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 = 0.860) or 24 months following THR (mean: 136 vs 132 points; p = 0.950). Whilst there was no significant difference in total PASE score from pre-operative to 12 months post-TKR (126 vs 121 points; p = 0.930), by 24 months people following TKR reported significantly greater physical activity (126 vs 142 points; p = 0.040). There was no statistically significant difference in physical activity between the normative matched and THR (p ≥ 0.140) or TKR (p ≥ 0.060) 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.