Advancing TJA Syllabus

2015-03-04

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3/3/2015
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SENSOR ASSISTED SURGERY
A Universal Solution to Customized Soft Tissue Balance
“You can’t change what you can’t measure”
Martin W. Roche, MD
DISCLOSURES
•OrthoSensor Inc: (Royalties, Board Member)
•Stryker-MAKO, Inc: ( Royalties)
SURGEON POLL
(VuMedi 2015)
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WHAT DO WE WANT TO CHANGE ?
•Reduce Rev TKA Burden
•Mal-rotation
•Mal-alignment
•Soft tissue Imbalance
•Patient Dissatisfaction
DRIVE TOWARDS A DEFINITION of “ KNEE BALANCE”
SENSOR MULTIFUNCTIONALITY allows DYNAMIC INTRA-OP KINETIC ASSESSMENT
INTRA-OP SCENERIOS
•Soft Tissue Asymmetry and Imbalance
•Selective Soft Tissue Releases
•Implant Congruency and Mal-rotation
•Relation of “Balance” and Alignment Adjustments
•Effects of Cementing Techniques
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PIE-CRUSTING MCL
ROTATION
Roche M et al. The Relationship of the Medial 1/3 of the Tibial Tubercle to the Posterior Aspect
of the Tibia, Holy Cross Hospital, Ft. Lauderdale, FL
•Retrospective analysis (n=170):
53% exhibited asymmetrical
tibiofemoral congruency
(68% IR, 32% ER)
•1000+ CT scans: exhibited the
mid-medial 1/3 of the tibial
tubercle can vary by ( ± 25°)
•Inter-compartmental balance can
be achieved by adjusting tibio-
femoral congruency
Importance of Proper
Tray Rotation
VALGUS KNEE
Concerns:
•Contracture / Recurvatum
•MCL Stability
•Femoral Rotation
•Extra-articular Deformity
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EFFECTS OF ALIGNMENT
PCL (POSTERIOR MEDIAL STABILIZER)
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CEMENTING TECHNIQUES
*Gustke et al. Primary TKA Patients with Quantifiably Balanced Soft-Tissue Achieve Significant Clinical Gains Sooner than Unbalanced Patients. Advan Orthop.2014
PATIENT REPORTED OUTCOMES
Prospective Data Collection
Balanced satisfaction: 96.7%
Unbalanced satisfaction: 82.1%
Meta-Analysis
•12 papers met inclusion criteria (B-F = 3.048;
homogeneity < 0.001; df = 11)
•81% average (“satisfied” to very satisfied”)
PATIENT SATISFACTION
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•Ligament Balance continues to be the most significant factor
impacting patient outcomes
•Functional improvement and satisfaction scores for
unbalanced patients at 1-year were inferior to those achieved
by balanced patients at 6-months
•Sensor-assisted TKA patients are statistically more likely to
achieve reduced pain, improved function, and greater activity
levels than unbalanced patients
•Patient Satisfaction scores for balanced patients show much
larger improvement than unbalanced patients
CONCLUSIONS
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Improving Accuracy & Intelligence
with Navigation in Total Knee
Arthroplasty
VuMedi Webinar Advancing TJA with Computer
Technologies
Paul K. Gilbert, MD
Clinical Assistant Professor
Keck Medical Center of USC
Huntington Memorial Hospital, Pasadena, California
March 3, 2015
General Ortho/subspecialty in joints
25 years in community private practice
Recently joined USC part time
Started doing CAS for hips and knees in 2004
400 robotic unicompartmental knees
Accelerometer based tools
•Teaching/research consultant for
Stryker/Mako Orthopaedics
Disclosures
3
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Why did I start?
•Accuracy, the biomechanical
sweet spot
•Better functional outcomes
•Happier patients
•Less bleeding, fat emboli
•Less revisions
The Literature
•Implant malalignment and malposition are
associated with decreased function and/or
higher revision rates
•Navigated TKA results in better alignment
and position
•Navigated TKA data does not show
improved functional outcomes
Pros and Cons
•Less blood loss
•Less thromboembolism
•Less cognitive changes
•Promotes teamwork and staff
satisfaction
•Fractures associated with pin
sites
•Pin site infections
•Cost
•Time
•Learning curve
•Vascular injury
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Patient Satisfaction
80%
What makes a good TKA?
Pre-op: evaluate, optimize,
educate, educate, educate
Surgery:
Post-op: rehab, hand holding,
rehab, rehab
Physical Therapists
Pain management docs
Patients feel they got the best
Surveys
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December 2, 2011
2014 Australian Joint Registry
December 2, 2011
2014 Australian Joint Registry
Accuracy and Intelligence
Thank you very much
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Patient Specific
Instruments:
Where Are We Now?
Adolph V. Lombardi, Jr., MD, FACS
Joint Implant Surgeons, Inc.; White Fence Surgical Suites;
The Ohio State University; Mount Carmel Health System
New Albany, Ohio
Adolph V. Lombardi, Jr. Disclosure
Consultant, Speaker’s Bureau:
♦Biomet, Inc.; Pacira
Royalties:
♦Biomet, Inc.; Innomed, Inc.
