Effect of obesity on inpatient rehabilitation outcomes following total knee arthroplasty.

OBJECTIVES: To examine obesity effects on outcomes following inpatient rehabilitation in patients following primary total knee arthroplasty or revision total knee arthroplasty.

DESIGN: Retrospective, comparative study.

SETTING: Fifty-bed, university-affiliated rehabilitation hospital.

PATIENTS: Obese (N = 139; body mass index >30 kg/m(2)) and non-obese (N = 146; body mass indexB <30 kg/m(2)) total knee arthroplasty patients. Participants were further stratified based on total knee arthroplasty type, primary and revision for a total of four groups.

INTERVENTION: Interdisciplinary inpatient rehabilitation.

MAIN MEASURES: Range of motion, length of stay, Functional Independence Measure (FIM) scores, FIM efficiency scores, total and daily hospital charges, and discharge disposition location.

RESULTS: Range of motion and FIM scores improved from admission to discharge in both obese and non-obese patients regardless of total knee arthroplasty type. FIM efficiency was lower in revision than primary total knee arthroplasty (2.8 versus 3.6 patients/day; P < 0.005) but not different between obese and non-obese groups. Total hospital charges were lower for the primary than for the revision patients (P < 0.05), but were directly related with body mass index (r = 0.140, P < 0.05). Discharge disposition locations were not different among groups.

CONCLUSION: Rehabilitation teams can expect comparable gains between obese and non-obese patients following total knee arthroplasty, but at a greater expense.