Total Knee Total Knee ArthroplastyArthroplasty

06/06/200606/06/2006

Dr. Rami Eid

IntroductionIntroduction

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

►The best results for TKA at 10 – 15 yrs. The best results for TKA at 10 – 15 yrs. compare to or surpass the best result compare to or surpass the best result of THA.of THA.

Indications for Knee Indications for Knee ArthroplastyArthroplasty

Indications for TKAIndications for TKA

►Relieve pain caused by Relieve pain caused by osteoarthritis of the knee (the osteoarthritis of the knee (the most common).most common).

►Deformity in patients with variable Deformity in patients with variable levels of pain:levels of pain: Flexion contracture > 20 degrees.Flexion contracture > 20 degrees. Severe varus or valgus laxity. Severe varus or valgus laxity.

Osteoarthritis Osteoarthritis

►American College of Rheumatology American College of Rheumatology classification criteria:classification criteria:

Knee pain and radiographic osteophytes Knee pain and radiographic osteophytes and at least 1 of the following 3 items: and at least 1 of the following 3 items: Age >50 years.Age >50 years. Morning stiffness <=30 minutes in duration.Morning stiffness <=30 minutes in duration. Crepitus on motion. Crepitus on motion.

Contraindications for TKAContraindications for TKA

►Recent or current knee sepsis.Recent or current knee sepsis.►Remote source of ongoing infection.Remote source of ongoing infection.►Extensor mechanism discontinuity or Extensor mechanism discontinuity or

severe dysfunction.severe dysfunction.►Painless, well functioning knee Painless, well functioning knee

arthrodesis.arthrodesis.

►Poor health or systemic diseases (relative Poor health or systemic diseases (relative contraindications).contraindications).

Unicondylar Knee Unicondylar Knee Arthroplasty Arthroplasty

► Indications:Indications:

Younger patients with Younger patients with unicompartmental unicompartmental disease instead of disease instead of HTO.HTO.

Elderly thin patient Elderly thin patient with with unicompartmental unicompartmental disease (shorter disease (shorter rehabilitation, greater rehabilitation, greater ROM) ROM)

► Contraindications:Contraindications:

Flexion contracture Flexion contracture >= 5 degrees.>= 5 degrees.

ROM < 90 degrees.ROM < 90 degrees. Angular deformity >= Angular deformity >=

15 degrees.15 degrees. Cartilaginous erosion Cartilaginous erosion

in the weight-bearing in the weight-bearing area of the opposite area of the opposite compartment. compartment.

Patellar Resurfacing Patellar Resurfacing

► Indication for leaving the patella Indication for leaving the patella unresurfaced:unresurfaced:

Congruent patellofemoral tracking.Congruent patellofemoral tracking. Normal anatomical patellar shape.Normal anatomical patellar shape. No evidence of crystalline or inflammatory No evidence of crystalline or inflammatory

arthropathy.arthropathy. Lighter patient. Lighter patient.

ClassificationClassification

1- Cruciate retaining2- Cruciate substituting3- Mobile bearing4- Unicondylar

ClassificationClassification

1

2

3

4

Biomechanics of Knee Biomechanics of Knee ArthroplastyArthroplasty

Kinematics Kinematics

► The TRIAXIAL The TRIAXIAL motion of the motion of the knee:knee:

Articular geometryArticular geometry Ligamentous Ligamentous

restraintsrestraints

Degrees of Freedom Degrees of Freedom

Degrees of FreedomDegrees of Freedom

►Constrained ProsthesesConstrained Prostheses

►Non-constrained ProsthesesNon-constrained Prostheses

► Intermediated Prostheses Intermediated Prostheses

Constrained ProsthesesConstrained Prostheses

► Hinged implants.Hinged implants.► One degree of freedom.One degree of freedom.

Non-constrained ProsthesesNon-constrained Prostheses

► Ideal implants.Ideal implants.

► 5 degrees of 5 degrees of freedom.freedom.

► Intact Intact ligamentous ligamentous system.system.

Intermediated Prostheses Intermediated Prostheses

►Anterior-posterior stability.Anterior-posterior stability.

►Two types:Two types:

FREEMANFREEMAN (a cylinder in a non (a cylinder in a non conforming trough).conforming trough).

