Feasibility of Home Monitoring After Primary Total Knee Arthroplasty
Phase: NA
Conditions: Osteoarthritis, Knee
Sponsor: The Cleveland Clinic

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Study Protocol 
 
Feasibility of Home Monitoring after Primary Total Knee Arthroplasty 
 
 
 
Principal Investigator: Carlos Higuera, MD 
Email: higuerc@ccf.org 
 
 

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Background 
Over one million primary total hip and total knee arthroplasties (TKAs) are being performed 
annually in the United States, and it is projected that 1.26 million TKAs will be performed by the 
year 2030.1 Simultaneously, there is a projected shortage of trained orthopaedic surgeons to 
care for these patients.2 Telemedicine and innovative home-based technologies to monitor 
patient outcomes after surgery have gained increasing attention.3 This was possible due to the 
recent technological advances in telecommunication, allowing the development of 
commercially-available, easily-accessible, and low-cost home monitoring and virtual 
rehabilitation systems to allow clinicians to monitor the patient’s adherence to post-operative 
rehabilitation and treatment protocols, particularly for relatively low-risk patients in which a 
normal recovery is expected.  
Recently, emerging evidence has shown that home monitoring systems may have comparable 
efficacy to conventional follow-up clinic visits in monitoring patient progress postoperatively.4–7 
Studies have also shown this technology may aid in lowering the cost of healthcare delivery to 
these patients while they are being monitored in real-time.8,9 In addition, it has been shown 
that postoperative interventions cost between 37% to 40% of the total episode payment for 
primary total joint arthroplasty.10 Therefore, with the recent paradigm shift from “volume-
based” to “value-based” healthcare, the use of modern technology allowing optimal patient 
outcomes while decreasing cost becomes extremely relevant.11  
 
Objectives 
In this pilot study, the objective was to assess a novel technology for postoperative home-based 
monitoring and communication for patients who underwent primary TKA. We specifically 
evaluated 1) the accuracy of patient mobility and knee range of motion (ROM) measurements 
obtained using home-based monitoring, and 2) the ability of the technology to monitor physical 
therapy compliance and collect patient-reported outcomes. 
 
Eligibility 
Data will be prospectively collected from a total of 10 patients over the age of 18 years who are 
scheduled for elective primary TKA.  All enrolled patients must meet the following eligibility 
criteria. 
Inclusion Criteria: 
1. Scheduled for unilateral primary TKA 
2. Reside within 75 miles (driving distance) from the hospital 
3. Expected to be discharged home with hospital home care 
4. Have wireless internet connectivity in their home 

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Exclusion Criteria: 
1. Scheduled for revision or simultaneous bilateral TKA 
2. English is not considered their preferred language for healthcare discussions 
3. Body mass index (BMI) greater than 45 kg/m2 
4. Enrolled in another research study 
 
Methods 
The monitoring technology that will be used in this study was developed by Vivanta Care 
(Chagrin Falls, Ohio, USA). The system consists of two sensors, each attached to an adjustable 
strap. One sensor is to be worn 4-6 cm above the knee and the other sensor is to be worn 4-6 
cm below the knee and are used together to capture knee ROM.  Patients will be instructed to 
wear these sensors during seated flexion and extension home exercises that are prescribed by 
the physician (up to 3 times per day) as part of their home therapy routine.  Additionally, an 
activity sensor that tracks the number of steps taken is included for patients to wear on their 
wrists. Information collected with all three sensors will be transmitted securely between the 
patient and health providers through an application on a tablet computer that is supplied to 
each patient preoperatively once he/she consents to participate in the study. This application is 
also utilized as a timer for the timed up and go (TUG) test, to collect patient reported 
outcomes, and to guide the patient through the prescribed home therapy exercises. Patients 
are provided with instructions to connect to the existing wireless internet at home prior to the 
date of surgery to confirm the connection. Proper installation is verified automatically by the 
tablet computer cloud server and all communication pathways (sensor ↔ tablet computer ↔ 
internet ↔ health provider) are verified automatically. 
Data Collection: 
All patient-reported and functional measurements will be collected electronically via the in-
home monitoring system at the intervals specified in the table below and manually by a 
clinician preoperatively, during one homecare visit per week, and at the 4, 8, and 12 week 
clinical follow-up visits.  The Knee injury and Osteoarthritis Outcome Score (KOOS) consists of 5 
subscales (Pain, other Symptoms, Function in daily living, Function in sport and recreation, and 
knee related Quality of life (QOL)).  However, we will only assess KOOS Pain, Function (using the 
KOOS – Physical Function Shortform) and QOL for this study. Each section is scored 
independently from the others on a 0-to-100 transformed scale, where zero represents 
extreme knee problems and 100 represents no knee problems.  Functional measures such as 
the maximum attainable ROM and the number of steps taken will be tracked using sensors 
worn by the patient. The ROM sensor values will be verified with range of motion 
measurements taken using a goniometer during therapy and MD visits. Patients will be asked to 
return all equipment at the time of their 12 week clinic visit.   
 

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Frequency 
Outcome 
Type 
Scale 
Electronically 
Monitored 
Collected at 
Follow-up Visit 
Patient-
Reported 
KOOS Pain 
qwk 
q4wk 
KOOS Function 
qwk 
q4wk 
KRQoL 
qwk 
q4wk 
 
VAS Pain 
tid 
q4wk 
  
  
  
  
Function 
Measure 
ROM 
tid 
q4wk 
TUG 
tid 
q4wk 
Rehabilitation Compliance 
qd 
q4wk 
qwk = every week; q4wk = every 4 weeks; tid = three times a day; qd = every day; KOOS = Knee 
injury and Osteoarthritis Outcome Score; KRQoL = knee related quality of life; VAS = visual 
analog scale; ROM= range of motion; TUG = timed up and go. 
 
Statistical Analysis 
A sample of 10 patients will be used as a proof of concept and can be used to refine future 
sample size calculations.  Statistical analysis will be primarily descriptive.  The Wilcoxon signed-
rank test will be used to evaluate the agreements between the home-monitoring and clinician-
based measurements to yield a concordance correlation coefficient the represents a measure 
of reliability of the method. 
 

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