Study finds, Influence of BMI and age on day-of-surgery disc
The indications for unicompartmental knee arthroplasty (UKA) have become less restrictive and, today, high age and high BMI are not considered contraindications by many surgeons. Researchers investigated the effect of BMI and age on day of surgery (DOS) discharge, prolonged admission, and 90-day readmission following UKA surgery.

This retrospective cohort study included 3,897 UKA patients in 8 fast-track arthroplasty centers. Patients were divided into 5 BMI groups and 5 age groups. Differences between groups in the occurrence of DOS discharge, prolonged admission more than 2 days, and 90-day readmission was investigated using a chi-square test and mixed-effect models adjusted for patient characteristics using surgical center as a random effect.

--Median LOS was 1 day. DOS discharge was achieved in 26% of patients with no statistically significant differences between BMI groups.

--DOS discharge was less likely in UKA patients aged more than 70 years.

--Prolonged admission was not affected by BMI or age in the adjusted analysis. 90-day readmission was more likely in patients with BMI more than 35 and patients aged 71–80.

More than 70 years of age, in particular, reduced the likelihood of DOS discharge after UKA. The risk of 90-day readmission was enhanced by having a high BMI and being older. Surgeons operating on patients with a high BMI and advanced age should be aware of this.