Manual versus robotic-assisted revision total knee arthroplasty for instability : a one-year cohort analysis

Revision total knee arthroplasty (rTKA) is a treatment option for failed primary TKA but is associated with higher complication rates and technical challenges. Robotic-assisted rTKA (rarTKA) is an emerging technique that may improve component alignment and surgical precision. However, its effect on early postoperative outcomes in rTKA for instability remains unclear.

A total of 133 consecutive rTKAs for instability (82 manual and 51 robotic) performed by two fellowship-trained arthroplasty surgeons at a single institution were retrospectively analyzed. All rarTKAs used the MAKO robotic-arm system. Operating time, length of stay (LOS), joint line change, posterior condylar offset (PCO) change, and all-cause 30-/90-day complications were compared using univariable analyses. Revision implant constructs were also compared. The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and range of motion (ROM) were assessed at three months and one year, respectively. Kaplan-Meier analysis assessed one-year reoperation-free survival.

RarTKA achieved a greater mean increase in PCO (3.4 mm vs 1.5 mm; p = 0.014), but required a longer operating time (186 minutes vs 173 minutes; p = 0.037). Joint line change, LOS, three-month KOOS-JR, and ROM did not differ significantly. The 30-day (4.9% vs 7.8%) and 90-day (7.3% vs 11.8%) complication rates and one-year reoperation-free survival (91.5% vs 94.1%; p = 0.900) were comparable. Although offset couplers were not used, rarTKA constructs incorporated augments more frequently.

RarTKA demonstrated early postoperative outcomes and complication rates comparable to those of conventional manual rTKA, while achieving improved PCO restoration despite longer operating times. LOS, functional outcomes, and one-year survivorship were similar between groups. Overall, rarTKA appears to be safe and effective; however, further investigation is required to determine the long-term benefits and clinical significance.