The early morbidity and mortality of one-session bilateral total knee arthroplasty (1-session BTKA) has been reported in the medical literature. However, there is less information about the long-term clinical impact of this strategy. The aim of this study was to report on the late complications (>90 days), clinical outcomes (KOOS and new KSS) along with the survivorship of 1-session BTKA. We hypothesised that 1-session BTKA will cause few late complications and that the implant survival will meet the criteria of the National Institute for Health and Clinical Excellence (NICE).

This single-centre retrospective study analysed a cohort of ASA-1 and ASA-2 patients who underwent 1-session BTKR over an 8-year period (2009 to 2016). The cohort consisted of 116 patients (66% women, 34% men) with mean age at inclusion of 69 years (32–85 years); 22% of patients were ASA-1 and 78% were ASA-2. The implant-related, infection-related or mechanical complications that occurred more than 90 days after the operation, the clinical outcomes (KOOS and New KSS) and radiological outcomes, along with the survivorship were determined during the scheduled follow-up visits at 3 months, 6 months and 1 year postoperative and during the long-term follow-up or during an intercurrent event.

No patients were lost to follow-up. Fifteen complications occurred (6.5%): four infections, four patellar problems (three cases of clunk syndrome and one of patellofemoral pain), four cases of stiffness, two of unexplained pain and one femoral periprosthetic fracture. Eight patients were readmitted to the hospital (7%); seven were reoperated (3%) and two implants were revised (1%). The functional outcomes (KOOS and New KSS) were significantly improved and 87% of patients were satisfied or very satisfied with this procedure. At a mean follow-up of 5 years, the survivorship estimated using the Kaplan–Meier method was 98.4% (95% CI: 0.933–0.996).

Performing 1-session BTKA is a reliable strategy as it produces a low rate of late complications, excellent medium-term functional outcomes and survivorship that meets NICE criteria, thus confirming our hypothesis.

IV, retrospective case series.