Pediatric Orthopaedic Unit Department of Orthopaedic Surgery Pusan National University Hospital
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Transcript of Pediatric Orthopaedic Unit Department of Orthopaedic Surgery Pusan National University Hospital
Improvement of femoral head roundness Improvement of femoral head roundness after valgus femoral osteotomyafter valgus femoral osteotomyin Legg-Calve-Perthes disease in Legg-Calve-Perthes disease
Pediatric Orthopaedic UnitDepartment of Orthopaedic SurgeryPusan National University Hospital
Hui Taek Kim, MD and Seong Ho Bae, MD
IntroductionIntroduction
Deformation of the femoral head in Deformation of the femoral head in Legg-Calve-Perthes disease (LCPD)Legg-Calve-Perthes disease (LCPD)
• • Latter in fragmentation or early in regenerationLatter in fragmentation or early in regeneration stagestage
Best time to perform surgeryBest time to perform surgery • • Avascular necrosis and fragmentation stageAvascular necrosis and fragmentation stage
IntroductionIntroduction
Containment of the affected femoral headContainment of the affected femoral head • • Abduction braceAbduction brace • • Soft tissue release and/or varus femoral osteotomy Soft tissue release and/or varus femoral osteotomy • • Salter innominate osteotomySalter innominate osteotomy
The results are frequently poorThe results are frequently poor • • > 8 years old> 8 years old • • Uncontained femoral head and hinge abductionUncontained femoral head and hinge abduction
IntroductionIntroduction
Valgus femoral osteotomy (VFO)Valgus femoral osteotomy (VFO) • • Relieves hinge abductionRelieves hinge abduction
• • Provides better functional range of movementProvides better functional range of movement
by rotating the less affected femoral head intoby rotating the less affected femoral head into
weight bearing positionweight bearing position
PurposePurpose
To quantify the changes of femoral head To quantify the changes of femoral head roundness after valgus femoral osteotomyroundness after valgus femoral osteotomy
• • Using new measuring methodUsing new measuring method
Materials and MethodsMaterials and Methods
48 children48 children •• September 1997 to January 2006September 1997 to January 2006
Group 1: Group 1: non-operative Tx. non-operative Tx. (25 hips) (25 hips) • • 21 hips in pillar B (19 > 8 yrs old)21 hips in pillar B (19 > 8 yrs old) • • 4 hips in pillar C (2 > 8 yrs old )4 hips in pillar C (2 > 8 yrs old )
Group 2: Group 2: treated by VFO treated by VFO (23 hips)(23 hips) • • 7 hips in pillar B (3 > 8 yrs old)7 hips in pillar B (3 > 8 yrs old) • • 16 hips in pillar C (7 > 8 yrs old)16 hips in pillar C (7 > 8 yrs old)
Materials and MethodsMaterials and Methods
Overall patient age was 8.3 Overall patient age was 8.3 yearsyears • • GGroup 1 : 8.7 yearsroup 1 : 8.7 years • • Group 2 : 8Group 2 : 8.1 years.1 years Chiari OT : 10.2 years (3 cases)Chiari OT : 10.2 years (3 cases) Triple innominate OT : 6.5 years (2 cases)Triple innominate OT : 6.5 years (2 cases)
Male : 43Male : 43 Female : 5Female : 5
Mean follow-up period : 6.4 yearsMean follow-up period : 6.4 years
Materials and MethodsMaterials and Methods
Indications for VFOIndications for VFO •• Hip painHip pain • • Decreased range of motionDecreased range of motion • • Hinge abduction on MRI and arthrographyHinge abduction on MRI and arthrography • • Significant deformity of the femoral headSignificant deformity of the femoral head
Open wedge typeOpen wedge type
Soft tissue release or shortening (Soft tissue release or shortening (×)×)
Materials and MethodsMaterials and Methods
