Acute knee sepsis may be rare following intramedullary nailing of open tibial shaft fractures using either intra- or extra-articular approaches, although the rate could be higher with suprapatellar nailing.
In a retrospective cohort analysis of adults treated with intramedullary nailing for open tibial shaft fractures at 2 academic Level I trauma centers between January 2010 and December 2023, investigators examined 293 patients with 295 fractures with at least 3 months of follow-up. The analysis included 90 fractures that underwent intra-articular suprapatellar nailing and 205 that underwent extra-articular nailing; 183 of the extra-articular nailing procedures were infrapatellar and 22 were lateral parapatellar.
The primary outcome was acute knee sepsis. Secondary outcomes included deep and superficial infection, nonunion, and hardware removal.
Acute knee sepsis occurred following 0.7% (n = 2) of fractures. One case occurred among 90 fractures treated with the intra-articular approach (1.1%), and 1 occurred among 205 treated with an extra-articular approach (0.5%). The difference was not statistically significant. Both cases were diagnosed about 2 months following intramedullary nailing, and cultures from both patients grew methicillin-susceptible Staphylococcus aureus.
Deep infection occurred in 9% of fractures treated with the intra-articular approach and 9% treated with an extra-articular approach, while superficial infection occurred in 4% and 5%, respectively. The investigators found no statistically significant differences between approaches in deep or superficial infection, aseptic or infected nonunion, or hardware removal.
The groups did not differ in injury energy, Gustilo-Anderson classification, or rates of provisional external fixation. However, those treated with the intra-articular approach had a lower body mass index, were more likely to currently smoke, and had a greater proportion of OTA/AO 42C fractures. Despite the numerically higher knee sepsis rate with intra-articular nailing, the investigators cautioned that the study was underpowered to determine relative risk. A post hoc calculation indicated that about 3,200 patients per group would be needed to achieve 80% statistical power at the observed event rates.
The study was limited by its retrospective design, small number of knee sepsis events, and minimum follow-up of 3 months, which could have resulted in complications being missed if they occurred later or were treated at other institutions. The small sample also limited subgroup analyses examining whether knee sepsis risk differed among more severe or grossly contaminated open fractures.
“Surgeons using either intra-articular or extra-articular approaches for nailing open tibial fractures should be aware of the low but nonzero risk of acute knee sepsis associated with both techniques,” wrote lead study author Bryce Jensen, MS, of the Harvard Orthopaedic Trauma Initiative, and colleagues.
Full disclosures of the study authors can be found in the study.
Source: OTA International
