Correlation of the Caprini Score and Venous Thromboembolism Incidence Following Primary Total Joint Arthroplasty-Results of a Single-Institution Protocol

Background: Venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis, is a serious complication after total joint arthroplasty (TJA). Risk assessment models are increasingly used to provide patient-specific risk stratification. A recently implemented protocol mandates calculation of a Caprini Score for all surgical patients at our institution. We investigated the accuracy of the Caprini Score in predicting VTE events following TJA.

Methods: A retrospective review of patients undergoing primary total hip (THA) and total knee arthroplasty (TKA) over a 1-year time period was performed. The 90-day postoperative incidence of emergency department evaluations, hospital readmissions, medical complications, need for revision surgery, and symptomatic VTE was recorded. "Preoperative" Caprini Scores routinely recorded per protocol and calculated during review ("Calculated") were compared and assessed for relationship with VTE events. A "VTEstimator" Score was calculated for each patient.

Results: Three hundred seventy-six arthroplasties (151 TKA and 225 THA) meeting inclusion criteria were identified. Ten patients (2.5%) had symptomatic VTE postoperatively, with 3 pulmonary embolism (0.8%) and 7 deep vein thrombosis (1.8%). Eight VTE (5.3%) occurred following TKA and 2 (0.9%) occurred following THA. For each surgical characteristic evaluated, no significant difference was observed between mean Preoperative or Calculated Caprini Scores for patients with and without VTE (P > .05). Additionally, the distribution of VTEstimator Scores for patients with and without VTE was not significantly different (P = .93).

Conclusion: The Caprini risk assessment model does not appear to provide clinically useful risk stratification for TJA patients. Alternative risk stratification protocols may provide assistance in balancing safety and efficacy of thromboprophylaxis.