The European Bone and Joint Infection Society definition of periprosthetic joint infection is meaningful in clinical practice: a multicentric validation study with comparison with previous definitions.

BACKGROUND AND PURPOSE: A new periprosthetic joint infection (PJI) definition has recently been proposed by the European Bone and Joint Infection Society (EBJIS). The goals of this paper are to evaluate its diagnostic accuracy and compare it with previous definitions and to assess its accuracy in preoperative diagnosis. PATIENTS AND METHODS: We retrospectively evaluated a multicenter cohort of consecutive revision total hip and knee arthroplasties. Cases with minimum required diagnostic workup were classified according to EBJIS, 2018 International Consensus Meeting (ICM 2018), Infectious Diseases Society of America (IDSA), and modified 2013 Musculoskeletal Infection Society (MSIS) definitions. 2 years' minimum follow-up was required to assess clinical outcome. RESULTS: Of the 472 cases included, PJI was diagnosed in 195 (41%) cases using EBJIS; 188 (40%) cases using IDSA; 172 (36%) using ICM 2018; and 145 (31%) cases using MSIS. EBJIS defined fewer cases as intermediate (5% vs. 9%; p = 0.01) compared with ICM 2018. Specificity was determined by comparing risk of subsequent PJI after revision surgery. Infected cases were associated with higher risk of subsequent PJI in every definition. Cases classified as likely/confirmed infections using EBJIS among those classified as not infected in other definitions showed a significantly higher risk of subsequent PJI compared with concordant non-infected cases using MSIS (RR = 3, 95% CI 1-6), but not using ICM 2018 (RR = 2, CI 1-6) or IDSA (RR = 2, CI 1-5). EBJIS showed the highest agreement between pre-operative and definitive classification (k = 0.9, CI 0.8-0.9) and was better at ruling out PJI with an infection unlikely result (sensitivity 89% [84-93], negative predictive value 90% [85-93]). CONCLUSION: The newly proposed EBJIS definition emerged as the most sensitive of all major definitions. Cases classified as PJI according to the EBJIS criteria and not by other definitions seem to have increased risk of subsequent PJI compared with concordant non-infected cases. EBJIS classification is accurate in ruling out infection preoperatively.

Definition of long-bone nonunion: A scoping review of prospective clinical trials to evaluate current practice.

AIM: Although nonunions are among the most common complications after long-bone fracture fixation, the definition of fracture nonunion remains controversial and varies widely. The aim of this study was to identify the definitions and diagnostic criteria used in the scientific literature to describe nonunions after long-bone fractures. METHODS: A comprehensive literature search was performed in PubMed, Cochrane Library, Web of Science, and Embase. Prospective clinical studies, in which adult long-bone fracture nonunions were investigated as main subject, were included in this analysis. Data on nonunion definitions described in each study were extracted and collected in a database. RESULTS: Although 148 studies met the inclusion criteria, only 50% (74/148) provided a definition for their main study subject. Nonunion was defined in these studies based on time-related criteria in 85% (63/74), on radiographic criteria in 62% (46/74), and on clinical criteria in 45% (33/74). A combination of clinical, radiographic and time-related criteria for definition was found in 38% (28/74). The time interval between fracture and the time point when authors defined an unhealed fracture as a nonunion showed considerable heterogeneity, ranging from three to twelve months. CONCLUSION: In the current orthopaedic literature, we found a lack of consensus with regard to the definition of long-bone nonunions. Without valid and reliable definition criteria for nonunion, standardization of diagnostic and treatment algorithms as well as the comparison of clinical studies remains problematic. The lack of a clear definition emphasizes the need for a consensus-based approach to the diagnosis of fracture nonunion centred on clinical, radiographical and time-related criteria.

The influence of duration of infection on outcome of debridement and implant retention in fracture-related infection.

AIMS: The principle strategies of fracture-related infection (FRI) treatment are debridement, antimicrobial therapy, and implant retention (DAIR) or debridement, antimicrobial therapy, and implant removal/exchange. Increasing the period between fracture fixation and FRI revision surgery is believed to be associated with higher failure rates after DAIR. However, a clear time-related cut-off has never been scientifically defined. This systematic review analyzed the influence of the interval between fracture fixation and FRI revision surgery on success rates after DAIR. METHODS: A systematic literature search was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, in PubMed (including MEDLINE), Embase, and Web of Science Core Collection, investigating the outcome after DAIR procedures of long bone FRIs in clinical studies published until January 2020. RESULTS: Six studies, comprising 276 patients, met the inclusion criteria. Data from this review showed that with a short duration of infection (up to three weeks) and under strict preconditions, retention of the implant is associated with high success rates of 86% to 100%. In delayed infections with a fracture fixation-FRI revision surgery interval of three to ten weeks, absence of recurrent infection was reported in 82% to 89%. Data on late FRIs, with a fracture fixation-FRI revision surgery interval of more than ten weeks, are scarce and a success rate of 67% was reported. CONCLUSION: Acute/early FRI, with a short duration of infection, can successfully be treated with DAIR up to ten weeks after osteosynthesis. The limited available data suggest that chronic/late onset FRI treated with DAIR may be associated with a higher rate of recurrence. Successful outcome is dependent on managing all aspects of the infection. Thus, time from fracture fixation is not the only factor that should be considered in treatment planning of FRI. Due to the heterogeneity of the available data, these conclusions have to be interpreted with caution. Cite this article: Bone Joint J 2021;103-B(2):213-221.

The influence of biomechanical stability on bone healing and fracture-related infection: the legacy of Stephan Perren.

Bone healing is a complicated process of tissue regeneration that is influenced by multiple biological and biomechanical processes. In a minority of cases, these physiological processes are complicated by issues such as nonunion and/or fracture-related infection (FRI). Based on a select few in vivo experimental animal studies, construct stability is considered an important factor influencing both prevention and treatment of FRI. Stephan Perren played a pivotal role in the evolution of our current understanding of the critical relationship between biomechanics, fracture healing and infection. Furthermore, his concept of strain theory and the process of fracture healing is familiar to several generations of surgeons and has influenced implant development and design for the past 50 years. In this review we describe the role of biomechanical stability on fracture healing, and provide a detailed analysis of the preclinical studies addressing this in the context of FRI. Furthermore, we demonstrate how Perren's concepts of stability are still applied to current surgical techniques to aid in the prevention and treatment of FRI. Finally, we highlight the key knowledge gaps in the underlying basic research literature that need to be addressed as we continue to optimize patient care.