Mobility metrics in individuals with and without an indication for knee arthroplasty: An explorative analysis.

Background: It is conceivable that candidates for total knee arthroplasty due to knee osteoarthritis have poorer walking ability than people who do not have an indication for total knee arthroplasty. This study explored the discriminative ability of mobility metrics between individuals with and without an indication for total knee arthroplasty.

Methods: Mobility metrics were collected with inertial sensors on the same day as the consultation with the orthopedic surgeon in which the decision for total knee arthroplasty eligibility was made. Inertial sensors on both feet, lower back and trunk were used to collect gait data during short mobility tests. Participants walked along a 10-m walkway for two minutes, and performed sit-to-stand tasks. Based on the orthopedic surgeon's indication for total knee arthroplasty, individuals were assigned to the indication (N = 58) group or no indication (N = 73) group. Mobility metrics reflecting walking, turning and rising from a chair were compared between groups, and corrected for confounding variables.

Findings: Both groups had similar demographic and clinical characteristics, except for higher radiographic osteoarthritis severity in the indication group. Gait speed was 0.08 m/s (95 %CI: [-0.15, -0.01]) lower in the indication group compared to the no indication group. No significant differences were found in other mobility metrics.

Interpretation: Unlike expected, the difference in mobility metrics between individuals with and without a total knee arthroplasty indication was small. This finding implies that the ability to walk, turn and rise from a chair plays a minor role in the decision-making process regarding TKA.