Abstract
Wearable sensors and associated supporting technologies (i.e., patient applications) can provide both objective (joint position, step counts, etc.) and subjective data (i.e., pain scores and patient-reported outcome measures) to track a patient's episode of care. Establishing a subjective and objective baseline of a patient's experience may arguably be beneficial for multiple reasons, including setting recovery expectations for the patient and demonstrating the effectiveness or success of the intervention.
In this pilot study, we characterized a subset of patients (n = 82 from 7 surgeons) using a wearable sensor system at least 6 days prior to total knee arthroplasty and provided post-surgical data up to 50 days post-intervention. The 5-day average prior to surgery for total step counts (activity), achieved flexion and extension on a progress test (functional limit) and visual analog scale (VAS) daily pain score were calculated. The difference from baseline was then calculated for each patient for each day post-surgery and reported as averages.
On average, a patient will experience a relative deficit of 4,000 steps immediately following surgery that will return to near-baseline levels 50 days post-intervention. A 30-degree deficit in flexion and a 10-degree deficit in extension will return at a similar rate as steps. Relative pain scores will worsen with an increase of approximately 3 points immediately following surgery. However, pain will decrease by two points relative to baseline between 40 and 50 days.
The results of this pilot study demonstrate a method to baseline a patient's presurgical subjective and objective data and to provide a reference for postsurgical recovery expectations. Applications for this data include benchmarking for evaluating intervention success as well as setting patient expectations.