Intraarticular Inflammation and Catabolic Markers in Femoroacetabular Impingement during Progression of Disease -comparison between early and late stage disease

• Published in: Orthopaedic journal of sports medicine 2020-07, Vol.8 (7_suppl6)
• Main Authors: Haneda, Masahiko, Clohisy, John, Rai, M. Farooq, O’Keefe, Regis, Brophy, Robert, Pascual-Garrido, Cecilia
• Format: Article
• Language: English
• Subjects: Cartilage; Inflammation; Orthopedics; Sports medicine
• ISSN: 2325-9671; 2325-9671
• DOI: 10.1177/2325967120S00348

Objectives: Femoroacetabular impingement (FAI) has been proposed as an etiologic factor in up to 50% of osteoarthritis hips (OA). Inflammation is thought to be one of the main initiators of hip OA, yet little is known about the location and progression of intraarticular inflammation in FAI hips. The aim of this study is to characterize inflammation and catabolic markers in the early and late stage of FAI hips in patients with symptomatic Cam FAI. Methods: Head-neck cartilage, acetabular cartilage, and synovial samples were obtained from 30 patients undergoing hip surgery. Fifteen patients had a diagnosis of symptomatic Cam FAI (early FAI-symptomatic FAI) and 15 presented with advanced OA secondary to Cam FAI (late FAI/secondary OA). Control cartilage samples were procured from the head-neck junction of 7 osteochondral fresh allografts from healthy young-adult donors (control). Radiographically, the α-angle was utilized to confirm hip impingement and Tönnis grade was used to define pre-OA (Tönnis grade 0-1) and advanced OA (Tönnis grade >2). Safranin O stained sections were used to assess cartilage degeneration using the Mankin score. Immunostaining of IL-1β, MMP-13, ADAMTS-4, type II collagen (COL2), and the NITEGE aggrecan neoepitote was performed to evaluate inflammation and catabolic markers. Quantification of immunopositive cells was performed and one-way analysis of variance with Tukey’s post hoc test was applied to analyze differences between groups. Results: Characteristics of the study participants are presented in Table 1. Cartilage from the impingement zone (head-neck and acetabulum) of hips with early and late FAI showed microscopic osteoarthritic degenerative changes. Compared to control, head-neck cartilage from early and late stage FAI hips highly expressed inflammatory and catabolic markers IL-1β (69.7±18.1, 72.5±13.2 vs 20.2±4.9), MMP-13 (79.6±12.6, 71.4±18.8 vs 25.3±9.5), ADAMTS-4 (83.9±12.2, 82.6±12.5 vs 24.3±11.1), NITEGE (89.7±7.7, 95.7±4.7 vs 39.8±20.5) (p