Research Support:
♦Biomet, Inc.; Stryker; Pacira; Kinamed
Publications Editorial Boards:
♦Journal of Arthroplasty; Journal of Bone and Joint
Surgery - American; Clinical Orthopaedics and Related
Research; Journal of the American Academy of
Orthopaedic Surgeons; Journal of Orthopaedics and
Traumatology; Surgical Technology International; The
Knee
Boards:
♦Operation Walk USA; The Hip Society; The Knee
Society; Mount Carmel Education Center at New
Albany
1. PSI has a
2-decade
history.
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History of Technology
Radermacher 1994
Materialise, founded 1990
•Mimics and Magics software
released 1991, 1992
Kinamed, since 1995
ConforMIS, founded 2004
OtisMed, founded 2005
2. PSI are based
on a proven
technology
–Rapid
Prototyping.
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Studies of Custom Triflange Components in
Revision THA
Authors
(Country)
# of
Patients
(Hips)
Males
:
Females
Mean
Age
(years)
Type of
Acetabular
Defect
Time
Results
Christie et al.
(US) [6]
76 (78) 20:56 59
AAOS types III/IV
-
6 reoperations for recurrent
dislocation (7.8%); no removal of
triflange components.
Pre
-op HHS: 33; Post-op HHS: 82
Colen
et. al
(Belgium) [7]
6 (6) 3:3 69
AAOS types III/IV
-
0 revisions.
Post
-op HHS: 61
DeBoer
et al.
(US) [10]
18 (20) 3:15 56
Pelvic discontinuity
-
6 revisions (30%); no removal of
triflange components.
Pre
-op HHS: 41; Post-op HHS: 80
Holt et al. (US)
[12]
26 (26) 8:18 69
Paprosky type 3B;
AAOS types III/IV
3 failures of triflange components
(11.5%).
Pre
-op HHS: 39; Post-op HHS: 78
Joshi et al. (US)
[13]
27 (27) 9:18 68
AAOS type III
-
2 revisions with removal of
triflange
components (7.4%).
Taunton et al.
(US) [25]
57 (57) 6:51 61
Pelvic discontinuity
-
20 revisions for any reason (35%); 3
failures of
triflange components
(5.3%).
Post
-op HHS: 75
Wind Jr. et al.
(US) [27]
19 (19) 7:12 58
Paprosky types
3A/3B; AAOS types
III/IV
-
2 revisions for failure of
triflange
components (10.5%).
Pre
-op HHS: 38; Post-op HHS: 63
Lombardi et al.
CORR (in
submission)
26 (28) 7:19 68
Paprosky type 3B
-
4 revisions for any reason (14%); 2
failures of
triflange components
due to infection (7.1%).
Pre
-op HHS: 42; Post-op HHS: 64
US=United States; f/u=follow-up.
3. PSI are offered
by multiple
orthopaedic
manufacturers.
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Current TKA Platforms for
Patient Specific Alignment Guides
Manufacturer
Product Imaging US Launch
Biomet
Signature™ MRI
CT
10/2007
01/2010
ConforMIS
iTotal®CT 2011-2012
DePuy
Trumatch™CT 04/2009
Medacta
MyKnee®CT or MRI 04/2010
Smith & Nephew
Visionaire™
MRI & X
-
ray
11/2008
MicroPort
*Prophecy™ CT or MRI 03/2009
Zimmer
PSI MRI
CT
11/2009
06/2012
*formerly Wright Medical
4. PSI are expanding:
UKA
THA
TSA
TA
Osteotomy alignment
correction
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Current PSI Platforms for UKA
Manufacturer
Product Imaging US Launch
Biomet
Signature™ MRI 10/2011
Zimmer
PSI MRI
CT
02/2012
10/2012
PSI for
Acetabular
Positioning
PSI for Shoulder Component Positioning
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The patient
receives a CT
scan following
the protocol.
The surgical
plan is
approved via
website. The
surgeon may
alter the plan if
desired.
A rapid prototyping
machine produces
patient-specific
guides out of high
resolution nylon.
Guides are then sent
out for surgery.
Pre-Op Post-Op
Virtual preoperative
alignment is performed
according to surgeon
preferences.
Surgery is performed
in accordance with
the preoperative
plan.
Victor & Premanthana, BJJ 2013
5. PSI utilization
is increasing
throughout the
world
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Numbers of PSI TKA, 2011-2012
Manufacturer
Global
2011
Europe
2011
Global
2012
Europe
2012
Biomet
11,192 3,169 22,506 6,501
DePuy
-Synthes 6,000 700 16,000 1,100
Medacta
4,600 3,400 6,200 4,600
Smith & Nephew
19,500 1,825 22,000 2,614
Wright
Medical 1,600 400 2,000 550
Zimmer
9,800 1,250 13,850 2,150
Thienpont et al., KSSTA 2013
6. PSI are extremely
useful in patients
with extra-articular
deformity or retained
hardware.
