Fixation of trapezial implants in a trapeziometacarpal total joint prosthesis tested in a model of porcine bone

Abstract

High aseptic loosening rates have been reported in total joint prostheses of the carpometacarpal joint of the thumb, particularly in the trapezial component. The primary fixation of new implants may be tested in cadaver bones, but the anatomy of the pig is in many ways similar to that of the human, so we compared the central carpal bone from the forefoot of 6-month-old pigs, which has a saddle joint surface similar to the trapezium, to the trapezium in patients with carpometacarpal osteoarthritis. The mean (SD) bone mineral density of the 13 pig forefoot bones was 0.88 (0.12) g/cm² compared with 0.63 (0.16) g/cm² in the 31 human trapeziums. The measured size of the porcine bones was slightly larger than that of the human trapeziums. The similarity in form, size, and bone mineral density means that the central bone of the forefoot of 6-month-old pigs may be used for fixation tests in trapezial implants.

Key Words::

• TM joint prosthesis
• pig bone model
• fixation test
• trapezium

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.