clinical research summary - orthosensor
TRANSCRIPT
CLINICAL RESEARCH SUMMARY
OrthoSensor.com 2 VERASENSE
PROVEN RESULTS
A multicenter randomized controlled trial, a prospective 3-year multicenter study,
and additional research have proven the following clinical and economic benefits
from the use of VERASENSE in Sensor-Assisted TKA:
VERASENSE Sensor-Assisted Total Knee Arthroplasty offers
proven clinical and economic advantages for surgeons and hospitals.
A MULTI-CENTER RANDOMIZED CONTROLLED TRIAL PROVED
THAT – WITHOUT VERASENSE – TKAs ARE ONLY BALANCED
APPROXIMATELY 50% OF THE TIME [P.4]
98% OF BALANCED PATIENTS REPORT BEING SATISFIED TO VERY SATISFIED 3 YEARS POST-OP [P.5]
SIGNIFICANTLY HIGHER FORGOTTEN JOINT SCORES . COMPARED TO UNBALANCED PATIENTS [P.6]
DECREASED THE NEED FOR ALL-COMPONENT REVISION BY 88% FACILITATING IMPLANT COST MITIGATION [P. 9]
ALMOST75% LOWER RATE OF SOFT TISSUE BALANCE-RELATED EARLY REVISION TKA (<2 YEARS) COMPARED TO NATIONAL AVERAGES [P.10]
VERASENSE PATIENTS REQUIRE LESS PT AND 67% FEWER MUAs POST-OP [PP.6-8]
109
OrthoSensor.com 3 VERASENSE
CLINICAL OUTCOMES
4 IsaSurgeon-Defined“BalancedKnee”FollowingTotalKneeArthroplastyReallyBalanced? Without VERASENSE, TKAs are only balanced approximately 50% of the time.
5 Patient-ReportedSatisfaction:3-YearMulticenterResults VERASENSE Sensor-Assisted TKA resulted in an increase to 98% patient-reported satisfaction at three years post-op.
6 RandomizedControlledTrial- DoesaBalancedTKAProducea MoreForgottenJoint? Patients with quantitatively balanced TKA have statistically significant higher forgotten joint scores than patients with unbalanced TKA based on 6-week, 6-month and 1-year outcomes data (p<0.05).
7 DecreasedRiskof90-DayPost-OpComplications(MUA) VERASENSE Sensor-Assisted TKA resulted in statistically significant reduction in MUA.
8 ImprovedPhysicalTherapyandShort-TermClinicalOutcomes VERASENSE patients have shown statistically significant improvement of PROMs and Physical Therapy performance.
ECONOMICS
9 CostMitigationDuringRevisionTKA Use of VERASENSE in revision TKA can potentially result in cost savings due to a decreased need for all-component revision.
10 PotentialforReducingIncidenceofEarlyRevisionTKA A VERASENSE multicenter study showed a significantly lower rate of early revision TKA compared to national averages.
SURGICAL TECHNIQUES
11 CanWeReally“Feel”aBalancedTotalKneeArthroplasty? Results from this study show that VERASENSE assists surgeons in decreasing the incidence of outliers in loading across the knee joint.
12 AccuracyofManualSurgeon-DefinedAssessmentofSoftTissueBalanceinTKAInComparisontoVERASENSESensor-GuidedMeasures–CanWeDetectAnUnbalancedKnee? Surgeon assessment is a poor predictor of knee compartmental loads and balance.
13 KneeBalancinginTotalKneeArthroplastyUsingtheVERASENSEArticularInsert.FindingsofaProspectiveCohortStudy Results have challenged traditional concepts of knee balancing.
THE PRESENTED VERASENSE™ DATA IS A COMPILATION OF RESEARCH PERFORMED THROUGH JANUARY 2018 EITHER IN COLLABORATION WITH OR INDEPENDENT FROM ORTHOSENSOR®, INC. THE CONTENT HEREIN IS TO BE USED FOR REFERENCE ONLY.
THERE ARE SURGEONS INVOLVED IN THIS RESEARCH WHO ARE PAID CONSULTANTS OF ORTHOSENSOR AND RECEIVE ROYALTY PAYMENTS FROM ORTHOSENSOR. ORTHOSENSOR HAS ALSO PROVIDED OR PROVIDES INSTITUTIONAL FUNDING IN SUPPORT OF THIS RESEARCH.