INSALLINSALL (posterior stabilized knee). (posterior stabilized knee).

Intermediated ProsthesesIntermediated Prostheses

FreemanInsall

Longitudinal Longitudinal Alignment Of Alignment Of

KneeKnee► Tibial components Tibial components

are implanted are implanted perpendicular to the perpendicular to the mechanical axis.mechanical axis.

► Femoral component Femoral component is implanted in 5 – 6 is implanted in 5 – 6 degrees of valgus.degrees of valgus.

Longitudinal Alignment Of Longitudinal Alignment Of KneeKnee

► Posterior tibial Posterior tibial tilt is about 5 tilt is about 5 – 7 degrees.– 7 degrees.

► Usually Usually depend on the depend on the articular articular design.design.

Anatomic tilt 5 degrees

Rotational Alignment Of KneeRotational Alignment Of Knee

► Create a Create a rectangular flexion rectangular flexion space.space.

► External rotation of External rotation of the femoral the femoral component 3 component 3 degrees.degrees.

Role of PCL – Femoral Roll-BackRole of PCL – Femoral Roll-Back

Role of PCL – Femoral Roll-Role of PCL – Femoral Roll-BackBack

PCL-retention or PCL-PCL-retention or PCL-substitution ?substitution ?

► PCL retaining PCL retaining prostheses:prostheses:

Better ROM (roll-back, Better ROM (roll-back, flat tibial surface).flat tibial surface).

More symmetrical gait More symmetrical gait (stair climbing).(stair climbing).

Less femoral bone Less femoral bone resection is required.resection is required.

PCL needs to be PCL needs to be accuracy balanced.accuracy balanced.

► PCL substituting PCL substituting prostheses:prostheses:

Easier surgical exposure.Easier surgical exposure. See-saw effect See-saw effect

prevention.prevention. Lower tibial polyethylene Lower tibial polyethylene

contact stresscontact stress Posterior tibial Posterior tibial

component component displacement.displacement.

Patella clunk syndrome.Patella clunk syndrome.

PCL-retention or PCL-PCL-retention or PCL-substitution ?substitution ?

PCL-retention or PCL-substitution ?PCL-retention or PCL-substitution ?

Patella Clunk SyndromePatella Clunk Syndrome

Patellofemoral JointPatellofemoral Joint

► The patella acts to The patella acts to lengthen extensor lengthen extensor lever arm.lever arm.

► This arm is greatest This arm is greatest at 20 degrees of at 20 degrees of flexion.flexion.

Patellofemoral JointPatellofemoral Joint

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

Patellofemoral JointPatellofemoral Joint

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

► Preventing Preventing subluxation:subluxation: Prosthetic component.Prosthetic component. Vastus medialis (in Vastus medialis (in

early flexion).early flexion).

Polyethylene IssuesPolyethylene 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 Surgical Technique for Primary TKATKA

Preoperative EvaluationPreoperative Evaluation

► Soft tissue defects around the knee. Soft tissue defects around the knee.

► Vascular status to the limb.Vascular status to the limb.

► Extensor mechanism.Extensor mechanism.

► Preoperative range of motion.Preoperative range of motion.

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

Surgical PreparationSurgical Preparation

► Administer a dose of Administer a dose of a 1a 1stst generation generation cephalosporin (or cephalosporin (or vancomycin, vancomycin, clindamycin)clindamycin)

► Avoid pressure on Avoid pressure on peripheral nerves.peripheral nerves.

Surgical Approaches Surgical Approaches

► Medial Medial parapatellparapatellar ar retinacularetinacular r approach.approach.

► Subvastus Subvastus approach.approach.

► Midvastus Midvastus approach.approach.

Surgical ApproachesSurgical Approaches

► Subvastus Subvastus approach:approach:

Intact extensor Intact extensor mechanism.mechanism.

Decreasing pain.Decreasing pain. More limited.More limited. Postoperative Postoperative

hematoma.hematoma.

► Midvastus Midvastus approach:approach:

Preserve genicular a. Preserve genicular a. to the patella.to the patella.

Contraindication in Contraindication in limited preoperative limited preoperative flexion.flexion.

Postoperative Postoperative hematoma.hematoma.

