DROR PALEY
PRINCIPLES OF 0 E FOR M I TV
CORRECTION
With Editorial Assistance from J. E. Herzenberg
With More Than 1,800 Separate Illustrations,
Clinical Photographs, and Radiographs

1 Normal lower limb Alignment
and Joint Orientation ... 1
Mechanical and Anatomic Bone Axes . . .
Joint Center Points ...
Joint Orientation lines
Ankle. . ..... .
5
5
5
Knee. . . . . . . . . . . 5
Hip. . . . . . . . . . .. . ........... 8
Joint Orientation Angles and Nomenclature . . . . .. 8
Mechanical Axis and Mechanical Axis Deviation (MAD). 10
Hip Joint Orientation . 12
Knee Joint Orientation . . . . . . . . . . . . . . . . . 13
Ankle Joint Orientation . . . . . . . . . . . . . . . . . 16
References. . . . . . . . . . . . . . . . . . . . . . . . 17
2 Malalignment and Malorientation
in the Frontal Plane ... 19
Malalignment . . . . . . . . . . . .
MAT ................. .
· . 19
· . 23
Malorientation of the Ankle and Hip . . 28
Orientation of the Ankle and Hip in the Frontal Plane . 28
MOT of the Ankle . . . . . . . . . . . . . . . . . . . . 28
MOT of the Hip. . 30
References. . . . . . . . . . . . . . . . . . . . . . . . 30
3 Radiographic Assessment
ofLower Limb Deformities ... 31
Knee ........................... 31
Ankle and Hip . . . . . . . . . . . . . . . . . . . . . . 40
Radiographic Examination in the Sagittal Plane .... 46
Knee ......................... 46
Ankle. . . . . . . . . . . . . . . . . . . 51
Hip .......................... 53
Radiographic Examination in One Plane
When There Is a Deformity Component
in the Other Plane . . 57
4 Frontal Plane Mechanical
and Anatomic Axis Planning ... 61
Mechanical Axis Planning . . . . . . . . . . . . . .. 61
Anatomic Axis Planning . . . . . . . . . . . . . .. 63
Determining the CORA by Frontal Plane Mechanical
and Anatomic Axis Planning: Step by Step. 64
Part I: CORA Method, Tibial Deformities. . . . . 64
Mechanical Axis Planning
ofTibial Deformities . . 64
Anatomic Axis Planning
of Tibial Deformities. . 74
Part II: CORA Method, Femoral Deformities . 76
Mechanical Axis Planning
of Femoral Deformities 76
Anatomic Axis Planning
of Femoral Deformities
Multiapical Deformities . . . .
5 Osteotomy Concepts
and Frontal Plane Realignment ... 99
81
97
Angulation Correction Axis (ACA) . . . . . . . . . .. 99
Bisector Lines ...................... 101
Relationship of Osteotomy Type to Bisector Lines. 101
Osteotomy Rules . . . . . . . . . . . . 102
Translation and length Displacement
atthe Osteotomy Line . . . . . . 105
Opening Wedge Osteotomy. . 106
Closing Wedge Osteotomy. . . . . . . . 106
Focal Dome Osteotomy. . . . . . . . . . . . 112
Clinical Choice of Osteotomy Level and Type 114
Multiapical Osteotomy Solutions . . . 140
Single Osteotomy Solutions. . . . . . . 140
Multiple Osteotomy Solutions. 142
References . . . . . . . . . . . . . . . . . . . . . . . 154
6 Sagittal Plane Deformities ... 155
References. . . . . . . . . . . . . . . . . . · . 60 Sagittal Plane Alignment in the lower Limb . 155
157
157
Sagittal Plane MAT . . . . . . .
Knee Joint Malorientation . . . . . . . . . . .
.. Contents
Overall Sagittal Plane MOT ...... .
Knee Level Sagittal Plane MOT .... .
Overall Sagittal Plane MOT of the Ankle.
Ankle Level Sagittal Plane MOT of the Ankle
Sagittal Plane Anatomic Axis Planning
ofTibial Deformity Correction . . .
Sagittal Plane Anatomic Axis Planning
of Femoral Deformity Correction. .
Osteotomies in the Sagittal Plane.
References . . . . . . . . . . . . . . . .
7 Oblique Plane Deformities ... 175
Plane of Angulation . .
