Using Intraoperative Sensing Technology to Evaluate Revision Total Knee Arthroplasty
Conditions: Knee Osteoarthritis
Sponsor: Orthosensor, Inc.

Revision TKA Sensor Study 
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RESEARCH PROTOCOL 
 
 
Date 
January 9, 2017 
Title 
Using Intraoperative Sensing Technology to Evaluate Revision TKA 
Research Sponsor 
OrthoSensor, Inc., Dania Beach, FL USA 
Principal Investigator 
William Leone, MD 
Department 
The Leone Center for Orthopedic Care, Holy Cross Hospital, Fort 
Lauderdale, FL USA 
 
Project Summary/Abstract 
 
This study will attempt to draw relationships between the soft-tissue related complications 
contributing to early TKA revision and the loading and positional patterns from intraoperative 
tibial trial sensors. The data from the sensors may enable the surgeon to address such soft- 
tissue abnormalities that may otherwise be unknown during traditional total knee revision 
procedures. The utilization of sensors should in theory, help diagnose the potential causes 
attributing to soft-tissue imbalance and may lead to a decreased need for an all component 
revision. Furthermore, the economic implications from converting a total revision to a partial 
revision could have a profound effect to the patient and healthcare provider such as decreased 
rehabilitation regimes and opportunity for cost savings. Eligible revision patients who agree to 
participate will be followed for a period of 12 months following the revision procedure. Patient 
reported outcomes measures (PROM) such as the 2011 Knee Society Score (KSS) and the 
Veterans Rand 12-Item Health Survey (VR-12) will be collected at baseline (pre-operatively) 
and at 6 weeks, 6 months and 12 months post-procedure. All outcomes will be scored to 
observe changes from baseline at 12-months. Cost-analyses of sensor-assisted revision TKA 
will be performed to include OR costs, facility and physician fees, as well as payments to post- 
acute collaborators such as SNFs, rehab hospitals, PT and home care providers. A quantitative 
analysis of commercial payer claims / usage data (e.g., CMS Medpar data) will be used to 
examine costs associated with traditional revision TKA procedures. 
 
Purpose of Study 
 
A. 
Research Objective: 
 
Primary: The objective is to evaluate and link the possible causes of early TKA 
revision procedures using intraoperative sensors in effort to understand why 
knees fail in addition to examining the economic implications to the patient and 
hospital. 
Secondary: To observe changes in patient reported outcome measures from 
baseline at 12-months. Patients will be stratified by diagnosis and revision type 
(partial / total) to observe changes in outcome measures. 
 
B. Hypothesis or Research Question 
 
This study is observational and not intended to be a hypothesis driven trial. However, it is 
believed that sensor guidance during revision TKA may lead to a decreased need for all 
component revision while optimizing post-operative satisfaction and clinical outcomes. 

Revision TKA Sensor Study 
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Background and Significance 
 
Several advances in technology have been incorporated into total knee arthroplasty over the 
past decade to improve clinical outcomes and implant survivorship. Yet despite these advances, 
revision rates of TKA are expected to rise1. While total hip arthroplasty revision rates have 
steadily declined over the past several years, the revision rate for TKA is projected to increase 
fivefold by 2030 despite improvements in infection control, surgical methods, innovative 
prosthesis designs, and accelerated rehabilitation programs2,3. “Early” revision is typically 
defined as occurring within five years of the primary procedure, and is considered a devastating 
failure for both the patient and physician4. Fehring, et al. found that as many as 63% of TKA 
failures occur within the first five years4. Of these early failures, 35% can be attributed to soft 
tissue imbalances5. Ligamentous alignment and component attenuation are intrinsically linked2. 
Imbalance may manifest as stiffness, instability, prosthetic loosening, tibiofemoral incongruency, 
or as defects in patellofemoral tracking6. In a study by Babazadeh, et al., 86% of knees with 
asymmetrical component wear lacked ligamentous balance. This study also found that balanced 
knees have a significantly lower rate of prosthetic loosening. Micromotion in an asymmetric joint 
may result in accelerated osteoclast activity leading to osteolysis and component loosening or 
failure6. Sharkey, et al. reviewed the etiology of revision in 781 failed TKAs and determined that 
aseptic loosening was most common cause along with a significant number of revisions due to 
instability5. If all total knee replacements exhibited proper soft-tissue balance, the rate of early 
failures would improve by 40%, and the overall TKA failure rate by 25%. 
 
