Title: Prosthesis Selection
Liaisons: Claudio Diaz-Ledezma MD
Leaders: Javad Parvizi MD, FRCS (US), Yixin Zhou MD (International)
Delegates: Valentin Antoci MD, Paul Ducheyne PhD, Andrew Freiberg MD, Gustavo Garcia Rangel MD, Seung Beom Han MD, Noreen Hickok PhD, Carlos Higuera MD, Constantinos Ketonis MD, Feza Korkusuz MD, Jacek Kruczynski MD, Francisco Macule MD, Jacek Markuszewski MD, Oliver Marín-Peña MD, Dinesh Nathwani MD, Phillip Noble PhD, Kevin Ong PhD, Nelson Ono MD, Mohammad Sadegh Parvizi PhD, Zachary Post MD, Salvador Rivero-Boschert MD, Thomas Schaer VMD, Irving Shapiro DDS, PhD
Vol 1, Num S1, September 2014
Question 1: Does the type of prosthesis influence the incidence of surgical site infection (SSI) or periprosthetic joint infection (PJI)?
Consensus: The type of prosthesis (cemented versus uncemented) or coating with hydroxyapatite does not influence the incidence of SSI or PJI.
Delegate Vote: Agree: 92%, Disagree: 4%, Abstain: 4% (Strong Consensus)
Question 2A: Does antibiotic-impregnated cement reduce the incidence of PJI following elective primary total joint arthroplasty (TJA)?
Consensus: Yes. Antibiotic-impregnated polymethylmethacrylate cement (ABX-PMMA) reduces the incidence of PJI following TJA and should be used in patients at high risk for PJI following elective arthroplasty.
Delegate Vote: Agree: 90%, Disagree: 9%, Abstain: 1% (Strong Consensus)
Question 2B: Does antibiotic-impregnated cement reduce the incidence of PJI following elective revision joint arthroplasty?
Consensus: Yes. Antibiotic should be added to cement in all patients undergoing cemented or hybrid fixation as part of revision arthroplasty.
Delegate Vote: Agree: 88%, Disagree: 9%, Abstain: 3% (Strong Consensus)
Question 3: Does the type of bearing surface in THA influence the incidence of SSI/PJI?
Consensus: Observational data suggest that metal-on-metal bearing may be associated with a higher risk of PJI.
Delegate Vote: Agree: 78%, Disagree: 15%, Abstain: 7% (Strong Consensus)
Question 4: Does the size of prosthesis (volume of foreign material) influence the incidence of SSI following TJA?
Consensus: Yes. The incidence of infection is higher following the use of mega prostheses.
Delegate Vote: Agree: 85%, Disagree: 11%, Abstain: 4% (Strong Consensus)
Question 5: Is there a difference between various types of cement with regard to the incidence of SSI/PJI after TJA?
Consensus: There is no clear difference in the incidence of SSI/PJI following joint arthroplasty when different PMMA cement formulations are used.
Delegate Vote: Agree: 92%, Disagree: 3%, Abstain: 5% (Strong Consensus)
Question 6: Is there a difference between various types of cement with regard to antibiotic elution?
Consensus: There is a clear difference in the elution profile of antibiotics from PMMA cement that is determined by the type of cement, type, and dose of antibiotic.
Delegate Vote: Agree: 96%, Disagree: 0%, Abstain: 4% (Strong Consensus)
Question 7: Is there a difference in the incidence of SSI/PJI with the use of different uncemented prostheses?
Consensus: The incidence of SSI/PJI may be lower with the use of porous metal (tantalum) implants during revision arthroplasty compared to titanium.
Delegate Vote: Agree: 44%, Disagree: 33%, Abstain: 23% (No Consensus)
Question 8: Is there a role for the use of antibiotic powder (such as vancomycin) in the wound during TJA?
Consensus: No. There is no literature to suggest that the use of vancomycin powder poured into the wound or placed in the vicinity of an implant reduces the incidence of PJI. A few studies have shown that the use of vancomycin powder reduces the incidence of SSI following non-arthroplasty procedures. Future studies are needed.
