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Total Knee Arthroplasty - PowerPoint Presentation

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					Total Knee Arthroplasty
        Dr. Rami Eid
        06/06/2006
             Introduction

    is one of the most successful and
► TKA
 commonly performed orthopedic surgery.

    best results for TKA at 10 – 15 yrs.
► The
 compare to or surpass the best result of
 THA.
Indications for Knee Arthroplasty
          Indications for TKA
► Relievepain caused by osteoarthritis
 of the knee (the most common).

► Deformity   in patients with variable levels of
 pain:
   Flexion contracture > 20 degrees.
   Severe varus or valgus laxity.
              Osteoarthritis
► American   College of Rheumatology
 classification criteria:

  Knee pain and radiographic osteophytes
 and at least 1 of the following 3 items:
   Age >50 years.
   Morning stiffness <=30 minutes in duration.
   Crepitus on motion.
     Contraindications for TKA
► Recent  or current knee sepsis.
► Remote source of ongoing infection.
► Extensor mechanism discontinuity or severe
  dysfunction.
► Painless, well functioning knee arthrodesis.


► Poorhealth or systemic diseases (relative
 contraindications).
  Unicondylar Knee Arthroplasty
► Indications:                  ► Contraindications:


   Younger patients with          Flexion contracture >=
    unicompartmental                5 degrees.
    disease instead of HTO.        ROM < 90 degrees.
   Elderly thin patient with      Angular deformity >=
    unicompartmental                15 degrees.
    disease (shorter               Cartilaginous erosion in
    rehabilitation, greater         the weight-bearing area
    ROM)                            of the opposite
                                    compartment.
         Patellar Resurfacing

           for leaving the patella
► Indication
 unresurfaced:

   Congruent patellofemoral tracking.
   Normal anatomical patellar shape.
   No evidence of crystalline or inflammatory
    arthropathy.
   Lighter patient.
Classification
Classification
                        1   3



1- Cruciate retaining
2- Cruciate
substituting
3- Mobile bearing
4- Unicondylar



                        2   4
Biomechanics of Knee Arthroplasty
                   Kinematics


► TheTRIAXIAL
 motion of the knee:

   Articular geometry
   Ligamentous
    restraints
Degrees of Freedom
        Degrees of Freedom

► Constrained   Prostheses

► Non-constrained   Prostheses

► Intermediated   Prostheses
Constrained Prostheses




► Hingedimplants.
► One degree of freedom.
     Non-constrained Prostheses

► Ideal   implants.

►5  degrees of
  freedom.

► Intact
  ligamentous
  system.
     Intermediated Prostheses
► Anterior-posterior   stability.

► Two   types:

   FREEMAN (a cylinder in a non conforming
    trough).
   INSALL (posterior stabilized knee).
     Intermediated Prostheses




                 Freeman
Insall
   Longitudinal
   Alignment Of
       Knee
► Tibialcomponents are
  implanted
  perpendicular to the
  mechanical axis.

► Femoral component is
  implanted in 5 – 6
  degrees of valgus.
 Longitudinal Alignment Of Knee

► Posterior  tibial
  tilt is about 5 –
  7 degrees.

► Usually depend
  on the articular
  design.



                      Anatomic tilt 5 degrees
   Rotational Alignment Of Knee

► Create  a rectangular
  flexion space.

► Externalrotation of
  the femoral
  component 3 degrees.
Role of PCL – Femoral Roll-Back
Role of PCL – Femoral Roll-Back
    PCL-retention or PCL-substitution ?
►   PCL retaining                    ►   PCL substituting
    prostheses:                          prostheses:

     Better ROM (roll-back, flat         Easier surgical exposure.
      tibial surface).                    See-saw effect prevention.
     More symmetrical gait (stair        Lower tibial polyethylene
      climbing).                           contact stress
     Less femoral bone resection         Posterior tibial component
      is required.                         displacement.
     PCL needs to be accuracy            Patella clunk syndrome.
      balanced.
PCL-retention or PCL-substitution ?
PCL-retention or PCL-substitution ?
Patella Clunk Syndrome
           Patellofemoral Joint

► The  patella acts to
  lengthen extensor
  lever arm.

► Thisarm is greatest at
  20 degrees of flexion.
            Patellofemoral Joint




► Changes in the patellar area of contact can leads
 to eccentric loading of the patellofemoral joint.
               Patellofemoral Joint

►   Limb with larger Q angle
    has a greater tendency
    for lateral subluxation.



