Chemical and Cellular Characterization of Hemarthrosis After Traumatic Knee Joint Injury in Military Personnel- MHSRS 2025
lai s, soriano j, pham k, wu m, jeon j, o’donovan k, aderm m, trump j, curtain j, gee s, donohue m, cameron k
Abstracted accepted for a poster session at the 2025 Military Health System Research Symposium
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 [e.g. meniscus or anterior cruciate ligament (ACL) tears] 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 identify whether mesenchymal stem cells (MSC) are present acutely after an intra-articular knee injury and quantify their concentration.
Methods: A prospective case-series study design was conducted among participants enrolled at a United States Service Academy from 2021-2024. Potential subjects with a knee joint injury were referred to and screened by a military orthopedic surgeon to determine eligibility for the study. Eligible subjects underwent informed consented and provided pertinent demographic and injury history information. An aspiration of the knee was conducted during this initial evaluation. Samples were collected within 96 hours of the injury incident. The aspirate sample was tested on a WOLF cell sorter to determine the presence of specific cell surface markers (CD90, CD105, CD73, CD45, CD34, CD19, CD11b, HLA-DR) representative of MSC presence.
Results: It was determined through the WOLF flow cytometer output analysis that cell surface markers consistent with MSC presence were identified in some samples. However, the concentration of cells containing MSC biomarkers remains low and is inconsistent. The observed cell populations demonstrated a biomarker profile more closely resembling peripheral blood mononuclear cells (PBMCs), though varying degrees of MSC marker expression were present.
Conclusion: Preliminary findings suggest that MSCs may be present in the acute phase following intra-articular knee injuries in varying amounts and low quantities. High variability in data across several samples suggests that variability in the mechanism and severity of injury may result in varying physiological responses. Further research controlling for these factors may be needed to better understand the role of MSCs in post-traumatic osteoarthritis development to help inform targeted OA treatment for military personnel.