ABSTRACT
INTRODUCTION: Limited range of motion (ROM) after total knee replacement (TKR) is associated with low function and might require manipulation under anaesthesia (MUA). In order to identify factors associated with a limited ROM we investigated predictors for MUA. We hypothesized that older age was associated with higher MUA due to limited ROM post TKR. METHODS: In a case control study we investigated all patients undergoing primary TKR at a University Hospital in Sweden between 2007-2012. We registered background factors and compared those between the group who underwent MUA and those who did not. Odds ratios (OR) were calculated in a univariate analysis and an adjusted regression analysis. RESULTS: Of the total of 669 TKRs performed, 31 patients who had undergone MUA were identified. The prevalence of MUA was 4.6%. The mean increase in ROM after MUA was 27 degrees at final minimum one-year follow-up. After controlling for confounders, patients with good health and young age had increased OR for MUA. OR decreased 0.93 (CI 0.93-0.97) per increased age year in the multiple regression analysis. Diabetes mellitus, BMI and sex did not have a significant effect on the odds ratio for MUA. DISCUSSION: Young patients undergoing TKR has earlier been identified as a group with a higher grade of dissatisfaction and complications. We found an association between young age and MUA after TKR indicating an additional, rather unknown complication for this group of patients. The background and reasons for this has to be further investigated. LEVEL OF EVIDENCE: II, cohort study/case control study (case control is level III).
