Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2 osteochondritis dissecans (OCD) of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture and collection of effusion were only significantly associated with synovial aggrecan and C5b-9 levels (P<0.001). Furthermore, synovial expressions of both proteins correlated with each other (P<0.001). Although IL-1βexpression was relatively low, intra-articular levels correlated with C5a (P<0.01) and serological C-reactive protein concentrations 2 days after surgery (P<0.05). Joint effusions were initially dominated by neutrophils, but the portion of monocytes constantly increased reaching 50% at day 6 after fracture (P<0.02). Whereas aggrecan and IL-1βconcentrations were not different in fracture and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P<0.01). Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures.
Commentary on an article by Matthew D. Milewski, MD, et al.: “Lyme Arthritis in Children Presenting with Joint Effusions”
