Physical activity measured using a triaxial accelerometer in early after surgery rehabilitation in patients with hip fracture affects walking ability: a retrospective observational study.

[Purpose] To clarify the association between physical activity measured using a triaxial accelerometer in early after surgery rehabilitation sessions and short-term walking ability in older adult patients with hip fractures and investigate indicators for determining the appropriate intensity and volume of early mobilization. [Participants and Methods] We analyzed 109 patients aged ≥75 years (median, 88.0 years) with hip fractures who underwent surgical treatment. A triaxial accelerometer was used to quantify physical activity. We investigated the association between physical activity (≥1.6 METs) measured early after surgery and walking ability at 1 and 2 weeks after surgery. [Results] The rehabilitation intervention times were 119.0 [104.7-129.3] min/day. Factors associated with walking independence were as follows: 1 week after surgery, fracture type, cognitive function, and physical activity during rehabilitation sessions; 2 weeks after surgery, surgery type, cognitive function, and physical activity during rehabilitation sessions. The cutoff values for physical activity during rehabilitation sessions for determining walking independence were ≥21.6% and ≥17.8% at 1 and 2 weeks after surgery, respectively. [Conclusion] Physical activity during early after surgery rehabilitation sessions affects short-term walking ability. Our findings emphasize the importance of establishing indicators of physical activity and early mobilization during early after surgery rehabilitation sessions.