Clopidogrel is a platelet inhibitor widely prescribed for vascular disease to decrease the likelihood of thrombosis. Although effective in this regard, clopidogrel has the potential to cause intraoperative and postoperative bleeding in patients undergoing arthroplasty [19
]. The decision to discontinue clopidogrel is complicated by the resultant increased risk of vascular events [2
]. There is a paucity of literature on the outcome of perioperative clopidogrel administration in patients undergoing nonelective orthopaedic surgery and no evidence-based guidelines for perioperative clopidogrel management in hip and knee arthroplasties [5
]. It also is unknown which patients are particularly susceptible to the potentially deleterious effects of clopidogrel. As a result, we determined (1) the relationship between time of perioperative clopidogrel administration and postoperative bleeding-related events after hip and knee arthroplasties and (2) patient characteristics or surgical factors that may predict these events.
Although our exploratory study may provide some seed information helpful in this difficult clinical situation, we understand our work has limitations. First, although our findings were statistically significant, there exists the potential for Type I error. The generalizability of our findings may be limited by characteristics unique to our study population. Second, because observational studies are vulnerable to confounding factors, we were able to observe only correlations, not determine causal relationships. A multivariate model may have helped eliminate some confounders, but owing to the low number of observed postoperative events, we did not have the power to adjust for other variables. Third, the retrospective design of our study may represent an inherent source of error as we were limited by the accuracy of the patient records available. Fourth, we did not have access to postdischarge records from outside institutions, so the patient data we collected may be incomplete.
Our data suggest patients who do not discontinue clopidogrel at least 5 days before surgery may have a higher incidence of reoperation for infection and antibiotics prescribed for operative-site cellulitis and/or wound drainage. The timing of postoperative clopidogrel resumption did not influence the rate of postoperative events. One study reported no bleeding events in a patient undergoing hip and knee arthroplasties who was given clopidogrel for postoperative DVT prophylaxis [3
]. However, only one patient receiving clopidogrel was studied, thus precluding any conclusions.
We found increased age, ASA score of 4, and revision surgery were associated with increased rates of postoperative events in patients receiving clopidogrel undergoing hip or knee arthroplasty. These risk factors are associated with increased postoperative complications in the population receiving hip and knee arthroplasties [13
]. However, in our cohort of patients taking clopidogrel, the rate of complications was severalfold greater than that previously observed in the population receiving arthroplasty as a whole. For example, as compared with published rates of complications after revision arthroplasty, patients taking clopidogrel who underwent revision had a four- to 13-fold higher rate of mortality, six- to 24-fold higher rate of infection, and twofold higher rate of readmission [13
] (Table ). Although this observation may be unique to the population at our institution or a function of our sample size, the possibility exists that the deleterious effects of age, comorbidities, and revision surgery are magnified in patients taking clopidogrel. Consideration should be given to preoperative platelet administration, meticulous surgical technique, and close postoperative monitoring in at-risk patients undergoing hip and knee arthroplasties taking clopidogrel.
Rates of complications after revision arthroplasty.
A larger retrospective or prospective investigation may further reinforce and expand our findings. A prospective study would allow for more sensitive detection of smaller hematomas and bleeding secondary to clopidogrel administration that may result in prolonged recovery or joint stiffness. Future work also may examine reversal of the effects of clopidogrel with platelet infusion, particularly in emergent (eg, sepsis) circumstances.