Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz Specialty Update summaries.
This month, Thomas K. Fehring, MD, co-author of the July 17, 2019 “What’s New in Musculoskeletal Infection,” selected the five most clinically compelling findings—all focused on periprosthetic joint infection (PJI)—from among the more than 90 noteworthy studies summarized in the article.
Preventive Irrigation Solutions
–An in vitro study by Campbell et al.1 found that the chlorine-based Dakin solution forms potentially toxic precipitates when mixed with hydrogen peroxide and chlorhexidine. The authors recommend that surgeons not mix irrigation solutions in wounds during surgery.
–A clinical evaluation by Stone et al. showed that alpha-defensin levels in combination with synovial C-reactive protein had high sensitivity for PJI diagnosis, but the alpha-defensin biomarker can lead to false-positive results in the presence of metallosis and false-negative results in the presence of low-virulence organisms.
–In an investigation of next-generation molecular sequencing for diagnosis of PJI in synovial fluid and tissue, Tarabichi et al. found that in 28 revision cases considered to be infected, cultures were positive in only 61%, while next-generation sequencing was positive in 89%. However, next-generation sequencing also identified microbes in 25% of aseptic revisions that had negative cultures and in 35% of primary total joint arthroplasties. Identification of pathogens in cases considered to be aseptic is concerning and requires further research.
–A multicenter study found that irrigation and debridement with component retention to treat PJI after total knee arthroplasty had a failure rate of 57% at 4 years.2
–Findings from an 80-patient study by Ford et al.3 challenge the assumption that 2-stage exchanges are highly successful. Fourteen (17.5%) of the patients in the study never underwent reimplantation, 30% had a serious complication, and of the 66 patients with a successful reimplantation, only 73% remained infection-free. Additionally 11% of the patients required a spacer exchange for persistent infection.
- Campbell ST, Goodnough LH, Bennett CG, Giori NJ. Antiseptics commonly used in total joint arthroplasty interact and may form toxic products. J Arthroplasty.2018 Mar;33(3):844-6. Epub 2017 Nov 11.
- Urish KL, Bullock AG, Kreger AM, Shah NB, Jeong K, Rothenberger SD; Infected Implant Consortium. A multicenter study of irrigation and debridement in total knee arthroplasty periprosthetic joint infection: treatment failure is high. J Arthroplasty.2018 Apr;33(4):1154-9. Epub 2017 Nov 21.
- Ford AN, Holzmeister AM, Rees HW, Belich PD. Characterization of outcomes of 2-stage exchange arthroplasty in the treatment of prosthetic joint infections. J Arthroplasty.2018 Jul;33(7S):S224-7. Epub 2018 Feb 17.
Orthopaedic surgeons have developed a heightened awareness of the scientific evidence that supports the decisions that they make in the care of patients. Levels of evidence and grades of recommendation have been used in scientific articles in order to frame information in an evidence-based manner. However, despite the substantial strides that have been made in promoting evidence-based practice throughout orthopaedic surgery, some historical dogma still exists and many surgeons do things based on what they were told or taught many years ago. One example is the so-called “six-hour rule,” in which it is considered the standard of care to urgently perform irrigation and debridement of an open tibial fracture within six hours after the time of injury.
Fractures of the tibial diaphysis are among the most common major long-bone fractures treated by orthopaedic surgeons. Up to 24% of these fractures present as open injuries, and a considerable portion are associated with severe soft-tissue compromise. Open tibial fractures receive different levels of treatment based on the severity of the injury according to the Gustilo and Anderson classification system. In the February 2015 edition of JBJS Reviews, Mundi et al. explore the practice patterns and clinical evidence to support four aspects of treatment that are essential to the management of open tibial fractures: irrigation and debridement, antibiotic prophylaxis, fracture stabilization, and wound management.
With regard to irrigation and debridement, although timely treatment within six hours after injury is considered the standard of care, there is insufficient evidence to support this practice. Moreover, the ideal irrigation solution and the optimum pressure of the irrigation are unknown.
Information on the use of antibiotics in the management of open tibial fractures is based on various well-designed studies, so the quality of the evidence to support some of these recommendations is better. Investigators agree that antibiotic prophylaxis should be started as soon as possible after presentation to an emergency department or hospital and that patients should receive antimicrobial coverage against gram-positive bacteria, typically with a first-generation cephalosporin. Gustilo and Anderson type-III injuries require additional antibiotic coverage, and the use of aminoglycosides is indicated, although the optimum regimen has not been established. Local antibiotic administration at the site of the injury (e.g., antibiotic-laden cement beads) is potentially beneficial but is primarily used for patients with type-III injuries.
The optimum time for closure of these wounds has yet to be determined, although primary closure is warranted under specific circumstances. For those injuries that require delayed closure, definitive coverage should not be delayed beyond seven days, even in the setting of negative-pressure wound therapy.
With regard to stabilization, techniques for the operative management of open tibial fractures have evolved and current evidence shows superior outcomes in association with intramedullary nailing as compared with plate fixation. However, there had been a debate regarding reamed versus unreamed intramedullary nailing. Interestingly, a randomized controlled trial was conducted to answer this question, and the results showed that both reamed and unreamed intramedullary nailing are reasonable options for the fixation of open tibial fractures, with the two techniques demonstrating comparable outcomes.
At this time, there remains a need for additional high-quality evidence to clarify the efficacy of specific techniques and treatments. In particular, guidelines detailing the optimal irrigation solution and pressure as well as the ideal duration of antibiotic prophylaxis are needed. Continued efforts to design and organize large-scale randomized clinical trials will be required in order to provide the kind of evidence that orthopaedic surgeons need so that they can provide the best care for their patients.
Thomas A. Einhorn, MD, Editor