Effects of obesity on inpatient rehabilitation outcomes following total knee arthroplasty

Abstract Objective To investigate the effects of obesity on inpatient rehabilitation outcomes following total knee arthroplasty. Participants Two hundred and thirty-nine total knee arthroplasty patients (12 men and 227 women). Interventions Patients were divided in two groups (non-obese and obese) according to pre-operative body mass index (BMI). After surgery, all patients received standard post-operative treatment from a physiotherapist, including continuous passive motion, active-assistive and active range of motion exercises, isometric and isotonic strengthening exercises, gait training and transfer training. Main outcome measures Patients were evaluated pre-operatively and at discharge using BMI, knee function score [Hospital for Special Surgery (HSS) score], pain and range of motion of knee flexion. Functional activities were evaluated using the Iowa Level of Assistance Scale, and walking speed was evaluated using the Iowa Ambulation Velocity Scale. Results There were no statistically or clinically significant differences between the two groups of patients at discharge, with obese patients recording a mean HSS score of 62.6 points (95% confidence interval 61.3 to 63.9) and non-obese patients recording a mean HSS score of 62.6 (95% confidence interval 61.6 to 63.7, P = 0.950). Both groups improved in all parameters at the time of discharge compared with pre-operative values, with the exception of walking speed and the range of knee flexion. There was no significant difference in length of hospital stay between obese (median 9 days, interquartile range 4–22) and non-obese (median 9 days, interquartile range 4–23) patients. Conclusions Obesity had no negative effects on inpatient rehabilitation outcomes following total knee arthroplasty. This finding is significant given implementation of the prospective payment system in rehabilitation hospitals in parts of Turkey, and the effect that this will have on length of hospital stay for patients who have undergone total knee arthroplasty.