Nutritional rickets in children is a global health concern. It manifests in generalized skeletal deformities including angular or coronal plane knee deformities. Guided growth surgery is a recognized treatment option for angular knee deformities in general. However, there is insufficient citations on its use in the treatment of angular knee deformities in children with nutritional rickets. Rachitic lower limb deformities can be complex. They are usually multiostotic, multiapex and multiplane and require extensive corrective osteotomies. However osteotomies are fraught with complications and can be technically demanding. In this presentation we present our experience with the use of surgical guided growth as a minimally invasive treatment option to correct angular knee deformities in children with nutritional rickets.

1. Guided Growth for Angular Knee Deformities in
Nutritional Rickets Children: Expanding the
Indications of a Minimally Invasive Surgery
Dr. Tamer A. El-Sobky
Department of Orthopedic Surgery, Faculty of Medicine,
Ain Shams University, Cairo, Egypt
tamer.ahmed@med.asu.edu.eg

2. 2

3. Background
• Nutritional rickets in young children is a global health problem especially
in countries with low-resource settings.
• Nutritional rickets results from either inadequate dietary calcium intake,
insufficient exposure to sunlight or both.
• It usually manifests in generalized bone softening and deformities as
angular -coronal plane- knee deformities namely “Genu Varum” and “Genu
Valgum”.
3

4. Bilateral Genu Varum Unilateral Genu Valgum
4

5. Windswept Deformity (Combined Genu Varum + Valgum)
Right genu varum and left genu valgum Note the right distal femoral varus and left
femoral and mid-diaphyseal tibial valgus.

6. Deformities in Nutritional Rickets
• Coronal plane knee deformities are commonly associated with torsional -
transverse plane- deformities of long bones e.g. tibial varus deformity and
internal tibial torsion.
• Torsional deformities contribute to gait difficulties.
• Rachitic activity tends to heal spontaneously over time with/without
medical treatment. However, some deformities persist and continue to
cause significant functional disability in spite of healing.
6

7. 7
Note the metaphyseal cupping, broadening
and fraying of the distal femoral, tibial and
fibular epiphyses.
Note the appearance of a dense metaphyseal
line in epiphyses around the knee. This
indicates healing rickets.
Active Rickets Healing Rickets

8. 8
Note the metaphyseal cupping,
broadening and fraying of distal
radial and ulnar epiphyses.
Note the growth plate widening, and metaphyseal
broadening and irregularities. The bilateral white
metaphyseal lines indicates emerging healing.
Active Rickets of Wrist Active Rickets of Hips

9. Osteotomies
Traditionally, persistent long bone
deformities in rachitic
children/adolescents have been
managed by corrective osteotomies
with/without internal fixation.
9
Preoperative Postoperative

10. Osteotomy Versus Guided Growth
• Corrective osteotomies achieve acute
correction through extensive
subperiosteal dissection.
• Contrastingly, guided growth surgery
achieves gradual correction through
minimally invasive extra-periosteal
placement of plates/staples.
10
Healing medial opening wedge
osteotomies

11. Osteotomy Versus Guided Growth (continued)
• Osteotomies are fraught with risks of complications as over/under
correction, neurovascular insults and healing problems.
• Osteotomies require postoperative casting and immobilization
whereas guided growth patients are allowed to weight bear
immediate postoperative according to tolerance.
11

12. Complications of Osteotomies: Overcorrection
12
Overcorrection Following a Tibial
Diaphyseal Osteotomy
Bilateral Marked Genu Varum

13. Why Are Rachitic Deformities A Management Challenge ?
Multi-ostotic
13
Multi-apical
Multi-plane
Sagittal plane
deformity
Multi-apicaltibial
deformities
Femoral+tibial

14. How Does Surgical Guided Growth Work?
• It achieves coronal plane deformity correction
through temporary growth arrest/hemi-
epiphysiodesis of one hemiside of the epiphysis.
• Consequently, the un-arrested hemiside
(arrow) of the epiphysis grows at an advantage
over the arrested hemiside and gradually
achieves deformity correction. The plate is implanted on the lateral
hemiside of the proximal tibial physis.
Herein, it is being used to correct a
tibial varus deformity.

15. General Indications Of Guided Growth Surgery?
• Guided growth surgery is now considered the gold standard of treatment of
angular knee deformities in children as idiopathic,
osteochondrodysplasias, post-traumatic and resistant rickets.
• Guided growth has also been used to correct sagittal plane deformities in
children.
• This is the first study to investigate the use of guided growth for angular
knee deformities in a “homogeneous” series of nutritional rickets children.
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 15

16. Study Objectives
1. To investigate: prospectively the radioclinical intermediate term results
of guided growth surgery for correction of coronal plane deformities in a
“homogenous” sample of children (≤ 7 years) with nutritional rickets.
2. To evaluate: the clinical behavior of tibial torsion deformities during
coronal plane correction.
3. To suggest: a management roadmap for coronal plane deformities based
upon our treatment outcomes.
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 16

17. Study Material
1. Fifty children (male:female, 27:23) with knee coronal plane deformities
(knees:physes, 86:99), (varum:valgum, 51:35) secondary to nutritional
rickets were subjected to femoral and/or tibial temporary
hemiepiphysiodesis using a two-hole 8-plate.
2. Mean age at implantation was 3.8 years. The mean follow-up was 2.8
years.
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 17

