Incidence and risk factors for symptomatic venous thromboembolism following anterior cruciate ligament reconstruction

Forlenza EM, Parvaresh KC, Cohn MR, Lavoie-Gagne O, Khazi ZM, Lu Y, Cregar W, Forsythe B. Knee Surgery, Sports Traumatology, Arthroscopy. Publish online 10 May 2021.

Take-Home Message

The incidence of venous thromboembolism (VTE; e.g., deep vein thrombosis) is low after an anterior cruciate ligament (ACL) reconstruction, most occurring within 90 days of surgery. The risk for VTE is higher among patients >45 years of age, tobacco users, and those undergoing certain concomitant surgeries.


Patients can expect favorable outcomes after ACL reconstruction; however, complications such as VTE (e.g., deep vein thrombosis, pulmonary embolism) may still occur. An older patient is at greater risk for VTE after an ACL reconstruction; however, controversy still exists regarding how often VTE occurs, VTE risk factors, and the timing of VTE after ACL reconstruction.

Study Goal

The authors sought to determine the incidence of VTE within one year of ACL reconstruction and to identify demographic and surgical risk factors for VTE.


The authors performed a retrospective review of patients who underwent ACL reconstruction between 2007 and 2017. They identified patients using the PearlDiver Patient Record Database, specifically the deidentified patient cohort provided by the Humana Orthopedic private payer database. The researchers then collected patient demographics, comorbidities, concomitant surgeries, and symptomatic events of VTE. The researchers excluded patients who had a second surgery during the first year after an ACL reconstruction.


Overall, 11,910 patients met inclusion criteria –1.0% experienced a VTE within 30 days, 1.2% within 90 days, and 1.6% within 1 year after ACL reconstruction. Seven out of 10 VTEs that patients experienced within one year occurred within the first 30 days after surgery (84% occurred within the first 90 days after surgery). A patient over 45 years of age, undergoing inpatient hospital surgery, or someone with a history of chronic obstructive pulmonary disease or tobacco use, was more than 50% more likely to experience a VTE after an ACL reconstruction than their peers. Also, concomitant surgeries (e.g., posterior cruciate ligament reconstruction, meniscal transplant, or osteochondral allograft) were independent risk factors of VTE.


The authors found that the incidence of VTEs after ACL reconstruction is low, with most VTEs occurring within 90 days of surgery. The authors also identified numerous risk factors for VTE. Several other researchers have evaluated the incidence of VTE after ACL reconstruction, with rates between 0.2%-4.0%. Surgeons should be cautious with patients receiving concomitant surgeries with their ACL reconstructions, as several concomitant procedures may increase the risk of VTE. Concomitant procedures can add operation time, prolong the rehabilitation timeline, and postpone when patients can weight bear after ACL reconstruction – all of which may contribute to an increased risk of VTE. Interestingly, the authors highlight that VTE can still occur after 90 days, with ~16% of the VTEs observed between 90 days and 1 year after surgery. Controlled studies and evidence-based clinical guidelines may help clinicians minimize the risk of VTE after ACL reconstruction.

Clinical Implications

Patients with one or several independent risk factors for VTE may benefit from prolonged chemoprophylaxis after ACL reconstruction. Clinicians should consider patient demographics and concomitant procedures when planning post-operative care.

Questions for Discussion

Are the independent risk factors for asymptomatic VTE similar to the risk factors identified in this current study for symptomatic VTE? How should clinicians adjust the chemoprophylaxis they provide to high-risk patients?

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Written by: Ryan Paul
Reviewed by: Jeffrey Driban