Post on 01-Jun-2015
Frank R. Ebert, MDFrank R. Ebert, MDUnion Memorial HospitalUnion Memorial Hospital
Baltimore, MarylandBaltimore, Maryland
TOTAL KNEE TOTAL KNEE
ARTHROPLASTYARTHROPLASTY
Frank R. Ebert, MDUnion Memorial Hospital
Baltimore, Maryland
TOTAL KNEE
ARTHROPLASTY
Total Knee Arthroplasty
Goal—Restore mechanical alignment—Restore joint line
Normal Knee Anatomy
Position in single leg stance Mechanical axis valgus 3º Femoral shaft axis valgus 6º Proximal tibia varus 3º
Total Knee Arthroplasty
Radiographic Evaluation—Standing full length – AP—Standing AP—Extension/Flexion laterals—Tunnel view—Sunrise view
Total Knee Arthroplasty
Radiographic Evaluation
Weight Bearing X-rays—Extent of joint space narrowing—Ligament stretch out—Subluxation of femus on tibia
Total Knee Arthroplasty
Radiographic AnalysisAnatomic Axis – Femur
—Line that bisects the medullary canal of the femur
—Determines the entry point of the femoral medullary guide rod
Total Knee Arthroplasty
Radiographic Analysis
Mechanical Axis – Femur (MAF)—A line from center of femoral
head to center of distal femur
Total Knee Arthroplasty
Radiographic Analysis
Anatomic Axis Tibia (AAT)—A line that bisects the
medullary canal of the tibia—Determines the entry point of
the guide rod
Total Knee Arthroplasty
Radiographic Evaluation
Mechanical Axis – Tibia (MAT)—Line from center of proximal
tibia to center of ankle—Proximal tibia is cut
perpendicular to (MAT)
Issues with Surgical Techniques
Traditional Joint Line Orientation Tibial cut perpendicular to the MAT Femoral shaft at a valgus angle 5º to
8º valgus based off the ong standing x-ray
Surgical Technique
Incision — straight longitudinal incisionTissue handling keyAvoid flapsPreserve soft tissue flap about the patella
Surgical Technique
Remember 7cm Rule between incisions
Issues with Surgical Techniques Exposure options
— Subvastus / midvastus Routine knee replacements
Quicker rehab— Medial parapatellar / midline
Difficult total knee — obese patients
Revisions
MIS vs MINI TKA
Capsulotomy only?
Mid vastus?
Sub vastus?
MIS
MIS vs MINI TKA
Mid vastus?
Sub vastus?
Quad sparing? MIS
Area of Variation
Type I-High Insertion
Type II-Pole Insertion
Type III-Low Insertion
Anatomic Variations of VMO Insertion
Type I- High VMO Insertion
Retinacular Incision
Area of extended retinaculumMuscle
Insertion
Type II-Pole Insertion
Capsular or Retinacular Incision
Muscle Insertion
Type III-Low VMO Insertion
Area of Extended VMMuscle
Insertion
Issues with Surgical Techniques
Alignment— Extramedullary vs Intramedullary
Accuracy vs increased PE riskFemur – Intramedullary Overdrill opening and
insert slowly IM guide Caution with bilateral Total
Knee ArthroplastyTibia – Extramedullary
Issues with Surgical Techniques
Femoral Rotation— Landmarks
Posterior femoral condyles
Epicondyles 5º external rotation to the posterior condyles
Issues with Surgical Techniques Femur
— Measured resections: equal bone distally and posteriorly
— Tensioning devices & ligament releases
— Do not alter bone resection for ligament tightness
Issues with Surgical Techniques
Tibial Component Rotation
— Transmalleolar axis
— Posterior tibial plateau
— Tibial tubercle — lies lateral
Malalignment
Tibial Component
Internally Rotated
Tubercle Too Lateral
Management of Deformity
1. Release the tight side of the deformity
2. Tighten the loose side
3. Accept some residual soft tissue imbalance
4. Combination
Surgical Techniques
Varus Knee
1. Pes anserinus
2. Joint Capsule
3. Deep Tibial Collateral
4. Semimembranosus
5. Posterior Medial Capsule
Varus Knee
Varus Knee
Varus KneeVarus Knee
Varus Knee
Surgical Techniques
Valgus Knee
1. Iliotibial Band
2. Popliteus Tendon
3. Posterior Lateral Capsule