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7. PSI have
been used
successfully in
revision knee
arthroplasty.
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8. PSI
facilitate
preoperative
planning.
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9. PSI offer
distinct
advantages to
lower volume
surgeons.
With a 6-fold increase in the incidence of TKA projected over the next 2
decades, an increasing burden on lower volume/inexperienced arthroplasty
surgeons, who tend to have longer operative times and increased
complication rates compared with high-volume surgeons, is expected.
Improved efficiency and reproducibility in implant positioning and limb
alignment is paramount to decreasing complications, improving outcomes,
and meeting the increasing demand. Patient-customized cutting guides that
are being developed by most major manufacturers of total knee prostheses are
an emerging technology that will allow the lower-volume surgeon to meet
many of these demands. One of the primary drivers of increased surgical
times for lower-volume surgeons is the significant number of steps and
complexity of instrumentation required to perform a TKA. The use of CPI
eliminates numerous steps in the surgical technique and eliminates the need
for as many as 80 instruments, which allows for significantly improved
surgical efficiency. The elimination of this instrumentation also allows for
significant improvement in processing and operating room efficiency with
decreased incidence of processing error. The 31-minute decrease in operating
room set-up and breakdown in the study reported here was realized by an
operating room staff who is very experienced with TKA. A greater
improvement in efficiency may be realized by a lower volume operating room
staff.
Johnson, AJO 2011
10. PSI require less
instrumentation resulting
in less OR time setup and
breakdown, a decrease in
the number of
instruments requiring
sterile processing.
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Traditional Setup
PSI Setup
11. PSI easily fit into
the operative
workflow, and in the
majority of timed
studies actually
decrease operative
time.
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PSI Workflow
Value of PSG in TKA
Significant reduction in:
♦Processing and sterilization time
♦Turnover time
♦OR time
♦Number of trays used
♦Hospital stay
Noble et al., J Arth 2012
Johnson, Am J Orthop 2011
Duffy, Am J Orthop 2011
Lionberger et al., AAHKS 2011
Nunley et al., CORR 2011
Tibesku et al., AOTS 2013
12. PSI has more
supportive
literature than
negative
literature.
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Patient Specific Guides - Pro
Barrett et al., J Arth 2014
Boyd et al., Clin Sports Med 2014
Cenni et al., J Ortho Res 2014
Ensini et al., KSSTA 2014
Marimuthu et al., J Arth 2014
Silva et al., KSSTA 2014
Bonicoli et al., Eur J OST 2013
Chareancholvanich et al., BJJ 2013
Daniilidis & Tibesku, Int Orthop 2013
Issa et al., J Knee 2013
Kerens et al., Acta Orthop 2013
Koch et al., KSSTA 2013
MacDessi et al., The Knee 2013
Thienpont et al., The Knee 2013
Thienpont et al., KSSTA 2013
Tibesku et al., AOTS 2013
Volpi et al., KSSTA 2013
Yaffe et al., Int J CARS 2013
Ast et al., OCNA 2012
Bali et al., J Arth 2012
Boonen et al., Acta Orthop 2012
Heyse & Tibesku, The Knee 2012
Johnson, Am J Orthop 2012
Lombardi & Frye, CRMSM 2012
Nam et al., JKS 2012
Mayer et al., J Arth 2012
Ng et al., CORR 2012
Noble et al., J Arth 2012
Slammin & Parsley, CRMSM 2012
Yaffe et al., Biomed Tech 2012
Yeo et al., ISRN Orthop 2012
Stulberg et al., KS IM 2012
Mont et al., KS IM 2012
Duffy, Am J Orthop 2011
Johnson, Am J Orthop 2011
McGovern, Am J Orthop 2011
Watters et al., JSOA 2011
Lombardi et al., Orthopedics 2008
Patient Specific Guides –
Con / Questionable
Barrack et al., JBJS Br 2012
Conteduca et al., KSSTA 2012
Conteduca et al., Int Orthop
2012
Lustig et al., J Arth 2012
Nam et al., J Arth 2012
Nunley et al., CORR 2012
Stronach et al., CORR 2012
Bellemans et al., KS IM 2012
Chen et al., KSSTA 2014
Conteduca et al., Int Orthop
2014
Scholes et al., KSSTA 2014
Victor et al., CORR 2014
Hamilton et al., J Arth 2013
Nam et al., The Knee 2013
Parratte et al., KSSTA 2013
Roh et al., CORR 2013
Stronach et al., CORR 2013
13. PSI has been reported
to be associated with
significant improvement
in Knee Society
Functional Score in
short-term follow-up.
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Yaffe et al.,
Int J CARS 2013
14. PSI technology is in a
state of constant
evolution –Now based on
preoperative CT/MRI and
moving in the direction of
preoperative x-rays only.
2D X-Ray to 3D
Shape Model
Full Automation
Rapid Turn Around
Cost Effective
Guide Technology
X-Ray based 3D Planning
Procedure Specific Kits
Core Set of Reusable Instruments
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15. PSI are part of
the future
delivery of
implants.
