Body mass index and functional mobility outcome following early rehabilitation after a total knee replacement: A retrospective study in Taiwan

Objective Obesity is associated with an increased risk of osteoarthritis, and the incidence of obese patients requiring a total knee replacement (TKR) has increased in recent years. A high body mass index (BMI) may influence post-TKR rehabilitation outcomes. We investigated the effects of obesity on functional mobility outcomes following post-TKR rehabilitation in Asian patients whose BMIs were not as high as those reported in similar studies performed in non-Asian countries. Methods A total of 113 patients were categorized as normal weight (n=23), overweight (n=32), class I obese (n=31), or class II/III obese (n=27). Patients were retrospectively followed up for 6 months after undergoing TKR followed by 2 months of active rehabilitation. Outcome measures were recorded at baseline and at the 2-month and 6-month followup assessments and included the Western Ontario and McMaster Universities Osteoarthritis Index and the following tests: functional reach, single-leg stance, ten-meter walk, timed up and go, chair rise, and stair climbing. Results A 4 × 3 (group × time) repeated-measures analysis of variance showed significant improvement in all of the outcome measures for all of the BMI groups at the 2-month and 6-month followup assessments (P<0.05 for all). No significant intergroup differences at the 2-month and 6-month followup assessments were observed for any of the mobility measures except the functional reach and single-leg stance (P<0.05). Conclusion Patients with class II/III obesity benefit from early post-TKR outpatient rehabilitation and respond as well as patients with lower BMIs.