4. Lateral Head of Gastroc
5. Biceps Femoris
Surgical Techniques
Valgus Knee
— Peroneal nerve palsy – valgus / flexion deformity
— Treatment Release dressings or flex the knee
Surgical Techniques:
Flexion Contracture
1. Posterior capsule
2. Gastroc origins
3. Posterior cruciate
4. Distal femur
Fixed Flexion Deformity in TKA
Complex Combinations:
— musculotendinous contracture
— ligamentous contracture
— capsular contracture
— osteophytes of posterior condyle
Fixed Flexion Deformity in TKA
Biomechanics
— increased quadriceps force for knee stabilization during weight bearing
— increased forces transmitted to the patellofemoral joint
Fixed Flexion Deformity in TKABiomechanics
— increased forces are placed on posterior tibial plateau
— femoral condyles sink into the tibial plateau
— contact between intercondylar notch and tibial eminence form a boney block
Fixed Flexion Deformity in TKA
Associated deformity
— varus deformity 40% - > 5º range 5 to 30º varus
— valgus deformity 30% - > 5º range5 to 22º valgus
Firestone et alCOOR ‘92
Fixed Flexion Deformity in TKA
Incidence of Problem – Review of 700 TKA & Revision TKA’s
— 60% before primary TKA
— 21% before revision TKA
Tew & ForsterJBJS (B) 87
Fixed Flexion Deformity in TKA
Soft tissue release
— Varies with angular deformity
Firestone et alCOOR ‘92
Fixed Flexion Deformity in TKA
Surgical Treatment Soft tissue release Additional bone resection Combination
Fixed Flexion Deformity in TKA
Postoperative Correction
— the more severe the deformity must consider the pros and cons of additional bone resection and/or soft tissue release
Volz COOR ‘89
Fixed Flexion Deformity in TKA
Additional bone resection – pros
— joint line is positioned slightly more proximal
— functionally lengthens the collaterals and posterior capsule forward extension
— doesn’t compromise flexion stability
Firestone et alCOOR ‘92
Fixed Flexion Deformity in TKA
Additional bone resection — cons (excessive)
• Collateral ligament laxity
• Quadriceps redundancy
• Hyperextension
• Bone quality can be compromisedMcPherson et al ‘94
Additional Femoral
Resection
Fixed Flexion Deformity in TKA
Surgical Treatment for Deformity < 10º FFC Soft tissue release – only necessary
— posterior capsule
— possibly PCL
— posterior osteophytes
Fixed Flexion Deformity in TKA
Surgical Treatment for Deformity 10-20º FFC
— consider distal femoral resection 3 to 5 mm
— Posterior capsule
— PCL resection posterior osteophytes
Firestone et al COOR ‘92
Fixed Flexion Deformity in TKA
Surgical Treatment for Deformity 20-30º FFC
— distal femoral resection 3 to 5 mm
— posterior capsule
— PCL resection posterior osteophytes
Firestone et al COOR ‘92
Fixed Flexion Deformity in TKA
Surgical Treatment for Deformity > 30º FFC
— consider pre-op casting ≠
— distal femoral resection 5 mm
— proximal tibial resection
— PCL resection
— posterior osteophytesFirestone et al COOR ‘92
et al J of Arthro ‘99
Fixed Flexion Deformity in TKA
Peroneal Nerve Palsy
Vascular Insufficiency
Anterior Pressure Ulcers
Manipulation
Fixed Flexion Deformity in TKA
No formula is exact for treatment of the problem
Consider a balance between soft tissue release vs bone resection
Issues with Surgical Techniques
Stiff Knee Remove osteophytes Insall Turn Down Osteotomize the tibial tubercle Rectus snip
Issues with Surgical Techniques
Stiff Knee
Epicondylar osteotomy for large flexion / contracture
Lateral release to evert the patella
Issues with Surgical Techniques
Patellar resurfacing
— Recommended for all RA patients
— Without resurfacing 4% to 6% incidence of anterior knee pain
— With resurfacing increased incidence of fracture
Issues with Surgical Techniques
Patellar resurfacing— Thickness shouldn’t exceed 25
