Effects of implant material and plate design on tendon function and morphology.
Titanium implants are an alternative to stainless steel implants for internal fixation after fracture. The advantages of titanium include decreased implant stiffness, increased bio-compatibility, and diminished stress shielding. However, titanium has been implicated in tendon irritation and adhesions when used in the hand and wrist. We evaluated the relationship between extensor tendon morphology and dorsal plating of the distal radius in a canine model using distal radius pi plates made of stainless steel, titanium, and titanium alloy with a modified ramped edge design. We found marked histologic changes in the tendons and surrounding soft tissues including tendon deformation and degeneration (fibrillation, cartilage metaplasia, hypocellularity and hyalinization of blood vessels), peritendonous adhesions and neovascularity in the parenchyma. Only a minimal inflammatory cell infiltrate was identified and was limited to the tenosynovium and/or paratenon. No differences were identified between titanium and stainless steel implants and those with a ramped design. Although all animals lost wrist motion with time, no differences were observed between groups. Our results suggest that pi plate placement on the dorsal surface of the distal radius may lead to extensor tendon irritation and dysfunction. There is no evidence to suggest that this is specifically related to titanium or plate edge design.
Cohen
Mark S
MS
Rush University Medical Center, Department of Orthopaedic Surgery, Chicago, Ilinois 60612, USA.
Turner
Thomas M
TM
Urban
Robert M
RM
D000818:Animals; D001860:Bone Plates; D004285:Dogs; D005552:Forelimb; D008422:Materials Testing; D023421:Models, Animal; D011474:Prosthesis Design; D011885:Radius Fractures / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D013193:Stainless Steel; D013710:Tendons / Q000473:pathology* / Q000503:physiopathology*; D014025:Titanium
D013193:Stainless Steel; D014025:Titanium