Fracture-Related Infection Criteria Identify More Cases Than CDC Definitions, Study Finds

1-Minute Summary

Fracture-related infections (FRIs) can develop after surgical fixation of fractures and may present beyond the conventional surveillance period used for surgical site infections. A single-center retrospective study involving 401 cases of postoperative FRI found that the Fracture-Related Infection Consensus Group criteria classified all cases as infections, whereas the Centers for Disease Control and Prevention (CDC) surgical site infection definitions identified 55.9%.

The difference was particularly pronounced beyond 90 days after surgery. According to the study presented at the 2026 Orthopaedic Trauma Association (OTA) Annual Meeting, no infections outside the 90-day surveillance period were classified as infections under the CDC definitions, although the FRI consensus criteria were designed to assess fracture-associated infections without a fixed time limit.

The findings highlight how diagnostic and surveillance definitions can influence reported infection rates, comparisons between institutions, and interpretation of orthopedic trauma research. However, because the analysis was retrospective, single-center, and restricted to identified postoperative FRI cases, the findings should not be interpreted as proving that one classification system is universally superior in every clinical or surveillance setting.

Why This Matters

Fracture fixation differs from many other surgical procedures because infection can involve both the injured bone and implanted fixation devices. These infections may be difficult to diagnose, and some become apparent well after the initial operation.

The CDC surgical site infection definitions are widely used for public health surveillance and hospital quality metrics. However, the criteria were developed for general surgical procedures and use defined surveillance periods.

The Fracture-Related Infection Consensus Group developed a classification framework specifically for infections associated with fractures and their fixation constructs. It distinguishes confirmed FRI from suggestive FRI and does not impose a fixed time limit for classifying an infection.

These differences can affect whether an infection is counted in a hospital database or research study. If late infections are not captured by a surveillance definition, reported rates may not fully represent the longer-term burden of fracture-related infection.

Abhishek Ganta, MD, an orthopedic trauma surgeon at NYU Langone Health, explained the limitations of applying general surgical criteria to this population:

“The CDC criteria are widely adopted for public health reporting and hospital quality metrics, but they were developed for general surgical procedures and specifically account for the biologic and mechanical complexities of fracture fixation and the potential for latent implant-related infection.”

He contrasted this approach with the FRI consensus framework:

“The [fracture-related infection] consensus criteria were purposely built for infections involving fracture as a fixation construct, and they distinguish confirmed from suggestive infection with no time limit.”

The study therefore raises an important methodological question: do the definitions used to measure postoperative infection adequately capture infections that emerge later in the course of fracture treatment?

Study at a Glance

What the Researchers Found

1. The two classification systems identified different numbers of infections

The investigators retrospectively reviewed 401 cases of postoperative fracture-related infection in adults. They compared how the CDC surgical site infection definitions and the FRI Consensus Group criteria classified the same cohort.

The FRI consensus criteria captured 100% of the infections included in the analysis, compared with 55.9% identified using the CDC definitions.

Interpretation: The study found a substantial difference in case ascertainment between the two systems. Because all participants were drawn from a cohort of identified postoperative FRI cases, these percentages describe classification within the selected study population, not the sensitivity or specificity of either system across all patients undergoing fracture surgery.

2. The 90-day surveillance window was an important distinction

The researchers reported stronger agreement between the classification systems within the first 90 days after surgery.

Within that period, 224 infections were classified as some form of surgical site infection according to the CDC definitions. Beyond 90 days, the report stated that no cases were identified as infection under the CDC framework, while 137 cases were classified as having no infection by that system.

The supplied report does not provide a complete breakdown of all 401 cases by timing and classification. The figures above should therefore be interpreted as reported rather than used to infer unreported categories or totals.

The findings suggest that surveillance limited to a defined postoperative period may fail to represent the full spectrum of fracture-related infections that become evident later.

3. The choice of definition can change reported infection rates

Ganta emphasized that the selected classification framework can materially influence the infection rate reported in orthopedic trauma research.

“The definition you choose materially changes the reported infection rate, and this has real implications for surveillance for national databases and in any study to be used in orthopedic trauma.”

This distinction matters when researchers compare infection rates across hospitals, evaluate surgical outcomes, or use administrative and surveillance databases to assess quality of care.

If different studies use different case definitions or surveillance periods, their reported infection rates may not be directly comparable—even when they investigate similar patient populations.

4. Some cases remain diagnostically uncertain

The presentation also addressed the challenges clinicians face when evaluating possible fracture-related infection.

Ganta noted that cases meeting confirmatory FRI criteria are generally more straightforward to classify. Patients with suggestive findings, however, may fall into an uncertain diagnostic category.

He described these patients as being:

“in an in-between phase”

This uncertainty is clinically important because suggestive findings may warrant further evaluation but do not necessarily establish a confirmed infection. Consistent terminology and standardized diagnostic pathways can help clinicians communicate the degree of diagnostic certainty more clearly.

Ganta told Healio that standardization could improve both research and clinical communication:

“To classify everything in a standardized, uniformed fashion will not only help us understand and be able to study infections better in the future, but help our field stay on the same page when we talk about future research.”

Clinical Significance

The findings have implications for orthopedic trauma practice, hospital surveillance, research methodology, and interpretation of postoperative outcomes.

