P024 - Tissue Inhibitor of Metalloproteinase as a Synovial Fluid Biomarker of Post-Operative Pain Following ACL Reconstruction
Abstract
Purpose
The purpose of the current study was to investigate the association between synovial fluid biomarkers found in ACL-deficient knees at the time of surgery and early postoperative clinical outcomes including pain, range of motion, and symptomatic joint effusion.
Methods and Materials
Synovial fluid samples were collected in the operating room after sterile preparation prior to the surgical incision. The concentrations of 10 synovial fluid biomarkers of interest were determined using a multiplex magnetic bread immunoassay. Patient reported pain level on the visual analog scale were recorded at the first post-operative visit. Enrolled patients were categorized as high pain (VAS 5) or low pain (VAS < 5) based on their reported VAS pain score.
Results
The current study included synovial fluid samples from 105 patients undergoing surgery for primary ACL reconstruction with bone-tendon-bone (BTB) autograft. The mean age of patients on the day of surgery was 32.17 +/- 9.03 years.
There was a positive correlation between synovial fluid concentration of TIMP-2 and early postoperative VAS (r = 0.271, p = 0.005). When comparing the high pain and low pain group, there was a statistically significant difference in the synovial fluid concentration of TIMP-1 (p = 0.04) and TIMP-2 (p = 0.02).
There were no statistically significant relationships between synovial fluid biomarker concentrations and the incidence of symptomatic post-operative joint effusions or deficits in range of motion.
Conclusion
Two anti-inflammatory cytokines (TIMP-1 and TIMP-2) were found to be significantly elevated in patients reporting higher pain levels in the early post-operative period. With the widespread overuse and misuse of opioids for management of postoperative pain, there is increased attention directed towards curbing excessive narcotic prescription. Based on this data, TIMP may be a predictive synovial biomarker for pain, capable of clinical use in formulating individualized post-operative analgesic and rehabilitation regimens following ACL reconstruction.
