Comparison of early post-operative complications following unilateral or single-stage bilateral unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) demonstrates excellent functional outcomes and patient satisfaction with low complication rates for single compartment knee arthritis. For patients with bilateral symptoms, single-stage bilateral UKA (SSBUKA) provides an alternative to staged procedures but may risk increased blood loss and systemic complications. Therefore, the purpose of this study is to compare 90-day postoperative complications between unilateral UKA and SSBUKA without exclusion for comorbidities.

A retrospective review was completed for 555 consecutive patients having undergone UKA (317 unilateral and 238 bilateral). Data collection included patient demographics and 90-day complications. Independent t-tests (continuous) and Fishers’ Exact tests (nominal) were performed to determine differences between unilateral UKA and SSBUKA patients.

The SSBUKA group had more male patients than the unilateral group (51.3% and 43.8%, respectively). There was no difference in age, body mass index or comorbidity classification. More SSBUKA patients experienced nausea than unilateral patients (17.6% and 11.0%), however, no significant differences were observed in the overall incidence of wound or systemic complications, and no transfusions were required. Significantly more unilateral patients (96.2%) were discharged home compared to SSBUKA (63.0%) (p < 0.001). Two SSBUKA (1.7%) and two unilateral UKA (0.6%) patients required readmission within 90-days with systemic complications.

SSBUKA did not increase the risk of early postoperative systemic or wound complications, when performed in all patients with symptomatic disease without exclusion criteria as compared to patients undergoing unilateral UKA. Therefore, SSBUKA can safely be performed on the majority of patients who present to experienced high volume community hospitals.