Implications for clinical practice

FRI may present with a range of findings, and the timing of presentation alone should not be assumed to exclude infection. Clinicians evaluating patients after fracture fixation should consider the overall clinical picture, including whether findings meet confirmed or suggestive FRI criteria.

The study does not establish a new diagnostic test or treatment protocol. Instead, it highlights the importance of applying an appropriate fracture-specific framework when evaluating suspected infection and communicating diagnostic certainty.

Implications for hospital surveillance

Hospitals use infection definitions to report surgical outcomes, support quality improvement, and meet public health reporting requirements. A surveillance window designed for general surgical site infections may not capture all late fracture-related infections.

Consequently, infection rates based on different definitions or observation periods may measure different outcomes. This can complicate comparisons between hospitals and the interpretation of trends over time.

Implications for orthopedic research

Researchers should clearly specify which infection definition they use, how cases are categorized, and how long patients are followed. Such transparency can help readers determine whether results from different studies are comparable.

Using consistent, clearly defined criteria may improve the reproducibility of orthopedic trauma research and help distinguish confirmed infection from cases requiring further investigation.

Limitations

Several limitations should be considered when interpreting the findings.

Retrospective design

The investigators reviewed existing cases rather than prospectively enrolling and following a new cohort. Retrospective analyses depend on the completeness and quality of the available clinical records and classifications.

Single-center study

The analysis was conducted at one center. Classification practices, referral patterns, patient characteristics, and follow-up procedures may differ at other institutions.

Selected population of postoperative FRI cases

The study included 401 cases already identified as postoperative fracture-related infections. Therefore, the finding that the FRI consensus criteria captured 100% of cases should not be interpreted as a validated estimate of diagnostic sensitivity in an unselected population of all patients undergoing fracture fixation.

Differences in intended purpose

The two frameworks were developed for different purposes. CDC definitions support general surgical site infection surveillance, whereas the FRI consensus criteria address fracture-associated infections. Differences in classification may reflect their distinct objectives and time windows rather than a direct test of one system against a universally accepted gold standard.

Limited detail in the meeting report

The supplied report does not provide the full study protocol, detailed patient characteristics, confidence intervals, or a complete cross-tabulation of the two classification systems. It also does not provide enough information to independently calculate diagnostic performance measures.

Generalizability and clinical outcomes

The report does not establish whether using one framework rather than the other improves patient outcomes, changes treatment decisions, or reduces complications. Further prospective and multicenter research would be needed to address these questions.

What Doctors Should Know

• Consider fracture-specific criteria when evaluating suspected FRI. These criteria were designed for the biological and mechanical complexities of fracture fixation.
• Do not assume that infection is excluded solely because 90 days have passed. The study highlights the potential for late fracture-related infections to fall outside the CDC surveillance window used in the analysis.
• Distinguish confirmed from suggestive infection. Suggestive findings can warrant further assessment but should not automatically be treated as definitive proof of infection.
• Interpret infection rates in context. Rates generated using different classification systems or surveillance periods may not be directly comparable.
• Document the definition used in research and quality reporting. Clear reporting of criteria and follow-up periods supports reproducibility and meaningful comparisons.
• Do not overinterpret the 100% case-capture result. It applies to the selected cohort described in this study and does not establish perfect diagnostic accuracy in all clinical settings.

Future Research Priorities

Further research could clarify how fracture-specific infection criteria should be incorporated into clinical studies and surveillance systems.

Important priorities include:

1. Prospective, multicenter comparisons of CDC surgical site infection definitions and FRI consensus criteria.
2. Standardized reporting of confirmed and suggestive FRI.
3. Longer follow-up to characterize infections that become apparent beyond 90 days.
4. Evaluation of how classification differences affect treatment decisions, complications, reoperations, and patient outcomes.
5. Development of reporting methods that distinguish public health surveillance outcomes from fracture-specific clinical diagnoses.
6. Validation of classification approaches in broader populations, including patients with suspected infection rather than only previously identified FRI cases.

Bottom Line

A retrospective, single-center study of 401 postoperative fracture-related infection cases found that the FRI Consensus Group criteria captured all cases in the selected cohort, compared with 55.9% identified by CDC surgical site infection definitions. The discrepancy was particularly notable beyond the 90-day surveillance period used in the analysis.

The findings emphasize that infection classification systems influence reported rates and may affect comparisons across orthopedic trauma studies and surveillance databases. Fracture-specific criteria may better accommodate late and implant-related infections, but the study does not establish that either framework is universally superior for every purpose.

Clinicians and researchers should clearly distinguish confirmed from suggestive FRI, specify the diagnostic definitions used, and interpret surveillance results in light of the population and follow-up period.

Original Research and DOI

Study: Vu N, et al. Paper 5, comparing fracture-related infection consensus criteria with CDC surgical site infection definitions.

Presentation: Orthopaedic Trauma Association Annual Meeting, September 23–26, 2026, Nashville, Tennessee.

Publication status: The supplied source describes a conference presentation. A peer-reviewed journal publication was not identified in the supplied material.

DOI: Not provided in the supplied report.

Presenter: Abhishek Ganta, MD, associate professor in the Department of Orthopedic Surgery at NYU Grossman School of Medicine.

Disclosure: Ganta reported serving as a consultant for Arthrex.

Editorial note: The full conference abstract or subsequent peer-reviewed publication should be consulted for complete methods, classification details, and statistical analyses.