►   Preventing subluxation:
     Prosthetic component.
     Vastus medialis (in early
      flexion).
            Polyethylene Issues




1- Dished polyethylene avoids the edge loading. (as PCL substitution)
2- Minimal polyethylene thickness >= 8 mm to avoid higher contact
stress.
Surgical Technique for Primary TKA
          Preoperative Evaluation
► Soft   tissue defects around the knee.

► Vascular   status to the limb.

► Extensor   mechanism.

► Preoperative   range of motion.

► Standing  (AP) view, a lateral view of the knee, and
  a skyline view of the patella.
           Surgical Preparation

► Administer  a dose of a
  1st generation
  cephalosporin (or
  vancomycin,
  clindamycin)
► Avoid pressure on
  peripheral nerves.
           Surgical Approaches
► Medial
  parapatellar
  retinacular
  approach.
► Subvastus
  approach.
► Midvastus
  approach.
          Surgical Approaches
► Subvastus   approach:   ► Midvastus   approach:

   Intact extensor          Preserve genicular a. to
    mechanism.                the patella.
   Decreasing pain.         Contraindication in
   More limited.             limited preoperative
   Postoperative             flexion.
    hematoma.                Postoperative
                              hematoma.
            Surgical Approaches

► Lateral parapatellar
  retinacular approach:

   In valgus knees.
   Improve patellar
    tracking and
    ligamentous balancing.
Bone Preparation – IM Femoral
           Guide
Bone Preparation – Gap Technique
Bone Preparation – Tibial Resection

 ► Theguide is aligned
  with the anterior tibial
  tendon and first web
  space of the toes.
Balancing of The Knee
              Varus Deformity
► 1st   Osteophytes must be removed.

► 2nd   Release the deep MCL.

► 3rdRelease semimembranosus and pes
  anserinus insertion.

► 4th   release posterior capsule and PCL.
Varus Deformity
            Valgus Deformity
► 1st Remove all osteophytes.
► 2nd release lateral capsule.
► 3rd
   Lesser deformity: release Iliotibial band.
   Greater deformity: release LCL +/- PCL.


► Valgus deformity + flexion contracture >>
  release posterior capsule.
Valgus Deformity
            Flexion Contracture

► Extensiongap < Flexion gap >> more distal
 femoral bone cut, posterior capsule release.



► Flexion   gap < Extension gap >> larger tibial
 insert.
Flexion – Extension
     Balancing
Computer Assisted Surgery in
  Total Knee Arthroplasty
Management of Bone Deficiency
        Patellofemoral Tracking
► Internal rotation of
  tibial component
  increases the tendency
  to lateral patellar
  subluxation.

► Prostheticpatella
  should be medially
  positioned.
Postoperative Management
Roentgenographic Evaluation
Total knee replacement exercise protocol

► Postoperative   day 1
   Bedside exercises (e.g. ankle pumps, quadriceps
    exercises…)
► Postoperative   day 2
   Exercises for active ROM and terminal knee extension
   Gait training with assistive device
► Postoperative   day 3-5
   Progression of ambulation on level surfaces and stairs
    (if applicable)
► Postoperative   day 5 to 4 weeks
   Stretching of quadriceps and hamstring muscles
   Progression of ambulation distance
Specific Disorders
               Previous HTO

► Difficult surgical
  exposure.
► Lateral ligamentous
  laxity.
► Difficult stem
  placement.
► Patella infera.
        Previous Patellectomy



► PCLretaining
 arthroplasty for better
 results.
   Complications of Total Knee
          Arthroplasty
► Thromboembolism.


► Infection.


► Neurovascular    complications.

► Patellofemoral   complications.

► Periprosthetic   fractures.
    Patellofemoral Complications


► Patella  clunk syndrome.
► Patellar component
  failure.
► Rupture of patellar
  ligament.
Periprosthetic Fractures
THANK YOU
                     MoKazem.com

‫• هذه المحاضزة هي من سلسلت محاضزاث حم إعدادها و حقديمها من قبل األطباء المقيمين‬
             .‫في شعبت الجزاحت العظميت في مشفى دمشق, ححج إشزاف د. بشار ميزعلي‬
                          .‫• المىقع غيز مسؤول عن األخطاء الىاردة في هذه المحاضزة‬

This lecture is one of a series of lectures were prepared and •
    presented by residents in the department of orthopedics in
Damascus hospital, under the supervision of Dr. Bashar Mirali.
 This site is not responsible of any mistake may exist in this •
                                                        lecture.

   Dr. Muayad Kadhim                                        ‫د. مؤيد كاظم‬

				
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