Deformity: It’s the position of a limb/Joint, from which it cannot be brought back to its normal anatomical position. Described as abnormalities of : Length Angulation Rotation Translation Combination

1. PRINCIPLES OF
DEFORMITY
CORRECTION
Prepared by: Supervised by:
Dr. Abdullah K. Ghafour Dr. Hamid Ahmed Jaff
3rd year IBFMS trainee

2. Reminders
frontal plane-mechanical frontal plane-anatomical sagittal plane-anatomical

3. Introduction
 Deformity: It’s the position of a limb/Joint, from which it
cannot be brought back to its normal anatomical
position.
 Described as abnormalities of :
 Length
 Angulation
 Rotation
 Translation
 Combination

4. Introduction
 Evaluation of Deformity:
 History
 Clinical examination
 Radiological Examination
 X-rays
o Long films (51 Inches)
o Frontal plane (AP view)
o Sagittal plane (Lateral view)
 CT Scans
o CT Scanogram

5.  Malalignment refers to the loss of
collinearity of the hip, knee, and
ankle in the frontal plane.
 Therefore, if the MAD exceeds
the normal range, there is
malalignment
 Frontal plane MAD may arise
from four anatomic sources:
1. femoral frontal plane deformity
2. tibial frontal plane deformity
3. frontal plane knee joint laxity
4. femoral or tibial condylar
deficiency.
Malalignment and
Malorientation

6. Malalignment and
Malorientation
 Paley and Tetsworth (1992) designed a malalignment test
(MAT) to identify the source(s) of the MAD. MAT identifies
only which bone or joint source contributes to the MAD that
is measured. It does not identify the level of deformity in
the femur or tibia
 Steps of MAT:
 Step 0: Measure the MAD
 normal range is 1-15 mm medial
 Varus > 15mm – 1mm< valgus
 Step 1: Measure the mLDFA
 normal range is 85°-90°
 outside the normal range femur
is contributing to the MAD.
 Varus > 85° - 90° < valgus

7. Malalignment and
Malorientation
 Step 2: Measure the MPTA
 normal range is 85°-90°
 outside the normal range tibia
is contributing to the MAD.
 Valgus > 85° - 90° < varus
 Step 3: Measure the JLCA
 normal range is 0°_2° medial
 Medial JLCA > 2° means varus
 lateral JLCA > 2° means valgus
 outside the normal range loss
of cartilage height and ligamentous
laxity is contributing to the MAD.

8. Malalignment and
Malorientation
 Addendum 1: Rule Out Knee
Joint Subluxation
Compare the midpoints of the
femoral and tibial knee joint
orientation lines.
Normally, they should be within 3
mm of each other.

9. Malalignment and
Malorientation
 Addendum 2: Rule Out Condylar
Malalignment
Compare the joint lines of the medial and
lateral plateaus with each other. They should
be collinear.
Compare
the lines tangential to the medial and lateral
femoral condyles. They should be collinear.

10. Malalignment and
Malorientation
 Malorientation of the ankle or
hip joints usually leads to
minimal or no MAD because
the deformity apex is at or near
the ends of the mechanical axis
of the lower limb.
 Ankle joint orientation assessed
by measuring mLDTA and
aLDTA.
 Hip joint orientation assessed
by measuring mLPFA, aMPFA
and aMNSA.

11. center of rotation of angulation
 When a bone is divided and
angulated, the mechanical and
anatomic axes of the bone are
also divided into proximal and
distal segments.
 The pairs of proximal and distal
axis lines intersect to form an
angle, this point is called the
center of rotation of angulation
(CORA).

12. center of rotation of angulation
 CORA Method:
Step 0: malalignment test (MAT)
Step 1: draw PAA and PMA
Step 2: draw DAA and DMA
Step 3: Decide whether this is
uniapical or multiapical angulation:
mark the CORA(s), and measure
the magnitude(s)

13. Sagittal Plane Deformities
 the sagittal plane alignment of the hip, knee,
and ankle changes with normal knee motion
and gait.
 The line from the center of rotation of the
hip to the center of rotation of the ankle is
the mechanical axis of the lower limb in the
sagittal plane.
 With the knee in full extension, it passes
anterior to the center of rotation of the knee
joint while it become collinear at
approximately 5°_10° of knee flexion

14. Sagittal Plane Deformities
 Knee malalignment in the sagittal plane
is better tolerated than in the frontal
plane because all three joints move in
the sagittal plane and can therefore
compensate for sagittal malalignment.
 Flexion malalignment is present when
the mechanical axis of the lower limb
does not pass anterior to the center of
rotation of the knee in maximum
extension.
 Extension malalignment is present
when the knee can be hyperextended
passively more than 5°

15. Sagittal Plane Deformities
 Knee Joint Malorientation: The joint
orientation of the distal femur and of the
proximal tibia is measured to the
adjacent anatomic axis line by using
PDFA (83±4°) and PPTA (81 ±4°).
 PDFA < 79°, there is overall procurvatum
deformity of the distal femoral joint line
 PDFA > 87°, there is overall recurvatum deformity
of the distal femoral joint line

16.  Knee Joint Malorientation:
 PPTA < 77°, there is overall procurvatum
deformity of the proximal tibial joint line.
 PPTA > 85°, there is overall recurvatum
deformity of the proximal tibial joint line.
Sagittal Plane Deformities

17. Sagittal Plane Deformities
 Hip Joint Malorientation:
• The aPPFA is normally 90°.
• The anterior NSA (ANSA) is
normally 170±5°.
• The proximal and distal mid-
diaphyseal lines of the femur
intersect in the mid-femur. The
normal (MDA) is approximately
10°.

