Unicompartmental knee arthroplasty: long-term success in middle-age and obese patients.

The purpose of this study is to report long-term results of unicompartmental knee arthroplasty (UKA) in general and specifically to address the results in middle-age and obese patients. One hundred consecutive medial compartment UKAs performed in 82 patients between 1974 and 1999 were reviewed. Survivorship analysis and Knee Society scores were compiled and stratified based on age at the time of surgery, gender, and body habitus. Mean survivorship of the procedure was 93.7% at 5 years (95% CI 88.8-98.6%), 89.8% at 10 years (83.3-96.1%), 85.9% at 15 years (77.8-93.9%), and 80.2% at 20 years (69.5-90.9%). Females had significantly better survivorship than males at 10, 15, and 20 years. Obese patients had better survivorship than nonobese patients at 20 years. There was no significant difference in survivorship based on age over or under 60 at the time of surgery. The average Knee Society knee score at most recent follow-up was 89.3 and the average function score was 73.1. There were no significant differences in Knee Society scores among the subgroup. UKA offers reliable long-term survival. Age less than 60 and obesity do not appear to be contraindications to the procedure.