S.ALEVROGIANNIS, MD, PhD.CONSULTANT ORTHOPAEDIC SURGEON

2ND Orth. Dept.251 General Air Force Hospital, Athens/GR.

G. A. SKARPAS, MSc, PhD8TH Orth. Dept., General Hospital “Askepieion Voulas”, Athens-GR.

11th EFORT CONGRESS MADRIT 2010

• The Population is Aging-Age 55+, peak knee pain candidates, will grow 3 times the average rate of the U.S. population-Reaching 96 million by 2020

• Obesity Rates are Rising-In 2000, 31% of the adult U.S. population had a BMI of 30-Estimated rise to 40% by 2010

Knee Pain Patient Population: Underserved and Growing

• Patient – Centric Healthcare Increase in Internet education Increase in Direct to Consumer

Marketing Patients desire superior high

tech CAOS/ Robotic Solutions

• Early outcomes Robotic Surgery Improved accuracy Repeatability Enabling: minimally

invasive surgery Next frontier is

orthopedics

Major Healthcare Trends

© MAKO Surgical Corp. 2009

Patients Desires in Knee Surgery

No Lifestyle Change

Latest Technology

No Hospitalization- Short Rehab

No pain

Long Term Solutions

AAOSSurvey

TKA Gold Standard For Surgeons

• Total Knee Arthroplasty (TKA) considered Gold Standard for degenerative joint disease

• John Insall, M.D. – Father of Modern TKA• Proven long term survivorship 90% out 15 years• One of the most successful procedures in modern medicine

Limitations• Highly invasive• Requires extensive rehabilitation • Addresses late stage osteoarthritis (OA)• Often over utilized due to lack of equally successful / predictable

alternatives, (UKA) • Aggressively removes healthy cartilage when treating early stage

OA• Per Duke University Study: 88-92% of men and women

respectively decline Total Knee / Hip Arthroplasty .

Limitations of Instruments

Improper cutting block pin to bone alignment Vibration of blade can cause deflection & skiving Learning curve with instrumentation Pins can be a stress riser to bone Intramedullary alignment guides (standard for femur)

are invasive and can cause pulmonary emboli upon tourniquet release

Extramedullary alignment relies on the palpation of bony landmarks underneath varying thicknesses of soft tissue

Requires larger incisions

TKA outcomes have been shown to be dependenton implant positioning and alignment

With conventional techniques:

Limited preoperative planning (templates, x-ray) Instrumentation does not provide consistent

alignment Instrument cutting guides do not always deliver

precise resection (blade skiving) Requires large, sufficient size incision to inserts jigs Jigs require pinning, thus there is more bone

disruption

AIM OF THE STUDY

To present our preliminary results, using Navigation for TKR.

EARLY NAVIGATION SYSTEMS

WHAT IS CAS ?

A NEW TECHNIQUE:

Navigation Passive Robotics Joint Surgery Bridging the gap between

TKR and technology Bringing More Treatment

Options

Move to Kinematics Klee is the Software for evaluation of

joint kinematics developed on the basis of surgeon’s requirements to help the surgeon to analyze laxity values during the standard kinematics evaluation which are performed several times during the surgical procedure.

In particular Klee addresses the standard kinematics tests executed before and after arthroplasty interventions to evaluate parameters such as the anterior-posterior (AP), the rotational laxity, the internal/external (IE) and varus/valgus (VV), and let the surgeon to define , to acquire and investigate further references.

Klee quantifies the kinematics parameters and displays the knee position when they are performed, and therefore supports the surgeon to reproduce more precisely the same kinematics tests before and after the reconstruction for interventions such as: ACL, TKR,THR.

ΤΕCHNIQUECAS surgery, made simple VOYAGER platform combines

surgeon’s experience with accuracy and visualization features of computer technology.

VOYAGER provides the surgeon with improved information of surgical tools position related to patient’s anatomy, in order to significantly decrease positioning errors and to obtain better long-term results.

