Safety and efficacy of sequential simultaneous bilateral total knee arthroplasty: A single centre retrospective cohort study.

Background: Simultaneous bilateral total knee arthroplasty (TKA) is a promising option for patients with bilateral arthritis of the knee because of the requirement of a single hospitalization and anesthetic regimen, reduced overall hospital stay, lower overall costs, and quicker recovery compared to staged bilateral TKA. However, there are conflicting reports on the safety of the procedure, with little data available in the Indian setting. Herein, we compared the efficacy and safety of sequential simultaneous bilateral TKA (SSBTKA) with those of unilateral TKA (UTKA).

Methods: This retrospective analysis included cases of SSBTKA (n = 380, 760 knees) and UTKA (n = 754) performed by the same surgeon and followed up for a minimum duration of 1 year. The functional outcomes (postoperative changes in Oxford Knee Score [OKS] and Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), length of hospital stay (LOS), complications, and rates of revision and mortality were compared between the two groups.

Results: The mean follow-up durations were 40.59 and 36.69 months for the UTKA and SSBTKA groups, respectively. The LOS was significantly longer in the SSBTKA group than in the UTKA group (Median [Interquartile range]: 4[1] vs. 3[0], p < 0.001). The OKS and WOMAC scores increased with time in both groups. The improvements in each of these scores at 3, 6, and 12 months postoperatively were either statistically similar between the two groups or, if statistically different, the differences were too small to be clinically meaningful. Blood transfusions (4% [SSBTKA] vs.0.3% [UTKA], p < 0.001), cardiac complications (1.6% vs. 0.4%, p = 0.034), urine retention (3.7% vs. 1.2%, p = 0.005), and deep infection (0.8% vs. 0%, p = 0.015) were significantly more frequent in the SSBTKA group. None of the patients in the UTKA group had to undergo revision surgery, whereas in the SSBTKA group, 2 (0.6%) patients underwent revision TKA. The overall mortality rates were low in both groups (0.8% [SSBTKA] and 0.3% [UTKA]), with no significant between-group difference (p = 0.209).

Conclusion: The functional outcomes and mortality rates associated with SSBTKA are comparable to those associated with UTKA. The risk of complications and the need for revision, although higher with SSBTKA, the actual numbers are low enough to justify its use. Although the LOS in SSBTKA is longer than that in UTKA, it is likely to be shorter than the cumulative LOS for two UTKA procedures (i.e. a staged bilateral TKA). Thus, SSBTKA appears to be a safe and effective choice for appropriately selected patients.