Longitudinal documentation of serum cartilage oligomeric matrix protein and patient-reported outcomes in collegiate soccer athletes over the course of an athletic season

Background: Serum cartilage oligomeric matrix protein (sCOMP) is a biomarker for cartilage degradation. Patient-reported outcomes (PRO) are used to document postinjury recovery and may be used to prospectively identify changes in the course of a season. It is unknown what effect intense, continuous physical activity has on sCOMP levels and PRO values in athletes over the duration of a soccer season. Hypothesis/Purpose: The purpose of this study was to longitudinally document sCOMP levels and to determine whether changes in PROs occur in collegiate soccer athletes during a season. The hypotheses tested were that sCOMP levels and PRO scores would remain stable over the duration of the spring soccer season. Study Design: Case series; level of evidence, 4. Methods: Twenty-nine National Collegiate Athletic Association Division-I soccer athletes (18 men, 11 women; age, 19.6 ± 1.2 years; height, 177.8 ± 7.4 cm; mass, 73.8 ± 10.2 kg) participated in 3 (pre-[T ₁], mid-[T ₂], and postseason [T ₃]) data collection sessions. Subjects were included if they were participants in the spring soccer season and were free of severe knee injury at the time of data collection. At each session, subjects completed PROs (Lysholm, International Knee Documentation Committee scores) before serum collection. Results: For sCOMP (ng/mL), there was a significant effect for time, with significant increases at T ₂ (1723.5 ± 257.9, P<.001) and T ₃ (1624.7 ± 231.6, P = .002) when compared with T ₁ (1482.9 ± 217.9). For each of the PROs, there was a significant effect for time from T ₁-T ₃, and at T ₂-T ₃ for the IKDC. Conclusion: These data indicate sCOMP levels increased as athletes reported an increased level of function over time. However, the differences in sCOMP levels did not reach the calculated minimal detectable change (MDC) value and the differences in PRO scores did not reach previously calculated MDC values. It is unclear whether these increases in sCOMP levels were caused by an increase in cartilage matrix breakdown or turnover. Even though these elevations may not be clinically meaningful, this biomarker may have the potential to be used for future research studies investigating the effects of exercise on overall joint health in longitudinal studies. In addition, these results indicate fluctuations in sCOMP occur during a competitive season and must be taken into consideration for future biomarker studies.