Outcomes of a First Total Knee Arthroplasty Are Associated With Outcomes of the Subsequent Contralateral Total Knee Arthroplasty

To determine if preoperative characteristics and postoperative outcomes of a first total knee arthroplasty (TKA) were predictive of characteristics and outcomes of the subsequent contralateral TKA in the same patient.

Retrospective administrative claims data from (SPARCS) database were analyzed for patients who underwent sequential TKAs from September 2015 to September 2017 (n = 5,331). Hierarchical multivariable Poisson regression (length of stay [LOS]) and multivariable logistic regression (all other outcomes), controlling for sex, age, and Elixhauser comorbidity scores were performed.

The cohort comprised 65% women, with an average age of 66 years and an average duration of 7.3 months between surgeries (SD: 4.7 months). LOS was significantly shorter for the second TKA (2.6 days) than for the first TKA (2.8 days; P < .001). Patients discharged to a facility after their first TKA had a probability of 76% of discharge to facility after the second TKA and were significantly more likely to be discharged to a facility compared with those discharged home after the first TKA (odds ratio [OR]: 63.7; 95% confidence interval [CI]: 52.1-77.8). The probability of a readmission at 30 and 90 days for the second TKA if the patient was readmitted for the first TKA was 1.0% (OR: 3.70; 95% CI: 0.98-14.0) and 6.4% (OR: 9; 95% CI: 5.1-16.0), respectively. Patients with complications after their first TKA had a 27% probability of a complication after the second TKA compared with a 1.6% probability if there was no complication during the first TKA (OR: 14.6; 95% CI: 7.8.1-27.2).

The LOS, discharge disposition, 90-day readmission rate, and complication rate for a second contralateral TKA are strongly associated with the patient’s first TKA experience. The second surgery was found to be associated with an overall shorter LOS, fewer readmissions, and higher likelihood of home discharge.

Level 3-retrospective cohort study.