Comparative study of simultaneous and staged bilateral total knee arthroplasty: is age a key factor in surgical outcomes?

Background The present study aimed to compare the outcomes of simultaneous bilateral total knee arthroplasty (simBTKA) and staged bilateral total knee arthroplasty (stgBTKA) across different age groups, with a specific focus on patients under and over 65 years old. Methods A retrospective cohort study design was employed to analyze the medical records of patients who underwent simBTKA or stgBTKA between August 2018 and May 2023. Patients were categorized into 4 groups based on age and surgical approach. Various outcome measures including knee extension strength, patient-reported outcome measures (PROMs), length of stay (LOS), operating room time (ORT), and complication rates were evaluated. Results The study included a total of 162 patients, with 48 patients in the simBTKA group and 114 patients in the stgBTKA group. Across all age groups, simBTKA resulted in a significantly shorter LOS and ORT than stgBTKA (p < 0.05). However, there were no significant differences in PROMs or in knee extension strength between the two surgical approaches. The complication rates were comparable between the groups, with no reported deaths within one year after surgery. Conclusion Compared with stgBTKA, simBTKA demonstrated superior efficacy in terms of reduced hospitalization duration and ORT, irrespective of age. Both surgical approaches yielded comparable clinical outcomes and complication rates across all age groups. Overall, the findings suggest that simBTKA is a viable option for appropriately selected patients, offering outcomes comparable to those of stgBTKA, with the added benefit of reduced hospitalization time and operating room utilization.