Physical activity in the acute hospital following elective lower limb joint arthroplasty

Abstract

The objective of this study was to quantify physical activity undertaken by patients in the acute setting following elective lower limb joint replacement and determine the relationship between physical activity and hospital outcomes (length of stay [LOS] and discharge destination). This prospective observational study included 74 adults with osteoarthritis who underwent lower limb arthroplasty (total hip replacement n = 38, total knee replacement n = 36). Participants were fitted with an accelerometer and inclinometer-based device (activPAL3TM) post-operatively prior to first mobilisation for the duration of the acute hospital admission. Physical activity data collected were steps, sit-to-stand transitions and upright time (standing and stepping). The relationship between each physical activity variable and hospital outcomes was calculated using logistic regression (for discharge destination) and linear regression (for LOS). Potential confounding factors considered in multivariable models included age, sex, body mass index, Risk Assessment Prediction Tool, American Society of Anesthesiologists Score and surgical procedure. Analyses for the relationship with these outcomes used physical activity data from day two as these comprised the largest dataset for a single day. Participants’ mean (SD) age was 67 (10) years and 53% were female. Participants performed a median (IQR) of 136 (50–294) steps, 17 (11–75) transitions and 52 (32–94) upright minutes per day. All physical activity variables were significantly negatively associated with LOS (steps p = 0.016, transition p = 0.025, upright time p = 0.024). There was a significant association between discharge to inpatient rehabilitation for steps (p = 0.010) and transitions (p = 0.005).