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2021 FDA Science Forum

Shoulder Joint Modeling for Range of Motion Evaluation

Download the Poster (PDF; 0.84 MB)
Authors:
Poster Author(s)
Sadeqi, Sara, CDRH/OSEL/DAM; Kontson, Kimberly, CDRH/OSEL/DBP; Baumann, Andrew, CDRH/OSEL/DAM; Goel, Vijay, University of Toledo, Lilling, Victoria, CDRH/OPEQ/OHT6, Sullivan, Stacey, CDRH/OSEL/DAM
Center:
Contributing Office
Center for Devices and Radiological Health

Abstract

Poster Abstract

Reverse total shoulder arthroplasty (rTSA) has increasingly become the solution for many seeking relief from immobility and pain. The success of this procedure has pushed rTSA to exceed the growth rate and usage of anatomic shoulder arthroplasty. From 2011 to 2017, inpatient rTSA procedures increased over 190% with projections for 2025 reaching near 290,000 procedures 1. First cleared for use in the US in 2004 by the FDA, this innovative design inverted the ball and socket of the shoulder joint, enabling stability and function for those with an irreparable rotator cuff. The design of rTSA implants can result in an interference contact situation between the rim of the polymer “socket” liner on the humerus and the bone of the scapular neck, just inferior to the glenoid (the original anatomic socket). The interference manifests as “scapular notching,” the removal of bone by the humeral liner rim, and consequently, gross liner rim wear. Study reports range from a 4% to 96% incidence rate of scapular notching associated with the use of rTSA, with the extent of contact being dependent on surgical placement and the implant system 2.

The goal of this project is to create a validated anatomic shoulder joint model to assess the effectiveness of range of motion (RoM) measures at detecting potential scapular notching conditions. Clinical RoM measures are standardized and well defined in anatomical planes. Requirements for the functional RoM of implants are conveyed in the Standard Specification for Shoulder Prosthesis (ASTM F1378-18). However, there is a disconnect between the clinical RoM of the shoulder, the functional RoM for shoulder arthroplasty devices as defined in ASTM F1378, and the natural RoM limits of a shoulder. The clinical and natural RoM data applied to the model were acquired using a 10-camera 3D optical motion capture system (Vicon Motion Systems) 3. Results from the model generation and validation will be presented, along with a comparison of the clinical and natural RoM assessments. By creating a better understanding of the differences between the clinical and natural RoM limits through modeling, we can work to improve shoulder standard specifications and rTSA implant performance.

  1. 1Wagner, E.R., et al., The incidence of shoulder arthroplasty: rise and future projections compared with hip and knee arthroplasty. J Shoulder Elbow Surg, 2020. 29(12): p. 2601-2609.
  2. 2Friedman, R.J., D.A. Barcel, and J.K. Eichinger, Scapular Notching in Reverse Total Shoulder Arthroplasty. JAAOS - Journal of the American Academy of Orthopaedic Surgeons, 2019. 27(6).
  3. 3Oliver, T., et al., Establishing an Age-Matched, Healthy Control Dataset of Joint Kinematics for Comparison to rTSA Patient Joint Kinematics, in American Society of Biomechanics. 2020: (Virtual) Atlanta, GA.
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Download the Poster (PDF; 0.84 MB)

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