Factors affecting short-term functional gain following total knee arthroplasty in patients aged from 75 years at a postacute rehabilitation setting.

The intensive rehabilitation of older patients after total knee arthroplasty (TKA) is vital for short-term improvement in mobility and daily living activities. We aimed to investigate the effectiveness of multidisciplinary rehabilitation and assess the early postoperative predictors that are associated with functional gain in TKA patients aged from 75 years in a postacute care setting. This study included 190 patients following primary TKA who were admitted at the postacute rehabilitation hospital. The main outcome measures were the motor component of functional independence measure (M-FIM), M-FIM effectiveness, numerical rating scale, knee extension strength and range of motion, 10-m walk test, Berg balance scale (BBS), and mini-mental state examination (MMSE). The functional gain between patient age groups of ≥75 ( n  = 105) and <75 ( n  = 85) years were compared. Although patients aged ≥75 years showed lower improvement in BBS score compared with <75 years, the M-FIM gains and other physical functions were similar in both age groups. In multivariate analysis, the results for M-FIM at admission (β: -0.703; P  = 0.001), BBS (β: 0.342; P  = 0.032) and MMSE (β: 0.446; P  = 0.021) were independently associated with functional gain in the patients following TKA aged ≥75 years. Multidisciplinary inpatient rehabilitation was beneficial for basic functional gain except for improvement in balance ability in patients after TKA aged ≥75 years. Functional level, balance ability and cognitive status in the early postoperative period can be useful predictors for short-term functional gain in the postacute care phase.