Measurement of physical activity in the pre- and early post-operative period after total knee arthroplasty for Osteoarthritis using a Fitbit Flex device

• Published in: Medical engineering & physics Vol. 51; pp. 31 - 40
• Main Authors: Twiggs, Joshua, Salmon, Lucy, Kolos, Elizabeth, Bogue, Emily, Miles, Brad, Roe, Justin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2018
• Subjects: Aged; Arthroplasty, Replacement, Knee; Early recovery period; Exercise; Female; Humans; Length of Stay; Male; Monitoring, Physiologic - instrumentation; Osteoarthritis - physiopathology; Osteoarthritis - surgery; Pedometer; Physical activity; Postoperative Period; Preoperative Period; Step count; Total knee arthroplasty; Total knee arthroplasty; Pedometer; Early recovery period; Physical activity; Step count
• ISSN: 1350-4533; 1873-4030
• DOI: 10.1016/j.medengphy.2017.10.007

•Pre- and early post-operative daily step count measured with Fitbit Flex devices for patients with OA undergoing TKA.•Pre-operative step count, SF-12 PCS score and BMI were strong correlators with post- operative stepcount.•Semi-individualised benchmarks based on correlating scores and grouping are presented.•A stepwise multivariate regression model is used to develop a patient specific 6 week step count target. Total knee arthroplasty (TKA) is a standard treatment for patients with end stage knee Osteoarthritis (OA) to reduce pain and restore function. The aim of this study was to assess pre- and early post-operative physical activity (PA) with Fitbit Flex devices for patients with OA undergoing TKA and determine any benchmarks for expected post-operative activity. Significant correlations of pre-operative step count, post-operative step count, Body Mass Index (BMI) and Short Form 12 Physical Component Summaries (SF-12 PCS) were found. Mean step counts varied by 3,203 steps per day between obese and healthy weight patients, and 3,786 steps per day between those with higher and lower SF-12 PCS scores, suggesting the need for benchmarks for recovery that vary by patient pre-operative factors. A backwards stepwise regression model developed to provide patient specific step count predictions at 6 weeks had an R2 of 0.754, providing a robust patient specific benchmark for post-operative recovery, while population means from BMI and SF-12 subgroups provide a clinically practical alternative.