Graphic Method. . . . .
Graphic Method Error ..
Base ofTriangle Method . . . . . . . .
Axis of Correction of Angulatory Deformities .
Definition of Angulation. .
References . . . . . . . . . . . . . . . . . . .
8 Translation and Angulation-Translation
Deformities ... 195
Translation Deformity . . . . . . . . . . .
Two Angulations Equal One Translation . .
Translation Effects on MAD ...
Osteotomies for Correction
ofTranslation Deformity . .
Combining Angulation and Translation . .
a-t Deformities and MAD .....
Graphic Analysis of a-t Deformities . .
Type 1: Angulation and Translation
in the Same Plane. . . . . . .
Anatomic Plane Deformity . . . .
Oblique Plane Deformity . . . . . . . .
Type 2: Angulation and Translation
159
163
163
165
165
169
169
174
175
179
183
183
186
193
193
· .. 195
· .. 200
· .. 200
. 202
· 203
· 205
· 205
. . 205
· 205
.208
in Different Planes . . . . . . . . . . . . . . . . · 209
Anatomic Plane Deformity with Angulation
and Translation 90° Apart . . . . . . . . . . . 209
Oblique Plane Deformity with Angulation
and Translation 90° Apart ........... 211
One Anatomic and One Oblique Plane
Deformity with Angulation and Translation
in Different Planes Less Than 90° Apart ... 214
Oblique Plane Deformity with Angulation
and Translation Less Than 90° Apart. . 216
Osteotomy Correction of a-t Deformities . . 218
Osteotomy Correction of Angulation
and Translation in the Same Plane .. 219
Correction of Angulation and Translation
in Different Planes . . . . . . . . 222
Multilevel Fracture Deformities. . . . .. 231
References . . . . . . . . . . . . . . ..... 234
9 Rotation and Angulation-Rotation Deformities
... 235
Clinical Assessment of Rotation Deformities . . 235
Level of Osteotomy for Rotation Deformities . . 243
Frontal Plane Preoperative Planning
for Rotation Deformities . . . . . . . . . . 249
Factoring in Rotation for Mechanical Axis
Planning of the Femur . . . . . . . . . . 250
Frontal Plane Anatomic Axis Planning
for Rotation Deformities . . . . . . . . . 252
Combined Angulation and Rotation Deformities . . . 252
Locating the Inclined Axis . . . . . . . . . . . . . 259
Locating the Inclined Osteotomy .... 261
Inclined Focal Dome Osteotomy . . . . . . . 266
Clinical Examples. . . . . . . 266
References . . . . . . . . . . . . . . . . . . 268
10 Length Considerations: Gradual Versus
Acute Correction of Deformities ... 269
Length Considerations for Angular Corrections. . 276
Neurovascular Structures . . . . . . . . 278
Nerves . . . . . . . . . . . . . . 282
Vessels .............. . · 287
Muscles, Tendons, and Fascia · 287
Ligaments .. . · 287
Skin .... . · 288
References . . . ........ 289
11 Ha rdware and Osteotomy Considerations
... 291
Choice of Hardware. . . .
Patient Age . . . . . .
Osteotomy Types. . .
Closing Wedge Osteotomy.
Opening Wedge Osteotomy . . . . .
Angulation-Translation Osteotomy.
Dome Osteotomy.
Hardware ......... .
Plate Fixation . . . . . .
Intramedullary Nails ..
External Fixation . .
Order of Correction. . .
Lever Arm Principle ..
Method of Osteotomy
References . . . . . . .
· 291
· 291
· 291
· 291
· 297
· 300
· 300
· 300
· 300
. . 307
.. 346
· 383
· 387
· 389
· 410
12 Six-Axis Deformity Analysis and Correction
. . . 411
The Taylor Spatial Frame Fixator. .
Introduction . . . . . . .
Modes of Correction. .
Planning Methods . . .
Fracture Method . .
· 412
· 412
· 416
· 418
· 418
CORAgin Method .. .420
CORAsponding Point Method ....
Virtual Hinge Method . . . . . . . .
Line of Closest Approach (LOCA) .
..... 422
.424
Taylor Computer-assisted Design
(CAD) Software. . . . . . . . . . .
