Inflammation and Neovascularization in Hip Impingement: Not Just Wear and Tear

Background:Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis (OA) in young active patients, but the pathophysiology remains unclear. Increasingly, mechanistic studies point toward an inflammatory component in OA.Purpose:This study aimed to characterize inflammatory cell subtypes and neovascularization in FAI by exploring the phenotype and quantification of inflammatory cells and neovascularization in FAI versus OA samples.Study Design:Descriptive laboratory study.Methods:Ten samples of the labrum were obtained from patients with FAI (confirmed diagnosis) during open osteochondroplasty or hip arthroscopic surgery. Control samples of the labrum were collected from 10 patients with OA who were undergoing total hip arthroplasty. Labral biopsy specimens were evaluated immunohistochemically by quantifying the presence of macrophages (CD68, CD206, interleukin-13 [IL-13]), T cells (CD3), mast cells (mast cell tryptase), and vascular endothelium (CD34, vascular endothelial growth factor)....