Total Knee Replacement: Do’s and Don'ts Ronald S. LaButti, DO, FAOAO Lower Extremity and Joint Reconstruction Advanced Orthopedics of Oklahoma Central States Division Tulsa, Oklahoma
Total Knee Replacement: Do’s and Don'ts
Ronald S. LaButti, DO, FAOAOLower Extremity and Joint
Reconstruction
Advanced Orthopedics of OklahomaCentral States Division
Tulsa, Oklahoma
Background
ØHome Town- Glocester, RIØProvidence College 1987
Providence, RIØUniv. of New England College of
Osteopathic Medicine 1994Biddeford, ME
Background
Ø Internship- Brown University/ Rhode Island Hospital, 1995
ØResidency-Orthopedic Surgery, Oklahoma State University College of Osteopathic Medicine/Tulsa Regional Medical Center, 1999
Ø Fellowship- Lower Extremity and Joint Reconstruction, State Univ. of NY at Buffalo, Kenneth Krackow, MD, 2000
Clinical Experience
Ø2000-Fellowship, Kenneth Krackow, MD-1st generation Stryker Navigation and robotic surgery
ØIntroduced computer assisted total knee replacement to State of Oklahoma 2001
ØAdjunct Clinical Assistant Professor-OSUCOM Orthopedic Residency
ØAlmost exclusively TJA practice
Did You Know?
ØIn 2006, 1 million TJA’s performed in US
ØBy 2030, demand for TKA projected to grow by 673% to 3.48 million TKA/yr
Did You Know?
ØIn 2005--38,300 Rev. TKA performed in US
ØDemand for Rev. TKA will double by 2015
ØBy 2030, demand for Rev. TKA will grow 601% to 268,200/yr
Did You Know?
ØCost of revisions-- $3.2 billion
Ø80% of TJA in US are performed by Surgeons who do < 20 TJA/year(<2/month)
Did you Know?
ØPt’s < 65 exceed 50% of TKA
ØPt’s <65 exceed 50% of Rev. TJA
Common Causes of Revision TKA
ØInfection (25.2%)ØImplant loosening (16.1%)ØMost commonly performed @large,
urban, nonteaching hospitals in Pt’s 65-74 y/o
ØAve. LOS 5.1 daysØAve. charges $49,360
Total Knee ReplacementØIndicationsØSevere disabling pain from arthritis affecting more than one compartment of the knee ØFailed non-operative treatmentØX-rays must show advanced arthritis
Ø95% good or excellent resultsØ95% 15-20 yrs survival
Evaluation
ØHistoryØReview of RecordsØPhysical ExamØDiagnostic TestingØLabs
Evaluation
ØHistoryØDifficulty with ADL’sØCatching, grinding, lockingØSwellingØPain-at rest, w/ activityØLocationØTreatments-present/prior ØImprovement?
Physical ExamØSwelling, effusion, warmth, erythema?ØPalpation- joint lines, med./lat. patella
retinaculum, inf./sup. pole, patella tendon and tubercle, add. tubercle
ØLigament exam--pivot shift, quad. active test, lochman’s, ant. draw
ØAROM/PROM—flex. contr., ext. lag.?ØMotor, sensory, DTR’s, SLR
Diagnostic TestingØX-Rays
ØA/P, Lat., WBØDifferential Injection
ØKnee vs. HipØMRI
ØKnee vs. Lumbar SpineØEMG/NCS
ØNeuropathy
Non-operative Treatment
ØLifestyle changes/activity modification
ØNSAID’s
ØGlucosamine/Chondroitin sulfate??