Surgical ApproachesSurgical Approaches

► Lateral parapatellar Lateral parapatellar retinacular retinacular approach:approach:

In valgus knees.In valgus knees. Improve patellar Improve patellar

tracking and tracking and ligamentous ligamentous balancing.balancing.

Bone Preparation – IM Femoral Bone Preparation – IM Femoral GuideGuide

Bone Preparation – Gap Bone Preparation – Gap TechniqueTechnique

Bone Preparation – Tibial Bone Preparation – Tibial ResectionResection

► The guide is aligned The guide is aligned with the anterior with the anterior tibial tendon and tibial tendon and first web space of first web space of the toes.the toes.

Balancing of The Knee Balancing of The Knee

Varus DeformityVarus Deformity

►11stst Osteophytes must be removed. Osteophytes must be removed.

►22ndnd Release the deep MCL. Release the deep MCL.

►33rdrd Release semimembranosus and pes Release semimembranosus and pes anserinus insertion.anserinus insertion.

►44thth release posterior capsule and PCL. release posterior capsule and PCL.

Varus DeformityVarus Deformity

Valgus DeformityValgus Deformity

►11stst Remove all osteophytes. Remove all osteophytes.►22ndnd release lateral capsule. release lateral capsule.►33rdrd

Lesser deformity: release Iliotibial band.Lesser deformity: release Iliotibial band. Greater deformity: release LCL +/- PCL.Greater deformity: release LCL +/- PCL.

►Valgus deformity + flexion contracture Valgus deformity + flexion contracture >> release posterior capsule.>> release posterior capsule.

Valgus DeformityValgus Deformity

Flexion ContractureFlexion Contracture

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

►Flexion gap < Extension gap >> larger Flexion gap < Extension gap >> larger tibial insert.tibial insert.

Flexion – Flexion – Extension Extension

BalancingBalancing

Computer Assisted Surgery in Total Knee Arthroplasty

Management of Bone Management of Bone DeficiencyDeficiency

Patellofemoral Tracking Patellofemoral Tracking

► Internal rotation of Internal rotation of tibial component tibial component increases the increases the tendency to lateral tendency to lateral patellar subluxation.patellar subluxation.

► Prosthetic patella Prosthetic patella should be medially should be medially positioned.positioned.

Postoperative Management Postoperative Management

Roentgenographic EvaluationRoentgenographic Evaluation

Total knee replacement exercise Total knee replacement exercise

protocolprotocol ► Postoperative day 1 Postoperative day 1

Bedside exercisesBedside exercises (e.g. ankle pumps, quadriceps (e.g. ankle pumps, quadriceps exercises…) exercises…)

► Postoperative day 2 Postoperative day 2 Exercises for Exercises for active ROM and terminal knee active ROM and terminal knee

extensionextension GaitGait training with assistive device training with assistive device

► Postoperative day 3-5 Postoperative day 3-5 Progression of ambulation on level surfaces and Progression of ambulation on level surfaces and

stairs (if applicable)stairs (if applicable)

► Postoperative day 5 to 4 weeks Postoperative day 5 to 4 weeks Stretching of quadriceps and hamstring muscles Stretching of quadriceps and hamstring muscles Progression of ambulation distance Progression of ambulation distance

Specific DisordersSpecific Disorders

Previous HTOPrevious HTO

► Difficult surgical Difficult surgical exposure.exposure.

► Lateral ligamentous Lateral ligamentous laxity.laxity.

► Difficult stem Difficult stem placement.placement.

► Patella infera. Patella infera.

Previous PatellectomyPrevious Patellectomy

► PCL retaining PCL retaining arthroplasty for arthroplasty for better results.better results.

Complications of Total Knee Complications of Total Knee ArthroplastyArthroplasty

►Thromboembolism. Thromboembolism.

► Infection. Infection.

►Neurovascular complications. Neurovascular complications.

►Patellofemoral complications.Patellofemoral complications.

►Periprosthetic fractures.Periprosthetic fractures.

Patellofemoral ComplicationsPatellofemoral Complications

► Patella clunk Patella clunk syndrome.syndrome.

► Patellar component Patellar component failure.failure.

► Rupture of patellar Rupture of patellar ligament.ligament.

Periprosthetic FracturesPeriprosthetic Fractures

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•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.

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كاظم. مؤيد Dr. Muayad Kadhimد