Total versus unicompartmental knee arthroplasty

One of the most significant achievements in orthopedic surgery in the 20^th century was the introduction and further development of total knee arthroplasty (TKA).[1,2]

Recently, medial unicompartmental knee arthroplasties (UKAs) are commonly used in the treatment of isolated end-stage anteromedial osteoarthritis.[3-5]

The UKA survivorship is poorer compared to TKA in all arthroplasty registries.[6-11] It is lower than TKA survivorship in 27-year Finnish registry study.[6] From this cohort, the authors calculated the Kaplan-Meier survivorship for revision performed for any reason. It was 89.4% at five years, 80.6% at 10 years, and 69.6% at 15 years for UKAs, while the corresponding rates for TKAs were 96.3%, 93.3%, and 88.7%, respectively.

Recently, in a retrospective study, Ma et al.[12] compared the mid-term outcomes of UKA that was performed in one knee and TKA performed in the other knee in the same patient and the same stage. According to the study results, TKA was found to be superior to UKA in terms of the Hospital for Special Surgery (HSS) Knee score, Joint Forgotten Score (JFS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Visual Analog Scale (VAS) score. Complications were comparable between the groups; however, UKA had a higher rate of prosthesis revision. After a follow-up of at least five years, more patients preferred TKA.[12]

Finally, in a recent systematic review and metaanalysis of case series and national registry reports with pooled registry data, Evans et al.[13] showed that approximately 82% of TKAs lasted 25 years and 70% of UKAs lasted 25 years.

In conclusion, until we have convincing scientific data in terms of higher safety and efficacy for UKA, it should not be used in marketing by orthopedic surgeons.