Non-operative TreatmentØSteroid injection
ØCan worsen degenerationØOne to three times
ØHyaluronic acid injectionØBest results with mild degeneration, mild
mechanical axis deviation and no meniscal injury
ØCan help persistent symptoms after arthroscopy
Non-operative Treatment
ØPhysical TherapyØStrength and flexibility
ØBracingØOrthoticsØAmbulatory assistance device
Radiographic Findings in Advanced Arthritis
ØBone spursØComplete/near complete joint space lossØSevere joint deformityØBoney erosion
Total Knee Replacement
ØFemur– highly polished CoCrØTibia– CoCr or TitaniumØPatella– UHMWPEØ“all poly”ØMetal backed
Total Knee Replacement
After Surgery
Ø24 hours in hospitalØHome PT for 6 weeksØOut patient PT for 4 weeksØNo driving for 6 weeks(R TKA)ØRTW at 6 wks for sedentary jobØRTW at 12 wks for high demand job
Controversies in TKA
ØCemented vs. Un-cementedØResurface vs. Retaining patellaØPCL retaining vs. PCL sacrificingØAll poly/non-modular vs. modular tibia
componentØComputer assisted robotics vs. shape
matching technology
General Principles in Total Knee Replacement
Ø Neutral mechanical axisØ Classical alignment
Ø Joint line 90 degrees to mechanical axisØ Anatomic alignment
Ø Joint line 3 degrees oblique to mechanical axisØ Symmetric flexion and extension gaps
Classical Alignment
Anatomic Alignment
Total Knee Replacement:6 degrees of Movement
ØFlexion and extension
ØVarus and valgus
ØInternal and external rotation
Consequences of Mal-positioning: Femoral Component
ØExcessive flexionàdecreased ROM in flexion of knee, over sizing
ØExcessive extensionànotching femur increasing risk of fracture distal femur
Consequences of Mal-positioning: Femoral Component
ØExcessive varus or valgusàligament instabilty and mal-alignment mechanical axis
ØExcessive distal resectionà Extension instability, ligament damage, patella baja
Consequences of Mal-positioning: Femoral Component
ØExcessive internal rotationà mal-tracking of patella or PF instability
ØExcessive distal resectionà Extension instability, ligament damage, patella baja
Consequences of Mal-positioning: Tibial Component
ØExcessive posterior slopeà flexion instability, loss of extension, impacts insertion PCL
ØLack of posterior slopeà extension instability, loss of flexion
Consequences of Mal-positioning: Tibial Component
ØExcessive internal rotationà mal-tracking patella, PF instability
ØExcessive varus or valgusà ligament instability, mal-alignment mechanical axis
ØExcessive resectionà general instability, patella tendon damage
Consequences of Mal-positioning:Patella Component
ØAsymetric resectionà PF mal-tracking, anterior knee pain
ØOver replacingà 5 degrees loss of flexion/ 1 mm
ØUnder replacingà 5 degrees of extension lag/ 1 mm
Total Knee Replacement
ØLongevity dependant upon alignment and ligament balance
ØFailure usually results from polyethylene wear and loosening of one or all components
Total Knee ReplacementPatient Factors Affecting Longevity
ØActivityØMore active
ØAgeØYounger patients usually more active
ØWeightØJoint reactive forces in knee 3 X body
weight in normal walking, 6 X running
Total Knee ReplacementSurgeon Factors Affecting Longevity
ØAlignmentØMal-alignment of as little as 3 degrees can have negative impact on survival
ØLigament balanceØResurface patella vs. Unresurfaced
Total Knee ReplacementOther Factors Affecting Longevity
ØFixationØCemented vs. un-cemented vs. hybrid
ØPCL retaining vs. PCL substituting vs. PCL sacrificing
ØMetal backed vs. all poly patella
The Literature is ClearØCorrect limb alignment is
crucial for TKRØMechanical Axis within 3° of
neutralØCAS-TKR is more Accurate
than Conventional TKRØ CAS-TKR is also more
Accurate than CCB-TKR or PSG’s*
*Accuracy of CT-Based Patient SpecificTotal Knee Arthroplasty Instruments
~ Francis B. Gonzales, MD, C. Anderson Engh, Jr., MD, Deborah Ammeen, BS, Robert Hopper, PhD
AAHKS 2010 Poster Presentation.
Total Knee ReplacementNew Technology
ØComputer Assisted Robotic Surgery
ØShape Matching Technology (SMT)
Computer Assisted Robotic Total Knee Replacement
ØMore accurate and reproducible alignment
ØVirtually eliminates issues of mal-alignment and poor ligament balance
Computer Assisted Robotic Total Knee Replacement
ØGPS for the bodyØProvides surgeon with comprehensive
understanding of the patient’s knee mechanics before any bone is cut
ØAllows surgeon to make adjustments within a fraction of a degree before bone is cut
ØUseful in difficult anatomic situations and retained hardware
Computer Assisted Robotic Total Knee Replacement
ØTheoretically improve longevity of TKA
ØUseful in conjunction with minimally invasive techniques
Shape Matching TechnologyØUses CT scan or MRI to make 3D mold of
patients knee.ØThe surgeon picks the thickness and alignment
of the cuts with a computer programØUsing a computer program, customized blocks
are made to match the moldsØThese blocks are fixed to the bones with pins
during surgery and will allow the bone cuts to made as planned with the computer.
My PracticeØ134 knees- 114 varus, 20 valgusØPre op deformity
ØRange 15 varus -11valgusØAve. varus-7.18ØAve. valgus-3.35
ØPost op deformity ØAve,. Varus-1.61ØAve valgus-2.37
Ø92% < 3 degrees mal-alignmentØ95% < 4 degrees mal-alignment
Conclusions:Total Knee Replacement
ØChallenging procedure to perform correctly because of the 6 degrees of movement
ØAccurate positioning of components is critical for longevity and function in knee replacement
ØComputer assisted robotic technology reduces variability in component placement improving function and longevity
Thank You