A matter of definition

Aims

The establishment of the fracture-related infection (FRI) consensus definition and the FRI classification system provide a foundation for research and the development of clinical recommendations. To date, however, the evaluation of treatment success is still impeded by a lack of clear and standardized outcome definitions. We hypothesized that applying different outcome measurements to the same cohort of FRI patients results in significantly different treatment success rates.

Methods

Adult patients undergoing curative surgery for FRI at the Center of Musculoskeletal Infections, University Hospital Basel, between 1 January 2020 and 31 December 2023 were included in this prospective cohort study. Treatment success was evaluated by review of patient charts; after one year of follow-up according to seven predefined outcome definitions (S1 to S7): no infection persistence at one year (S1); no recurrence within one year (with the same (S2) or a new (S3) pathogen); bony union (S4); no infection recurrence, or persistence and bony union (S5); no unplanned revision surgery (S6); and bony union and no infection recurrence, or persistence and no unplanned revision surgery (S7).

Results

In total, 106 patients with 112 confirmed FRIs were included. At one year, treatment success varied significantly (p < 0.001) between the different outcome definitions: for S1 the success rate was 95.5% (n = 107), for S2 89.3% (n = 100), for S3 92.9% (n = 104), and for S6 60.7% (n = 68). In cases with healed fractures (n = 28) success rate was 100% for S1 to 3 definitions and 92.9% for S6 (n = 26). In cases with non-healed fractures (n = 84) the success rate decreased significantly from 94.0% (n = 79) for the S1 definition to 39.3% for S7 (n = 33; p < 0.001), with 50% of these patients (n = 42) undergoing an unplanned revision surgery. In unhealed fractures a recurrent infection (p < 0.013) and the need for an unplanned revision surgery (p < 0.001) were significantly more frequent than in healed fractures.

Conclusion

At the one-year follow-up, treatment success differed significantly within a single cohort depending on the outcome metric used to define success.

Cite this article: Bone Joint J  2026;108-B(8):1038–1044.