Does high activity after total and unicompartmental knee arthroplasty increase the risk for aseptic revision?

Abstract

It has been suggested that high activity might negatively impact implant survival following total and unicompartmental knee arthroplasty (TKA/UKA) and many surgeons advise their patients to only participate in moderate level sport activities. To date, it remains unclear whether such restraints are necessary to assure longevity of the implants. We conducted a retrospective study on 1906 knees (1745 TKA, 161 UKA) in 1636 patients aged 45-75years who underwent primary arthroplasty for primary osteoarthritis. Lower extremity activity scale (LEAS) at a two year follow-up was assessed to define the activity level. Cases were grouped in low (LEAS ≤ 6), moderate (LEAS 7-13) and high activity (LEAS ≥ 14). Cohorts were compared with Kruskal-Wallis- or Pearson-Chi2-Test. Univariate logistic regression was conducted to test for association between activity level at two years and later revisions. Odds ratio was reported and converted to predicted probability. A Kaplan-Meier curve was plotted to predict implant survival. The predicted implant survival for UKA was 100.0% at twoyears and 98.1% at fiveyears. The predicted implant survival for TKA was 99.8% at twoyears, 98.1% at fiveyears. The difference was not significant (p = 0.410). 2.5% of the UKA underwent revision, one knee in the low and threeknees in the moderate activity group, differences between the moderate and high activity group were not significant (p = 0.292). The revision rate in the high activity TKA group was lower than in the low and moderate activity groups (p = 0.008). A higher LEAS twoyears after surgery was associated with a lower risk for future revision (p = 0.001). A one-point increase in LEAS twoyears after surgery lowered the odds for undergoing revision surgery by 19%. The study suggests that participating in sports activity following both UKA and TKA is safe and not a risk factor for revision surgery at a mid-term follow-up. Patients should not be prevented from an active lifestyle following knee replacement.