2023 ISAKOS Biennial Congress ePoster
Urinary CTX-II, Serum MMP-3 And Serum PIIANP Following Anterior Cruciate Ligament Reconstruction: A Pilot Study
Lachlan Batty, FRACS, Melbourne, VIC AUSTRALIA
Julian A. Feller, FRACS, FAOrthA, Melbourne, VIC AUSTRALIA
Timothy S. Whitehead, MBBS, FRACS, Richmond, VIC AUSTRALIA
Brian M. Devitt, MD, PhD, FRCS, FRACS, Dublin, Leinster IRELAND
Kate E. Webster, PhD, Bundoora, Victoria AUSTRALIA
OrthoSport Victoria Research Unit, Melbourne, Victoria, AUSTRALIA
FDA Status Not Applicable
Summary
Urinary and serum biomarkers after anterior cruciate ligament reconstruction
ePosters will be available shortly before Congress
Abstract
Background
Changes in the levels of urinary and serum biomarkers of chondral metabolism have been identified after anterior cruciate ligament (ACL) injury and reconstruction. These markers may hold value in identifying patients at risk of premature osteoarthritis (OA).
Hypothesis/Purpose: To measure trends in three biomarkers with potential clinical value during the first year following ACL reconstruction. To evaluate any association between biomarker levels and age or body mass index (BMI).
Methods
Twenty-two ACL injured patients from a longitudinal cohort study were included (mean age 25.2 (SD 8.0) years; 12 (54.5%) male). Urine and serum samples were taken at the time of primary ACL reconstruction and at the 6 and 12 months post operative timepoints. Levels of urinary C-terminal cross-linked telopeptide of type II collagen (CTX-II), serum Matrix Metalloproteinase 3 (MMP-3) and serum N-propeptide of collagen IIA (PIIANP) were measured using commercially available enzyme-linked immunosorbent assays (ELISA). CTX-II levels were normalized to urinary creatinine levels and initial testing with the CloudClone® ELISA. CTX-II levels were retested with a second commercially available ELISA (CartiLaps®) as the initial testing results differed from the anticipated levels.
Results
Measured levels of CTX-II differed significantly between the 2 assays at each timepoint (p<0.01 for all timepoints). Levels of CTX-II using the CartiLaps® Assay decreased over time; however, this was not statistically significant (F (2, 38) = 1.29, p=0.29, eta2 = 0.64). Whereas levels of CTX-II when using the CloudClone Assay significantly increased over the measured timepoints (F (2,40) = 3.7, p=0.03, eta2 = 0.16). Levels of MMP3 significantly increased over the measured timepoints (F (2,40) = 3.34, p=0.046, eta2 = 0.14). Levels of PIIANP significantly increased over the measured timepoints (F (2,42) = 12.83, p<0.001, eta2 = 0.38). With the CartiLaps® Assay there was a significant negative correlation between patient age and CTX-II levels at baseline (r= -0.66, p=0.001), 6 months (r=-0.56, p=0.008) and 12 months (r= -0.61, p=0.004).There were no other associations between biomarker levels and age or BMI at any time point.
Conclusion
The assay used is relevant to the levels and trends of CTX-II, with levels either decreasing or increasing with time depending upon the assay used. There was a negative association between CTX-II levels and patient age on one assay. Levels of MMP-3 and PIIANP increase during the first year following ACLR.
Clinical Relevance: Changes in biomarker levels can be seen during the first year following ACLR. These measurements may provide insight into changes occurring in the knee at the cellular level. Future work should aim to identify if these markers have a role in predicting patients at risk of premature OA, before clinical and radiological signs become apparent.