Traditional Instrument/Implant
Delivery System
1. Orthopaedic Assessment
2. Surgery Scheduled
3. Orthopaedic Rep Contacted
4. Physician/Rep Template Case
5. Plan Developed
6. Instruments/Implants
Delivered to Hospital
7. Instruments Signed into
Central Sterile
8. Implants Stored
9. Washer/Sterilizer
Decontamination
10. Instruments Wrapped/Labeled
Traditional Instrument/Implant
Delivery System
11. Instruments Autoclaved
12. Case Cart Loaded
13. Delivered to OR
14. Trays Opened and Checked
15. Implants Inventory to Field
16. Trays Removed from Field
Loaded on Cart
17. Preliminary Decontamination
18. Returned to Decontamination
19. Load Washer/Sterilizer
20. Organize Trays/Wrap/ Label
21. Autoclave Trays
20. Organize Trays and Lable
21. Autoclave
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Traditional Re-Usable
Cutting Blocks & Trials
Sterile-Packed
Single-Use Cutting
Blocks & Trials
Mont et al., J Arth 2013
The Future of Orthopaedic
Implant Delivery
Marrying PSG with single-use instruments
streamlines the delivery of orthopaedic products
Decreased number of instruments with SUI
reduces:
♦OR setup time
♦OR turnover time
♦Overall surgical time
♦Infection?
PSG and SUI increase efficiency
Restoring mobility •Giving hope
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Patient Specific Instrumentation
and Implants: Do They Significantly
Impact Patient Satisfaction and
Outcome?
Brian S. Parsley, MD
Clinical Associate Professor
Director- Adult Reconstruction Fellowship
Ryan Palmer, DO
Adult Reconstruction Fellow
Baylor College of Medicine
Houston, Texas
Disclosures
•Consultant for Nimbic Air Barrier System
•Royalties from Conformis Inc.
•AAHKS Board
Orthopaedist Love New Toys!
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New Technology for TKA- PSI
•Rapid growth in the offerings of Patient Specific Guidance
•Customized cutting blocks for knee replacements
•Computer based guidance for hip and knee replacements
•From simple to complex
•Both imageless and image based
•Individual vs robotically guided
•Custom made implants for knee replacements
•What is the justification?
•Cost reduction?
•Time Efficiency?
•Patient outcomes?
Let’s Look at Function
•Patient Specific Instrumentation (PSI) vs. Conventional
•40 patients randomized into 2 groups; 20 each group
•All pts received Zimmer NexGen LPS-Flex mobile cemented implants
•Patients evaluated pre-operatively and 3 months post-operatively
•New Knee Society Score [KSS], KOOS, SF-12, & Gait Analysis
•Results:
•In the PSI group, 25% of cases required intra-operative modifications
•Overall, there were no differences in the new KSS, KOOS, or SF-12 between the PSI and
conventional TKA groups (see graft)
•Overall, there were no differences in the analyzed gait parameters between the two groups
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Comparison of Pre & Post Op Function
Comparison of Pre & Post Op Gait
Complications
•3 complications in the PSI group
•2 patients had post-operative flexion contractures of 5 and 10 degrees
•Both patients had pre-operative flexion contractures
•1 patient had pre-operative patellar subluxation that continued post-operatively
•No complications in the conventional TKA group
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Custom Cutting Guides Do Not Improve Total Knee
Arthroplasty Outcomes at 2 Years Follow-up
D. Nam, A. Park, J. Stambough, S. Johnson, R. Nunley, R. Barrack
•95 custom cutting guides vs. 95 conventional cutting guides for TKA by same surgeon
•Patient self selection into either group
•UCLA Score, SF-12, Oxford Knee & Forgotten Joint scores collected pre & postoperatively
•Rotational alignment, Patient Satisfaction scores post-operatively,
Presented at AAHKS Annual Meeting Nov. 2014
Results
•No differences for range of motion, UCLA, SF-12, Oxford Knee, or
Forgotten Joint scores between the two cohorts (p=0.09 to 0.76)
•No differences were present for the incremental improvement in these scores
from preoperatively to postoperatively (p=0.1 to 0.9)
•No difference in mean tourniquet time (59.1 + 13.2 mins in CCG vs. 59.7 +
14.7 mins in standard cohort; p=0.75)
•Percentage of outliers for overall mechanical alignment (31% in CCG versus
23% in standard cohort with HKA outside of 0° + 3°; p=0.2).
Presented by Nam at AAHKS Annual Meeting Nov. 2014
Conclusions
•At two years follow-up, custom cutting guides fail to demonstrate any
advantages in clinical outcomes versus the use of standard instrumentation in
total knee arthroplasty.
•The benefit of CCGs must be proven prior to continued implementation of
this technology.
Presented by Nam at AAHKS Annual Meeting Nov. 2014
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•Do patient specific cutting blocks achieve neutral mechanical alignment more
reliably during TKA when compared with conventional methods?
