Summary
Persistent postoperative synovitis was common with half of patients demonstrating moderate synovitis at 3 months with male patients being at increased risk
Abstract
Objective
The purposes of this study were to evaluate the prevalence of persistent postoperative synovitis three months after anterior cruciate ligament reconstruction (ACLR) using ultrasonographic superb microvascular imaging (SMI), and determine whether patient factors, injury characteristics, or preoperative MRI measures of effusion synovitis are associated with postoperative synovitis.
Methods
Twenty-three patients took part in this prospective, IRB-approved study (11 females, 12 males; age=28.7±9.7 y; BMI=25.6±3.3 kg/m2). The intra-rater reliability of SMI synovitis grading was assessed, and an exploratory multivariable logistic regression was used to determine if age, biological sex, BMI, graft type, meniscus status, days between injury and surgery, and/or preoperative MRI effusion-synovitis were associated with moderate synovitis 3 months after ACLR.
Results
Three months following ACLR, 3 (13.0%) participants had no synovitis, 8 (34.7%) participants had mild synovitis, 12 (52.2%) had moderate synovitis, and no participants had severe synovitis. SMI synovitis grades demonstrated excellent intra-rater reliability (Kappa=0.82 [95%CI: 0.66, 0.98]), and synovitis was more frequently observed in the lateral suprapatellar recess. Male sex was a significant predictor of persistent synovitis after ACLR (p=0.03, Odds Ratio=8.0 [95%CI: 1.2, 51.5]), but no other demographic or injury characteristics were associated (p>0.17).
Conclusions
Persistent postoperative synovitis was common with half of patients demonstrating moderate synovitis at three months. SMI synovitis grading was reliable, and synovitis was more readily apparent in the lateral suprapatellar recess. Male patients were at significantly increased risk of persistent synovitis, and future research is needed to further elucidate sex-specific mechanisms of posttraumatic osteoarthritis after ACLR.