mm— For every 1 mm thicker reduces
flexion by 3º
Issues with Surgical Techniques
Patellar Baja
• Proximal tibial osteotomy
• Tibial tubercle shift
• Prior fracture
Issues with Surgical Techniques
Patellar Baja
• Don’t raise joint line
• Consider lowering joint line
— Distal femoral alignment
• Trim anterior tibial poly to avoid impingement of patella
Issues with Surgical Techniques
Patellar Clunk Syndrome
— Seen at 35º-40º knee flexion
— Treatment is arthroscopic or open resection
Issues with Surgical Techniques Sagittal Plane Balancing
Situation Problem Solution
Cut Tight Symmetrical – cut morein extension gap proximal tibiaCut Tight in flexion
Cut Tight Asymmetrical – Release PCL;in extension gap Posterior capsule Cut Loose Consider PCL in flexion substituting prosthesis
– Resection distal femur AVOID recurvatum
Issues with Surgical Techniques Sagittal Plane Balancing
Situation Problem Solution
Cut Good Asymmetrical – Resection additional in extension gap tibia
Cut Tight in flexion – May need to release PCL
– Ensure posterior slope of tibia
Cut Good Asymmetrical – Need femoral in extension gap augmentation
Cut Loose – Adjust to larger in flexion femoral component
Complications in Total Knee Arthroplasty
Periprosthetic FracturesInfected Total Knee
Arthroplasty
SupracondylarFractures of the
Femur
After Total Knee Arthroplasty
Supracondylar Fractures After TKR
l Notching of the femoral cortex
l Osteoporosis
l Prolonged steroid use
l Preexisting neurologic disorders
Supracondylar Fractures After TKR
OSTEOPOROSIS
Bogoch, et al, CORR 1986
Supracondylar Fractures After TKR
l Major trauma is not required to produce fractures in many TKA patients
l Alignment not correlated with fracture
l Weight not a significant factor
Fractures After TKANeer Classification of Supracondylar Fracturesl Type I - Minimal displacementl Type IIA - Medial displacement of
condylesl Type IIB - Lateral displacement
of condylesl Type III - Supracondylar and shaft
fractures
Supracondylar Fractures After TKR
TREATMENT
Type 1 – Nondisplaced
Supracondylar Fractures After TKR
Type 1 fractures 83% success rate
Chen, et al, 1994
Supracondylar Fractures After TKR
Type 2 fractures 69% success rate
Chen, et al, 1994
Supracondylar Fractures After TKR
l Casting
l Traction followed by rest
Non Operative Method
Supracondylar Fractures After TKR
Type 2 fractures 67% success rate
Chen, et al, 1994
Supracondylar Fractures After TKR
l Plates / Screw fixationl Intramedullary rodsl Rush pinsl External fixationl Primary arthrodesisl Revision arthroplasty
Operative Method
Supracondylar Fractures After TKR
l Patients’ ability to tolerate traction
l Ability of bone to hold screwsl Ability of the surgeon
Type 2Considerations
Intercondylar Distances of Commonly Used Femoral Prostheses
Biomet, (Warsaw, IN) AGC 18 Universal 18
DePuy, (Warsaw, IN) AMK 20
Dow Corning Wright, (Arlington, TN) Whitesides modular 20Howmedica, (Rutherford, NJ) PCA 18.5Intermedics, (Austin, TX) Natural 14Johnson and Johnson, (New Brunswick, NJ) Press-fit condylar 20
Insall-Burstein* 15 (posterior stabilized)
Kirschner, (Timonium, MD) Performance 14Zimmer, (Warsaw, IN) Insall-Burstein I* 16
Insall-Burstein II 15 (posterior stabilized* or constrained condylar†) Miller-Galante I Small / small + ‡ 11 Regular / regular + 12.5 Large / large + 15 Large + + 18 Miller-Galante II 13
Manufacturer ModelModelIntercondylar Distance(Smallest Size) (mm))
Supracondylar Fractures After TKR
No one form of treatment gives uniformly good
results
Infection in Total Knee Arthroplasty
Complications in Arthroplasty
Infection – Risk Factors
l Skin ulcerations / necrosis
l Rheumatoid Arthritis
l Previous hip/knee operation
l Recurrent UTI
l Oral corticosteroids
Complications in Arthroplasty