The use of VOYAGER platform allows to reduce the learning curve of surgical interventions and to decrease surgical times.

ΤΕCHNIQUE

Simplicity is the key of success

Mirò is the software for total knee arthroplasty.

Even the surgical instrumentation has been designed focusing on accuracy and minimally invasive surgery.

ΤΕCHNIQUESurgical sequence: This surgical sequence has been studied to

obtain at once both the maximum precision and an easy recovering of any unsatisfactory situations.

The tibial resection gives the surgeon a good benchmark to perform the femoral cuts, and more room to operate in the femoral part.

To leave the chamfers as the last cuts, allows a much more precise measurement of the articular gap, and a much easier recutting, if any is needed.

A functional system of augmentations of the trial balance helps the surgeon to select the correct thickness of the insert.

At any stage, the surgeon may verify the articular alignment with a metal rod inserted in the proper eyelets present in most of the instrumentation parts.

ΤΕCHNIQUE

Every patient is different The unique bone visualization method of

VOYAGER, combines the enhanced information given by bone morphing and the registration speed of imageless navigation systems.

Only few points are required to define patients’ specific anatomy, which is represented in a clear way to avoid any possible misleading information.

In each step the congruency of the patient's data are verified with the anatomical database of the system.

Implant positioning can be planned considering the soft tissue envelope through the ligament balance screen.

A well balanced knee means long term results and patients’ satisfaction.

ΤΕCHNIQUE

Accuracy Particular attention was

bend to the design of surgical instrumentation.

Only one hand is necessary to hold firmly the cutting guide in the exact position, while drilling for fixation.

During the positioning of the cutting guide the VOYAGER interface warns the surgeon with a red frame if it is exceeding the tolerance ranges.

PROSTHESES

PROSTHESESTrekking knee system includes: Τwo femoral components: CR component (Cruciate Rataining)

which provides for the preservation of the posterior cruciate ligament and PS component (Posterior Stabilized) which instead provides for its removal

Τwo tibial components for rotating and fixed inserts Τibial inserts for mobile plate and inserts for fixed plate Ρatellar components Both the femoral components CR and PS and the fixed and

mobile tibial components are also available in the uncemented version, with a VPS (Vacuum Plasma Spray) treated TiCoat

PROSTHESES The TREKKING mobile bearing tibial components are manufactured in a

CoCrMo alloy by micro fusion and machining. The plate of the mobile model is mirror-polished to reduce the back-side

wear and provided with a central hole to accommodate the UHMWPE insert peg. For a better anatomical congruency, the keel comes in five different sizes.

The posterior plate slope is 0° and allows for a better insert mobility. The TREKKING MBH tibial plate system includes a 3 mm plate for

considerable bone sparing. Moreover, a finite element method (FEM) has been used to design the

keel in such a way that an optimal mechanical strength is ensured. Components are available in cemented and uncemented versions with a

VPS treated (Vacuum Plasma Spray) TiCoat surface.

PROSTHESES The TREKKING MBH System features a rotating insert in a mirror-

polished tibial plate and an articular surface perfectly congruent with the corresponding surface on the femoral component.

The Trekking mobile bearing knee system has three main advantages:• Reduced polyethylene wear, thanks to an optimised articular contact area.• Improved implant function: each movement is accommodated by a different

joint. Moreover, each surface has been specifically designed for a dedicated movement, thus considerably improving both wear performance and joint function.

• Tibial plate rotation is a less critical parameter, since optimal alignment can be naturally reached by the bearing.

The mobile bearing knee system is indicated in relatively young and active patients with good ligaments.

PROSTHESES

The TREKKING CR cemented femoral component is manufactured in a CoCrMo alloy.

It is a Posterior Cruciate retaining system and therefore indicated in patients with ligaments in good conditions.

Components are available in cemented and uncemented versions with a VPS treated (Vacuum Plasma Spray) TiCoat.

