Comparative Study of Body Mass Index Effects on Physical Therapy Results after Total Knee Arthroplasty During Hospitalization

Background: Rates of total knee arthroplasty (TKA) are increasing each year and considered as an effective management for obese patients with degenerated knee joints. Objectives: To determine the effect of the degree of body mass index on inpatients results of physical therapy program after total knee arthroplasty during hospitalization period. Participants: Forty patients with knee osteoarthritis were involved in this study after total knee arthroplasty and they were randomly distributed into two experimental groups. The first group was consisted of 20 patients (16 females, 4 males) with BMI ranged from 25 to 29.9kg/m^2 (overweight degree). The second group was consisted of 20 obese patients (15 females and 5 males) with BMI ranged from 35 to 40Kg/m^2 (moderate obesity degree). Methods: All patients after surgery were treated by the same standard plan of physical therapy including continuous passive motion, active assisted and active free range of motion exercises, isometric and isotonic strengthening exercises, gait training and transfer training. Main Outcomes Measures: Both groups were evaluated pre-operatively and after the 6th day of hospitalization period post-operatively by knee function test score [Hospital for Special Surgery (HSS) score], pain, and range of motion of knee flexion. Results: The overweight group showed that there is significant increase in physical therapy outcomes than the moderate obese group (p 0.05). Both groups significantly improved in all parameters after 6 days of hospitalization. Conclusions: The decreased BMI is more effective for physical therapy outcomes during the hospitalization period than the increased BMI after total knee arthroplasty. By these findings the patients who will undergo TKA should follow weight reduction program to decrease their BMI before the surgery.