Incidence, outcomes, and risk factors of Heparin-induced thrombocytopenia in patients undergoing primary and revision knee arthroplasty.

Background: Heparin-induced thrombocytopenia (HIT) is a serious complication associated with heparin use in orthopedic surgery. However, its incidence and risk factors in total knee arthroplasty (TKA) and revision TKA (RTKA) remain unclear. This study aimed to evaluate how preoperative comorbidities, hospital characteristics, and patient demographics influence the incidence of HIT in patients who underwent TKA and RTKA. Differences in postoperative complications, mortality, hospital length of stay, HIT-related costs, and changes in HIT risk following revision surgery were examined.

Methods: This retrospective study examined data from the National Inpatient Sample (NIS) on patients with TKA and RTKA from 2010 to 2019, categorizing them by the incidence of HIT. Demographics (race, sex, and age) and hospital (admission type, insurance, hospital size, teaching status, and region) details were analyzed. Mortality, comorbidities, and perioperative complications were assessed, and logistic regression analyses were performed to identify potential risk factors.

Results: Pulmonary circulatory disorders were strongly associated with HIT in both TKA (P < 0.01, OR = 3.43) and RTKA (P < 0.01, OR = 4.13) groups. Teaching hospitals were associated with lower odds of HIT in the TKA group (P = 0.01, OR = 0.62). Risk factors in RTKA included valvular heart disease (OR = 2.50, 95% CI 1.12-5.57). Common complications among HIT cases included deep vein thrombosis, acute myocardial infarction, and acute renal failure. Pulmonary embolism, postoperative pneumonia, procedural pain, and prosthetic joint infection were more common in TKA group, whereas dyspnea was more prevalent in RTKA group.

Conclusions: Certain preoperative comorbidities and baseline characteristics are associated with increased HIT risk following TKA. RTKA is associated with higher odds of HIT and a greater incidence of adverse clinical outcomes. These findings may support the need for improved risk stratification and postoperative planning to reduce complications and enhance recovery.