Investigations&KeyTakeaways
OrthoSensor.com 4 VERASENSE
CLINICAL OUTCOMES
PURPOSE
Residual soft tissue imbalance in TKA may cause
instability, leading to greater pain and worse function.
This study compared blinded surgeons’ subjective, feel-
based evaluation of TKA balance to quantitative, intra-op
VERASENSE load measurements. It was hypothesized
that the surgeon-defined assessment is a poor predictor
of the actual state of soft tissue balance in TKA.
METHODS
• 170 primary TKA patients
• At the end of each case, surgeons were asked to
provide a manual assessment of balance in
extension and flexion
• Quantified balance data—blinded to the surgeon—
was then captured with VERASENSE
intraoperatively
• Mismatch between VERASENSE balance data and
surgeon-defined assessment were analyzed
(BALANCED = M/L load differential ≤ 15 lbf)
RESULTS
• By surgeon feel, all knees were deemed to be
acceptably balanced in both extension and flexion
• Blinded VERASENSE data showed only 51% (n=86)
of surgeon-guided TKAs were quantifiably balanced.
CONCLUSIONS
WITHOUT VERASENSE, TKAS ARE ONLY BALANCED APPROXIMATELY 50% OF THE TIME.
SURGEON-DEFINED ASSESSMENT CORRELATES POORLY WITH SENSORIZED FEEDBACK. QUANTITATIVE SENSOR DATA MAY PROVE USEFUL TO HELP ENSURE A BALANCED TKA.
Hospital for Joint DiseasesNYU LANGONE MEDICAL CENTER
IsaSurgeon-Defined“BalancedKnee” FollowingTotalKneeArthroplastyReallyBalanced?
BLINDED VERASENSEASSESSMENT OFSURGEON-GUIDED TKA
49% 51%
UNBALANCED
BALANCED
VERASENSE Multicenter Randomized Controlled Trial. Pending Publication. Data on file at OrthoSensor, Inc.
Statistics presented here represent study data analyzed as of January 24, 2018.
OrthoSensor.com 5 VERASENSE
CLINICAL OUTCOMES
PatientReportedSatisfaction:3-YearMulticenterResults
PURPOSE
This sensor-assisted, multicenter study cohort was
prospectively assessed for concluding (3-year)
patient-reported outcomes. Scores were compared to
existing peer-reviewed publications reporting a similar
follow-up interval (2-3 years) to determine the impact
of consistent TKA soft tissue balance on patient
satisfaction.
METHODS
• 129 sensor-assisted patients (quantifiably balanced)
• 7-question survey administered (5-point Likert scale)
• Literature review conducted via PRISMA guidelines
RESULTS
• 98.3% of balanced, sensor-assisted patients
reported being “satisfied” to “very satisfied” at
3-years post-op1
• On average, 87% of patients reported being
“satisfied” to “very satisfied” in comparative
literature during the same follow-up interval2-9
CONCLUSION
THE VERASENSE GROUP EXHIBITED THE HIGHEST REPORTED SATISFACTION AMONG CONTEMPORARY TECHNOLOGIC AND MANUAL SURGICAL MODALITIES FOR THE SAME 3-YEAR POST-OP INTERVAL.
*Dr. Martin Roche participated in this research and is Founder and Chief Medical Officer of OrthoSensor, Inc.
Hospital
2-3 YEAR PATIENT REPORTED SATISFACTION:COMPARISON OF LITERATURE
60
75
70
65
95
90
85
80
100MANUAL ROBOTICS PSI NAVIGATION
“SA
TIS
FIE
D”
TO
“V
ER
Y S
AT
ISF
IED
” (%
)
Jaco
bs,
et
al.
(20
14)
Keu
dell,
et
al.
(20
14)
Lio
w, et
al.
(20
16)
Nam
, et
al.
(20
16)
Merl
e-V
incen
t, e
t al.
(20
11)
Sp
en
cer, e
t al.
(20
07)
Lio
w, et
al.
(20
14)
Nam
, et
al.
(20
16)
Mart
in e
t al.
(20
06
, C
T-b
ase
d)
Mart
in e
t al.
(20
06
, im
ag
ele
ss)
Sp
en
cer, e
t al.
(20
07)
Sin
gis
ett
i, et
al.
