Assessment of Free-Living Cadence Using ActiGraph Accelerometers Between Individuals With and Without Anterior Cruciate Ligament Reconstruction

Context: Anterior cruciate ligament reconstruction (ACLR) and gait speed are risk factors for developing knee osteoarthritis (OA). Measuring minute-level cadence during free-living activities may aid in identifying individuals at elevated risk of developing slow habitual gait speed and, in the long term, OA. Objective: To assess differences in peak 1-minute cadence and weekly time in different cadence intensities between individuals with and without ACLR. Design: Cross-sectional study. Setting: Short-term, free-living conditions. Patients or Other Participants: A total of 57 participants with ACLR (34 women, 23 men; age = 20.9 +/- 3.2 years, time since surgery = 28.7 +/- 17.7 months) and 42 healthy control participants (22 women, 20 men; age = 20.7 +/- 1.7 years). Main Outcome Measure(s): Each participant wore a physical activity monitor for 7 days. Data were collected at 30 Hz, processed in 60-second epochs, and included in the analyses if the activity monitor was worn for at least 10 hours per day over 4 days. Mean daily steps, peak 1-minute cadence, and weekly minutes spent at 60 to 79 (slow walking), 80 to 99 (medium walking), 100 to 119 (brisk walking), >= 100 (moderate-to vigorous-intensity ambulation), and >= 130 (vigorous-intensity ambulation) steps per minute were calculated. One-way analyses of covariance were conducted to determine differences between groups, controlling for height and activity-monitor wear time. Results: Those with ACLR took fewer daily steps (8422 +/- 2663 versus 10 033 +/- 3046 steps; P = .005) and spent fewer weekly minutes in moderate- to vigorous-intensity cadence (175.8 +/- 116.5 minutes versus 218.5 +/- 137.1 minutes; P = .048) than participants without ACLR. We observed no differences in minutes spent at slow (ACLR = 77.4 +/- 40.5 minutes versus control = 83.9 +/- 34.3 minutes; P = .88), medium (ACLR = 71.6 +/- 40.2 minutes versus control = 82.9 +/- 46.8 minutes; P = .56), brisk (ACLR = 115.3 +/- 70.3 minutes versus control = 138.3 +/- 73.3 minutes; P = .18), or vigorous-intensity (ACLR = 24.3 +/- 36.5 minutes versus control = 38.1 +/- 60.9 minutes; P = .10) cadences per week. Conclusions: Participants with ACLR walked approximately 40 fewer minutes per week in moderate- to vigorous-intensity cadence than participants without ACLR. Increasing the time spent at cadence >= 100 steps per minute and overall volume of physical activity may be useful as interventional targets to help reduce the risk of early development of OA after ACLR.