Habitual Physical Activity and Sedentary Behavior Following Total Knee Arthroplasty
Condition: Knee Osteoarthritis
MeSH terms: Osteoarthritis
Study type: Observational

Summary: 
      The purpose of this study is to determine whether habitual physical activity and sedentary
      behaviour improve six weeks and between three to six months after total knee replacement
      surgery in people with osteoarthritis.
    

Detailed description: 
      The aims of this study are to

        1. describe habitual physical activity and sedentary behaviour patterns in knee
           osteoarthritis patients who are scheduled for total knee arthroplasty,

        2. investigate the effects of unilateral primary total knee arthroplasty on objectively and
           subjectively measured physical activity, sedentary behaviour and health outcomes of knee
           OA patients and

        3. compare subjective measures of functional ability and sedentary behaviour
           (questionnaires) with objective measures of habitual physical activity and sedentary
           behaviour (accelerometry) both before and after total knee arthroplasty.

      Study design:

      This a longitudinal follow-up study of a cohort of participants who have been diagnosed with
      knee osteoarthritis and who will all be undergoing total knee arthroplasty. After enrolment
      into the study, baseline assessments will be done prior to total knee arthroplasty. After
      total knee arthroplasty, participants will be followed-up and the same assessments done at
      baseline will also be done at 6 weeks, and 3 to 6 months post-operatively. Habitual physical
      activity and sedentary behaviour will be measured using accelerometry (Actigraph GTX3+ and
      ActivPal monitors) at the specific time points.The ActiGraph will be worn by participants for
      24 hours/day for seven days at each of the assessment time points. It will be attached to an
      elastic nylon strap which the participants can wear as a belt around the waist on the side of
      right/left hip (depending on which knee is being operated on). Thus, the ActiGraph will be
      worn on the side of left hip if the total knee arthroplasty is on the left knee and vice
      versa. Participants will be asked to remove the ActiGraph when showering, bathing or
      swimming. After seven days of accelerometer wear, the accelerometers will be collected at the
      next possible visit to the hospital or arrangement will be made for collection from
      participants at a location most convenient to them. An ActivPAL will be taped to the thigh of
      the patient with waterproof taping and the patient will be asked to keep the ActivPAL on for
      the same amount of time as the ActiGraph. The ActivPAL can be covered with waterproof taping
      therefore, there will be no need to remove the ActivPAL when showering, bathing or swimming.
      The ActivPAL will be collected at the same time as the ActiGraph. In addition, general
      health, functional ability, generic quality of life and sleep and pain questionnaires will be
      conducted at each time point on each participant.

      Study Site:

      The study will be conducted at the Charlotte Maxeke Academic Hospital in Johannesburg, South
      Africa. It is an accredited central hospital with about 1088 beds serving patients from
      across Gauteng and neighbouring provinces. The hospital is situated in Parktown and also,
      serves as the main teaching hospital for the University of the Witwatersrand, Faculty of
      Health Sciences. Study participants will be recruited from the Division of Orthopaedics in
      the hospital. This hospital is chosen because: (1) it is a tertiary hospital that runs
      several specialist clinics including the Orthopaedic Division where total knee arthroplasty
      is performed and (2) there is a collaboration between the Academic staff of the Faculty of
      Health Sciences of University of the Witwatersrand and the hospital Staff for teaching and
      research which will facilitate accessibility to patients.

      Sample Size Determination:

      Based on an anticipated 2% decrease in the amount of time spent in sedentary behaviour per
      day (which, for an average 16 hour day, equates to a 20 minute reduction), a sample size
      calculation shows that a total sample of 107 participants will be required in this study to
      detect a significant effect of knee arthroplasty on sedentary behaviour with a power of 80%.

      The effect of the total knee arthroplasty on the change in habitual physical activity and
      sedentary behaviour will be assessed between the three timepoints (baseline, six weeks and
      three to six months).
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The study population will include all knee osteoarthritis patients receiving care at the
        Charlotte Maxeke Johannesburg Academic Hospital. Patients will be recruited from the
        Orthopaedic Division of the hospital. The participants for this study will be knee
        osteoarthritis patients scheduled (on surgical waiting list) for a single primary total
        knee arthroplasty. Knee osteoarthritis will be diagnosed based on clinical criteria as
        defined by the American Rheumatism Association. The grade of knee osteoarthritis will be
        graded using the Kellgren and Lawrence classification of severity.
      
Keywords: Accelerometry; Osteoarthritis; Habitual physical activity; Sedentary behaviour; Knee arthroplasty