Recovery of Ambulation After Staged Bilateral Total Knee Arthroplasty is Not Affected by Timing of Second Side Surgery: A Retrospective Analysis of Implanted Sensor Data.

Abstract

Background: Bilateral knee osteoarthritis is often treated with staged bilateral total knee arthroplasty (BTKA). However, the optimal surgical timing for staging remains contended. In this study, a smart implant sensor was used to assess the association between surgical timing of stages and recovery of ambulation after the second total knee arthroplasty (TKA).

Methods: Overall, 246 staged bilateral and 2,209 unilateral TKA patients received a sensor-enabled knee implant between 2021 and 2023. Staged BTKA patients were stratified into three subgroups based on time intervals between surgeries: extra-early (< six weeks), early (< 13 weeks), or standard (≥ 13 weeks). Mixed effects repeated measures modeling methods were used to compare daily qualified step count, walk speed, and functional knee range of motion (ROM) during ambulation between the groups.

Results: The three BTKA groups had significantly different daily step counts, walking speed, and knee ROM during the preoperative period before the second TKA. The extra-early bilateral group took fewer qualified steps (P < 0.05), walked slower (P < 0.05), and had less knee ROM (P < 0.05) than both the early and standard groups at the two-week point before their second TKA (P < 0.0 5). At 26 weeks after the second TKA, walking speed, and knee ROM showed no significant difference across the extra-early, early, standard, and unilateral groups (P > 0.05).

Conclusion: Close staging of BTKA surgeries, even less than six weeks apart, did not negatively affect the recovery of postoperative ambulation after the second TKA. Our results may help inform surgeons and patients on timing for staging, especially if a shorter staging is preferred for convenience and shorter overall recovery time.