Serum Inflammation Characterization of Hemarthrosis After Traumatic Knee Joint Injury in Military Personnel- MHSRS 2026

d gordon, a whitfield, n lawson, m humphrey, e starr, m aderman, j trump, j curtin, k o’donovan, m donahue, k cameron

Abstract accepted for poster presentation at the 2026 Military Health System Research Symposium (MHSRS)

INTRODUCTION: Cases of osteoarthritis (OA) are a common cause of disability among medically separated military service members and rates of OA in the military have been observed at higher rates than the general population. Emerging evidence has revealed an association between intra-articular soft tissue injuries and cases of OA resulting in total joint replacements. These acute, traumatic soft-tissue injuries typically result in significant hemarthrosis containing inflammatory biochemicals and cells associated with OA. To attain a better understanding of the OA development process, the purpose of this study was to determine the expression profile of inflammatory cytokines in the patient plasma near the time of injury.

Methods: A prospective case-series study design was conducted among Cadets enrolled at a US Service Academy. Potential subjects with a knee joint injury were referred to and screened by a military orthopaedic surgeon to determine eligibility for the study. Subjects underwent informed consent and provided demographic and injury history information. In addition to an aspiration of the knee during initial evaluation, blood plasma samples were collected within 96 hours of injury.  Plasma samples were collected, stored, and batch-screened by ELISA to probe for the presence of a panel of pro- and anti-inflammatory cytokines and select other blood-based biomarkers.

Results: We performed ELISAs on plasma collected from 15 enrolled suspected knee joint injury subjects. Preliminary analyses show that while some cytokines like IL8 and VEGFA were mostly undetectable, other biomarkers like OPN, MMP3, and A2M, as well as pro-inflammatory markers IL6, TNFA, MIP1, and MCP1were readily detected and largely consistent across all subjects. Notably, however, anti-inflammatory cytokines IL10, IL1RA, and TGFB1 were elevated in several subjects with concordance across some subjects. 

Conclusion: These observations suggest several conclusions: 1) undetectable IL8 and VEGFA are consistent with limited angiogenesis and a lack of neutrophil recruitment; 2) consistent levels of several biomarkers suggests ongoing but regulated immune signaling, low-grade matrix turnover, and protective counterbalance against excessive extracellular matrix degradation; and 3) the elevation of IL10, IL1RA, and TGFB1 suggests some patients may be exhibiting inflammation resolution and joint homeostasis, while others may remain in a more persistent inflammatory equilibrium.