Small Increase of Actual Physical Activity 6 Months After Total Hip or Knee Arthroplasty

Abstract

Limitation in daily physical activity is one of the reasons for total hip arthroplasty (THA) or total knee arthroplasty (TKA). However, studies of the effects of THA or TKA generally do not determine actual daily activity as part of physical functioning. We determined the effect of THA or TKA on patients' actual physical activity and body function (pain, stiffness), capacity to perform tasks, and self-reported physical functioning. We also assessed whether there are differences in the effect of the surgery between patients undergoing THA or TKA and whether the improvements vary between these different outcome measures. We recruited patients with longstanding end-stage osteoarthritis of the hip or knee awaiting THA or TKA. Measurements were performed before surgery and 3 and 6 months after surgery. Actual physical activity improved by 0.7%. Patients' body function, capacity, and self-reported physical functioning also improved. The effects of the surgery on these aspects of physical functioning were similar for THA and TKA. The effect on actual physical activity (8%) was smaller than on body function (80%-167%), capacity (19%-36%), and self-reported physical functioning (87%-112%). Therefore, in contrast to the large effect on pain and stiffness, patients' capacity, and their self-reported physical functioning, the improvement in actual physical activity of our patients was less than expected 6 months after surgery.

Do Activity Levels Increase After Total Hip and Knee Arthroplasty?

“…Hence, the physical activity guidelines provided a clinically relevant benchmark to measure physical activity against pre-and postoperatively. Four previous studies have measured physical activity using accelerometers before and at 6 months after arthroplasty [4,9,12,44]. One of these studies from The Netherlands [12] included a mixed cohort of people after either THA or TKA and in contrast to our study, a significant increase in physical activity at 6 months after THA and TKA was reported.…”

“…Four previous studies have measured physical activity using accelerometers before and at 6 months after arthroplasty [4,9,12,44]. One of these studies from The Netherlands [12] included a mixed cohort of people after either THA or TKA and in contrast to our study, a significant increase in physical activity at 6 months after THA and TKA was reported. However, this only equated to an increase of 10 minutes of activity per day, which the authors considered to be clinically insignificant.…”

“…However, this can be considered a limitation given that recovery after THA has been reported to be greater and occur earlier than after TKA [14], and thus may have influenced the degree of change we observed in the secondary outcomes of pain, physical function, and quality of life. However, for the primary outcome of physical activity, there is evidence to suggest there is no difference between these two groups [6,12]. Although we performed a subgroup analysis of change in physical activity for THA and TKA participants separately, it is important to note the small samples in each group mean these analyses are underpowered and the findings should be considered hypothesis-generating rather than conclusive.…”

“…The success of THA and TKA in relieving pain and improving function for patients with end-stage OA has been well established [14,24]. Another important goal of arthroplasty is to increase physical activity [6,7]; however, this goal is poorly understood and has received relatively little evaluation [4,9,12,44].…”

“…Contained within small activity monitors, they measure activity counts (summation of the frequency and intensity of vertical accelerations and decelerations measured during select time intervals), steps taken, and intensity of movement [2]. Recent studies exploring physical activity levels in the arthroplasty population using accelerometers [4,9,12,44] have reported conflicting findings regarding changes in physical activity after arthroplasty. Unfortunately, all but one of these studies measured physical activity over short durations of 24 to 48 hours [9,12,44], which is less than the recommended minimum of 3 to 5 days (including a weekend day) required to gain accurate measures of habitual physical activity [42].…”