Femoral head roundnessFemoral head roundness •• Roundness of the lateral third (RLT) Roundness of the lateral third (RLT) •• Roundness of the medial third (RMT) Roundness of the medial third (RMT) •• Maximal epiphyseal height in middle third (MEH) Maximal epiphyseal height in middle third (MEH)
•• Ratio of radii of curvature of the medial third over Ratio of radii of curvature of the medial third over the lateral third (RML) the lateral third (RML)
Materials and MethodsMaterials and Methods
• Radiograph and MRI were taken at the same time (fragmentation stage)• MRI enables the visualization of the cartilaginous femoral head
Materials and MethodsMaterials and Methods
Measuring methodsMeasuring methods
Materials and MethodsMaterials and Methods
Most clear imageMost clear image • • EEntire proximal femur ntire proximal femur
• • FFragmentation stage in MRI / residual stage in APragmentation stage in MRI / residual stage in AP
radiographradiograph
Image-analysis softwareImage-analysis software • • Adobe PhotoshopAdobe Photoshop
• • Microsoft Power PointMicrosoft Power Point
Materials and MethodsMaterials and Methods
Drawing Drawing • • FFemoral shaft axisemoral shaft axis
•• Femoral neck axisFemoral neck axis
• • FFemoral head waistemoral head waist
•• Radius of circle in lateral and medial third of Radius of circle in lateral and medial third of
femoral head (RLT and RMT)femoral head (RLT and RMT)
•• Maximal epiphyseal height (MEH) in middle thirdMaximal epiphyseal height (MEH) in middle third
Materials and MethodsMaterials and Methods
First stepFirst step • • MMagnificationagnification • • Medial aspect of the femoral head and calcarMedial aspect of the femoral head and calcar
Materials and MethodsMaterials and Methods
# Medial aspect of the femoral head and calcar are minimally affected during disease process
Second stepSecond step • • FFemoral shaft and neck axisemoral shaft and neck axis • • The most superolateral and inferomedial point of femoral head The most superolateral and inferomedial point of femoral head • • Base lineBase line
Materials and MethodsMaterials and Methods
a
a′
A
A’
Materials and MethodsMaterials and Methods
a
a′
A
A’
Third stepThird step • • DDivide the base line into thirds ivide the base line into thirds • • Draw lines parallel to the femoral neck axis through 2 points Draw lines parallel to the femoral neck axis through 2 points
‖‖
‖
‖
‖‖b
b′
B
B’
Materials and MethodsMaterials and Methods
a
a′
A
A’
b
b′
B
B’
Final stepFinal step • • BBest fitting circle passing a′(A′) and b′(B′) placing the centerest fitting circle passing a′(A′) and b′(B′) placing the center of circle to the median of the line connecting a′(A′) and b′(B′)of circle to the median of the line connecting a′(A′) and b′(B′)
# Definition of circle : The set of all points in a plane# Definition of circle : The set of all points in a plane whichwhich are equidistant from a given point (center of circle)are equidistant from a given point (center of circle)
┐ ┐
r R
RLT
Materials and MethodsMaterials and Methods
a
a′
A
A’
b
b′
B
B’
The ratio of maximal epiphyseal height (MEH) The ratio of maximal epiphyseal height (MEH) to the waist of the femoral head to the waist of the femoral head
• • Subchondral bone instead of articular cartilage (in MRI) Subchondral bone instead of articular cartilage (in MRI)
W W
MEH
Differential coefficient Differential coefficient isisdecreased as the point ofdecreased as the point ofcontact moves toward middlecontact moves toward middleportion in ellipse portion in ellipse
Maximal epiphyseal heightMaximal epiphyseal heightrepresent more effectively therepresent more effectively thehead growth or roundness head growth or roundness ininthe middle thirdthe middle third
