The effects of implant composition on extensor tenosynovitis in a canine distal radius fracture model.

PURPOSE: Dorsal plating of distal radius fractures with titanium plates has resulted in clinically observed tenosynovitis and tendon rupture. The goal of this study was to investigate whether titanium-based implants result in more extensor tendon inflammation than matched stainless-steel implants in a canine fracture model.

METHODS

An osteotomy was created in the distal radius of 18 beagles and fixed with 2.7-mm 4-hole plates composed of commercially pure titanium, titanium alloy (Ti-Al6-V4), or 316L stainless steel. Animals were killed at an average of 4 months. Tendon gliding was assessed by applying a force at the extensor musculotendinous junction and noting gliding. Histologic grading (mild, moderate, severe) was based on cellular hypertrophy, hyperplasia, and leukocytic infiltration.

RESULTS

Tendons glided freely in 100% stainless-steel specimens, 75% of titanium alloy, and 43% of commercially pure titanium groups. A severe inflammatory reaction was identified in 60% of the titanium alloy (Ti-A16-V4) group, 57% of the pure titanium group, and 0% of the stainless-steel group.

CONCLUSIONS

Dorsal plating of the canine radius with commercially pure titanium or titanium alloy implants produced a greater inflammatory peritendinous response than matched stainless-steel implants.