Humeral component retroversion in reverse total shoulder arthroplasty: a biomechanical study. Academic Article uri icon

Overview

abstract

  • BACKGROUND: Reverse total shoulder arthroplasty offers pain relief and functional improvement for patients with rotator cuff-deficient shoulders. The purpose of this study was to determine the optimal amount of humeral retroversion for this prosthesis. MATERIALS AND METHODS: Six cadaveric shoulders underwent computed tomography (CT) imaging and were then dissected of soft tissues, except for their tendinous attachments. A reverse total shoulder arthroplasty was implanted in 0°, 20°, 30°, and 40° of retroversion, and the shoulders were mounted on a simulator to determine the muscle forces required to achieve 30° and 60° of scaption. CT images were converted into 3-dimensional models, and the amount of internal and external rotation was determined with computer modeling at various scaption angles. RESULTS: No differences were found in the forces required for 30° or 60° of scaption for any muscle, at any retroversion. With increasing retroversion, more impingement-free external rotation was obtained, with a concomitant decrease in the amount of internal rotation. Above 60°, the humerus was allowed to rotate around the glenosphere unencumbered. CONCLUSIONS: Increasing retroversion did not affect the muscle force requirements for scaption across the shoulder. Placing the humeral component in 0° to 20° of retroversion allows maximum internal rotation with the arm at the side, a movement that is required for daily activities. This limits external rotation with the arm at the side, but has no effect on external rotation with the arm elevated.

publication date

  • October 29, 2011

Research

keywords

  • Arthroplasty, Replacement
  • Joint Prosthesis
  • Range of Motion, Articular
  • Shoulder Joint

Identity

Scopus Document Identifier

  • 84865096213

Digital Object Identifier (DOI)

  • 10.1016/j.jse.2011.07.027

PubMed ID

  • 22036543

Additional Document Info

volume

  • 21

issue

  • 9