Materials and MethodsMaterials and Methods
Final data analysisFinal data analysis • • Relative change of RLT (%) = × 100 (%)Relative change of RLT (%) = × 100 (%)
Materials and MethodsMaterials and Methods
r – R
r
a
a′
A
A’
b
b′
B
B’
# Definition of circle : The set of all points in a plane# Definition of circle : The set of all points in a plane whichwhich are equidistant from a given point (center of circle)are equidistant from a given point (center of circle)
┐ ┐
r R
RLT
Final data analysisFinal data analysis • • Relative change of MEH (%) = × 100 (%)Relative change of MEH (%) = × 100 (%)
Materials and MethodsMaterials and Methods
m – M
m
a
a′
A
A’
b
b′
B
B’
W W
MEH
D. Nelson, M. Zenios, K. Ward et al, JBJS 2007
r R
r’ R’
ROC in lateral third : rROC in medial third : r’The ratio of ROC (RML) : r’/r
ROC in lateral third : RROC in medial third : R’The ratio of ROC (RML) : R’/R
* ROC : Radius Of Circle
Amount of collapse in lateral portion of deformed femoral head# RML = ROC in medial 1/3 / ROC in lateral 1/3 (Rm / RL)
Final Stulberg classificationFinal Stulberg classification
Materials and MethodsMaterials and Methods
ResultsResults
Measurements
Group Total RLT (%) MEH (%) RML (△ )
All hips
Nonoperative 25 13.2 3.9 0.74 → 0.84 (0.10)
Operative 23 21.4 7.8 0.65 → 0.81 (0.16)
Total 48
Comparison of each value : p < 0.05 by paired t-test
Measurements
Group Total RLT (%) MEH (%) RML (△ )
Lateral pillar group B 28 15.0 4.5 0.76 → 0.88 (0.12)
Chron. Age ≤ 8.0 at disease onset
Nonoperative 19 16.8 4.5 0.76 → 0.90 (0.14)
Operative 4 10.2 3.5 0.74 → 0.82 (0.08)
Total 23
Chron. Age > 8.0 at disease onset
Nonoperative 2 5.5 4.4 0.82 → 0.88 (0.06)
Operative 3 16.7 5.6 0.73 → 0.84 (0.11)
Total 5
Comparison of each value : p < 0.05 by paired t-test
Measurements
Group Total RLT (%) MEH (%) RML (△ )
Lateral pillar group C 26.6 9.6 0.59 → 0.78 (0.19)
Chron. Age ≤ 8.0 at disease onset
Nonoperative 2 17.4 2.7 0.70 → 0.81 (0.11)
Operative 9 31.2 12.5 0.53 → 0.76 (0.23)
Total 11
Chron. Age > 8.0 at disease onset
Nonoperative 2 13.2 4.0 0.69 → 0.78 (0.09)
Operative 7 27.3 9.4 0.61 → 0.80 (0.19)
Total 9
2020
Comparison of each value : p < 0.05 by paired t-test
0.76
0.59
0.12
0.19
0
0.1
0.2
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1
Pillar B Pillar C
Mea
n v
alue
s (R
ML
)
Groups
Mean changes of head roundness (RML)
Residual stage
Fragmentation or early reossification stage
Final Stulberg classificationsFinal Stulberg classifications
ResultsResults
II III
Group 1 (n=25) 10 15
Group 2 (n=23) 4 19
p = 0.09 by Pearson chi-square test
ConclusionsConclusions
ConclusionsConclusions
Femoral head roundness was improvedFemoral head roundness was improved
with ossification of the affected hipwith ossification of the affected hip
More round femoral head can be expected More round femoral head can be expected
in the lateral pillar B hips than pillar Cin the lateral pillar B hips than pillar C
ConclusionsConclusions
However, VFO performed in theHowever, VFO performed in the
fragmentation stage of lateral pillar C hips fragmentation stage of lateral pillar C hips
leads to greater improvement in femoralleads to greater improvement in femoral
head roundness than does non-surgicalhead roundness than does non-surgical
treatment of lateral pillar B hipstreatment of lateral pillar B hips
Case 1Case 1M/7+3M/7+3
Group 1Group 1
RMTRMT
5.08 5.02 1%
RLTRLT
8.04 6.00 25%
MEHMEH
1.68/4.75 1.78/4.76 6%
RMLRML
5.08/8.04 = 0.63 5.02/6.00 = 0.84 0.21
Case 2Case 2M/10+0M/10+0
Group 2Group 2
RMTRMT
5.80 5.30 9%
RLTRLT
9.29 6.34 32%
MEHMEH
1.80 2.10 17%
RMLRML
5.80/9.29 = 0.62 5.30/6.34 = 0.84 0.22
Thank you for your attention !Thank you for your attention !