Abstract
Background
Total Knee Arthroplasty (TKA) provides patients with significant improvements in quality of life. Subjective patient reported outcome measures (PROMs) are traditionally used to measure preoperative functional status and postoperative outcomes. However, there are limitations to PROMs. In particular, they provide virtually no functional information in the first 3 weeks after surgery, which could be used to guide the patient's recovery. Newly available wearable electronic sensors make it possible to: 1) measure important functional outcomes following TKA; 2) guide the patient's physical therapy (PT); and 3) provide real-time functional and clinical information to the provider.
Compliance with PT after TKA is a challenge. Patients cite time, transportation, and cost as deterrents to PT appointments. However, an intensive PT program is essential in TKA. Surface sensor devices may be able to increase PT compliance by guiding patients through exercises at home. Additionally, these devices can transmit PT progress in real-time to the providers, allowing them to monitor and assist the patient's recovery.
Our study investigates the feasibility of using a surface sensor device (TracPatch™) on patients following TKA. We sought to answer the following questions: 1) Will patients tolerate the device; 2) Will patients comply with device instructions; 3) Will patients be able to use the smart phone application; 4) Will the device collect, transmit, and store data as it was designed? We believe these fundamental questions must be answered as we enter the era of personal sensor-measured functional outcomes.
Methods
20 patients undergoing primary, unilateral TKA were enrolled in this IRB approved study. At the pre-surgical visit, patients were given instructions for the device and smart phone application. Each patient used the device in the week prior to surgery, and data was collected. The device was again applied in the operating room. For 3 weeks post-operatively, the device collected functional data, along with WOMAC, OKS, KSS, PROMIS, and VAS pain scores. A satisfaction survey was collected on the device.
Results
The study results emphasize the importance of clear device instructions. Using the sensor and phone application prior to surgery was very helpful. The device was surprisingly well tolerated. Older patients were able to use the device without significant difficulty. Virtually all patients found the device helpful and, often fun. Physical therapists felt that the devices helped personalize the therapy program. The functional information from the device was much more helpful in guiding care in the first 3 weeks following surgery than PROM scores.
Conclusion
It is anticipated that sensor devices of the kind tested in this study will have a major impact on the care of TKA patients. The purpose of this study was not to measure that impact. Our goal was to examine the factors that optimize the use of these devices. It is critical that clear device instructions be given to patients. Office procedures must be established to monitor use of the devices. If protocols are established for their use, surface sensors have the potential to provide invaluable information to TKA patients and caregivers.
