Utility of Bilateral Single-Stage Unicompartmental Knee Arthroplasty

Bilateral single-stage unicompartmental knee arthroplasty (SS-UKA) is a less invasive procedure with shorter hospital stay, lower cost, faster functional recovery and lower mortality rate than total knee arthroplasty (TKR). Studies have reported fewer perioperative complications, less blood loss, lower transfusion rates and faster clinical recovery. The evaluation of excess risk related to the procedure’s bilateral nature is important, and there is no significant difference in blood losses or transfusion rates between the two groups. SS-UKA has a greater decrease in haemoglobin than TS-UKA, but no significant difference in postoperative haemoglobin or transfusion rate. Duration of surgery 90 min and use of tranexamic acid are protective factors. Perioperative complications are absent in both groups. SS-UKA and TS-UKA have similar mortality rates and no significant differences in complications or revisions of the implants. The current literature suggests that simultaneous bilateral procedures are safe and do not increase the postoperative rate of complications, but there is a potential selection bias with younger patients, fewer comorbidities and volunteers/motivated participants. Single-stage bilateral knee arthroplasty does not appear to be more painful or less well experienced than a traditional unilateral procedure, but functional recovery is less reliable. The SS-UKA group has higher preoperative functional scores than the TS-UKA group, but there is a selection bias due to younger patients, lower BMI and more favourable Knee Society Clinical Score. Single-stage bilateral UKA is as good as or better than unilateral UKA or two-stage strategies, with clinical scores and patient satisfaction as good as or better than for unilateral UKA or two-stage strategies. Immediate postoperative physical rehabilitation is not impacted by the bilateral nature of the procedure. The duration of hospital stay in the SS-UKA group was significantly shorter than the TS-UKA group, but rehabilitation was longer. Bilateral single-stage unicompartmental knee arthroplasty (SS-UKA) appears economically preferable, but current fee schedules impose a loss for healthcare facilities and surgeons, preventing the study and promotion of these procedures on a larger scale.