(20
15)
VE
RA
SE
NS
E
98.3%
A Overall satisfaction with surgery
B Overall pain relief after the surgery
C Overall satisfaction with the function of knee
D I can do most things I thought I would be able to do after surgery
E My pain relief is as good as expected
F I am happy with the resultsof my surgery
G I would have the same surgeryagain for the same problem
ITEMIZED SATISFACTION QUESTION SCORES
SA
TIS
FA
CT
ION
SC
OR
E (
RA
NG
E 1
-5)
4.0
5.0
4.8
4.6
4.4
4.2
A B C D E F G
SCORED ON LIKERT SCALE: 1 = LOWEST SCORE POSSIBLE “very dissatisfied” or “highly disagree” 5 = HIGHEST SCORE POSSIBLE “very satisfied” or “highly agree”
6. Spencer JM, Chauhan SK, Sloan K, Taylor A, Beaver RJ. Computer navigated versus conventional knee replacement. Bone Joint J. 2007; 89-B: 477-480.
7. Singisetti K, Muthumayandi K, Abual-Rub Z, Weir D. Navigation-assisted versus conventional total knee replacement: no difference in patient-reported outcomes measures (PROMs) at 1 and 2 years. Arch Orthop Trauma Surg. 2015; 135:1595-1601.
8. Liow MHL, Goh GSH, Wong MK, Chin PL, Tay DKJ, Y SJ. Robotic-assisted total knee arthroplasty may lead to improvement in quality-of-life measures: a 2-year follow-up of a prospective randomized trial. Knee Surg Sports Traumatol Arthrosc. 2017 Sep;25(9):2942-2951..
9. Martin A, von Strempel A. Two-year outcomes of computer tomography-based and computed tomography free navigation for total knee arthroplasties. Clin Orthop Relat Res. 2006; 49: 275-282.
1. 2-Year, 3-Year Clinical Outcomes, OrthoSensor Multicenter Evaluation. Pending Publication. Data on file at OrthoSensor, Inc.
2. Keudell AV, Sodha S, Collins J, Minas T, Fitz W, Gomoll AH. Patient satisfaction after primary total and unicompartmental knee arthroplasty: an age-dependent analysis. Knee. 2014; 21: 180-184.
3. Jacobs CA, Christensen CP, Karthikeyan T. Patient and intraoperative factoris influencing satisfaction two to five years after primary total knee arthroplasty. J Arthroplasty. 2014; 29: 1576-1579.
4. Nam D, Nunley RM, Berend KR, Lombardi AV, Barrack RL. The impact of custom cutting guides on patient satisfaction and residual symptoms following total knee arthroplasty. Knee. 2016; 23: 144-148.
5. Merle-Vincent F, Couris CM, Schott AM, Conrozier T, Piperno M, Mathieu P, Vignon E. /factors predicting patient satisfaction 2 years after total knee arthroplasty for osteoarthritis Joint Bone Spine. 2011; 78: 383-386.
OrthoSensor.com 6 VERASENSE
CLINICAL OUTCOMES
Hospital for Joint DiseasesNYU LANGONE MEDICAL CENTER
PURPOSE
The Forgotten Joint Score-12 (FJS-12) is a PROM
evaluating the degree to which a patient is able to forget
about their joint following surgery. The aim of this study
was to measure post-operative joint awareness in patients
with and without a quantifiably balanced knee
following primary TKA.
METHODS
BLINDED MANUAL vs. UNBLINDED VERASENSE TKA BALANCING
• 267 patients thus far blindly-randomized into two
groups:
– Sensor-guided TKA with quantified, UNBLINDED
VERASENSE balancing
– Surgeon-guided TKA with BLINDED VERASENSE
load measurement
• Intra-op sensors utilized in all cases. BLINDED group
TKAs were balanced using standard, manual
techniques, with VERASENSE data collection blinded
to the surgeon.
RANDOMIZED GROUPS WERE POOLED POST-OP AND RE-STRATIFIED BY STATE OF SOFT TISSUE BALANCE:
– BALANCED = M/L load differential ≤ 15 lbf
through ROM
– UNBALANCED = any M/L load differential > 15 lbf
PRELIMINARY RESULTS
BALANCED PATIENTS REPORTED BEING LESS AWARE OF THEIR JOINT REPLACEMENT COMPARED TO UNBALANCED PATIENTS AT BOTH 6-WEEKS & 6-MONTHS POST-OP.