However, the use of advanced technology to understand why total knee arthroplasties fail today 
has not been extensively evaluated. A recent development has made it possible to embed 
microelectronics into the standard tibial trial (VERASENSE, OrthoSensor, Inc., Dania Beach, 
FL). This array of sensors provides dynamic, intraoperative feedback regarding tibiofemoral 
position and quantitative pressure at peak contact points in the medial and lateral compartments 
during total knee arthroplasty (TKA) trialing. Using sensor-derived data, the surgeon can now 
evaluate intercompartmental loading throughout the range of motion (ROM) and correct for soft- 
tissue abnormalities while receiving real-time feedback regarding joint position and the 
tibiofemoral relationship defined by the contact point location. Utilization of these sensors during 
revision TKA should in theory, help diagnose the potential causes of revision if they relate to soft 
tissue imbalance. 
 
Research Plan 
 
A. Study Design 
• 
Prospective, multicenter, single-cohort evaluation of patients undergoing sensor- 
assisted revision total knee arthroplasty 
• 
All eligible patients will be asked to participate and sign informed consent 
• 
The surgeon will use Verasense on all patients. Data will be electronically 
captured by designated research personnel. 
• 
Patients will be assessed preoperatively and will have standard of care follow up 
appointments at 6 weeks, 6 months and 12 months. 
o 
During these visits the following outcome measures will be assessed: 
✓ New Knee Society Score (KSS)7 
✓ The Veterans Rand 12-Item Health Survey (VR-12) 
 
B. Setting 
The study will be conducted at institutions within the United States. 

Revision TKA Sensor Study 
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C. Participants: Patients requiring revision total knee arthroplasty will be recruited from the 
respective clinical practice at the participating institutions. Up to 200 patients will be 
enrolled and followed for a period of 12 months in order to assess patient outcomes. Any 
patient who is a candidate for revision TKA and meets all inclusion and no exclusion will 
be offered study participation without regard to race, sex, economic status, or religious 
belief. 
 
Inclusion criteria: 
o 
Patients undergoing revision unilateral total knee arthroplasty within the first 5- 
years of the index procedure 
a. Include Male and Female subjects 
b. Include subjects 18 years and older 
o Patients should present with idiopathic pain and/or instability/stiffness attributed 
to aseptic loosening, polyethylene wear or malrotation 
o Patients able to understand study intent, and agree to study participation 
o Patients must be previously implanted with the following cruciate-retaining (CR) 
or posterior-substituting (PS) total knee systems: Stryker TRIATHLON, Zimmer- 
Biomet VANGUARD or NEXGEN or Smith and Nephew LEGION or JOURNEY 
II. 
 
Exclusion criteria: 
o No prior revision surgery on operative side 
o Ligament insufficiencies, prior surgeries such as PCL reconstructions, 
posterolateral reconstructions, osteotomies, tibia plateau fractures 
o Culture positive aspiration indicating infection of the joint 
o ASA class > III 
o History of drug or alcohol abuse 
 
Methods/Procedures: 
 