•16 studies, Level I-III evidence
•Does patient-specific instrumentation (PSI) provide financial benefit through
improved surgical efficiency?
•13 studies, Level I-III evidence
•Does the use of patient-specific cutting blocks translate to improved clinical
results after TKA when compared with conventional instrumentation?
•2 studies, Level III evidence
Do Patient Specific Instrumentation Achieve Neutral Mechanical Alignment More Reliably?
Variable Results From Improvement in Reduction in Outliers When PSI Used
Do Patient Specific Instrumentation Achieve Neutral Mechanical Alignment More Reliably?
To No Difference In Benefit
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Do Patient Specific Instrumentation Achieve Neutral Mechanical Alignment More Reliably?
To The Reverse Effect with PSI
Do Patient Specific Instrumentation Achieve Neutral Mechanical Alignment More Reliably?
Conclusion:
No Significant Difference Overall in Ability to
Achieve Overall Alignment
Does PSI Provide Financial Benefit Through Improved Surgical Efficiency?
Minimal decrease in OR Time if any except one study (12min) and one at 10
min
Frequent need to recut despite PSI
Decrease in # of trays and cost associated
Increase in cost associated with Custom Cutting Blocks and CT or MRI
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Does The Use of PSI Translate to Improved Clinical Results?
No Difference in Functional Scores at Short Term Follow-up
Limited number of studies available
Conclusions
•Limited data exist with regard to the effect of PSI on post-operative function,
improvement in pain, and patient satisfaction
•Neither of the 2 studies evaluating clinical results provided strong evidence to
support an advantage favoring the use of PSI
•There is a need for Mid- and long-term data regarding PSI’s effect on
functional outcomes and component survivorship
•Short-term data scarce
•Limited available literature does not clearly support any improvement of
post-operative pain, activity, function, or ROM when PSI is compared with
traditional instrumentation
•Retrospective case-control study
•122 Total Knee Arthroplasties by one surgeon
•44 with (PSI) vs 38 with Computer Assisted Surgery (CAS) vs 40 with manual instrumentation
•Groups were identical with regard to age, gender, diagnosis, BMI, and perioperative
management but had significantly different starting points
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Pre-operative and post-operative knees scores were higher in the PSI group.
Similar improvements from pre to post-op.
Bias? Lack of randomization? Skewed results?
Change in Score Pre to Post 33.8 43.0 36.7
NS
Pre and post-operative knee function scores were higher in the PSI group.
PSI showed a higher function score improvement when compared to manual
instrumentation (24.5 pts vs 3.8 pts)
Bias? Lack of randomization? Skewed results?
Pre and post-operative range of motion was higher in the PSI group. The change in ROM
between groups was no different.
Change in ROM 1.5 1.3 2.4
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Pre to post-operative knees pain score improvement was higher in the PSI group but the
improvement within groups was similar.
Change in pain score 30.7 26.4 26
CAS showed a more varus mechanical axis compared to manual (2.00 degrees varus vs. 0.24 degrees
valgus)
No difference found in post-operative mechanical axis between PSI and CAS, or PSI and manual groups
Conclusions
•The PSI group showed greater improvement in Knee Society function scores over
6 months when compared to manual TKA
•But the PSI group also had higher pre-operative function scores
•Lack of randomization limits conclusions
•No statistical differences seen in knee score, ROM, or pain score improvement
from pre-operative to the 6-month post-operative period among all groups
•No difference in mechanical alignment
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•62 patients Smith and Nephew Genesis II TKA Visionaire(31) vs Conventional(31)
•Randomized in 1:1 linear fashion
•Mean follow up: short- 200+days
•Results:
•No statistical difference in Satisfaction
•No statistical differences between pre-operative and post-operative KOOS scores
•Total KOOS scores (see graft)
•KOOS subscales (see graft)
•No statistical differences in VAS scores
Results
•Flexion Contracture
•Visionaire
•13/31 (43%) unable to obtain full extension
post-operatively
•Conventional
•6/31 (19%)
•Strict adherence to pre-operative
plan and cutting blocks as a cause
of residual flexion deformity
•Did not recut distal femur, followed
planned resection
•No statistically significant differences between groups for
•Satisfaction, Pain scores, or Functional outcome scores
•Gait, Flexion, EBL & transfusion needed, or alignment
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Biomet Signature PSI System
•Average $4000 per standard Vanguard TKA hospital contract
•General number in Houston, TX Medical Center region
•Add approximately $950 upcharge for PSI creation with Signature system
•Cost of MRI to create instrumentation-?? Cost
•248 TKA’s by one surgeon: 126 ConforMIS TKA vs. 122 Off-the-shelf (OTS) TKA
•Retrospective review
•Data collected:
•Length of procedure,
•LOS,
•Transfusions,
•Cost,
•Disposition
Presented at ICJR Pan-Pacific Meeting 2014
Results
•Demographics, LOS: No statistical differences
•Transfusion rates
•Conformis showed significantly less (2.4% ConforMIS vs 10.7% OTS)
•Adverse event rate
•Conformis showed significantly less (1.6% ConforMIS vs 13.9% OTS)
•Specific adverse events not published in abstract
•Total hospital cost
•Not statistically significant ($16,192 vs $16,240)
•Discharge disposition
•Significantly lower percentage of patients in the ConforMIS group were discharge to
acute care facilities (ConforMIS 2.4% vs 13.9% OTS)
Presented by Martin at ICJR Pan-Pacific Meeting 2014
3/3/2015
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Presented by Martin at ICJR Pan-Pacific Meeting 2014
Conclusions
•Significantly lower transfusion rates
•Likely related to eliminating the need for intra-medullary guides
•General estimated associated cost of $2200 per blood transfusion
•Significantly lower reported adverse event rates
•Specific adverse events not defined in abstract
•Costs associated with these specific adverse events not know
•Fewer patients discharged to acute care facilities with ConforMIS
•Authors reasons for this not revealed
•Criteria for discharge to acute care facility unknown
•Estimated $16,000 per discharge to acute care facility
•No statistical difference in overall hospital costs between the two groups
Presented by Martin at ICJR Pan-Pacific Meeting 2014
PSI vs. OTS TKR vs. Custom TKR
•Is the difference in the cutting blocks vs. the conventional cutting systems
when an OTS type knee is still being used??
