Experimental implant-associated orthopaedic infections
Author: Johansson, Åke
Date: 1999-06-11
Location: Föreläsningssal C187, Huddinge Sjukhus
Time: 9.00
Department: Centrum för kirurgisk vetenskap CFSS / Center for Surgical Sciences CFSS
Abstract
Although indispensable in today's medicine, orthopaedic implants may also
cause adverse reactions. A foreign body increases the local
susceptibility to colonisation by microorganisms, and hence the risk of
infections. These infections are rare, but many result in prolonged or
permanent impairment. In orthopaedic infections staphylococci are the
commonest pathogens, but less aggressive anaerobic bacteria are also
encountered. The first objective was to develop an animal model for
investigating the role of anaerobic bacteria in orthopaedic infections.
In rabbits, polyvinyl sponges were placed bilaterally in the proximal
tibial metaphyses, and Bacteroides fragilis was injected unilaterally.
All animals developed bilateral osteomyelitis, suggesting haematogenous
seeding to the control side. Metronidazole treatment was ineffective,
despite adequate serum levels, illustrating the difficulties of treating
orthopaedic infections, without removal of the implants.
To study the importance of implant design and material, rabbits had a
plate applied with screws on die tibia. Either standard stainless steel
dynamic compression plates (SS-DCP), identically designed titanium plates
(Ti-DCP), or titanium PC-FIX plates (Ti-PC-FIX) were used. The local
injection of Staphylococcus aureus resulted in similar infection rates in
SS-DCP- and Ti-PC-FIX-plated animals. Plated animals had a higher
infection rate than shamoperated rabbits did. In contrast, intravenous
injection of the S. aureus strain caused a higher infection rate in
SS-DCP animals than in Ti-PC-FIX animals, and sham-operated ones. The
risk of infection was intermediate with Ti-DCP. Adherence of
microorganisms to matrix proteins may be another pathomechanism in
infections. In a mouse model, we studied collagen and fibronectin binding
of S. aureus in implant-associated osteomyelitis. Bacterial strains, with
or without collagen- or fibronectin-binding ability, were injected close
to an intramedullary tibial nail. Unlike the collagenbinding ability,
fibronectin-binding ability seemed to enhance the microorganisms'
capacity to induce an infection. Our studies illustrated some
characteristics in experimental models of orthopaedic infections.
Implants facilitate the establishment of an infection. Also, the
bacterial inoculum size is critical within a narrow dose range, usually
around 107-8 colony-forming units, below which no infection occurs and,
if exceeded, there is a high risk of a fatal outcome. The clinical
presentations of implant-related infections vary, and the understanding
of the underlying pathomechanisms is dependent on experimental studies.
Further investigations of the importance of different microorganisms in
orthopaedic infections, the importance of implant features, and the
ecology and interactions at an implant site, are necessary for future
progress in treatment of biomaterial-associated infections.
Issue date: 1999-05-21
Publication year: 1999
ISBN: 91-628-3562-9
Statistics
Total Visits
Views | |
---|---|
Experimental ...(legacy) | 218 |
Experimental ... | 42 |
Total Visits Per Month
July 2020 | August 2020 | September 2020 | October 2020 | November 2020 | December 2020 | January 2021 | |
---|---|---|---|---|---|---|---|
Experimental ... | 2 | 1 | 1 | 3 | 3 | 5 | 6 |
Top country views
Views | |
---|---|
China | 48 |
Germany | 37 |
United States | 37 |
Sweden | 24 |
India | 8 |
Russia | 7 |
Denmark | 3 |
Egypt | 3 |
Finland | 3 |
Hong Kong | 3 |
Top cities views
Views | |
---|---|
Kiez | 17 |
Beijing | 13 |
Shenzhen | 9 |
Sunnyvale | 6 |
Klockrike | 4 |
Tianjin | 4 |
Woodbridge | 4 |
Easton | 3 |
Mountain View | 3 |
University Park | 3 |