Urinary C-terminal telopeptide of type II collagen, radiological severity, and functional assessment in knee osteoarthritis: are these related?

Abstract

Introduction Osteoarthritis (OA) is a chronic, debilitating joint disease characterized by the degeneration of articular cartilage, sclerosis of the subchondral bone, and osteophyte formation. This work aimed at estimating the level of urinary C-terminal telopeptide of type II collagen (CTX-II) as a biomarker of cartilage turnover and to determine its relation with radiological and functional assessment of knee OA. Patients and methods The current study included 40 postmenopausal women with symptomatic knee OA fulfilling the American Rheumatism Association clinical diagnostic criteria for knee OA. A total of 20 healthy volunteers were enrolled as a control group. Patients were assessed radiologically using the Kellgren-Lawrence grading system and functionally using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Urinary CTX-II was measured for the patient and control groups. Results There was no statistically significant difference as regards age and BMI between patients and controls. Disease duration affects both function assessed using the WOMAC and cartilage degradation assessed using urinary CTX-II. There was a statistically significant correlation between the WOMAC and urinary CTX-II, whereas there was no statistically significant correlation between the Kellgren-Lawrence scale and both urinary CTX-II and the WOMAC. Conclusion This study further confirms that urinary CTX-II is an index of early cartilage degradation in knee OA even before radiological changes occurs. The functional assessment using the WOMAC is an easy inexpensive method in reflecting cartilage degradation. Moreover, this work supports the lack of association between the functional status of knee OA patients assessed using the WOMAC and their radiological severity measured using the Kellgren-Lawrence grading scale.

Keywords

• knee osteoarthritis, urinary C-terminal telopeptide of type II collagen, Western Ontario and McMaster Universities Osteoarthritis Index