4. Normal Knee Anatomy
Position in single leg stance
Mechanical axis valgus 3º
Femoral shaft axis valgus 6º
Proximal tibia varus 3º
5.
6. Total Knee Arthroplasty
Radiographic Evaluation
—Standing full length – AP
—Standing AP
—Extension/Flexion laterals
—Tunnel view
—Sunrise view
7.
8. Total Knee Arthroplasty
Radiographic Evaluation
Weight Bearing X-rays
—Extent of joint space narrowing
—Ligament stretch out
—Subluxation of femus on tibia
9.
10. 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
11.
12. Total Knee Arthroplasty
Radiographic Analysis
Mechanical Axis – Femur (MAF)
—A line from center of femoral
head to center of distal femur
13.
14. 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
15.
16. 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)
17.
18. 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
19.
20. Surgical Technique
Incision — straight longitudinal incision
Tissue handling key
Avoid flaps
Preserve soft tissue flap about the patella
33. Issues with Surgical
Techniques
Alignment
— Extramedullary vs Intramedullary
Accuracy vs increased PE risk
Femur – Intramedullary
Overdrill opening and insert
slowly IM guide
Caution with bilateral Total
Knee Arthroplasty
Tibia – Extramedullary
34.
35. Issues with Surgical
Techniques
Femoral Rotation
— Landmarks
Posterior femoral condyles
Epicondyles 5º external rotation
to the posterior condyles
36.
37.
38.
39. Issues with Surgical
Techniques
Femur
— Measured resections: equal bone
distally and posteriorly
— Tensioning devices ligament
releases
— Do not alter bone resection for
ligament tightness
47. 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
65. Fixed Flexion Deformity in TKA
Biomechanics
— increased quadriceps force for
knee stabilization during weight
bearing
— increased forces transmitted to the
patellofemoral joint
66. 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
67. 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
68. 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
69. Fixed Flexion Deformity in TKA
Soft tissue release
— Varies with angular deformity
Firestone et al
COOR ‘92
70. Fixed Flexion Deformity in TKA
Surgical Treatment
Soft tissue release
Additional bone resection
Combination
71. 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
72. 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
73. 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
84. Fixed Flexion Deformity in TKA
No formula is exact for treatment
of the problem
Consider a balance between soft
tissue release vs bone resection
85. Issues with Surgical
Techniques
Stiff Knee
Remove osteophytes
Insall Turn Down
Osteotomize the tibial tubercle
Rectus snip
86.
87.
88.
89.
90. Issues with Surgical
Techniques
Stiff Knee
Epicondylar osteotomy for large
flexion / contracture
Lateral release to evert the patella
91.
92.
93.
94. 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
95.
96. Issues with Surgical
Techniques
Patellar resurfacing
— Thickness shouldn’t exceed 25
mm
— For every 1 mm thicker reduces
flexion by 3º
101. 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
102. Issues with Surgical Techniques
Patellar Clunk Syndrome
— Seen at 35º-40º knee flexion
— Treatment is arthroscopic or
open resection
103. Issues with Surgical Techniques
Sagittal Plane Balancing
Situation Problem Solution
Cut Tight Symmetrical – cut more
in extension gap proximal tibia
Cut 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
104. 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
105. Complications in Total Knee
Arthroplasty
Periprosthetic Fractures
Infected Total Knee
Arthroplasty
111. 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
112. 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
119. Supracondylar Fractures
After TKR
Operative Method
l Plates / Screw fixation
l Intramedullary rods
l Rush pins
l External fixation
l Primary arthrodesis
l Revision arthroplasty
120. 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
121.
122.
123. Intercondylar Distances of Commonly Used Femoral Prostheses
Manufacturer MMooddeell
Intercondylar Distance
(Smallest Size) (mm))
Biomet, (Warsaw, IN) AGC 18
Universal 18
DePuy, (Warsaw, IN) AMK 20
Dow Corning Wright, (Arlington, TN) Whitesides modular 20
Howmedica, (Rutherford, NJ) PCA 18.5
Intermedics, (Austin, TX) Natural 14
Johnson and Johnson, (New Brunswick, NJ) Press-fit condylar 20
Insall-Burstein* 15
(posterior stabilized)
Kirschner, (Timonium, MD) Performance 14
Zimmer, (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
127. Complications in Arthroplasty
Infection – Risk Factors
l Skin ulcerations / necrosis
l Rheumatoid Arthritis
l Previous hip/knee operation
l Recurrent UTI
l Oral corticosteroids
128. Complications in Arthroplasty
Infection – Risk Factors
l Chronic renal insufficiency
l Diabetes
l Neoplasm requiring chemo
l Tooth extraction
129. Complications in Arthroplasty
Infection – Clinical Course
l Pain #1
l Swelling
l Fever
l Wound breakdown drainage
Windsor et al
JBJS; 1990
130. 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
131. Late 3 months
Symptoms: 52 patients
¥ Pain 96%
¥ swelling 77%
¥ Debride 27%
¥ Active drainage 27%
¥ Sed rate 63 mm/hr
¥ WBC - 8300
Windsor et al
JBJS; 1990
Infections About TKR
132. Complications in Arthroplasty
Infection – Surgical Techniques
l Avoid skin bridges
l Avoid creation of skin flaps
l Hemostasis
l Prolonged operating time
133.
134. 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
135.
136. Complications in Arthroplasty
Infection
Arthrocentesis
l Cell count
l Diff 25,000 pmn
l Protein – high
l Glucose – low
146. Complications in Arthroplasty
Two-Stage Reimplantation Procedure
l Remove components, cement,
ID
l Fabricate and place spacer
l 6 weeks of antibiotics
l Reimplantation
147. Complications in Arthroplasty
Two-Stage Reimplantation
Stage I
l create antibiotic spacer
impregnated with antibiotics
l wound closure
148.
149. 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
150. Complications in Arthroplasty
Intra-operative Frozen Section
l 5 PMN’s per HPF – no
infection
l 10 PMN’s per HPF – infection
Mirra; JBJS
152. Complications in Arthroplasty
Resection Arthroplasty
l Removal all components
l Remove all cement
l Effective in medically
compromised patient
153. Complications in Arthroplasty
Arthrodesis Indications
l Extensor mechanism disruption
l Resistant bacteria
l Inadequate bonestock
l Inadequate soft tissues
l Young patient
