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Mast Cells And Hypoxia Drive Tissue Metaplasia And Heterotopic Ossification In Idiopathic Arthrofibrosis After Total Knee Arthroplasty., Theresa A Freeman, Javad Parvizi, Craig J Dela Valle, Marla J Steinbeck

Department of Orthopaedic Surgery Faculty Papers

ABSTRACT: BACKGROUND: Idiopathic arthrofibrosis occurs in 3-4% of patients who undergo total knee arthroplasty (TKA). However, little is known about the cellular or molecular changes involved in the onset or progression of this condition. To classify the histomorphologic changes and evaluate potential contributing factors, periarticular tissues from the knees of patients with arthrofibrosis were analyzed for fibroblast and mast cell proliferation, heterotopic ossification, cellular apoptosis, hypoxia and oxidative stress. RESULTS: The arthrofibrotic tissue was composed of dense fibroblastic regions, with limited vascularity along the outer edges. Within the fibrotic regions, elevated numbers of chymase/fibroblast growth factor (FGF)-expressing mast cells were …