OR
•Is it the combination of PSI and a custom patient specific TKR?
3/3/2015
13
In Conclusion
•There is NO clear data that PSI demonstrates consistent improvement in
function, ROM, alignment, or patient reported outcomes in the current
literature.
•The literature is limited and short term at this time.
•The cost justification is lacking with few exceptions.
•Should the Healthcare System be paying the bill?
THANK YOU
•20 patients by single surgeon
•11 ConforMIS CR TKA
•9 Off-the-shelf (OTS) CR TKA (Zimmer NexGen)
•Mobile fluoroscopic system used to analyze knee motion
•Deep knee bend
•Chair rise
•Fluorscopic 2D images were converted into 3D representation of kinematics
•Comparison of kinematics
•ROM
•Posterior femoral rollback
•Axial rotation
Presented at ICJR Pan-Pacific Meeting 2014
3/3/2015
14
Presented by Kurtz at ICJR Pan-Pacific Meeting 2014
Presented by Kurtz at ICJR Pan-Pacific Meeting 2014
Conclusions
•Authors conclude ConforMIS TKA patients experienced a more normal
kinematic pattern of the knee compared to an OTS TKA
•OTS TKA experienced greater variability in kinematic patterns
•No patient satisfaction or outcome scores reported
•Do differences in kinematic patterns equate to improved patient satisfaction,
function, or longevity of the implant?
Presented by Kurtz at ICJR Pan-Pacific Meeting 2014
3/3/2015
1
Robotics in UKA: Latest Advances in
Technique and Cost Efficiency
Jess H. Lonner, MD
Rothman Institute
Associate Professor, Department of Orthopaedic Surgery
Thomas Jefferson University
Philadelphia, PA
Disclosure
Royalties
Zimmer, Blue Belt Technologies
Consultant
Zimmer, Blue Belt Technologies
Speaker’s bureau
Zimmer, Blue Belt Technologies
Publishers: Saunders, Lippincott Williams Wilkins
Shareholder: Blue Belt Technologies, CD Diagnostics
Growing Use of UKA in US
1998-2005
UKA utilization increased 32.5% (vs TKA: 9.4%)
Expanding use of early intervention strategies
Improved surgeon education
Better diagnosis
Demographics- younger, employed, restless
Riddle DL, Jiranek WA, McGlynn FJ.
J Arthroplasty 2008
3/3/2015
2
Advantages of UKA vs TKA
Tissue sparing
Safer (Lower M &M)
Rapid recovery
More normal feel
Greater functionability
Less expensive
Growing emphasis on outpatient surgery
UKA:
94% survivorship at 10-15 yrs in hands of high
volume surgeons…
…But
> Age 65 < Age 65
10-yr survivorship 77% 7-yr survivorship 74%
Ong, Lonner etal AAHKS 2014
3/3/2015
3
What Impacts the Results of UKA?