BALANCED patients showed:
– Fewer physical therapy sessions
– Fewer 90-day complications
CONCLUSIONS
PATIENTS WITH QUANTITATIVELY BALANCED TKA HAVE STATISTICALLY SIGNIFICANT HIGHER FORGOTTEN JOINT SCORES THAN PATIENTS WITH UNBALANCED TKA BASED ON 6-WEEK, 6-MONTH AND 1-YEAR OUTCOMES DATA (P<0.05).
FEWER PHYSICAL THERAPY VISITS AND FEWER COMPLICATIONS MAY TRANSLATE TO POTENTIAL COST SAVINGS.
RandomizedControlledTrial–DoesaBalancedTKA ProduceaMoreForgottenJoint?
PATIENT COHORTS
UNBALANCED BALANCEDTOTAL ENROLLED 267
6-WEEK DATA 220 92 128
6-MONTH DATA 149 59 90
0
10
20
30
40
50
60
FORGOTTEN JOINT SCORE
6-WEEK 6-MONTH
2433
4957
UNBALANCED
BALANCED
ME
AN
FJ
S
AVERAGE PT SESSIONS/PATIENT
MANIPULATION UNDERANESTHESIA
0
5
10
15
20
25
0
1
2
3
UNBALANCED BALANCED UNBALANCED BALANCED
2218
3
1
DA
YS
Golladay et al. Does a Balanced TKA Produce a More Forgotten Joint? ISTA/AAHKS 2017.
Longer-term follow-up data evaluating FJS-12 and additional PROMs along with the economic implications is ongoing.
OrthoSensor.com 7 VERASENSE
CLINICAL OUTCOMES
PURPOSE
Manipulation under anesthesia (MUA) is a common
treatment for stiffness and arthrofibrosis post-TKA.
Studies show a higher degree of success when
treatment is performed earlier (<3 mo.) post-TKA2 ;
however, bundled payments models focusing on a
90-day episode of care may not provide reimbursement
within this timefreame.
MUA rates were compared for manual TKA versus
VERASENSE Sensor-Assisted TKA to determine if
consistent soft-tissue balance had any effect on the
rates of 90-day post-op complications.
METHODS
MUA RATE: VERASENSE VS. NON-SENSOR
• 252 sensor-assisted vs. 690 non-sensor
• All cases were performed by the same surgeon.
• There were no significant cohort demographic or
co-morbility differences.
• No difference in outcomes was seen based on
implant type, age or BMI.
RESULTS
VERASENSE: STATISTICALLY-SIGNIFICANT REDUCTION IN MUA
• 67% decrease in rate of MUA
• 62% of observed MUAs were within the 90-day
post-op interval
CONCLUSIONS
VERASENSE CAN MITIGATE 90-DAY POST-OP COMPLICATIONS THROUGH SOFT-TISSUE BALANCE.
A DECREASE IN MUAS SHOULD REDUCE OVERALL TKA READMISSIONS AND LESSEN THE COSTS AND RISKS CURRENTLY UNDER FOCUS THROUGH CMS’S COMPREHENSIVE JOINT REPLACEMENT PAYMENT PROGRAM.
DecreasedRiskof90-DayPost-OpComplications(MUA)THE USE OF ELECTRONIC SENSOR DEVICE TO AUGMENT LIGAMENT BALANCING LEADS TO A LOWER RATE OF ARTHROFIBROSIS AFTER TOTAL KNEE ARTHROPLASTY1
1. Geller JA, Lakra A, Murtaugh T, The Use of Electronic Sensor Device to Augment Ligament Balancing Leads to a Lower Rate of Arthrofibrosis After Total Knee Arthroplasty . J Arthroplasty. 2017 May;32(5):1502-1504
2. Fitzsimmons SE, Vazquez EA, Bronson MJ. How to Treat the Stiff Total Knee Arthtoplasty?: A Systematic Review. Clinical Orthopaedics and Related Research. 2010;468(4):1096-1106.
0
1
2
3
4
5
NON-SENSOR VERASENSE
4.9%
1.6%P=0.004O
VE
RA
LL
RA
TE
OF
MU
A
OrthoSensor.com 8 VERASENSE
CLINICAL OUTCOMES
PURPOSE
The use of sensorized technology in TKA may help to
mitigate early soft-tissue complications and thereby
improve functional outcomes over manual techniques.
