Outcomes in total knee arthroplasty patients after inpatient rehabilitation: influence of age and gender.

OBJECTIVES: To examine age and gender effects on outcomes after inpatient rehabilitation in primary total knee arthroplasty (TKA) and revision TKA patients.

DESIGN: This retrospective, comparative study was conducted in a 50-bed, university-affiliated rehabilitation hospital. Patients included primary TKA patients (n = 286) and revision TKA patients (n = 138) placed into one of three age brackets: <60 yrs, 60-70 yrs, or >70 yrs. Measurements included length of stay (LOS), FIM scores, hospital charges, and discharge disposition location.

RESULTS: FIM scores improved from admission to discharge in both primary and revision patients (P = 0.015). LOS was shorter in primary than revision patients (8.3 vs. 10.4 days, P = 0.001), and the LOS was longest in patients >70 yrs compared with those <60 or 60-70 yrs (10.6 vs. 8.7 and 8.8 days, respectively; P = 0.004). FIM efficiency was greater in primary than in revision TKA patients (3.68 vs. 2.77 points/day, P = 0.001), and greater for men than women in each age bracket regardless of TKA type (3.68 vs. 2.78 points/day, P = 0.001). Total hospital charges were lower for men than women for both TKA types ($9,656 +/- 823 vs. $11,544 +/- 1,359; P = 0.015), and were highest in patients >70 yrs of age (P = 0.015).

CONCLUSIONS: Primary and revision TKA patients make improvements in functional independence during inpatient rehabilitation. Although FIM gains were similar among age and gender groupings, FIM efficiency is lowest in women. Despite similar daily hospital costs among the groups, slower progress with functional gains (decreased FIM efficiency) increases the LOS and total hospital charges, especially in older women.