At the time of the revision procedure, the implanted polyethylene will be removed and 
the corresponding VERASENSE insert type will be placed with the original implanted 
components still intact. With the patella reduced and the capsule provisionally closed, 
the knee will be taken through a range of motion to record and observe contact point 
location and medial and lateral loading at 10, 45, and 90 degrees of flexion as dictated 
by VERASENSE. Kinematic tracking embedded in the computer software will be 
engaged to observe femoral rollback patterns in each respective knee. Once the pre- 
revision “diagnostic” data is recorded, the surgeon will proceed with the standard of care 
revision procedure. Dependent upon the complexity of the case and output of the 
VERASENSE data, the surgeon may elect to salvage some or all of the original 
implanted components or choose to completely revise the knee with the preferred 
implant system. All revision cases will be cataloged by type (“partial” or “total”). A 
“partial” revision will be indicated when only the tibial liner is changed or only the tibial 
liner with the tibial tray or only the tibial liner with the femoral component; A “total” 
revision will be indicated when all components are completely removed and replaced 
(tibial tray, femoral component and tibial liner). The VERASENSE sensor will be utilized 
for final balancing prior to completing the partial or total revision procedures and loading 
and positional data will be documented once again. All surgical corrections made (i.e., 

Revision TKA Sensor Study 
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bony resections and/or soft tissue releases) during the revision procedure will be 
documented. 
 
D. Data Collection 
 
• 
Demos/History/Clinical: Patient’s age at time of surgery, gender, ethnicity, height/weight 
and body mass index, occupational status, health insurance type, tobacco and alcohol 
use. Patients medical history and comorbidities will be obtained as well as principal / 
secondary diagnosis and pre-operative plan for revision (i.e., total revision, partial 
revision). Preoperative radiographs (AP, lateral and skyline views) should be taken as 
standard of care. 
 
• 
Intra-operative /discharge data: OR and tourniquet times, surgical technique and 
approach, operative complications (if applicable), length of stay and discharge 
destination. Pre and post-revision sensor data will be obtained (operative findings / 
operative action/surgical correction). Length of stay and discharge status will be 
captured as well as any post-operative complications and readmissions within 90 days of 
discharge following the revision procedure. 
 
• 
Clinical Outcome Measures: Dependent variables or outcome variables will be collected 
pre-operatively and at 6 weeks, 6 months and 12 months post-operatively. The 
outcomes measures will include the 2011 Knee Society Score and THE VETERANS 
RAND 12-ITEM HEALTH SURVEY (VR-12). 
 
• 
Cost Data: Hospital cost data including OR costs, facility and physician fees, as well as 
payments to post-acute collaborators such as SNFs, rehab hospitals, PT and home care 
providers will be collected. MEDPAR data from Centers for Medicare and Medicaid 
(CMS) will be used as benchmark to understand the national averages of hospital cost, 
hospital charges and average reimbursement. Implant cost data will be obtained from 
literary sources and market reports. 
 
Data Sheet: See attached data sheets. 
 
E. Study Device 
VerasenseTM is developed by Orthosensor Inc., Dania Beach, Florida, USA and is FDA 
approved for commercial distribution in the United States. The 510(k) number is 
K090474. 
 
F. Statistical Analysis 
 
Analysis of the data will be performed using SPSS version 21. Comparative Statistics 
will be run between outcomes data stratified by revision type: Analysis of variance 
(AVOVA) will be used to assess the difference between groups stratified by reasons for 
revision, with post-hoc TUMHANE’S test to demonstrate significance. Separate analyses 
will be performed to evaluate power of sample sizes and any correlative affect that 
demographic/clinical variables may have on patient outcomes. The alpha value is 0.05 
with a lower power threshold of 0.7. 

Revision TKA Sensor Study 
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G. Ethical Considerations 
 
a. Informed consent: Research assistants/coordinators will obtain patient consent 
and the consent statements will be kept in a secure location. Copy of the 
informed consent statement is attached. 
 
b. Privacy information: The data will be stored electronically on a restricted 
access network folder and will only be accessible to the investigator and 
research team. The information collected does not include information that may 
be damaging to the individual should it be wrongfully disclosed. Data sheets may 
be used in the collection of data, however, will not document PHI. Data analysis 
will be performed using only the de-identified database. No data will be disclosed 
to another institution and all identifiers linking to the patient will be destroyed after 
data collection is complete. 
 
