Abstract / Summary
Purpose: The aim of the study was to identify potential biomarkers of pre-arthritic condition and early osteoarthritis (OA) in patients with femoroacetabular impingement (FAI), by analysing clinical data and quantifying inflammatory molecules, typically involved in OA pathology, in body fluids.
Methods: FAI patients undergoing hip arthroscopy were enroled after providing written informed consent. Demographic data (age, sex, body mass index [BMI]) were collected, together with radiographic grading of hip degeneration (Tönnis scale) and intra-articular pathology grading (Outerbridge classification). Cartilage degradation markers and immunomodulating molecules were quantified by commercially available sandwich-enzyme-linked assay and multiplex bead-based sandwich immunoassay kits.
Results: Forty-nine patients were enroled, 38 synovial fluids (SFs) and urine samples were available. Median age 32 years ± 8.35 standard deviation (SD); median BMI 24 kg/m2 ± 4.89 SD. Higher BMI corresponded to acetabular chondropathy and was associated with increased C-telopeptide fragments of Type II collagen (CTX-II) release in both SFs and urine. Radiological and intra-operative scores showed moderate-to-strong positive correlation with synovial CTX-II and slight-to-strong positive correlation with vascular endothelial growth factor (VEGF). CTX-II and Cartilage Oligomeric Matrix Protein (COMP) in SFs were positively correlated, showing a high-to-moderate positive correlation with VEGF. VEGF demonstrated a high-to-moderate positive correlation with interleukin (IL)-6 and IL-8. IL1-β correlates moderately positively with IL-8, MIP-3β and TNF-α, which in turn is linked to the release of 6kine, MIP-3β and RANTES. Except for IL-8, all chemokines showed a similar release pattern, suggesting a synergistic and continuous inflammatory mechanism.
Conclusions: A higher BMI was associated with increased CTX-II in both body fluids, suggesting a potential link between metabolic status and early cartilage degradation in FAI patients. Radiographic and intraoperative indicators of joint degeneration were also associated with selected synovial biomarkers (CTX-II, VEGF, IL-6, IL-8). These findings suggest that synovial and urinary biomarkers may represent candidate markers of early joint degeneration in FAI, useful for clinical evaluation of FAI patients at risk of progression toward OA.
Level of evidence: Level IV, case series with no comparison group.