Characteristics, treatment patterns and outcomes of patients presenting with venous thromboembolic events after knee arthroscopy in the RIETE Registry

Knee arthroscopy is the most common orthopedic procedure worldwide. While incidence of post-arthroscopy venous thromboembolic events (VTE) is low, treatment patterns and patient outcomes have not been described. Patients from the "Registro Informatizado Enfermedad TromboEmbolica" who had confirmed post-arthroscopy VTE were compared to patients with provoked, post bone-fracture, and to patients with unprovoked VTE. Baseline characteristics, presenting signs and symptoms, treatment and outcomes including recurrent VTE, bleeds or death were compared. A total of 101 patients with post-arthroscopy VTE and 19,218 patients with unprovoked VTE were identified. Post-arthroscopy patients were younger (49.5 vs. 66 years, P < 0.0001) and had less history of VTE [5.9% vs. 20%, OR 0.26 (0.11-0.59)]. Among patients with isolated DVT, there were fewer proximal DVT in the post-arthroscopy group [40% vs. 86%, OR 0.11 (0.06-0.19)]. Treatment duration was shorter in the post-arthroscopy group (174 ± 140 vs. 311 ± 340 days, P < 0.0001) and more often with DOAC [OR 3.67 (1.95-6.89)]. Recurrent VTE occurred in 6.18 (1.96-14.9) and 11.9 (11.0-12.8) per 100 patient years [HR 0.52 (0.16-1.26)] after treatment in the post-arthroscopy and unprovoked groups, respectively. Recurrent VTE occurred in 5.17 (1.31-14.1) per 100 patient years in a separate post bone-fracture group (n = 147), also not statistically different than the post-arthroscopy recurrence rate. After anticoagulation cessation, some patients post-knee arthroscopy develop VTE. While our small sample size precludes drawing firm conclusions, this signal should warrant further research into the optimal treatment duration for these patients, as some patients may be at increased risk for long-term recurrence.