Unicompartmental Knee Arthroplasty Survivorship is Lower Than TKA Survivorship: A 27-year Finnish Registry Study

Abstract

Background Balancing the relative advantages and disadvantages of unicompartmental knee arthroplasties (UKAs) against those for TKAs can be challenging. Survivorship is one important end point; arthroplasty registers repeatedly report inferior midterm survival rates, but longer-term data are sparse. Comparing survival directly by using arthroplasty register survival reports also may be inadequate because of differences in indications, implant designs, and patient demographics in patients having UKAs and TKAs. Questions/purposes The aims of this study were to assess the survivorship of UKA in the context of one large, northern European registry, and to compare the rates of survivorship with those of cemented TKAs performed for primary knee osteoarthritis during the same 27-year period. Methods From the Finnish Arthroplasty Register, we obtained the data for 4713 patients undergoing UKAs for primary osteoarthritis (mean age, 63.5 years; minimum followup, 0 years; mean, 6.0 years; range, 0-24 years) who had surgical revision between 1985 and 2011. From this cohort, we calculated the Kaplan-Meier survivorship for revision performed for any reason and compared it with the survivorship of 83,511 patients (mean age, 69.5 years; minimum followup 0 years; mean, 6.4 years; range, 0-27 years) with TKAs treated for primary osteoarthritis during the same period. Data were adjusted for age and sex in a comparative analysis.

An Analysis of Risk Factors for Short-Term Complication Rates and Increased Length of Stay Following Unicompartmental Knee Arthroplasty

“…Despite these benefits, there appears to be conflicting reports in the literature with regards to the long-term survival of UKA implants; with registry data demonstrating increased rates of revision compared to TKA [20,21,28], while case series demonstrate equivalent outcomes [5,10,16,17,25,27,30,32,34]. Furthermore, controversy surrounds the impact of obesity on the long-term outcomes following UKA [8,11].…”

Downhill walking gait pattern discriminates between types of knee arthroplasty: improved physiological knee functionality in UKA versus TKA

“…The primary reason for this is the substantially lower revision rates in total knee arthroplasty (TKA) as reported by the registries [2,25]. This empowers surgeons to recommend it as implant survival is a therapeutic measure of success.…”

Revision total knee arthroplasty for unexplained pain after unicompartmental knee arthroplasty: a case report

“…However, several joint registries reported that the overall survival of UKA is still poor compared with TKA (2-6). The reasons for revision after UKA are aseptic loosening, malalignment, prosthesis breakage, instability, infection, bone fracture, and OA in another compartment (16)(17)(18)(19). In the national registry, pain that cannot be explained by the abovementioned reasons were classified as unexplained pain.…”