Bilateral simultaneous unicompartmental knee arthroplasty versus unilateral total knee arthroplasty: A comparison of the amount of blood loss and transfusion, perioperative complications, hospital stay, and functional recovery.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is a good alternative treatment option to total knee arthroplasty (TKA) for single compartment knee osteoarthritis. Several recent reports suggest that UKA results in more rapid functional recovery than TKA, together with fewer complications. Few performed a comparison of bilateral simultaneous UKA and unilateral TKA.

HYPOTHESIS: Bilateral simultaneous UKA would result in fewer perioperative complications, less blood loss, less transfusion and faster recovery of short-term clinical outcomes, compared with unilateral TKA patients.

MATERIAL AND METHODS: In a retrospective trial, the bilateral simultaneous UKA (bUKA) cases were matched one to one with a cohort of unilateral TKA (uTKA) cases according to age, body mass index, gender, Kellgren-Lawrence grade of knee osteoarthritis and American Society of Anesthesiologists score. In bilateral simultaneous UKA group, patients had KL grade 4 of bilateral knee osteoarthritis, and in unilateral TKA group, patients had KL grade 4 of unilateral knee osteoarthritis. The transfusion requirements, estimated blood loss (EBL), duration of hospital stay, incidence of complications, and knee clinical scores of the bUKA and uTKA groups were compared at the 6-month short-term follow-up.

RESULTS: Patients were categorized into the bUKA group (n=52) and uTKA group (n=52). The number of patients requiring transfusion and the amount of EBL was smaller in the bUKA group (P<0.001 for transfusion and P=0.043 for EBL). The duration of hospital stay was shorter and the number of complications was smaller in the bUKA group (P<0.001 for hospital stay and P=0.028 for complications). The clinical outcomes were also superior in the bUKA group (P<0.001).

CONCLUSIONS: Bilateral simultaneous UKA shows fewer perioperative complications, less blood loss, less transfusion, and better functional outcomes at 6 months postoperatively than unilateral TKA. The data suggest that bilateral simultaneous UKA can be performed safely, and results in acceptable clinical outcomes.

LEVEL OF EVIDENCE: III, case-control study.