Traditional home health care for individuals recovering from unilateral TKA is expensive and provides a higher level of service than most individuals, aged 45 to 64, require. Use of smartphone technology has the potential to drive down costs while maintaining outcomes for this patient population. The proposed randomized controlled trial would determine the efficacy and proper dose-response of a smartphone app to reduce costs and maintain outcomes for the desired patient population compared to traditional home care.

As of 2013, it was estimated that 4.0 million individuals in the U.S. were living with a TKA, representing 4.2% of the population fifty years of age or older (8). As of 2010, there were 81,489,445 people aged 45 to 64 in the U.S. (4), with a rate of 39.5 total knee arthroplasties per year per 10,000 individuals in that age group (3). Therefore, approximately 322,000 TKAs were performed in 2010 for those aged 45 to 64. A 2010 study from The Centers for Disease Control and Prevention found the average cost of home health care following TKA to be $3,709 per episode of care per patient (5). This results in nearly $1.2 billion dollars in U.S. healthcare spending in 2010 for home care following TKA for those aged 45 to 64. The reason for the high cost of home health care may be the state regulations governing home health care agencies. The Louisiana Department of Health and Hospitals states that 'skilled home health care,' found under the definition of 'home health agency' in the official Louisiana Home Health State Regulations, is to include skilled nursing and at least one of the following services: physical therapy, occupational therapy, speech therapy, medical social services, or home health aide services (9). These regulations place pressure, whether conscious or subconscious, on the home health agency to over utilize skilled nursing services for those patients aged 45 to 64 recovering from TKA. Skilled nursing home health care services for this particular patient population usually involves managing the patient's medications and providing wound care services. A cohort study by Bleijenberg et al published in the Journal of the American Geriatric Society in 2017 found that only 10.3% of adults aged 65 to 69, which is above the age cutoff for this prospective study, had difficulty with managing their medications (10). Also, in the author's clinical experience, it is rare for an orthopedic surgeon to allow any other clinician to manage post-operative dressing changes except those clinicians under the surgeon's direct supervision; though further research in this area would be helpful. Furthermore, utilization of TKA, and the home care cost associated with recovery from TKA, is on the rise. As of 2009, the number of primary TKAs performed annually in the U.S. among all age groups exceeded 620,000 procedures, which is more than doubled when compared to the previous decade (7). Smartphones and other technologies may provide a solution to the rising costs of home health care following TKA for those aged 45 to 64. Over the past decade, the smartphone has become an integral part of most people's lives. The latest Pew Research Data from February 2018 shows that 73% of individuals aged 50 to 64 own a smartphone (8). Smartphones would allow the patient to have direct multimedia access to a prescriptive exercise program designed by a licensed Physical Therapist without an in-person home visit, as well as to have communication directly with their Physical Therapist through secure in-app messaging or e-mail. The patient would benefit by having reduced intrusion in their home environment, convenient access to their Physical Therapist and their Physical Therapist's plan of care, and financial savings due to the elimination of home health care services following TKA. The Physical Therapist would benefit from the ability to quickly interact with the patient to mitigate any adverse events and to efficiently assist a greater number of patients compared to traditional home-based physical therapy. Third-party payors would benefit from drastically reduced home care costs for those recovering from TKA.

Inclusion Criteria:

• participants aged 45 to 64
• unilateral TKA
• subject discharged directly to home from the hospital

Exclusion Criteria:

• subject does not engage with the app within 24 hours of discharge from the hospital
• subject neglects to engage with the app over any 24-hour period during the study
• subject is readmitted to the hospital at any point during the home bound portion of their recovery

There are no plans to make IPD available to other researchers