In order to evaluate the clinical efficacy of sensor-
assisted TKA at an early follow-up interval, 114 patients
were evaluated using patient reported outcomes
scores and clinical range of motion (ROM)
measurements.
METHODS
VERASENSE VS. MANUAL TKA BALANCING
• 57 consecutive sensor-assisted vs. 57 consecutive
manual
• All cases were performed by the same surgeon
with the same implant system.
• There were no significant cohort demographic or
co-morbidity differences.
RESULTS
VERASENSE: HIGHLY STATISTICALLY-SIGNIFICANT IMPROVEMENT ACROSS ALL OUTCOME MEASUREMENTS
• Faster improvement in PROMS (KSS, Oxford)
• Significantly higher Clinic ROM and improvement
in Clinic ROM from Pre-op
(P=0.002 AND P<0.001, RESPECTIVELY)
• More patients achieved active deep flexion
(>115 DEG.) during physical therapy
– 52% VERASENSE vs. 42% MANUAL
CONCLUSIONS
VERASENSE HAS SHOWN STATISTICALLY SIGNIFICANT IMPROVEMENT OF PROMS & PHYSICAL THERAPY PERFORMANCE.
AN INCREASE IN PHYSICAL THERAPY PERFORMANCE AND SHORT-TERM OUTCOMES DURING RECOVERY AND REHAB SHOULD TRANSLATE TO SHORTER TREATMENTS AND LOWER OVERALL COSTS IN THE COMPLETE TKA EPISODE OF CARE.
ImprovedPhysicalTherapyandShort-TermClinicalOutcomes
Breslauer L, Chow J. The use of intraoperative sensors significantly increases the patient-reported rate of improvement in primary total knee arthroplasty. Orthopedics. 2017 Jul 1;40(4):e648-e651.
KSS FUNCTION
PRE-OP 6-MONTHS
85
75
65
55
45
SC
OR
E
MANUAL
VERASENSE
IMPROVEMENTS PRE-OP TO 6 MONTHS
KSS Pain 29 36 0.001
KSS Function 23 27 <0.001
KSS Total 52 63 <0.001
Oxford 13 17 0.025
Clinic ROM 9 20 <0.001
MANUAL VERASENSE P-VALUE
°°
OrthoSensor.com 9 VERASENSE
ECONOMICS
CostMitigationDuringRevisionTKACOST SAVINGS WHEN PLANNED TOTAL REVISION CHANGED TO PARTIAL REVISION TREATING THE ‘LOOKS GOOD, FEELS BAD’ KNEE BY DIAGNOSING SOFT TISSUE IMBALANCE
PURPOSE
Despite long-term success rates associated with total
knee arthroplasty (TKA), a large proportion of patients
continue to report dissatisfaction with their surgical out-
comes. Complications such as pain, stiffness, or
instability can reduce a patient’s quality of life and may
be attributed to soft-tissue imbalance. The cause of
imbalance related complications is often difficult to
diagnose, but if unresolved may lead to early total
revision surgery. However, these procedures are associated
with a higher risk of post-operative complications, elicit
longer rehabilitation regimes, and can become a
financial burden to the patient and healthcare provider.
Therefore, the purpose of this study was to determine
if the use of intraoperative sensors during revision TKA
led to a decreased need for all-component revision.
METHODS
58 REVISION TKA PROCEDURES
• 7 sites, 7 surgeons
• Patients reported with idiopathic pain, instability
and/or stiffness.
• Radiographs showed acceptable component
alignment with symmetrical joint gaps.
• Patients reporting pain had culture-negative
aspiration findings.
RESULTS
CHANGES TO PARTIAL REVISION (N=36)
• 10 tibia-only, 26 polyethylene exchange
ESTIMATED COST SAVINGS: $4,990 PER CASE
• I n 36 of 58 cases, expected total revisions changed
to partial revisions, which equates to
a theoretical implant cost savings of $179,640.