c. Confidentiality and Management of Data: The data will be stored and will only 
be accessible to the investigator, research team and OrthoSensor. Data sheets 
may be used in the collection of data, however, will not document PHI. Data 
analysis will be performed using only the de-identified data. Information about 
study subjects will be kept confidential and managed according to the 
requirements of the Health Insurance Portability and Accountability Act (HIPAA). 
Patient data will be entered into electronic spreadsheets. One spreadsheet (the 
correlation tool) will contain the patient name, medical record number, and 
patient study number. The second spreadsheet will contain the patient study 
number, as well as all of the variables required by the study. The two 
spreadsheets will be stored as separate files. De-identified data will be provided 
to the Research Specialist for data analysis. Any paper records will be stored in 
hard copy in a locked filing cabinet for a minimum of five years. At this time the 
information will be shredded. 
 
d. Risks/Benefits of participation: There are no risks to participants. This study is 
intended for observational purposes only. There are no costs to exceed those 
associated with the standard of care which currently exists. This could potentially 
benefit those patients who are undergoing traditional revision TKA but this is not 
yet known. 
 
H. Estimated Period of Time to Complete 
 
When will study begin? 
February 2017 
IRB Approval 
3 weeks 
Data collection 
~2 years 
Data analysis 
1 month 
Presentation development 
(if applicable) 
1 month 
Manuscript Development 
(if applicable) 
3 months 
Journal submission 
process (if applicable) 
3-6 months 
Study closure 
1 year 

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When and how will results be disseminated? 
• 
OrthoSensor will notify the Investigator when adequate data have been collected or 
when the clinical evaluation is terminated for any reason. 
• 
The data collected in this study will be analyzed and compiled into a report for review by 
the Investigator per the contracted agreement between the Investigator/Institution and 
OrthoSensor. The results will be published in a scientific medical journal and will be 
presented at National and International congresses and symposia. 
 
I. 
Contact Information 
 
For assistance or questions regarding this evaluation, please contact the Department of 
Clinical Research at OrthoSensor, Inc as indicated below: 
 
Sr. Director, Clinical Research 
Chris Anderson 
Phone: 813-352-9887 
E-mail: canderson@orthosensor.com 
Clinical Research Associate 
Leah Elson 
Phone: 951-577-7343 
E-mail: lelson@orthosensor.com 
 
 
 
 
1855 Griffin Road, Suite A-310 | Dania Beach, FL 33004 | 888-75-ORTHO (888-756-7846) www.OrthoSensor.com 

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References: 
 
1. Kurtz SM, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision 
hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg. 
2007; 89-A:780--785. 
 
2. Kurtz S, Mowat F, Ong K, Chan N, Lau E, Halpern M. Prevalence of primary and 
revision total hip and knee arthroplasty in the United States from 1990 through 2002. 
J Bone Joint Surg Am. 2005;87:1487-97. 
 
3. Bansal A, Khatib ON, Zuckerman JD. Revision Total Joint Arthroplasty: The 
Epidemiology of 63,140 Cases in New York State. The Journal of Arthroplasty. 2014 
Jan; 29(1): 23–27. 
 
4. Fehring TK, Odum SM, Griffin W, et al. Early failures in total knee arthroplasty. Clin 
Orthop Relat Res 2001;392:315. 
 
5. Sharkey PF, Hozack WJ, Rothman RH, Shastri S, Jacoby SM. Why are total knee 
arthroplasties failing today? Clin Orthop Relat Res 2002;404:7-13. 
 
6. Babazadeh S, Stoney JD, Lim K, Choong PF. The relevance of ligament balancing in 
total knee arthroplasty: how important is it? A systematic review of the literature. 
Orthop Rev (Pavia). 2009 Oct 10; 1(2): e26. 
 
7. Scuderi GR, et al. The new Knee Society Scoring system. Clin Orthop 2012;470:3-19 

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Appendix I 
 
Holding the Leg using Verasense