PROSTHESES The fixed TREKKING System provides for a

technique to fix the insert to the tibial plate consisting in notches on the tibial component that fit with the stainless steel wire spring of the insert itself.

This system, beside granting a perfect fixation of the two components, minimizes the backside wear of the polyethylene insert, that can be compared to the wear rate of the articular surface, as recognized by several scientific works.

Material

35 patients (35 knees) Mean age 73 years (60 – 82) W: 23, M : 12 KNEES: L:15/R:20 Mean height 167cm ΒΜΙ: 34 ( 61% OVERWEIGHT) 1ST TKR FOLLOW UP: 1 year PRE-OP score KSS: 40+13(26-53)

KNEES

RIGHT

20LEFT15

ΦΥΛΟ

MEN

12

WOMEN

23

Aetiology for operation ΟΑ:30 RΑ:2Post.Traumatic:2 PVNS:1

METHOD Same surgeon Standard anterior midline approach/medial

parapatellar exposure of the joint Clean theater-vertical laminar airflow

system Special cutting guides-templates, lateral

release Antibiotics-Anticoagulants

OPERATIVE PLANNING VIA NAVIGATOR-assembling the sensors

PRE-OP MEASUREMENT

TIBIA

TIBIA

FEMUR

FEMUR

FEMUR

FEMUR

IMPLANT CHECK

FINAL ALIGNMENT

FINAL RESULT

POST-OP X-RAY

POST-OP

Cool Pads Drain-autotransfusion for 2 days Antibiotics -3 days LMWH-35 days Early Mobilization FROM + Special Rehab. Protocol PWB: 2nd post-op day FWB: 30 days Hospitalization :6 days(5– 10 )

RESULTS

No major complications were seen. Follow-up at 6 and 12 months post-op. No presence of radiolucent zones (very

early). Special tests for flexion-pain-well being

all excellent.

KNEE FUNCTION

KNEE FLEXION

PATIENT PRE-OP920( 70-1150)

Pt POST-OP1080 (80-1250)

< 700 3 _

70-890 15 _

90-1080 14 11

> 1100 3 24

KNEE FUNCTIONCLIMBING STAIRS PTs PRE-OP PTs POST-OP

NORMAL 3 25

CLIMBING UP NORMAL- CLIMBING DOWN WITH HELP

7 8

CLIMBING UP AND DOWN WITH HELP

15 2

CLIMBING UP WITH HELP- CLIMBING DOWN IMPOSSIBLE

8 -

TOTAL IN COMPETENCE 2 -

KNEE FUNCTION

WALKING PTs PRE-OP PTs POST-OP

ONLY AT HOME 19

< 10 BLOCKS 7 5

> 10 BLOCKS 9 8

WITHOUT LIMITATION

0 22

RESULTS KSS Score : 40 pre-op./ 70 at 6 m.p.o/

95 at 12 m.p.o. Knee Sore : 35-67-98. Function score: 43-75-99. Knee Pain Score:

Pre-op

Severe pain 69,2%/ Moderate 21%/ Mild 5,6%/ No pain 4,2%

Post-op

Painless 68,7%/ Mod 6.55%/ Mild 24.3%

Results

Caplan-Mayer Survey: All prostheses survived 1 year post-op uneventfully.

Tibio-femoral axis: 0-5 Valgus 52.4%

0-5 Varus 36.4%

CONCLUSIONS

Clinical and radiological results equal to international literature. The MIRO software is an innovative tool for computer assisted surgery. Navigation TKR by SAMO is time sparing and allows shorter learning

curve. Only crucial measurements and values are evaluated during the

procedure, anatomically. Less intraoperative bleeding and less risk for fat embolism-no

intramedullary guides. There is always the option for conventional TKR. Minimal invasive-instrumentation of same mentality-same cutting block

for both bones. For sure a greater number of cases and mid- and long-term follow

up is needed in order to prove the efficacy of the method.

THANK YOU