CONCLUSIONS
VERASENSE CAN FACILITATE IMPLANT COST MITIGATION DURING TKA REVISION1
POTENTIAL COST SAVINGS OF PARTIAL REVISIONS
• Shorter OR time, length of stay
• Less instrumentation, OR supplies
• Lower risk of complications (e.g., infection,
fracture)
• Shorter, easier post-op rehabilitation regime
• Less bone stock loss, internal constraint for patient
Hospital for Joint DiseasesNYU LANGONE MEDICAL CENTER
Leone W, et al. Using Sensors to Evaluate Revision TKA; Treating he “Looks Good; Feels Bad” Knee. EC Orthopaedics 3,5 (2016): 381-385
17
53
5
4170%
SCHEDULEDFOR TOTALREVISION
88%OF PLANNED
TOTALREVISIONSCHANGED TO
PARTIALREVISIONS (N=36)
PRE-OP PLAN PROCEDUREPOST-VERASENSE
REVISION TKAS USING VERASENSE
TOTAL r-TKA
PARTIAL r-TKA
AVERAGE REVISION TKA IMPLANT COST
TOTALREVISION
TIBIACOMPONENT POLYETHYLENE
$6,770* $2,880 $980
*REPRESENTS ⅔ OF MEDICARE DRG
OrthoSensor.com 10 VERASENSE
ECONOMICS
PotentialforReducingIncidenceofEarlyRevisionTKA
1 Medicare Provider Analysis and Review File. 2013: Centers for Medicare & Medicaid Services Database – Primary and Revision TKA.
2 Bhandari M, Smith J, Miller L, et al. Clinical and economic burden of revision knee arthroplasty. Clin Med Insights Arthritis Musculoskelet Disord. 2012. 5: 89-94.
3 Lavernia C, Lee DJ, Hernandez VH. The increasing financial burden of knee revision surgery in the United States. Clin Orthop Relat Res. 2006; 446: 221-226.
4 Bozic K, Kurtz S, Lau E, et al. The epidemiology of revision total knee arthroplasty in the united states. Clin Orthop Relat Res. 2010. 468: 45-51.
5 Thiele K, Perka C, Matziolis G, Mayr HO, Sostheim M, Hube R. Current failure mechanisms after knee arthroplasty have changed: polyethylene wear is less common in revision surgery. J Bone Join Surg. 2015; 97(9): 715-720.
6 Lombardi AV, Berend KR, Adams JB. Why knee replacements fail in 2013: patient, surgeon, or implant? Bone Joint J. 2014;96-B(11 Supple A): 101-104.
7 Schroer WC, Berend KR, Lombardi AV, et al. Why are total knees failing today? Etiology of total knee revision in 2010 and 2011. J Arthroplasty. 2013;28(8 Suppl):116–119.
8 Sharkey PF, Lichstein PM, Shen C, et al. Why are total knee arthroplasties failing today—has anything changed after 10 years? J Arthroplasty. 2014;29(9):1774–1778.
9 OrthoSensor Multicenter Evaluation. Pending Publication. Data on file at OrthoSensor, Inc.
The annual healthcare financial burden of revision TKA is estimated at $2.7 BILLION based
on average hospital charges of 73 thousand dollars per case. Analysis of facility costs and
Medicare reimbursements shows over 90% OF HOSPITALS LOSE MONEY ON REVISION TKA,
with a loss of nearly $10,000 PER PROCEDURE .
VERASENSE multi-center study patients showed an almost 75% LOWER RATE OF REVISION TKA compared
to national averages. This reduction represents clinical and financial benefit to both patients and providers.
SENSOR-ASSISTED TKA: MULTICENTER STUDY TKA EARLY REVISION BURDEN (<2 YEARS, SOFT-TISSUE COMPLICATIONS)
FINANCIAL BURDEN OF TKA REVISIONS: 2013 MEDICARE PROVIDER ANALYSIS AND REVIEW FILE (MED PAR)1
* VERASENSE CANNOT PREVENT REVISION DUE TO INFECTION
HOSPITAL LOSSNET
PER TKA REVISION
$9,540CMSREIMBURSEMENT$19,134
COST$28,674
HOSPITALLOSS$9,540
HOSPITAL AVERAGECHARGES $73,000 2,3
90.3%REPORTED LOSSES
ON REVISION TKA PROCEDURES
OF HOSPITALS ANNUALFINANCIAL
FOR REVISION KNEE SURGERY
BILLION2
2.7$
BURDEN
0.7%*
VERASENSEMULTICENTER STUDY
APPROXIMATELY 2.6%OF TOTAL KNEE ARTHROPLASTIESRESULT IN EARLY REVISIONRELATED TO SOFT-TISSUE COMPLICATIONS4-8
(<2 YEARS)
2.6%*
UNITED STATESAVERAGE
12-13%REVISIONBURDENFOR TKA4,5
VERASENSE: ONLY 1 OF 143 PATIENTS (0.7%) REVISED WITHIN 2 YEARS9
Hospital
OrthoSensor.com 11 VERASENSE
SURGICAL TECHNIQUES
PURPOSE
Intraoperative sensors were used in blinded (control)
and unblinded cohorts to compare the “feel” of an
experienced surgeon to sensor-generated data in
order to evaluate appropriate TKA balance through a
range of motion.
