Standard cobalt chrome, available in titanium for metal allergies
Modularity for a Custom Fit
Most CMC joint implants have been one-piece designs, requiring a compromise between the fit of the trapezium and that of the metacarpal. Our implant offers a Modular, two-piece design to better match patient's anatomy. This allows the head to be sized to the trapezium and the stem sized to the metacarpal, independent of each other. Additionally, the offset head sizes (0, +2mm and +4mm) allow for proper joint tensioning.
Varus Angle and Medial offset head
The Modular Thumb Implant incorporates two important features for an anatomically correct fit. The medial offset head aligns with the true center of the trapezium, ensuring proper joint alignment. The 15 degree varus angle stem allows the head to maintain good contact with the socket during flexion or opposition, minimizing chances of dislocation.
A common failure mode in previous CMC implant designs has been implant stem motion and migration within the metacarpal due to a lack of stem fixation. The Modular Thumb Implant stem features titanium plasma spray, which allows metacarpal bone-ingrowth into the implant stem. This biological fixation ensures implant stability while eliminating bone erosion, implant migration and pain within the metacarpal.