45 research outputs found
Staged Custom, Intramedullary Antibiotic Spacers for Severe Segmental Bone Loss in Infected Total Hip Arthroplasty
Introduction. Total hip arthroplasty (THA) infections with severe bone loss pose significant reconstructive challenges. We present our experience with two-stage hip reimplantation using an intramedullary, antibiotic-impregnated nail. Methods. Three patients with infected THA with severe proximal femoral bone loss (Mallory type IIIB or greater) were treated using a custom antibiotic spacer. Clinical outcomes and any complications were recorded. Average followup was 49 months from final reimplantation. Results. Mean age at spacer placement (stage 1) was 53 years. The mean Harris Hip Score at final followup was 80. Two patients had asymptomatic heterotopic ossification, and one patient had a 2 cm leg-length discrepancy. Conclusions. A custom intramedullary nail antibiotic spacer is a reliable option in the staged management of the infected THA with severe proximal femoral bone loss. Benefits of this technique include limb salvage with maintenance of leg length, soft tissue tension, and functional status
Diagnosis and management of periprosthetic joint infections
Periprosthetic joint infection (PJI) is a severe complication to hip and knee arthroplasty surgery. In the light of its devastating implications for the affected patient, its great economic impact on the health care system and the increasing antimicrobial resistance, it is important to develop efficient diagnostic methods, identify optimal treatment pathways and improve the care for patients.
Using a microbiological approach, Paper I aimed to identify the impact of biofilm production and susceptibility on clinical outcome. The result showed a greater risk of persisting PJI in patients infected by strong biofilm producing staphylococci compared to non- or weak biofilm producers, suggesting the implementation of biofilm diagnostics in clinical routine. Paper II aimed to compare two surgical techniques of DAIR (debridement, antibiotics and implant retention) treatment using a register-based approach. The superiority of modular component exchange compared to non-exchange was established and the exchange of modular components should be employed in cases where DAIR is a viable option. In terms of implant extracting treatment, Paper III aimed to identify re-revision rates after one- and two stage revision procedures using a national register. No difference in re-revision rates were observed, supporting the use of the one-stage procedure which is a more economic choice and more lenient alternative for patients. Paper IV aimed to investigate the experiences and emotional impact of PJI on surgeons using qualitative analysis. The results confirm a negative emotional impact in surgeons and highlight the importance of multi-disciplinary work and inter-collegial support for optimal PJI management and for the well-being of surgeons
Understanding Periprosthetic Joint Infection
Prosthetic joint infection (PJI) is a serious complication of joint replacement surgery associated with morbidity, mortality, and socioeconomic cost. The aim of this thesis is to improve our understanding of PJI by assessing the problem at both the population and the microbiological scale. Bacteria can establish biofilms on all implant grade material and there is in vitro evidence that certain material characteristics are less attractive to bacteria and impede early biofilm formation. Clinical evidence that the choice of materials affects the risk of PJI at the population level is limited. In the first section of this thesis, a population level assessment was made to determine the influence of different implant materials on PJI using infective revision as a surrogate indicator. Propensity score matched (PSM) cohorts from 679,006 knee replacement patients demonstrated that antibiotic impregnated bone cement had no protective benefit at reducing infective revision over plain cement. Analysis using PSM cohorts demonstrated that oxidised zirconium and highly crosslinked polyethylene had a statistically insignificant trend towards decreased infective revision compared to cobalt chromium and conventional ultrahigh molecular weight polyethylene, respectively, but the analysis was likely under powered. In the second half of the thesis, at the microbial level, an in vitro model of PJI was established and modified to produce biofilms of either low or high mass and vitality depending on the incubation conditions. The model was then used to trial novel disclosure agents to demonstrate the presence of biofilm on implant material. Biofilm characterisation techniques were then trialled at the mesoscale and microscale and analysed using a novel computer program which was developed and successfully trialled. Finally, biofilm was cultivated on implant grade material, disclosed, and characterised at the macro-, meso- and microscale using a novel multimodal imaging protocol paving the way for a future ex vivo assessment
Controlled delivery of antimicrobial and anti-inflammatory agents from un-cemented prosthesis
The prevalence of joint replacement procedures has increased by more than 119% in the last decade and as a result the demand for a prosthesis is very likely to increase. Uncemented prosthesis is the first-choice treatment option for patients under 68, due to its long-term and more stable fixation. The two major limitations that lead to the failure of joint replacement surgery are a prosthetic joint infection and aseptic loosening.
To counter these limitations this study aimed to develop a novel composite system with dual functionality for prophylaxis from postsurgical inflammation and infection. The system is versatile safe to use in in-vitro
A biodegradable gentamicin-hydroxyapatite-coating for infection prophylaxis in cementless hip prostheses
A degradable, poly (lactic-co-glycolic acid) (PLGA), gentamicin-loaded prophylactic coating for hydroxyapatite (HA)-coated cementless hip prostheses is developed with similar antibacterial efficacy as offered by gentamicin-loaded cements for fixing traditional, cemented prostheses in bone. We describe the development pathway, from in vitro investigation of antibiotic release and antibacterial properties of this PLGA-gentamicin-HA-coating in different in vitro models to an evaluation of its efficacy in preventing implant-related infection in rabbits. Bone in-growth in the absence and presence of the coating was investigated in a canine model. The PLGA-gentamicin-HA-coating showed high-burst release, with antibacterial efficacy in agar-assays completely disappearing after 4 days, minimising risk of inducing antibiotic resistance. Gentamicin-sensitive and gentamicin-resistant staphylococci were killed by the antibiotic-loaded coating, in a simulated prosthesis-related interfacial gap. PLGA-gentamicin-HA-coatings prevented growth of bioluminescent staphylococci around a miniature-stem mounted in bacterially contaminated agar, as observed using bio-optical imaging. PLGA-gentamicin-HA-coated pins inserted in bacterially contaminated medullary canals in rabbits caused a statistically significant reduction in infection rates compared to HA-coated pins without gentamicin. Bone ingrowth to PLGA-gentamicin-HA-coated pins, in condylar defects of Beagle dogs was not impaired by the presence of the degradable, gentamicin-loaded coating. In conclusion, the PLGA-gentamicin-HA-coating constitutes an effective strategy for infection prophylaxis in cementless prostheses