Traditional Home Health Physical Therapy Versus a Smartphone App for Patients Recovering From Total Knee Arthroplasty During the Home-bound Portion of Recovery: Study Protocol for a Randomized Controlled Trial
Phase: NA
Conditions: Total Knee Arthroplasty
Sponsor: Lagniappe Physical Therapy

Traditional Home Health Physical Therapy Versus a 
Smartphone App for Patients Recovering from Total Knee 
Arthroplasty During the Home-bound Portion of Recovery: 
Study Protocol for a Randomized Controlled Trial 
by Dr. Eric M Rippetoe, PT, DPT
Study Design 
Prospective randomized controlled trial comparing traditional home health care 
physical therapy to physical therapy provided via a smartphone app for patients 
recovering from total knee arthroplasty (TKA)
Background 
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 
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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. 
Objectives 
The primary objective will be to determine the eﬃcacy of the app for those recovering 
from TKA compared to traditional home care during the home bound portion of the 
patient’s recovery from TKA by comparing ROM improvement outcomes between the 
intervention group and the control, as well as measuring the subjective improvement in 
functional outcomes for the intervention group by using the Short MAC. A secondary 
objective of the study is to determine the relationship between the intervention 
participants’ self-reported frequency of engagement with the app and their qualitative 
and quantitative outcomes, otherwise known as the dose-response.
Methods
 
The intervention group for this study are those who will utilize the smartphone 
app to complete the home-based portion of physical therapy following TKA. The 
control group are those who have completed traditional home health physical therapy 
following TKA. Inclusion criteria for the study consists of participants aged 45 to 64, 
the participant will have undergone unilateral TKA, and the participant should be 
discharged directly to home from the hospital. Participant’s data from the intervention 
group will be excluded from the study if they do not engage with the app within 24 
hours of discharge from the hospital, if the participant neglects to engage with the app 
over any 24-hour period during the study, or if the participant is readmitted to the 
hospital at any point during the home bound portion of their recovery. 
 
Subjective outcomes for the participants in the intervention group will be 
assessed by the Short MAC and objective outcomes will be assessed by measuring 
total knee ROM improvement. The intervention participants’ self-reported frequency of 
app usage will be compared to the participants’ outcomes to determine the dose-
response of the app. The Short MAC has been previously shown to be a reliable, valid, 
and responsive indicator of qualitative improvement in a patient’s functional status 
post-TKA and total hip arthroplasty (THA) by Whitehouse et al (1). Minimum important 
change for Short MAC has been found to be 7.9 points for small change, 8.4 points for 
medium change, and 12.1 points for large change (2). The total knee ROM 
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improvement in the treatment group will be compared against a control group of 
patients who have completed traditional home care from a variety of physical 
therapists following TKA. 
 
The primary hypothesis is that the intervention group will show a statistically 
equal outcome to the control group, demonstrating the eﬃcacy of a low-cost 
alternative to traditional home care. The null hypothesis is that the research group will 
not show a statistically equal outcome to the control group. The ﬁrst alternative 
hypothesis is that the intervention group will show a statistically signiﬁcant 
improvement over the control group. The second alternative hypothesis is that the 
control group will show a statistically signiﬁcant improvement over the intervention 
group. 
 
Data for the control group will be taken from approximately 30 individuals aged 
45 to 64 that have previously completed traditional home health physical therapy care 
from a variety of physical therapists following TKA. Data for the intervention group will 
be taken within 48 hours of being discharged from the hospital from approximately 30 
participants who agree to use the smartphone app to complete the home-based 
physical therapy portion of their recovery from TKA. Intervention group participants will 
complete an introductory meeting with the physical therapist in-person to onboard the 
patient to the app and perform the initial data collection. Participants in the intervention 
group will be encouraged to engage with the app 3 to 5 times per day as able. The 
intervention participant will have the ability to communicate any questions or concerns 
to the Physical Therapist via e-mail or phone call throughout the homebound portion of 
their recovery. For safety monitoring, a physical therapist will contact the intervention 
group participant via phone or e-mail every 24 to 48 hours to ensure no adverse events 
have occurred. A ﬁnal in-person meeting will occur between the Physical Therapist and 
the participant at the conclusion of the homebound portion of the participants’ 
recovery for the purpose of ﬁnal data collection. A two-tailed t-test for two independent 
groups will be used to compare the means for total ROM improvement between the 
intervention group and the control group. Data from the Short MAC will be used to 
describe the overall subjective eﬀect of the intervention on the patient’s functional 
abilities. The relationship between the Participants self-reported frequency of app 
usage and their combined subjective and objective outcomes will be used to 
understand the dose-response of the app.  Information about dose-response will be 
integral in establishing guidelines regarding frequency of app usage for optimal results. 
Conclusion
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. 
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Citations
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