18. Sagittal Plane Deformities
 Ankle Joint Malorientation: Draw the distal mid-
diaphyseal line of the tibia, and measure the ADTA. If the
ADTA is less than 78° or greater than 85°, there is
malorientation of the ankle joint line relative to the DAA
line.

19. CORA in sagittal plane
 Step 1:Draw the mid-diaphyseal line(s) to represent the
diaphysis of the bone.
 Step 2:Decide whether the joint orientation angles are
normal (PPTA,ADTA) foe tibia and PDFA for femur.
 Step 3:Decide whether this is uniapical or multiapical
angulation. Mark the CORA(s) and measure the
magnitude(s)

20. Oblique Plane Deformities
 The apical direction of an oblique plane angulation is
either anterolateral, anteromedial, posterolateral, or
posteromedial.
 If a radiograph could be obtained exactly perpendicular
to the oblique plane, the magnitude could be measured
directly.

21. Oblique Plane Deformities
 Knowing the magnitudes of
angulation measured off the
AP and LAT radiographs, the
magnitude of the true
angulation in the oblique plane
can be calculated by:
(𝑂𝑏𝑙. 𝑚𝑎𝑔) = (𝐴𝑃 𝑚𝑎𝑔)2+(𝐿𝑎𝑡 𝑚𝑎𝑔)2

22. Translation Deformity
 Translation deformity refers to displacement deformity. It
occurs secondary to fractures and osteotomies.
 Translation deformity parameters:
(a) plane, (b) direction, (c) magnitude, and (d) level.

23. Osteotomy Concepts
 There are two basic osteotomy types for angular deformity
correction:
1. angulation-only osteotomies
 opening wedge
 closing wedge
2. angulation with translation osteotomies.
 circular cut (dome)
 Oblique cut
 The axis line around which the correction is performed is
the Angulation Correction Axis (ACA)

24. Osteotomy Concepts
 A line passing through the CORA dividing the transverse
angle into two equal parts is called the transverse
bisector line (tBL)
 Each point on tBL line can be considered a CORA
 When the ACA passes through CORA the point
is called an ACA-CORA

25. Osteotomy Concepts
 Osteotomy Rules:
 Osteotomy rule 1: When the osteotomy and
ACA pass through any of the CORAs,
realignment occurs without translation.

26. Osteotomy Concepts
 Osteotomy Rules:
 Osteotomy rule 2: When the ACA is through
the CORA but the osteotomy is at a different
level, the axis will realign by angulation and
translation at the osteotomy site.

27. Osteotomy Concepts
 Osteotomy Rules:
 Osteotomy rule 3: When the osteotomy
and ACA are at a level above or below the
CORAs the proximal and distal axes of
the bone will be parallel but translational
deformity will result.

28. Osteotomy types
 Opening Wedge Osteotomy:
 The CORA and ACA lie on the
cortex on the convex side of the
deformity.
 The cortex on the concave side of
the deformity is distracted to restore
alignment, opening an empty wedge
that traverses the diameter of the
bone.
 Opening wedge osteotomy
increases final bone length.

29. Osteotomy types
 Closing Wedge Osteotomy:
 The CORA and ACA lie on the
concave cortex of the deformity.
 The cortex on the convex side of
the deformity is compressed to
restore alignment, requiring
removal of a bone wedge across
the entire bone diameter.
 A closing wedge osteotomy
decreases final bone length.

30. Osteotomy types
 Neutral wedge osteotomy:
 The CORA and ACA lie in the middle of the bone.
 The concave side cortex is distracted and the convex side
cortex is compressed.
 A bone wedge is removed from the convex side.
 Neutral wedge osteotomy has no effect on final bone
length.

31. Osteotomy types
 Focal Dome Osteotomy:
 The osteotomy is a cylindrical
shaped cut in three dimensions .
 the osteotomy site cannot pass
through both the CORA and the
correction axis. Thus, translation will
always occur when using a dome
osteotomy.

32. Translation deformity correction
 Translational deformities may be
corrected in one of three ways.
 Transverse cut osteotomy:
 Oblique cut osteotomy:
 Multiple osteotomies:
a b

33. Length discrepancy correction
 Acute distraction or
compression methods obtain
immediate correction of limb
length by acute lengthening
with bone grafting or acute
shortening, respectively
 Gradual correction techniques
for length deformities typically
use Ilizarov external fixation/
LRS

34. PRINCIPLES OF DEFORMITY
CORRECTION
 For more information please read this genius
book for (Dr. DROR PALEY).

35. References
• Paley D., Herzenberg J. E. (editorial assistance), [2005] Principles Of
Deformity Correction, 1st ed. 2002. Corr. 3rd printing 2005. by Springer-
Verlag Berlin Heidelberg, New York, USA
• Browner B., [2014] skeletal trauma ,4th ed. . by Saunders, an imprint of
Elsevier Inc. , Philadelphia, USA.
• Solomon L., Warwick D. , Nayagam S.,[2010] Apley’s System of
Orthopaedics and Fractures, 9th ed. Hodderarnold comp.,London, UK.
• Bucholz R. W., Heckman J. D., [2010] Rockwood And Green’s fractures In
Adults, 7th ed., by Lippincott Williams & wilkins, Philadelphia, USA.
• Canale S. , Beaty J. , [2007] Campbell’s Operative Orthopaedics , 11th ed. By
Mosby, An Imprint of Elsevier , Tennessee, USA.
• Solomin L.,Schepkina E.,Kulesh P., [2004] Reference Lines and Angles, 1st
ed. By Mosby, An Imprint of Elsevier , Tennessee, USA.

36. ?
THANK