Unicompartmental Knee Arthroplasty (UKA) has gained in popularity as a treatment for medial compartment osteoarthritis of the knee. UKA benefits include the fact that it is less invasive than total knee arthroplasty, has a shorter recovery period, and it has a decreased risk of peri-operative complications. As the volume of UKA increases along with an aging population, the need for revision arthroplasty surgical care will continue to rise. The Alberta Bone and Joint Health Institute (ABJHI), established in 2004, is an independent not-for-profit organization dedicated to improving care for individuals with bone and joint health conditions in Alberta, Canada. ABJHI operates a comprehensive data repository under formal affiliation agreements with over 100 custodians of health data, including Alberta Health Services (AHS), orthopedic surgeons, and physicians of other specialties. Through comprehensive data sharing agreements, ABJHI captures all primary and revision hip and knee arthroplasty patient care data throughout Alberta. This paper will analyze revision rates and reasons for revision for UKA procedures performed within Alberta. What is the cumulative revision rate over ten years and reasons for revision following unicompartmental knee arthroplasties (UKA) performed in Alberta? This retrospective cohort study uses prospectively collected patient data from ABJHI. Patients that underwent a UKA for medial compartment knee OA between April 1, 2005 and March 31, 2022 were included. For statistical analysis, Cumulative revision rate (CRR) was calculated using survival analysis (Kaplan–Meier method) with 95% Confidence interval (CI) and a log rank test was used for comparisons between gender and Body Max Index (BMI) groups with a p-value of < 0 .05 considered statistically significant. The Cumulative Revision Rate (CRR) was 2.80, 5.92 and 10.66 percent at two, five, and ten years post-op respectively. Three hundred and sixty patients required revisions to a TKA within ten years of their primary UKA. The population at risk for the ten-year results was 3509 UKA patients. There were no statistically significant differences between revision rates based on gender (p=0.078). There were significant differences in cumulative revision rates at all time points based on BMI with ten-year cumulative revision rates of 7.46 percent for patients with a BMI less than 35 and a rate of 12.07 percent for patients with a BMI greater than or equal to 35 (p=0.009). The reasons for revision included arthritis in a previously unresurfaced compartment (24.7 percent), aseptic loosening (16.7 percent), and pain of unknown origin (10.2 percent) being the most common. This study demonstrates reliable ten-year outcomes for patients undergoing unicompartmental knee arthroplasty for isolated medial knee osteoarthritis. The results of this study are comparable to results from global registries and the literature. Patient selection is a key component in avoiding revisions in this knee arthritis sub-population. The most common reasons for UKA revision are arthritis progression in previously unresurfaced compartments and aseptic loosening. In addition, elevated BMI is a risk factor for revision and should be considered in surgical decision-making.
Werle et al. (Wed,) studied this question.