TOTAL KNEE
ARTHROPLASTY
Frank R. Ebert, MD
Union Memorial Hospital
Baltimore, Maryland
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 Analysis
Anatomic 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
incision

Tissue handling key

Avoid flaps

Preserve soft tissue flap about the
patella

Surgical Technique
Remember 7cm
Rule between
incisions
Issues with Surgical
Techniques

Exposure options
— Subvastus / midvastus
u
Routine knee
replacements
z Quicker rehab
— Medial parapatellar / midline
u
Difficult total knee —
obese patients
u
Revisions
MIS vs MINI TKA
Capsulotomy
only?
Mid vastus?
Sub vastus?
MIS
MIS vs MINI TKA
Mid
vastus?
Sub
vastus?
Quad
MIS
Anatomic Variations of VMO
Insertion
Type I-High
Insertion
Type II-Pole
Insertion
Type III-Low
Insertion
Area of
Variation
Type I- High VMO
Insertion
Muscle
Insertion
Area of
extended
retinaculu
m
Retinacula
r Incision
Type II-Pole
Insertion
Muscle
Insertion
Capsular
or
Retinacul
ar
Incision
Type III-Low VMO
Insertion
Muscle
Insertion
Area of
Extended
VM
Issues with Surgical
Techniques

Alignment
— Extramedullary vs Intramedullary
u Accuracy vs increased PE
risk
u Femur – Intramedullary
z Overdrill opening and insert
slowly IM guide
z Caution with bilateral Total
Knee Arthroplasty
u Tibia – 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 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
u 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 TKA
Biomechanics
— 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 range
5 to 22º valgus
Firestone et al
COOR ‘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 & Forster
JBJS (B) 87
Fixed Flexion Deformity in TKA
Soft tissue release
— Varies with angular deformity
Firestone et al
COOR ‘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 al
COOR ‘92
Fixed Flexion Deformity in TKA
Additional bone resection — cons
(excessive)
•
•
•
•
Collateral ligament laxity
Quadriceps redundancy
Hyperextension
Bone quality can be compromised
McPherson 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 osteophytes
Firestone 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
u
Epicondylar osteotomy for large
flexion / contracture
u
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
Cut Tight
Symmetrical
in extension
gap
Cut Tight in flexion
Cut Tight
in extension
Cut Loose
in flexion
Solution
– cut more
proximal tibia
Asymmetrical – Release PCL;
gap
Posterior capsule
Consider PCL
substituting prosthesis
– Resection distal femur
AVOID recurvatum
Issues with Surgical Techniques
Sagittal Plane Balancing
Situation
Problem
Cut Good
in extension
Asymmetrical
gap
Cut Loose
in flexion
– Resection additional
tibia
– May need to release
PCL
– Ensure posterior
slope of tibia
Cut Tight in flexion
Cut Good
in extension
Solution
Asymmetrical
gap
– Need femoral
augmentation
– Adjust to larger
femoral component
Complications in Total
Knee Arthroplasty
Periprosthetic Fractures
Infected Total Knee
Arthroplasty
Supracondylar
Fractures 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
Fractures After TKA
Neer Classification of Supracondylar
Fractures
l Type I - Minimal displacement
l Type IIA - Medial displacement of
condyles
l Type IIB Lateral displacement
of condyles
l 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
Non Operative Method
l Casting
l Traction followed by rest
Supracondylar Fractures
After TKR
Type 2 fractures
67% success rate
Chen, et al, 1994
Supracondylar Fractures
After TKR
Operative Method
l
l
l
l
l
l
Plates / Screw fixation
Intramedullary rods
Rush pins
External fixation
Primary arthrodesis
Revision arthroplasty
Supracondylar Fractures
After TKR
Type 2
Considerations
l Patients’ ability to tolerate traction
l Ability of bone to hold screws
l Ability of the surgeon
Intercondylar Distances of Commonly Used Femoral Prostheses
Manufacturer
Model
Intercondylar Distance
(Smallest Size) (mm)
Biomet,
(Warsaw, IN)
AGC
Universal
18
18
DePuy,
(Warsaw, IN)
AMK
20
Dow Corning Wright,
Howmedica,
Intermedics,
Johnson and Johnson,
(Arlington, TN)
(Rutherford, NJ)
(Austin, TX)
(New Brunswick, NJ)
Whitesides modular
PCA
Natural
Press-fit condylar
Insall-Burstein*
(posterior stabilized)
20
18.5
14
20
15
Kirschner,
Zimmer,
(Timonium, MD)
(Warsaw, IN)
Performance
Insall-Burstein I*
Insall-Burstein II
(posterior stabilized* or
constrained condylar†)
Miller-Galante I
Small / small + ‡
Regular / regular +
Large / large +
Large + +
Miller-Galante II
14
16
15
11
12.5
15
18
13
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
l
l
l
l
Infection – Clinical Course
Pain #1
Swelling
Fever
Wound breakdown drainage
Windsor et al
JBJS; 1990
Infections About TKR
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 months
Symptoms: 52 patients
 Pain
96%
 swelling
77%
 Debride
27%
 Active drainage
27%
 Sed rate 63 mm/hr
Windsor et al
 WBC - 8300
JBJS; 1990
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
l
l
l
l
Arthrocentesis
Cell count
Diff > 25,000 pmn
Protein – high
Glucose – low
Complications in Arthroplasty
Infection
l Host Response
Glycocalyx
Gristina
JBJS; 1983
Micro Organisms
Organisms Isolated from 71 Patients
With Infected Knee Replacement
Organism
Staphylococcus
S. aureus, penicillin sensitive
S. aureus, penicillin resistant
S. epidermis
Gram negative
Pseudomonas
Escherichia coli
Anærobic
Other
Percent
64
14
28
22
12
7
5
6
17
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 Arthrodesis
l Amputation
Complications in Arthroplasty
Treatment Options
l Debridement with antibiotic
suppression therapy
Strep/staphepi -- best
Avoid repeated attempts
Frozen tissue section
Suction 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
Arthrodesis
Advantages
 Definitive treatment
 Little chance of recurrence
Arthrodesis
Disadvantages
 Difficulty with transfers / small
spaces
 Increase energy requirements
Infections About TKR
Algorithm
TKA
Clinical
Sepsis
< 3 wks
Debridement
Antibiotics (6 wks)
(GRAM +
Organism)
> 3 wks
2-Stage
Replant
Infections About TKR
Algorithm
Debridement
Antibiotics
Success
No
Success
2-stage Replant
2-stage Replant
Success
No
Success
Arthrodesis Resection
Arthroplasty
Thank You