Does physical activity change following hip and knee replacement? Matched case-control study evaluating Physical Activity Scale for the Elderly data from the Osteoarthritis Initiative

Objectives: To determine whether physical activity measured using the Physical Activity Scale for the Elderly (PASE), changes during the initial 24 months post-total hip (THR) or knee replacement (TKR), and how this compares to a matched non-arthroplasty cohort.

Design: Case-controlled study analysis of a prospectively collected dataset.

Setting: USA community-based.

Participants: 116 people post-THR, 105 people post-TKR compared to 663 people who had not undergone THR or TKR, or had hip or knee osteoarthritis. Cohorts were age-, gender- and BMI-matched.

Main outcome measures: Physical activity assessed using the 12-item PASE at 12 and 24 months post-operatively.

Results: There was no significant difference in total PASE score between pre-operative to 12 months (mean: 136 vs. 135 points; p=0.86) or 24 months following THR (mean: 136 vs 132 points; p=0.95). Whilst there was no significant difference in total PASE score from pre-operative to 12 months post-TKR (126 vs. 121 points; p=0.93), by 24 months people following TKR reported significantly greater physical activity (126 vs. 142 points; p=0.04). There was no statistically significant difference in physical activity between the normative matched and THR (p≥0.14) or TKR (p≥0.06) cohorts at 12 or 24 months post-joint replacement.

Conclusions: Physical activity is not appreciably different to pre-operative levels at 12 or 24 months post-THR, but was greater at 24 months following TKR. Health promotion strategies are needed to encourage greater physical activity participation following joint replacement, and particularly targeting those who undergo THR.