Unicompartmental and total knee arthroplasty in the same patient for the treatment of bilateral knee osteoarthritis: a systematic review of literature

Purpose: The aim of this study is to report, through a systematic review of the literature, the outcomes of unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) in the same patient for the treatment of bilateral knee osteoarthritis. Methods: A systematic review was performed by searching PubMed/MEDLINE, SCOPUS, and CINAHL, adhering to PRISMA guidelines. Studies in English pertaining to all levels of evidence and reporting on UKA and TKA in the same patient were considered. Outcomes of interest included preoperative and postoperative clinical and functional assessments, complication rates, and survivorship. Results: Overall, ten studies met the inclusion criteria for this review. The search resulted in one prospective randomized study and nine retrospective cohort studies. From these studies, 437 patients were identified. Subjective outcomes, including pain and satisfaction, demonstrated improvement from preoperative status. Knee Society Scores (KSS), reported in six studies, ranged from 86.8 to 99.0, with no significant differences between TKA and UKA. Range of motion (ROM) typically favored UKA, with differences ranging from 6.6° to 11.2°. TKA showed slightly better survivorship and lower revision rates in studies with longer-term follow-up. Conclusion: The combination of UKA and TKA in the same patient appears to be a feasible procedure providing satisfactory postoperative functional outcomes and limited complications in selected patients. Superiority of UKA was observed in terms of ROM achieved in most papers, while no significant differences were found in total KSS between the two groups. TKA demonstrated a slight advantage over UKA, primarily due to lower reported revision rates and greater long-term implant survivorship.