Pathology/Disease
Patient selection
Component design
Polyethylene quality
Surgeon experience/volume
Accuracy of implantation
Malalignment Predisposes to Failure
Coronal malalignment of tibial component >3°varus
Mechanical limb varus >8°
Posterior tibial slope >7°
Collier /Engh et al. J Arthroplasty
2006; Hernigou JBJS 2004;
Chatellard Orthop Traumatol Surg
Res 2013
Outliers in Alignment in UKA with
Conventional Methods
40-60% of cases are malaligned beyond 2°of
plan
Keene G et al JBJS Br 2006;
Cobb J et al JBJS Br 2006
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4
Rationale of Robotics for UKA
Simplify the procedure
Reduce the amount of instrumentation
Eliminate surgical steps
Enhance accuracy
Bone preparation/component alignment
Soft tissue balance
Improve clinical results
Lonner JH. American Journal of Orthopedics 2009
Story of Robotics in UKA
Study in patterns that define technological
progress and innovation, in general
Declining capital and maintenance costs
Smaller space requirements
Broadening access
Increased utilization
Expanding Role for Robotics in
UKA
15% of UKA’s in US (2013)
www.OrthopedicNetworkNews.com. 2013
3/3/2015
5
Semi-autonomous Robotics in UKA
Mako (Mako Stryker, Ft. Lauderdale, FL)
Initial FDA approval 2005; revised 2008
Image-based (CT scan)
Navio PFS (Blue Belt Technologies, Plymouth, MN)
Initial FDA approval 2012
Image-free
1st Generation Semi-Autonomous
Robotic Arm for UKA: Mako*
FDA clearance 2005
Haptic constraint
Efficient
Safe
Image-based (preop CT scan)
Closed system (metal backed, FB UKA)
*Mako Stryker, Ft. Lauderdale, FL
Alignment –UKA
Conventional vs. Mako Robotic
2.6x more variability with manual techniques
(p<0.05)
Average error:
Manual: 2.7
Robot: 0.2(p<0.0001)
(Lonner, John, Conditt CORR 2010)
3/3/2015
6
Mako Results vs Conventional UKA
RCT, 100 patients
Conventional Oxford UKA vs Robotic Mako
Postop CT to assess coronal, sagittal, rot’l
alignment
Significantly less error in tibial slope, femoral
v/v, tibial rotation (p<0.01)
Blyth MJ et al. AAOS 2013
Downsides of 1st Generation
Robotic System in US
Capital expense
Preop CT scan
Additional expense
Denials common; high copays; bundled payments
Hospitals “eat cost”
Time/Inconvenience
Radiation exposure
Closed platform
2nd Generation Robotic System:
Navio PFS
FDA clearance: 2012
Image-free (No CT scan)
Intraop registration/mapping/planning
Intraop gap balancing
Semi-autonomous
Burr Speed/Exposure control
3/3/2015
7
Navio Technique:
Surface Mapping
Dynamic Intraop Gap Balancing
Selection of Implant Size/Position
and Virtual Gap Balance
3/3/2015
8
Virtual Tracking of Femur on Tibia
Technique:
Exposure Mode
Prepared Surface
3/3/2015
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Data???
Key Studies
Accuracy of bone preparation
Pre-clinical (cadaveric specimens)
Comparison of intraoperative plan for limb
alignment with postop limb alignment
Clinical (navigated measures)
Accuracy of tibial component alignment
Radiographic
Safety
Radiation avoidance
Study 1: Pre-Clinical Accuracy
25 cadaveric specimens
Medial UKA (Tornier HLS Uni Evolution)
3 surgeons
Lonner, Smith, Picard, Hamlin - Clin Orthop 2014
3/3/2015
10
Analysis Method
Preop plan
Postop analysis
Optical probe inserted into implant divots
Surface positions mapped
Postop position compared to plan
Lonner, Smith, Picard, Hamlin - Clin Orthop 2014
Alignment:
Vs. Other Semi-Autonomous (CT-based) Robots
and Manual
RMS Error NavioPFS Mako Rio Acrobot Manual
Flex/Ext (°)1.6 2.1 2.1 4.1
Varus/Valgus (°)2.3 2.1 1.7 6.0
Int/Ext (°)1.7 3.0 3.1 6.3
Prox/Dist (mm) 1.3 1.0 1.0 2.8
Ant/Post (mm) 1.3 1.6 1.8 2.4
Med/Lat (mm) 0.9 1.0 0.6 1.6
Dunbar et al J Arthrop 2012
Cobb J JBJS Br 2005
Jenny J Arthrop 2002
Lonner et al CORR 2014
Study 2: Planned versus Achieved Limb
Alignment
65 cases
Multiple surgeons
Postop limb alignment ≤1°from plan 92%
(60/65)
F Picard, A Gregori, J Bellemans, J Lonner, J Smith, D
Gonzales, A Simone, B Jaramaz –CAOS July 2014
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11
Study 3: Safety of Hand-Held Robot
Initial 1000 cases
No soft tissue complications
Study 4: Learning Curve
Mean of 8 procedures (range 5-11) to reach a
steady state surgical time.
Mean steady state surgical time was 50 minutes
(range 37-55 minutes)
A Gregori, F Picard, J Bellemans, J Lonner, R Marquez, J Smith, A Simone, B Jaramaz -
CAOS Abstract 2014
Study 5: Avoidance of Radiation from
preop CT Scans (Mako protocol)
236 scans 2011-2013
ED of radiation from LE CT scan:
4.8 +/- 3.0 mSv
25% had add’l CT scans (est cumulative ED
of 6-103 mSv)
Note: 10 mSv increases risk of fatal cancer by
1 in 2000
3/3/2015
12
Economics of Robotic Technologies
Assumptions:
Avg. Medicare payment per case: $12,500
Lien
Item
1
st Generation
2
nd Generation
System List Price
$1,200,000
$450,000
Svc Costs (List Price)
$100,000
$45,000
CT scan
$400
-$800
$0
Implant/Disposable
Costs
negotiated
negotiated
Break even on ROI
240 cases
60 cases
Costs of Care (Partial Knees)
Uhr A, Davis D, Lonner J. 2015
Cohort
Mean
Min
Max
Hospital
(Inpatient)
N=50
$16,495
$12,784
$28,644
Hospital
(Outpatient)
N=50
$13,295
$7,249
$24,758
ASC
N=50
$9,969
$3,406
$15,321
Conclusion:
Precise preoperative/intraop planning
Surface mapping
Gap balancing
Accurate bone preparation, implant
alignment, component positioning
Enhanced early outcomes
Impact on late results?
