Synovial Fluid Biomarkers in the Contralateral Knee Predict Patient-Reported Outcomes After Injury at Long-term...

Area of Science:

• Orthopedics and Sports Medicine
• Biomarker Research
• Inflammation and Immunology

Background:

• Knee injury can trigger systemic inflammatory responses.
• The predictive role of these systemic markers on long-term outcomes is not well understood.
• Understanding systemic inflammation may offer new insights into knee injury recovery.

Purpose of the Study:

• To determine if synovial fluid (SF) biomarkers from the uninjured knee can predict long-term patient-reported outcomes (PROs) after arthroscopic knee surgery.
• To investigate the relationship between contralateral knee SF biomarkers and operative knee outcomes.
• To assess the systemic inflammatory response following unilateral knee injury.

Main Methods:

• Retrospective analysis of 32 patients with ≥8 years follow-up.
• Knee SF aspiration from both injured and contralateral knees before arthroscopy.
• Quantification of 10 pro- and anti-inflammatory biomarkers.
• Assessment of PROs using VAS, Lysholm, Tegner, and KOOS-PS scores.
• Stepwise linear regression to identify predictive biomarkers.

Main Results:

• Elevated contralateral anti-inflammatory tissue inhibitor of metalloproteinase 1 (TIMP-1) predicted improved pain scores (VAS) and function (KOOS-PS).
• Increased contralateral pro-inflammatory markers (matrix metalloproteinase 3, regulated on activation normal T cell expressed and secreted) were linked to worse KOOS-PS scores.
• Higher levels of contralateral interleukin 1 receptor antagonist correlated with worse pain (VAS) and function (Lysholm, Tegner) scores.

Conclusions:

• Synovial fluid biomarkers in the contralateral knee predict long-term operative knee outcomes.
• Pro-inflammatory biomarkers are associated with poorer outcomes, while anti-inflammatory markers suggest better results.
• Unilateral knee injuries may induce a systemic inflammatory response impacting long-term recovery.