Early postoperative improvements in pain and dysfunction predict faster time to second procedure in staged bilateral total knee arthroplasty.

Abstract

Background The demand for total knee arthroplasty (TKA) continues to rise, with 40% of patients undergoing contralateral TKA within eight years. While prior studies examined perioperative outcomes in staged bilateral TKA, limited research assesses how patient-reported outcomes (PROs) influence the timing of second surgery. This study compared time to second TKA between patients with the most and least severe baseline PROs related to pain and function. Methods A retrospective cohort of staged bilateral TKA patients (2019-2024) was analyzed. Demographics, discharge disposition, length of stay (LOS), and PROs (PROMIS Physical Function, Physical/Mental Health, KOOS JR, VAS Pain) were collected. Principal component analysis identified the top and bottom quartiles of baseline function and pain. Multivariable linear regression assessed predictors of time to second TKA. Results A total of 192 patients (384 knees) were included. Groups differed by age (p = 0.004) but not laterality, anesthesia, ASA class, or LOS. Baseline PROs did not influence time to second TKA (β = -153.2, CI -320.6-14.2; pain β = -225.5, CI -465.7-14.7). However, patients in the top quartile of 3-month and 6-month PROs underwent second TKA sooner (3 months: β = -128.2, CI -244.9 to -11.4; pain β = -242.5, CI -447.8 to -37.2; 6 months: β = -136.0, CI -257.4 to -14.6; pain β = -215.1, CI -420.9 to -9.3). Conclusions Baseline PROs did not predict time to contralateral TKA. In contrast, greater early postoperative improvement at 3- and 6-months was associated with earlier second surgery. The 3-month follow-up may serve as a useful barometer for anticipating timing of staged contralateral TKA.