Cost analysis
3/3/2015
13
Conclusion: 2nd Generation Robot
Semi-autonomous system
Image-free
Cost favorable
ASC-feasible
Work flow intuitive
Implant-specific vs open platform
Expanding applications
3/3/2015
1
New Approaches:
Robotics in THA
Adam M Freedhand, MD
Assistant Professor
Disclosures
•Stryker
•Educational consultant
•OrthoSensor
•Stockholder
What are we improving?
•Implants
•Materials
•Approaches
i.e. Why robotics?
Goals of THA
Pain relief
Restoration of Function
Durable results
3/3/2015
2
Areas of Improvement
•Component /
Mechanical failures
•Product recalls
•Surgical Complications
THA Issues
•Component Malposition
•Leg length discrepancies
•Instability/Dislocation
Lawsuits
Upadhyay, JOA 2007
Critical Factors
•Implant Sizing
•Implant Positioning
•Fit
•Alignment
Biomechanics/Kinematics
3/3/2015
3
Component Malposition
•Early
•LLD/Dislocation
•4%
•Late
•Impingement/Wear
•Loosening
Component Malposition
Acetabulum
At Massachusetts General Hospital, only
36.9% of cups were in the desired zone of
placement.
Conventional Instruments
•Manual instruments
inconsistent
•Outcomes depend on
alignment
•Acetabulum / Femur
Little Guidance
3/3/2015
4
How Can We Improve?
•Surgical planning - template
•Intra-operative X-ray
•Alignment tools
•CAS
•Robotics
Low and High Tech
Robotics •Think Surgical
•Since 1992
•Femur
•Open platform
•Mako
•Since 2006
•Acetabulum
•Closed platform
What’s available
Robotics
•Advanced surgical
planning
•Precise robotic
machining of bone
•Improved component
placement
•Know result before
leaving the OR
Advantages
3/3/2015
5
Mako / Think Surgical
•Pre-operative CT scans
•3D virtual surgery
•Intra-operative execution of plan
•Optimize implant position
•Improve outcomes?
Accuracy and Precision
Robot vs Manual Instruments
•Leg lengths more accurate
•Slightly better JOA Clinical scores
•Less stress shielding in the Robot
Cohort
146 hips: 75 robot, 71 manual
3/3/2015
6
Patient Outcomes
Higher Harris Hip Scores, Lower Dislocation Rate
Think Surgical THA
•Less fractures
•Better fit/fill
•Precise placement of the femoral
component
•Size, alignment, depth of seat
Outcomes
Clinical Orthopaedics & Related Research:
September 1998 - Volume 354 - Issue - pp 82-91
Symposium: Computer Assisted Orthopaedic Surgery: Medical Robotics and Image
Guided Surgery
Mako THA
•Cup inclination/Version
•<5˙ from plan
•Acetabular COR
•<2mm from plan
More Cups in the Safe Zone
3/3/2015
7
Robotics in THA
•3D surgical plan
•Exposure
•Registration
•Machining of the
bone
•Trial / Implantation
•Closure
Workflow
Bone Registration
•Mako
•Pelvic array
•Acetabulum and Femur checkpoints
•Robodoc
•Femoral head armature
•CAS for acetabulum
Robotic Bone Resection
•Robodoc
•Surgeon clears workspace
•Active femur prep
•Mako
•Passive acetabular prep
•Visual, tactile and audible feedback
3/3/2015
8
Surgeon's Role
•Patient selection
•Implant selection
•Virtual Surgical Plan
•Expose / Protect /
Close tissues
•Execute / Verify
surgical Plan
Robotics
•Robodoc since 1992
•60 units worldwide
•Over 30K cases-
Hip/Knee
•Mako since 2006
•29K cases- Knee/Hip
Not Experimental
Industrial Revolution
Analogy
Before:
•Everything
Handmade
•Apprenticeship /
Artisans
•Variation in Quality
and Outcome
After:
•Mostly Machine-
made
•Quality Control
•Minimize Human
error
3/3/2015
9
Robotic Surgical
Revolution
Before
•Surgeon
Apprentices
•Apprenticeship /
Artisans
•Conventional
Instruments
•Variation in Quality
and Outcome
The Future is now!
•CAS/Robotics for
precision and
accuracy
•Quality Control
•Minimize Surgical
error

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