This retrospective research was performed to evaluate the acute care rehabilitation program provided for patients receiving total knee arthroplasties in one institution. Included were 146 patients with unilateral arthroplasties and 40 patients with bilateral arthroplasties. Care and charge data, functional scores, and discharge disposition were documented for all subjects. The mean hospital days and associated charges were, respectively, 9.9 and $16,149 for unilateral arthroplasties and 11.9 and $23,594 for bilateral arthroplasties. Significant improvements in function (bed mobility, transfers, locomotion, and stairs) occurred during the course of rehabilitation. Over 96% of the patients were discharged home (either with or without services). Predictive of both discharge disposition and hospital charges were arthroplasty type, initial bed mobility score, and discharge transfer score. The results demonstrate differences associated with unilateral and bilateral surgeries, verify that functional changes accompany rehabilitation, and show that functional capacity has implications for charges and discharge disposition.