Delegate Vote: Agree: 91%, Disagree: 5%, Abstain: 4% (Strong Consensus)
Question 9: Is there a difference in the incidence of SSI/PJI with the use of metal augments compared to allograft to reconstruct bone deficiency in the setting of infection?
Consensus: There is no difference in the incidence of SSI/PJI following the use of metal augments or allograft bone for reconstruction of bone defects.
Delegate Vote: Agree: 80%, Disagree: 7%, Abstain: 13% (Strong Consensus)
Question 10: Is there a role for modification of the prosthesis surface that may minimize PJI?
Consensus: There is a real need for surface modifications of implants that can help reduce bacterial colonization and subsequent SSI/PJI.
Delegate Vote: Agree: 76%, Disagree: 15%, Abstain: 9% (Strong Consensus)
Question 11: Are there any novel developments for the prevention of SSI/PJI?
Consensus: The orthopaedic community needs to explore the potential for surface modifications of the prosthesis in an effort to reduce the incidence of SSI/PJI.
Delegate Vote: Agree: 84%, Disagree: 10%, Abstain: 6% (Strong Consensus)
New Methods for the Detection and Prevention of Orthopaedic Biofilm Infections.
The limited activity of conventional antimicrobials against biofilm-centered device infections requires new strategies for 1) detection of biofilm on indwelling implants, 2) treatment options of infected implants, and 3) conferring protection onto implants against a priori bacterial colonization and resulting biofilm formation. Ehrlich et al. argued that the detection of biofilm infections is negatively impacted by the fact that biofilm cultures fail to recover and grow under current culture protocols. This compromises clinical decision making due to the lack of a causative pathogen aiding in the selection of an efficacious antimicrobial regimen. The consensus to improved diagnoses and biofilm detection is being addressed by workgroup 7. Novel engineering approaches to the control of orthopaedic biofilm infections have been discussed by Ehrlich et al. whereas microelectromechanical-systems-based biosensors monitor bacterial biofilm dynamics such as quorum sensing, with the goal to release a drug payload that will effectively eradicate both biofilm and planktonic bacteria. While the development and validation process for smart sensing implants is still in the benchtop phase, other strategies addressing implant surface modifications have advanced through rigorous preclinical testing, with some awaiting or entering early human clinical trials. These technologies are largely based on either releasing a timed payload of an antimicrobial to achieve high local tissue concentrations from a carrier coating such as a hydrogel, sol-gel, or other thin layer coating methodologies. Variable release kinetics associated with drug eluting technologies often heighten the concerns for bacterial resistance, an area that continues to draw attention both from a clinical and regulatory perspective. Other surface derivatization strategies achieve a deadly topography killing bacteria on contact, such as covalent tethering of antimicrobial peptides or the binding of charged molecules to the substrate surface. While some of these covalently-attached coatings aim to confer long-term protection to the implant, the longevity of these bactericidal coatings has not been established beyond short-term efficacy in an in vivo setting. The field of biomimetics is rapidly gaining mainstream interest in many engineering and material science disciplines. Hierarchical structures with dimensions of features ranging from the macroscale to the nanoscale are extremely common in nature to provide intriguing properties of interest. This field allows one to emulate biology or nature to develop nanomaterials, nanodevices, and processes which could provide desirable surface topographies in the battle against bacterial colonization of implants. The growing literature reports on a large number of objects including aquatic animals, insects, plants, and bacteria with surface properties of commercial interest. Although there are many appealing technologies addressing biofilm mitigation for implant-associated infections, considerable challenges remain. Challenges along the pivotal path of translation include successful development of concepts for the transfer of lab-type processes to mass production (eg surface synthesis) in a cost-effective manner, designing refined preclinical in vivo studies to address pertinent regulatory metrics for both safety and efficacy (eg local and systemic effects of chronic antimicrobial exposure, efficacy in the context of polymicrobial exposure.).
As our understanding of biofilm physiology, immune modulation, and systemic and local host interactions increases, so will our repertoire of anti-biofilm strategies. With continued interdisciplinary collaborative efforts between clinicians, academia, and the industry, new and effective interventions will follow. A critical cornerstone in the equation of successful periprosthetic infection control is a constructive educational dialogue with the various regulatory bodies. This effort is paramount to support the successful translation of innovative technologies from bench to bedside.