Fibronectin–aggrecan complex as a marker for cartilage degradation in non-arthritic hips

Abstract

Purpose To report hip synovial fluid cytokine concentrations in hips with and without radiographic arthritis. Methods Patients with no arthritis (Tonnis grade 0) and patients with Tonnis grade 2 or greater hip osteoarthritis (OA) were identified from patients undergoing either hip arthroscopy or arthroplasty. Synovial fluid was collected at the time of portal establishment for those undergoing hip arthroscopy and prior to arthrotomy for the arthroplasty group. Analytes included fibronectin-aggrecan complex (FAC) as well as a standard 12 cytokine array. Variables recorded were Tonnis grade, centre-edge angle of Wiberg, as well as labrum and cartilage pathology for the hip arthroscopy cohort. A priori power analysis was conducted, and a Mann-Whitney U test and regression analyses were used with an alpha value of 0.05 set as significant. Results Thirty-four patients were included (17 arthroplasty, 17 arthroscopy). FAC was the only analyte to show a significant difference between those with and without OA (p \ 0.001). FAC had significantly higher concentration in those without radiographic evidence of OA undergoing microfracture versus those not receiving microfracture (p \ 0.05). Conclusion There was a significantly higher FAC concentration in patients without radiographic OA. Additionally, those undergoing microfracture had increased levels of FAC. As FAC is a cartilage breakdown product, no significant amounts may be present in those with OA. In contrast, those undergoing microfracture have focal area(s) of cartilage breakdown. These data suggest that FAC may be useful in predicting cartilage pathology in those patients with hip pain but without radiographic evidence of arthritis. Level of evidence Diagnostic, Level III.

What Is the Utility of Biomarkers for Assessing the Pathophysiology of Hip Osteoarthritis? A Systematic Review

“…Synovial fluid access at the time of surgery is more feasible but often requires a lavage, which limits the accuracy of biomarker concentration measurements [2]. Significant heterogeneity exists across different studies that can be difficult to adequately account for in a systematic review.…”

“…The molecular biomarker profiles for these conditions are likely different and may account for heterogeneity in the current literature on biomarkers in hip OA that may contribute to the lack of identification of a clinically useful biomarker. The literature on biomarkers in prearthritic hip disease is limited with three studies investigating three different biomarkers [2,4,16] including two studies on FAI, one on pain of unspecified etiology and no studies investigated hip dysplasia. Bedi et al [4] performed the best study to date in a small population with FAI and demonstrated differences in serum COMP and CRP compared with control subjects.…”

“…Dragomir et al [16] found increased levels of COMP in a cohort of patients reporting recent hip pain or pain during hip examination (without a specific prearthritic diagnosis) compared with normal control subjects (insufficient detail to allow calculation of effect size). Abrams et al [2] demonstrated lower fibronectin aggrecan complex in patients with FAI compared with a cohort of patients with hip OA (effect size d = 0.7). No studies investigated biomarkers in a prearthritic population, which included patients with hip dysplasia.…”

“…Duration of followup to evaluate OA progression ranged from 1 year to 15 years. Three ''prearthritic hip disease'' studies [2,4,16] investigated the role of three unique biomarkers in this population.…”

Cytokines as a predictor of clinical response following hip arthroscopy: minimum 2-year follow-up

“…This work identified a biomarker (FAC), which was shown to be elevated in patients undergoing hip arthroscopy for FAI when compared to those undergoing arthroplasty for OA. Additionally, it was found that those patients undergoing arthroscopy who were noted to have cartilage loss requiring microfracture at the time of operative intervention had elevated levels of FAC compared to those with less cartilage loss who did not meet the indication for microfracture [44]. This previous study did not find a relationship between biomarker concentration and pre-operative assessment scores; however, it did not study the relationship between cytokine concentration and change in outcome scores.…”