METHODS
• A total of 22 primary TKA patients, in 2 groups (12
manual, gap-balanced; 10 VERASENSE, sensor-
assisted), were evaluated for any differences in
mediolateral loading and soft-tissue release type
performed.
• Intraoperative sensors were used in both groups.
• The surgeon (30 years of experience) was blinded
to the sensor data in the manual group, and was able
to use the sensor data in the sensor-assisted group.
RESULTS
• The VERASENSE cohort exhibited lower overall
loading, in both the medial and lateral
compartments, than the manual group.
• Intercompartmental loading through the range of
motion was significantly more symmetrical in the
VERASENSE group than the manual group.
CONCLUSION
SENSOR-ASSISTED SURGERY PROVIDES OBJECTIVE DATA THAT MAY ASSIST SURGEONS IN DECREASING THE INCIDENCE OF OUTLIERS IN LOADING ACROSS THE KNEE JOINT.
CanWeReally“Feel”aBalancedTotalKneeArthroplasty?
Elmallah RK, Mistry JB, Cherian JJ, Chugato M, Bhave A, Roche MW, Mont MA. Can We Really “Feel” a Balanced Total Knee Arthroplasty? J Arthroplasty. 2016; 31: 5102-5105.
COMPARTMENTAL LOADING AVERAGESIN MANUAL AND VERASENSE COHORTS
MANUAL (BLINDED)
VERASENSE (UNBLINDED)
MEDIAL10
LATERAL10
LATERAL45
MEDIAL45
MEDIAL90
LATERAL90
90
80
70
60
50
40
30
20
10
0
DEGREES OF FLEXIONL
OA
DIN
G (
LB
F.)
CHARACTERISTIC COMPARTMENTAL LOADING EXAMPLES IN MANUAL AND VERASENSE COHORTS
COMPARISON OF COMPARTMENT LOAD AT VARIOUS DEGREES IN RANGE OF MOTION IN MEDIAL AND LATERAL COMPARTMENTS
DEGREES OF FLEXION VERASENSE COHORT MEAN (RANGE) (SD)
MANUAL COHORT MEAN (RANGE) (SD) P VALUE
MEDIAL COMPARTMENT 10° 45° 90°
22.8 (16-44) (8) 23.1 (9-38) (8) 20.4 (7-38) (8)
79.3 (12-228) (62) 77.2 (6-177) (51) 55.4 (4-159) (48)
.0108
.0035
.0326
LATERAL COMPARTMENT 10° 45° 90°
17.2 (0-38) (10) 13.3 (4-25) (7) 16.1 (7-38) (8)
27.6 (0-102) (37) 31 .3 (0-99) (38) 28.4 (0-73) (29)
.39
.15
.21
SD, STANDARD DEVIATION
MANUAL (BLINDED)
VERASENSE (UNBLINDED)
OrthoSensor.com 12 VERASENSE
SURGICAL TECHNIQUES
PURPOSE
The accuracy of surgeon-defined assessment (SDA) of
soft tissue balance in TKA was compared to sensor-
guided assessment with VERASENSE to assess the ability
of sensor data in guiding the surgeon to achieve targeted
balance. The hypothesis is that arthroplasty-trained SDA
is a poor predictor of the state of soft tissue balance
in TKA.
METHODS
• 238 single-surgeon, sensor-assisted TKAs
– 159 varus (mean -6.5°)
– 67 valgus (mean 7.3°)
– 12 neutral
• Conventional intramedullary guides, same implant
system for all TKAs
• Standard trial surgical assessment and prediction
of knee balance status, THEN corresponding
VERASENSE trial inserted to quantify balance
(“balanced” = M/L difference ≤15 lbf)
RESULTS
ACCURACY OF SURGEON-DEFINED ASSESSMENT OF BALANCE – 62%
– Correct when predicting “balanced” – 61%
– Correct when predicting “unbalanced” – 65%
CHANGE OF SURGICAL PLAN IN 38% (N=90) OF CASES
– 29% (n=68) needed balancing
– 9% (n=22) prevented unnecessary balancing
CONCLUSIONS
SURGEON ASSESSMENT IS A POOR PREDICTOR OF KNEE COMPARTMENTAL LOADS AND BALANCE
WITH SURGICAL TECHNIQUES THAT AIM TO IMPROVE BALANCE, IMPROVEMENTS IN QUANTIFICATION AND VALIDATION OF KNEE BALANCE ARE REQUIRED.
