Time between anterior cruciate ligament injury and reconstruction and cartilage metabolism six-months following reconstruction.

BACKGROUND

To determine the association between time from injury to ACL reconstruction (Time) and biochemical markers of cartilage metabolism and inflammation six months following ACL reconstruction (ACLR).

METHODS

Individuals with a unilateral ACL injury were enrolled at initial presentation in the orthopedic clinic; blood was collected six months following ACLR. Enzyme-linked immunosorbent assays were used to analyze the ratio of serum concentrations of type-II collagen breakdown (C2C) to synthesis (CPII), plasma matrix metalloproteinase-3 (MMP-3), interleukin-6 (IL-6), and serum aggrecan neoepitope (ARGS). We used separate linear regressions to assess associations between biochemical markers and Time.

RESULTS

Twenty-two participants (50% females, mean [SD], age 21.9 [4.5] years old; BMI 23.8 [2.6] kg/m) completed the study. Time ranged from nine to 67days (31.0 [14.4days]). Greater Time predicted greater serum C2C:CPII ratios six months following ACLR (C2C:CPII=0.15 [0.02], R=0.213, P=0.030). Males (R=0.733, P=0.001) but not females (R=0.030, P=0.609) demonstrated a significant association between greater C2C:CPII and Time at the six-month follow-up exam. Time did not associate with IL-6, MMP-3, or ARGS at six months.

CONCLUSIONS

Greater time between injury and ACL reconstruction was associated with greater serum C2C:CPII six months following ACLR in males but not females, and IL-6, MMP-3, and ARGS levels were not associated with Time in males or females. The time between ACL injury and ACLR may affect collagen metabolism in males and should be further investigated in a larger study along with other patient-relevant outcomes.