Sedentary Behavior, Cadence, and Physical Activity Outcomes after Knee Arthroplasty

Purpose: This study comprehensively examined sedentary behavior and physical activity patterns in people with severe knee osteoarthritis awaiting total knee arthroplasty (TKA) and in individuals after TKA.

Methods: Preoperative (n = 32, mean ± SD = 69.9 ± 5.3 yr) and 1-yr postoperative participants with TKA (n = 38, 67.9 ± 7.3 yr) wore ActiGraph GT3X+ activity monitors for 6.8 ± 0.6 d. Total sedentary time, time in long sedentary bouts (≥30 min), and physical activity outcomes (steps, time in moderate-to-vigorous physical activity [MVPA], cadence) were examined.

Results: There were no differences between pre- and postoperative groups for total sedentary time (9.3 ± 1.4 vs 9.2 ± 1.4 h·d−1, P = 0.62) and number of long sedentary bouts per day (median [interquartile range] = 3.4 [1.9] vs 3.1 [2.0], P = 0.37). Daily steps, peak 30-min cadence, and peak 1-min cadence values were greater in people after TKA compared with those awaiting surgery (5935 [3316] vs 3724 [2338], 55.6 [31.0] vs 35.9 [19.3], and 91.5 ± 20.6 vs 70.0 ± 23.7, respectively, all P < 0.01). There were no differences in lifestyle MVPA between groups. The number of bouts of Freedson MVPA was greater in postoperative participants, but the differences were not substantial (one bout per week).

Conclusion: Patients report less knee pain and improved function after TKA; however, sedentary behavior does not differ and physical activity is only marginally increased compared with those awaiting surgery. After TKA, daily walking at slow, moderate, and brisk paces and engagement in MVPA do not match levels seen in healthy older adults, which, when combined with high levels of sedentary behavior, leaves patients at increased risk for physical disability and cardiovascular disease.