AccuracyofManualSurgeon-DefinedAssessmentofSoftTissueBalanceinTKAInComparisontoVERASENSESensor-GuidedMeasures–CanWeDetectanUnbalancedKnee?
TOTALPATIENTS
238
CHANGE OFSURGICAL
PLAN38%
SURGEON CLAIMSBALANCE
176
VERASENSECONFIRMS
108
VERASENSECONTRADICTS
68
VERASENSECONTRADICTS
22
VERASENSECONFIRMS
40
REQUIRING FURTHERADJUSTMENTS
29%
PREVENTINGADJUSTMENTS
9%
POSITIVEPREDICTIVE VALUE
61%
NEGATIVEPREDICTIVE VALUE
65%
SURGEON CLAIMSUNBALANCE
62
MacDessi S. Accuracy of manual surgeon defined assessment of soft tissue balance in TKA In comparison to VERASENSE sensor-guided measures – can we detect an unbalanced knee? AOA 2017.
OrthoSensor.com 13 VERASENSE
SURGICAL TECHNIQUES
PURPOSE
The aim of this prospective study was to define the
surgical techniques required to achieve optimal knee
balance during VERASENSE Sensor–Assisted TKA.
METHODS
• 238 single-surgeon, sensor-assisted TKAs
– 159 varus (mean -6.5°) – 67 valgus (mean 7.3°) – 12 neutral
• Conventional intramedullary guides, same implant
system for all TKAs
• Surgeon performed standard surgical treatment,
aimed for neutral mechanical alignment, and then
balanced the knee as per prior published
VERASENSE protocols
RESULTS
CONCLUSIONS
RESULTS HAVE CHALLENGED TRADITIONAL CONCEPTS OF KNEE BALANCING.
• Bone adjustments required to alter soft tissue
tensions in ¼ of cases
• Counterintuitive soft tissue releases not always
on the same side as the disease pattern
• Traditional soft tissue releases may have less
impact than thought
– ITB laterally
– Semimembranosus / PM Capsule medially
CONTINUED REFINEMENT OF TECHNIQUES TO OPTIMIZE BALANCE IS REQUIRED TO DETERMINE ASSOCIATION WITH NEWER ALIGNMENT STRATEGIES AND CLINICAL OUTCOMES.
KneeBalancinginTotalKneeArthroplastyUsingtheVERASENSEArticularInsert.FindingsofaProspectiveCohortStudy.
OVERALL65% Required Balance Adjustment
BONE ADJUSTMENTS
SOFT TISSUE RELEASE ONLYNO ADJUSTMENT
27%
38%
35%
MEDIAL
LATERALBILATERAL
89%
8%
3%
VARUS KNEE RELEASES65% Required Balancing
42% 54%
VALGUS KNEE RELEASES75% Required Balancing
4%
VARUS KNEE SOFT TISSUE RELEASES
VALGUS KNEE SOFT TISSUE RELEASES
MCL PIE CRUST
MCL & PM
PM CAPSULE
ARCUATE
ARCUATE & POPLITEUS
ARCUATE
ITB
POPLITEUS / LCL
MCL PIE CRUST
0 5 10 15 20 25
0 10 20 30 40 50 60
VARUS KNEE SOFT TISSUE RELEASES
VALGUS KNEE SOFT TISSUE RELEASES
MCL PIE CRUST
MCL & PM
PM CAPSULE
ARCUATE
ARCUATE & POPLITEUS
ARCUATE
ITB
POPLITEUS / LCL
MCL PIE CRUST
0 5 10 15 20 25
0 10 20 30 40 50 60
MacDessi S. New Concepts in Knee Balancing in Total Knee Arthroplasty Using the Verasense Articular Insert. Findings of a Prospective Cohort Study. COKS/AKS 2017.
OrthoSensor.com 14 VERASENSE
Notes
OrthoSensor.com 15 VERASENSE
Notes
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