Surgery - Implants

• Polished implants - thick fibrous capsule that does not adhere to implants:

• Textured implants - fibrous cells adhere tightly to implants

Surgery - Implants

• Microtexture promotes cellular attachmentBurnett DM. Exp Cell Research 164:1986

• Once tissue attachment achieved, bacterial progression retarded

Myojin K. Biomed Metal Research 12:1978

Surgery - Implants• Polished dense material resist acute

bacterial infections• Polished material required 40x greater

bacterial load to establish infection vs. porous implantCordero J et al. JBJS 76Br:717,1994Merritt K. J Biomed Material Research

13:101,1979

Implants

“the race for the surface”Gristina AG. Science 237:1588,1987

Tissue integrationImplant

Colonize ? infection

Surgery - ImplantsColonization - Moussa FW Am. Journal Ortho 26:617,1997

• Elective implant removal cultures - 10%positive in 21 pts

• Colonization can occur without sepsis

Surgery - Implants

Melcher Ga et al. Injury 27:SC3-26, 1996

• In an inoculated infection model in rabbits • Titanium implants lower infection rate than ss• Solid IMN lower infection rate than cannulated• Reaming increased infection rates• Implants may matter

• ? Statistically significant, clinically insignificant

Surgery - Stable Implants

Merritt K & Dowd JD. J Ortho Res 5:23,1987

• Contaminated rodent osteotomy• Infection rate

– Unstabilized (71%)– Stabilized - IMN (38%)

Worlock P. et al. Injury 25:31,1994

• Fracture - plate infection - 71%• Fracture - IMN infection - 35%

Surgery - ImplantsSummary

• In a contaminated wound, implants that are:– polished– solid– titanium– unreamed

• may be advantageous in preventing infection