International Orthopaedics May 2015, Volume 39, Issue 5, pp 871–877

Onsets of complications and revisions are not increased after simultaneous bilateral unicompartmental knee arthroplasty in comparison with unilateral procedures

Romagnoli, S., Zacchetti, S., Perazzo, P. et al.


The advantages of simultaneous bilateral procedures in joint arthroplasty have been widely described for in total joint replacements of both the hip and the knee. In contrast, unicompartmental knee arthroplasties, despite their effectiveness in pain relieving and functional improvement, are underinvestigated in these terms. The purpose of this study is to assess the possible benefits and risks of bilateral simultaneous knee replacements, in comparison with unilateral procedures.


A total of 567 surgery reports of bilateral simultaneous (220) or unilateral (347) unicompartmental knee arthroplasties were analysed to collect study parameters. Information like the onset of complications and need for revisions were recorded by phone interview (at least two years after surgery). All surgeries were performed by the same orthopaedic surgeon, assisted by the same anesthesiologist.


Complication and revision rates, as well as the length of hospital stay were similar between the two study groups, while blood and haemoglobin losses, and consequently the use of transfusion of allogeneic and autologous blood units, were higher in the simultaneous bilateral group.


Simultaneous bilateral unicompartmental knee arthroplasties could significantly reduce, if both joints are affected, the length of hospital stay and, therefore, patient management costs. At the same time, they do not lead to more frequent revisions or complications. The higher transfusion of allogeneic blood units could be reduced to unilateral surgery levels by the application of currently available protocols of autologous blood reinfusion.

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