Infection – Risk Factors
l Chronic renal insufficiency
l Diabetes
l Neoplasm requiring chemo
l Tooth extraction
Complications in Arthroplasty
Infection – Clinical Course
l Pain #1
l Swelling
l Fever
l Wound breakdown drainage
Windsor et alJBJS; 1990
Early < 3 months
Lab Value
Mayo Series Mean 7,500
l Differential 67 PMN’s
l Sed rate 71 mm/hr
l Arthrocentesis
Infections About TKR
Late > 3 monthsSymptoms: 52 patients
Pain 96% swelling 77% Debride 27% Active drainage 27% Sed rate 63 mm/hr WBC - 8300
Windsor et alJBJS; 1990
Infections About TKR
Complications in Arthroplasty
Infection – Surgical Techniques
l Avoid skin bridges
l Avoid creation of skin flaps
l Hemostasis
l Prolonged operating time
Complications in Arthroplasty
Infection – Work-Up
l Wound History
l Physical Exam
l Serial Radiographs
l Lab/sed rate/CRP
l Bone scan / Indium scan
Complications in Arthroplasty
Infection
Arthrocentesis
l Cell count
l Diff > 25,000 pmn
l Protein – high
l Glucose – low
Complications in Arthroplasty
Infection
l Host Response
Glycocalyx
GristinaJBJS; 1983
Micro Organisms
Organisms Isolated from 71 Patients Organisms Isolated from 71 Patients With Infected Knee ReplacementWith Infected Knee Replacement
StaphylococcusStaphylococcus 6464
S. aureusS. aureus, penicillin sensitive , penicillin sensitive 1414 S. aureusS. aureus, penicillin resistant, penicillin resistant 2828 S. epidermisS. epidermis 2222
Gram negativeGram negative 1212 PseudomonasPseudomonas 77 Escherichia coliEscherichia coli 55
AnærobicAnærobic 66
OtherOther 17 17
OrganismOrganism PercentPercent
Complications in Arthroplasty
Treatment Options
l Antibiotic suppression
l Aggressive wound debridement
Complications in Arthroplasty
Treatment Options
l Antibiotic suppression
Indicated in med compromised
Organism - gram+ strep staphepi
Complications in Arthroplasty
Treatment Options
l Resection arthroplasty
l 2 Stage re-implant
l Arthrodesisl Amputation
Complications in Arthroplasty
Treatment Optionsl Debridement with antibiotic
suppression therapyStrep/staphepi -- bestAvoid repeated attemptsFrozen tissue sectionSuction drains
Complications in Arthroplasty
Two-Stage Reimplantation
l Most successful treatment
l Procedure of choice
Complications in Arthroplasty
Two-Stage Reimplantation Procedure
l Remove components, cement, I&D
l Fabricate and place spacer
l 6 weeks of antibiotics
l Reimplantation
Complications in Arthroplasty
Two-Stage Reimplantation Stage I
l create antibiotic spacer impregnated with antibiotics
l wound closure
Complications in Arthroplasty
Two-Stage Reimplantation
l Spacer Antibiotic Regimen
Tobramycin 2.4 gm/3.6 gm per 40 gms of PMMA
Vancomycin > gm to 1 gm per gms of PMMA
Complications in Arthroplasty
Intra-operative Frozen Section
l < 5 PMN’s per HPF – no infection
l > 10 PMN’s per HPF – infection
Mirra; JBJS
Complications in Arthroplasty
Results — Gm positive
Windsor et al 92 % JBJS 1990
Insall et al 97% JBJS 1983
Complications in Arthroplasty
Resection Arthroplasty
l Removal all components
l Remove all cement
l Effective in medically compromised patient
Complications in Arthroplasty
Arthrodesis Indications
l Extensor mechanism disruption
l Resistant bacteria
l Inadequate bonestock
l Inadequate soft tissues
l Young patient
Advantages
Definitive treatment
Little chance of recurrence
Arthrodesis
Disadvantages
Difficulty with transfers / small spaces
Increase energy requirements
Arthrodesis
Algorithm
TKAClinical Sepsis
(GRAM + Organism)
< 3 wks > 3 wks
DebridementAntibiotics (6 wks)
2-StageReplant
Infections About TKR
Algorithm
DebridementAntibiotics
Success
2-stage Replant Arthrodesis
Infections About TKR
No Success
2-stage Replant
SuccessNo
Success
ResectionArthroplasty
Thank You