· .426
· . 429
Reference Concepts . . . . . . . . . . . . 429
Rate of Correction and Structure at Risk (SAR). 430
Parallactic Homologues of Deformity:
Proximal versus Distal Reference Perspective . . . 433
References . . . . . . . . . . . . . . . . . . . . . . . 436
13 Consequences of Malalignment . . . 437
Static Considerations. . . .
Dynamic Considerations . .
Rotational Considerations .
Animal Laboratory Models
Cadaver Laboratory Models
Clinical Longitudinal Studies . .
Summary.
· 438
.440
· 443
.444
.444
.446
· 448
References . . . . . . . . . . . . .... 448
14 Malalignment Due to Ligamentous Laxity
ofthe Knee ... 4S 1
LCL Laxity.
MCL Laxity
References
1 S Knee Joint Li ne Deformity
Sources of Malalignment ... 465
· . 451
· . 462
· .464
References ....................... 478
, 6 Realign ment for Mono-com partment
Osteoarthritis of the Knee ... 479
Contents
Deformities in Association with MCOA . . 479
Bone Deformities . . . 479
Joint Deformities. . . . . . . . . . . . 479
Customized HTO . . . . . . . . . . . . . . . . . 485
Malalignment Test form Mono-Compartment
Osteoarthritis. . . . . . . . . . . . . . . . 485
Femoral versus Tibial Osteotomy. . . . . . . 485
Level of Center of Rotation of Angulation. . 492
Magnitude of Correction . . . . . . . . . . 492
Type of Osteotomy and Fixation . . . . . . 494
Considerations. . . . . . . . . . . . . .. ... 495
Medial Compartment Osteoarthritis
Varus plus Medial Collateral
Ligament Pseudo laxity . . . . . . . . . . . 495
Medial Compartment Osteoarthritis
Varus plus Lateral Collateral
Ligament Pseudo laxity . . . . . . .. .. 497
Medial Compartment Osteoarthritis
Varus plus Rotation Deformity. . .. .. 497
Medial Compartment Osteoarthritis
Varus plus Hyperextension. . . . . . . . . 499
Medial Compartment Osteoarthritis
Varus plus Fixed Flexion Deformity. .. 502
Medial Compartment Osteoarthritis
Varus plus Lateral Subluxation. . . . . . . 503
Medial Compartment Osteoarthritis
Varus plus Medial Plateau Depression. . . 503
Lateral Compartment Osteoarthritis (LCOA) . 504
References . . . . . . . . . . . . . . . . . . . . . . . 507
17 Sagittal Plane Knee Considerations ... 509
Frontal Plane Knee Considerations . .
FFD ofthe Knee ........... .
HE and Recurvatum Knee Deformity. .
Knee Extension Contracture . . . .
Patella Baja and Alta .
References . . . . . . . . . . . . .
18 Ankle and Foot Considerations ... 571
Frontal Plane Ankle Deformities ...
Supramalleolar Osteotomy for Varus
· . 509
· . 509
· . 538
· . 563
· . 568
· . 569
. ... 574
and Valgus Deformities. . . . . . . . . . 579
Sagittal Plane Ankle Deformities . . . . .. 581
Supramalleolar Osteotomy for Recurvatum
and Procurvatum Deformities . . . . . . . . . . . 585
Compensatory Mechanisms and Deformities:
Mobile, Fixed, and Absent. . . . . . . . . . . . . . 596
DIll Contents
Specific Ankle Malalignment Deformities. ..... 611
Ankle Fusion Malunion . . . . . . . . 611
Flattop Talus Deformity. . . . . . . . . . 611
Ball and Socket Ankle Joint . . . . . . . . .. . 619
Overcorrected Clubfoot and Other Lateral
Translation Deformities of the Heel. . .
Posterior Tibial Tendon Dysfunction ....
Completely Stiff Foot Treatment
by Supramalleolar Osteotomy. . .
Partial Growth Arrest . . .
Malunion of Fibula ....
Ankle Contractu res .
References . . . . . . . . . . .
