The Interval Between Staged Bilateral Total Knee Arthroplasties Does Not Affect Early Complications of the Second Knee or Long-term Function of the First and Second Knees

Abstract

Background: This study explored the optimal time interval between staged bilateral total knee arthroplasty (BTKA) to minimise early complications of the second TKA and maximise long-term function of the first and second knees.Methods: We retrospectively reviewed 266 patients who underwent staged BTKA between 2010 and 2015. Groups 1–4 had time intervals between BTKAs of 1–6, 6–12, 12–18, and 18–24 months, respectively. Demographics, postoperative complications within 90 days of the second TKA, Knee Society Score (KSS), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) score were compared among the groups.Results: In total, 54, 96, 75, and 41 patients were assigned to groups 1–4, respectively. Although group 1 had the highest overall complication rate (11.11%), there was no significant difference in the complication rate among the four groups. Also, no significant differences were found among the four groups in functional and patient-reported outcomes, in either the first or second knee at 5 years postoperatively, including KSS-knee, KSS-function, WOMAC-pain, WOMAC-stiffness, and WOMAC-physical function. The interval between BTKA did not influence complications or the function of the second knee. The TKA type (posterior-stabilised vs. medial-pivot) and age did not correlate significantly with any scores.Conclusions: There was no group difference in early complications of the second TKA, and postoperative function was equivalent between the two knees and did not vary by the interval between surgeries. Our results can help surgeons discuss the timing of the second TKA with patients, which should be based on their own preferences. If patients cannot tolerate severe symptoms in the contralateral knee after the first TKA, the second TKA should be performed as early as possible.