Computer-simulated TOUCH prosthesis cup malposition and solutions

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Implant Design

Background:

• Total joint replacement is increasingly common for advanced trapeziometacarpal joint osteoarthritis.
• Dual-mobility prostheses offer good short-to-medium term functional results.
• Correct cup placement is vital for stability and preventing dislocation.

Purpose of the Study:

• To simulate and analyze intraoperative revision options for misaligned total joint replacement cups.
• To determine the best cup type and size for revision based on defect area and bone contact.

Main Methods:

• Computer-aided design (CAD) models of existing spherical and conical cups (sizes 9mm and 10mm) were utilized.
• Simulations analyzed revision outcomes for tilted or misplaced cups.
• Defect area and bony contact area were key metrics for evaluating revision strategies.

Main Results:

• A size 9 conical cup could be replaced by a size 9 spherical cup if well-centered.
• A size 9 spherical cup required a size 10 cup for revision.
• For tilted or misplaced size 9 cups, a size 10 conical cup, sometimes with bone grafting, provided the largest bony contact area.

Conclusions:

• Computer simulations provide guidance for intraoperative cup revision in total joint replacement.
• Revision strategies depend on cup size, shape, and type of misalignment.
• Further validation with anatomic specimens is recommended before clinical application.