19 Hip Joint Considerations ... 647
Limb in Neutral Alignment to Pelvis, No Intra-
· 623
. . . 627
· 627
· 630
· 630
. . 630
. .. 645
or Periarticular Limitation of Range of Motion . 647
Varus Deformity. . . . . . . . . . 647
Valgus Deformity . . . . . . . . . . . . . . . . . 653
Limb in Neutral Alignment to Pelvis,
Intra-articular Limitation of Range of Motion . . . 653
Varus Deformity. . . . . . . . . . . . . .. . 653
Valgus Deformity . . . . . . . . . . . . . . . 653
Lesser Trochanter Considerations . . . . . .. ... 656
Greater Trochanter Considerations . . . . . .. . 660
Sagittal Plane Considerations . . . . . . . . .. . 672
Deformities of the Head and Neck of the Femur. . . . 673
Pseudo-subluxation of the Hip ............ 684
Deformities Due to Hip Ankylosis and Arthrodesis
between the Femur and the Pelvis. . . . 686
Pelvic Support Osteotomy .
References . . . . . . . . . . . . . . . . .
20 Growth Plate Considerations ... 695
LLD .......... .
. 689
· 694
. .. 695
Predicting LLD . . . . . . . . 695
Multiplier Method . . . 697
Additional Growth Databases. . . . . . 701
Relationship of Multipliers for Boys
to Multipliers for Girls. . . . . . . . 701
Development of the Multiplier . . . . . . 702
Limb Length Discrepancy Prediction
Formulae . . . . . . . . . . . . . . . . .. 702
Prediction of Limb Length Discrepancy
at Skeletal Maturity Using the Multiplier
Growth-Remaining Method for Cases
of Postnatal Developmental Discrepancy. . 702
Percentage of Total Bone Growth from the
Distal Femur and Proximal Tibia . . . .. . 703
Using the Multiplier Method to Calculate
Timing for Epiphysiodesis. . . . 703
Growth Prediction Controversies. . . . . . 704
Growth Plate Considerations Relative
to Deformity. . . . . . . . . . . . . . . . . . . . . 705
Cause of Deformities . . . . . . . . . . . . . . . 705
Developmental Angular Deformities. . . . . . . 705
Angular Deformities: Gradual Correction
by Hemi-epiphysiodesis . .............. 708
Planning for Hemi-epiphyseal Stapling for
Angular Correction at the Knee in Children . 708
Multiplier Method for Timing
Hemi-epiphyseal Stapling for Correction
of Angular Deformity . . . . . . . . . .. . 710
Multiplier Method for Calculating
When to Remove Hemi-epiphyseal Staples
in Young Children. . 710
References ....................... 715
21 Gait Considerations ... 717
Gait Considerations in Association
with Lower Limb Deformities .
Sacrifice ofJoint Motion ....
Fixed Joint Position . . . . . . .
Abnormal Loading ofJoints ...
Compensatory Mechanisms . . . .
Frontal Plane Malalignment. . . .
Distal Tibia Varus or Valgus. . . . . . . .
Varus Deformity at the Knee .
Valgus Deformity of the Knee. . . . . .
Varus or Valgus Deformity of the
Proximal Femur. . . . .
Sagittal Plane Deformity. . . . . .
Ankle Equinus Deformity. . .
Excessive Ankle Dorsiflexion
or Calcaneus Deformity . . .
Ankle Arthrodesis Deformities.
Anterior Translation of the Foot .
Fixed Flexion Deformity of the Knee. .
Recurvatum of the Knee. . . . . . . .
Hip Flexion Deformity .......... .
Hip Fusion. . . . . . . .. . .... .
Rotational Malalignment . . . . . . . . .
Leg Length Considerations. . . . . . . . .
References . . . . . . . . . . . . . . . . .
22 Dynamic Deformities and Lever Arm
Considerations ... 761
Levers ........ .
Mechanical Advantage.
Moments and Motions .
Redundancy . . . .
Normal Function . . . .· 765
· 766
Introduction . . . . . . .. . . . . . 766
Mechanics of the Ankle: First Rocker ....... 766
Mechanics of the Ankle: Second Rocker ..... 766
Mechanics of the Ankle: Third Rocker ...... 767
Force Production and Compensation . . .
Pathological Function .
Short Lever Arm . . . . . . . .
Flexible Lever Arm. . .
Malrotated Lever Arm. . .
Unstable Fulcrum . . . . .
Positional Abnormalities
References . . . . . . . . . . .
23 TKR and Total Hip Replacement
Associated with Malalignment ... 777
Normal Alignment Versus Malalignment
in Association with Total Knee Arthroplasty.
