Canine carpal joint fusion: a model for four-corner arthrodesis using a porous tantalum implant.
OBJECTIVE
Interest has focused on porous materials that promote bony ingrowth. In this study a porous tantalum implant was used as an adjunct to intercarpal stabilization in a canine model of wrist arthrodesis.


METHODS
A defect was created at the junction of the radiocarpal, ulnocarpal, and fourth carpal bones, analogous to a four-corner fusion site in humans. A tantalum cylinder was press-fit and stabilized with K-wires. Controls were represented by creating the defect without implant placement. Animals were killed at 4, 8, and 12 weeks.


RESULTS
Histology showed bony ingrowth as early as 4 weeks and mechanical testing showed a statistically significant increase in strength of the construct over time. Controls failed to achieve union at any time point.


CONCLUSIONS
The implant served as an adjunct to stabilization of the carpus in this model of four-corner fusion, suggesting a novel application of this material in conditions in which bone graft has been required previously. This study represents a preliminary investigation of the use of a tantalum device for intercarpal stabilization; it does not compare this technique with conventional methods.
Adams
Julie E
JE
Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA.
Zobitz
Mark E
ME
Reach
John S
JS
An
Kai-Nan
KN
Lewallen
David G
DG
Steinmann
Scott P
SP
D000818:Animals; D001174:Arthrodesis / Q000379:methods*; D001861:Bone Regeneration; D001864:Bone Wires; D050824:Carpal Joints / Q000473:pathology / Q000601:surgery*; D002350:Carpus, Animal / Q000473:pathology / Q000601:surgery*; D004285:Dogs; D007593:Joint Instability / Q000601:surgery; D008422:Materials Testing; D008853:Microscopy; D023421:Models, Animal; D016062:Porosity; D019736:Prostheses and Implants; D013635:Tantalum
D013635:Tantalum