection (uncommon)
  • acromion stress fracture
Siehe auch: