title: Rationale, design and protocol of a longitudinal study assessing the effect of total knee arthroplasty on habitual physical activity and sedentary behavior in adults with osteoarthritis.
abstract: Physical activity levels are decreased and sedentary behaviour levels are increased in patients with knee osteoarthritis (OA). However, previous studies have shown that following total knee arthroplasty (TKA), objectively measured physical activity levels do not change compared to before the surgery. Very few studies have objectively assessed sedentary behaviour following TKA. This study aims to assess patterns of objective habitual physical activity and sedentary behaviour in patients with knee OA and to determine whether these change following TKA.
  
  
  
  Patients diagnosed with knee osteoarthritis and scheduled for unilateral primary total knee arthroplasty will be recruited from the Orthopaedic Division at the Charlotte Maxeke Johannesburg Academic Hospital. Eligible participants will have assessments completed one week before the scheduled arthroplasty, six weeks, and six months post-operatively. The primary outcomes are habitual physical activity and sedentary behaviour which will be measured using accelerometry (Actigraph GTX3+ and activPal monitors) at the specific time points. The secondary outcomes will be improvements in osteoarthritis-specific quality of life measures using the following questionnaires: Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), Knee Society Clinical Rating System (KSS), UCLA activity index; subjective pain scores, and self reported sleep quality.
  
  
  
  The present study will contribute to the field of musculoskeletal health by providing a rich detailed description of the patterns of accumulation of physical activity and sedentary behaviour in patients with knee OA. These data will contribute to existing knowledge using an objective measurement for the assessment of functional ability after total knee arthroplasty. Although studies have used accelerometry to measure physical activity in knee OA patients, the data provided thus far have not delved into the detailed patterns of how and when physical activity is accumulated before and after TKA. Accurate assessment of physical activity is important for physical activity interventions that target special populations.
  
  
  
  NCT02675062 (4 February 2016).
authors.affiliation: Exercise Physiology Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg, South Africa. Rebecca.Meiring@wits.ac.za.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Meiring
authors.affiliation: Exercise Physiology Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg, South Africa.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Frimpong
authors.affiliation: Division of Orthopaedics, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg, South Africa.
authors.forename: Lipalo
authors.initials: L
authors.lastname: Mokete
authors.affiliation: Division of Orthopaedics, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg, South Africa.
authors.forename: Jurek
authors.initials: J
authors.lastname: Pietrzak
authors.affiliation: Division of Orthopaedics, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg, South Africa.
authors.forename: Dick
authors.initials: D
authors.lastname: Van Der Jagt
authors.affiliation: Division of Rheumatology, Department of Medicine, Chris Hani Baragwanath Academic Hospital, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg, South Africa.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Tikly
authors.affiliation: Exercise Physiology Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg, South Africa.|School of Physiotherapy and Exercise Science, Curtin University, Kent St, Bentley, Western Australia.
authors.forename: Joanne A
authors.initials: JA
authors.lastname: McVeigh
mesh_terms: D000368:Aged; D006801:Humans; D008875:Middle Aged; D019645:Arthroplasty, Replacement, Knee; D015444:Exercise; D005500:Follow-Up Studies; D007719:Knee Joint / Q000503:physiopathology; D008137:Longitudinal Studies; D020370:Osteoarthritis, Knee / Q000523:psychology / Q000601:surgery; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D011446:Prospective Studies; D011788:Quality of Life; D020127:Recovery of Function; D057185:Sedentary Behavior; D057566:Self Report; D013019:South Africa; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D064887:Observational Studies as Topic
keywords: Accelerometery; Knee arthroplasty; Osteoarthritis; Physical activity; Sedentary behaviour