Management of Fixed Soft Tissue Deformities .
Clinical Assessment ............ .
Radiographic Assessment . . . . . . . . . . .
Intraoperative Placement of Components
and Consequences of Malalignment . . . .
Varus Deformities . . . . . . . . .
Valgus Deformities. . . . . . . . .
Flexion Deformity and Contracture
Recurvatum Deformity. . . . . . .
Peroneal Nerve Palsy and Operative Release .
Trial Reduction after Ligamentous Balancing.
Summary of Soft Tissue Balancing Principles . .
Extra-articular Bone Deformities . . . . .
Total Knee Arthroplasty after Failed HTO . . . .
Preoperative Assessment . . . . . . . . . . .
Proximal Tibial Osteotomy-Related Problems
forTKR ............. .
Proximal Femoral Deformities
and Total Hip Arthroplasty . . .
Preoperative Planning . . . . . . .
Soft Tissue Balancing. . . . .
Bone Deformity Correction.
References . . . . . . . . . .
Subject Index .. . 799
· · 797
Contents _
Glossary
a anatomic LOCA line of closest approach
A anterior LON lengthening over nail
ACA angulation correction axis LPFA lateral proximal femoral angle
ACL anterior cruciate ligament m mechanical
AOTA anterior distal tibial angle M medial
aJCO anatomic axis to joint center distance MAD mechanical axis deviation
aJCR anatomic axis: joint center ratio MAT malalignment test
aJEO anatomic axis to joint edge distance MCL medial collateral ligament
aJER anatomic axis:joint edge ratio MCOA medial compartment osteoarthritis
aLOFA anatomic lateral distal femoral angle MOA mid-diaphyseal angle
AMA anatomic-mechanical angle mLOFA mechanical lateral distal femoral angle
AP anteroposterior (for radiograph) MM medial malleolus
aPPTA anatomic posterior proximal tibial angle mMOFA mechanical medial distal femoral angle
ASIS anterior superior iliac spine MNSA medial neck shaft angle
a-t angulation-translation MOT malorientation test
CORA center of rotation of angulation MPFA medial proximal femoral angle
0 distal MPTA medial proximal tibial angle
OAA distal anatomic axis NSA neck shaft angle
OMA distal mechanical axis P posterior (when used in conjunction with
F femur A for anterior, M for medial, and L for lateral)
FAN fixator-assisted nailing P proximal
FFO fixed flexion deformity PAA proximal anatomic axis
GRV ground reaction vector POFA posterior distal femoral angle
HE hyperextension PPFA posterior proximal femoral angle
HTO high tibial osteotomy PMA proximal mechanical axis
IMN intramedullary nail PPTA posterior proximal tibial angle
JLCA joint line convergence angle SA surface area
L lateral SAR structure at risk
LAT lateral (for radiographic view only) SCFE slipped capital femoral epiphysis
IBL longitudinal bisector line SO standard deviation
LCL lateral collateral ligament T tibia
LCOA lateral compartment osteoarthritis tBL transverse bisector line
LOTA lateral distal tibial angle TKR total knee replacement
LLO limb length discrepancy WBF weight-bearing force
CHAPTER 1 _____________________________________________ 111

Normal Lower Limb Alignment and Joint Orientation
To understand deformities of the lower extremity, it is
important to first understand and establish the parameters
and limits of normal alignment. The exact anatomy
of the femur, tibia, hip, knee, and ankle is of great importance
to the clinician when examining the lower limb
and to the surgeon when operating on the bones and
joints. To better understand alignment and joint orientation,
the complex three-dimensional shapes of bones
and joints can be simplified to basic line drawings, similar
to the stick figures a child uses to represent a person
(~ Fig. I-I).
Fig.1-1
Axis lines. A stick figure can be used as a schematic of a complex
three-dimensional image of a person. In the same fashion,
axis and joint lines can be used to describe alignment and joint
orientation of the bones and joints of the lower limb.
Furthermore, for purposes of reference, these line
drawings should refer to either the frontal, sagittal, or
transverse anatomic planes. The two ways to generate a
line in space are to connect two points and to draw a line
through one point at a specific angle to another line. All
the lines that we use for planning and for drawing schematics
of the bones and joints are generated using one
of these two methods (~Fig.I-2).
a.