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Total knee replacement India with I Assist


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Title: Total knee replacement India with I Assist

I-Assist personalized guidance system
  • Dr.A.K.Venkatachalam
  • MS Orth, DNB Orth, FRCS, M.Ch Orth
  • Consultant Orthopaedic surgeon

Alignment in Knee replacement
  • It is one of the factors that ensures long life
    of the implant.
  • A proper alignment means the implant is
    perpendicular to the ground.
  • Mal aligned knee replacements tend to wear out
    sooner than normal.
  • Even experienced surgeons can make errors in
    placement of the components.

Mal-aligned car tyre
Wear on the inside
Improperly aligned knee replacement
Implants are tilted and leg is bowed
Properly aligned Knee replacements
Our patient
  • Mrs.Lakshmamma, Housewife, Age- 55 years
  • Resident of Guntur district, Seemandhara
  • Had both knee replacements on 7/8/14 and 13/8/14
  • Female special, Full bending knee implants with
  • Prolong Poly insert capable of long life.

Pre op x-rays
Properly aligned Knee replacements
Post op progress
  • The patient started walking on the next day after
    surgery on both knees.
  • Post - op X-rays of both knees show perfect
    alignment which was made possible by the I-Assist

What is the I-Assist?
  • It is a Personalized guidance system designed to
    assist the surgeon in positioning a total knee
    arthroplasty implant components intra
  • It uses surgical instruments and position sensors
    to determine alignment axes in relation to
    anatomical landmarks
  • To thus precisely position alignment instruments
    implant components relative to these axes.

I Assist components
What is inside it?
  • It consists of 4 half palm sized pods with
    electronic apps like
  • Wi-Fi found in smart phones.
  • Gyroscope found in air planes.
  • The electronic sensors inside calculate the
    alignment. The blinking lights on the display
    face indicate the correct position.
  • Red light means improper position and Green light
    means proper position.

How does it work?
  • It is inserted into the bones of the knee joint

How does it work?
  • After connecting it to the knee the surgeon moves
    the femur in 13 different positions and the tibia
    in 4 positions.
  • It calculates the position by the electronic
    devices inside it.
  • The surgeon makes fine adjustments so that
  • red lights turn to green.
  • Blinking green lights indicate zero percent
  • The surgeon can proceed to cut the bone confident
    that his cuts will be perfectly aligned.
  • He can then finally place the implant components
    in the correct alignment achieved and validated
    in the previous steps.

Surgeon is focused on the knee
Knee is moved to get Green light
Fine adjustment to get green light on the display
  • It guides the surgeon to get perfectly aligned
    cuts intra operatively.
  • It gives zero error cuts and again validates it
    in the next step.
  • Thus the surgeon gets the right fit during the
    surgery itself.
  • This ensures that the total knee implant knee
    components are positioned perfectly in the
    correct alignment.
  • Surgeon focusses his eyes in the operating field
    itself and not away from the field.
  • It thus saves time.

  • No additional incisions in the leg or thigh in
    contrast to computer assisted surgery.
  • As the intra medullary canal of the femur is not
    drilled, there is less blood loss post
  • No waiting time for instruments to come from
    abroad unlike Patient specific instruments.

What does it differ from?
  • 2) Patient specific instruments ( PSI)

1) Computer navigation ( CAS)
How does it differ from computer navigation?
  • The sensors are attached to the leg on the
    operating table as shown here.
  • The position of the cuts is shown on the monitor
    in the background.
  • Thus the surgeon has to shift his gaze from the
    leg to the monitor and back repetitively.

Two areas to focus on
How does it differ from Patient specific cutting
  • Scans done 6 weeks before surgery.
  • Pictures are sent to the laboratory abroad
  • 6 weeks waiting period for design, manufacture
    and supply of patient specific cutting blocks
    from abroad.

Patient specific cutting blocks placed on bone
Which patients benefit
  • Young patient had Computer assisted knee
    replacement in 2008
  • All age groups of patients benefit particularly
  • Young patients undergoing knee replacement for
    any reasons like injury, obesity, rheumatoid
    arthritis etc.

Which patients benefit?
  • Young patients with bad accidents and deformed
  • In these patients, other methods like computer
    assisted surgery patient specific instruments
    cant be used for technical reasons.
  • It can be used in severe deformities and bone
    loss, unlike the other modalities like Patient
    specific instruments and computer navigation.

Which patients benefit?
  • Middle aged patients with severe knee arthritis
    requiring a total knee replacement
  • Perfect alignment increases durability of knee

Older patients also benefit
  • Even experienced surgeons make errors while
    aligning components of a total knee arthroplasty.
  • Neutral alignment is the goal but this is not
    always achieved.
  • There is a correlation between perfect alignment
    and longevity of the implant.
  • Normal life of a knee is 15- 20 years.
  • With advanced techniques like the I-Assist, the
    life can be extended up to 35 years.

How patients benefit ?
  • Tailor made perfect alignment.
  • No waiting time
  • Perfect alignment contributes to increased
    longevity of the implant.
  • When I Assist is used in conjunction with
    durable materials, life of a knee replacement can
    be extended up to 35 years.

Surgeons benefit
  • Surgeons benefit as they save time during surgery
    by avoiding back and forth eye movements.
  • Reduced operating time decreases risk of

Hospital benefits
  • No capital investment on imaging systems like
    special MRI
  • No investment on Computer navigation system which
    costs about 1 crore.

I Assist
  • Gives perfect alignment during surgery itself.
  • Alignment along with durable materials like
    Zirconium and Cross linked polyetheylene increase
    of a knee replacement to 35 years.
  • No need for future revision surgery in young

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