Daily Walking and the Risk of Knee Replacement Over 5 Years Among Adults With Advanced Knee Osteoarthritis in the United States

Objective: To examine the association of the volume and intensity of daily walking at baseline with the risk of knee replacement (KR) over 5 years in adults with advanced structural knee osteoarthritis.

Design: Prospective, longitudinal, and multicenter observational study.

Setting: Osteoarthritis Initiative study with follow-up from 2008-2015.

Participants: Community-dwelling adults with or at risk of knee osteoarthritis were recruited from 4 sites in the United States (N=516; mean age, 67.7±8.6y; body mass index, 29.3±4.7 kg/m²; 52% female). We included participants with advanced structural disease, without KR and had valid daily walking data (quantified using Actigraph GT1M), at baseline.

Interventions: Not applicable.

Main outcomes: KR. Walking volume was measured as steps/day and intensity as minutes/day spent not walking (0 steps/min) and walking at very light (1-49 steps/min), light (50-100 steps/min), or moderate (>100 steps/min) intensities. To examine the relationship of walking volume and intensity with the risk of KR, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) adjusting for covariates.

Results: Of 516 adults with advanced structural disease, 88 received a KR over 5 years (17%). Walking an additional 1000 steps/d was not associated with the risk of KR (adjusted HR=0.95; 95% CI, 0.84-1.04). Statistically, replacing 10 min/d of very light and light walking with 10 min/d of moderate walking reduced the risk of KR incidence by 35% and 37%, respectively (adjusted HR=0.65, 95% CI, 0.45-0.94, for very light and adjusted HR=0.63; 95% CI, 0.40-1.00, for light).

Conclusions: Daily walking volume and intensity did not increase KR risk over 5 years and may be protective in some cases in adults with advanced structural knee osteoarthritis.