18. Preoperative Clinical Assessment?
1. History-taking for gait impairments, lifestyle habits, deformity
progression and similar conditions among family members.
2. Gait assessment from front, back and side views.
3. Torsional deformities of the femurs, tibias, or feet are of
particular importance to both gait assessment and couch examination.
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19. Preoperative Clinical Assessment? (continued)
3. Assess the degree of coronal/angular knee deformity by measuring the
Tibio-femoral angle?
4. Assess the origin of the coronal plane deformity i.e. femoral, tibial or
combined?
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20. Assessment of Tibial
Torsion?
• The Foot-Thigh angle is
on way to assess for
internal tibial torsion.
• If the foot itself is
deformed then this test
becomes invalid
20
Massive internal tibial torsion

21. Femoral Versus Tibial Deformity
Bilateral Genu Valgum
Deformity Disappearance After Knee
Flexion Indicates a Femoral Origin
21

22. Femoral Versus Tibial Deformity (continued)
• In the previous test, if the valgus deformity had Not disappeared with knee
flexion then this would indicate a Tibial Origin of deformity.
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23. Preoperative Radiographic Assessment
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 23
Value of standing full-length scanogram?
1. Determine degree of coronal plane deformity by means of Tibio-
femoral angle OR amount of mechanical axis deviation?
2. If the deformity is femoral or tibial or combined?
3. Determine the apex of deformity inside the femur or tibia?
4. If the deformity inside a bone is uni- or multi-apical?

24. Mechanical Axis Deviation
(Genu Varum)
• Mechanical axis deviation
medial to the central
1/3 of tibial metaphysis
diameter indicates varus
malalignment.
24

25. • Mechanical axis
deviation lateral to the
central 1/3 of tibial
metaphysis diameter
indicates valgus
malalignment.
25
Mechanical Axis Deviation
(Genu Valgum)

26. How To Assess The
Degree Of Mechanical
Axis Deviation?
• Deformity severity was graded
into four zones by measuring the
distance between mechanical
axis and midpoint of tibial
epiphysis expressed as
percentage to 1/2 of width of
tibial epiphysis (white arrow).
26

27. Degree Of VALGUS Mechanical Axis Deviation
•
27
R
Note the mechanical axis deviation of the right knee bisects
zone (1) whereas that of the left knee bisects zone (3).

28. Degree Of VARUS Mechanical Axis Deviation
28
R
Note the mechanical axis deviation of the right knee bisects zone 3
whereas that of the left knee bisects zone 2.
R

29. Rickets Versus Blount Disease?
• In Blount disease the deformity is strictly
tibial epiphyseal and sub-
physeal/metaphyseal i.e. uni-apical.
• In Rickets the deformity could be any
where along the tibia or femur. And
could be multi-apical.
29
A mid-diaphyseal tibial deformity in
a rachitic patient.

30. Rickets Versus Blount Disease? 2/3
• A metaphyseal-diaphyseal angle
>20◦ is strongly indicative of infantile
Blount disease (arrows).
• Laboratory markers (serum alkaline
phosphatase) are helpful.
30

31. Rickets Versus Blount Disease? 3l3
• Rickets can cause Sagittal plane
deformity as anterior tibial and
fibular kyphosis.
• Blount disease does Not cause
Sagittal plane deformity
• Beware! Nutritional rickets and Blount
disease could co-occur.
31

32. When to Intervene Surgically In Rachitic Children?
• The indications of surgical intervention on children with healed rickets and
residual angular knee deformities are vaguely defined in the literature.
• The literature does Not fully identify which patient sub-groups are more
likely to enjoy spontaneous deformity correction (remodeling) over time?
and which sub-groups are more likely to benefit from surgical correction of
deformities?
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33. When to Intervene Surgically? (continued)
• This vagueness applies to patient characteristics such as age and sex, and
disease characteristics such as type (varus versus valgus), sidedness (uni-
versus bilateral) and deformity severity etc.
• This issue can be better clarified by performing either a randomized
control trial (ethically demanding) or by a lengthy natural history study.
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34. Proposed Criteria for Surgery
We deemed surgery indicated when 1 or more of following criteria were present:
1. An overall coronal deformity “varum or valgum” ≥ 20° as
per tibiofemoral angle (TFA) that is persistent or
worsening over the past 6 months.
2. A mechanical axis deviation bisecting the knee outside the
central one-third of the transverse diameter of the
proximal tibial epiphysis i.e green or red zone.
34
Varus malalignment Normal alignment Valgus malalignment

35. Proposed Criteria for Surgery (continued)
3. A clinically symptomatic gait abnormality in the form of disabling
circumduction gait in association with genu valgum or massive intoeing
gait in association with genu varum or frequent falls.
4. A radiologic and biochemically healed rickets is an absolute prerequisite
for surgery.
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36. Technical Principles
1. keep the periosteum intact (extra-periosteal
plate insertion)
2. Insert the epiphyseal screw first.
3. Avoid violating the articular cartilage and the
physeal (growth) plate.
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37. Technical Principles (continued)
4. Screw parallelism and placement in the mid-
lateral/sagittal position are advisable but Not
mandatory (try to avoid multiple drilling
attempts).
5. Use of longer screws is permissible and advisable
so long the far cortex is not penetrated.
6. Use of tourniquet is recommended to reduce
operative time.
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38. Technical Tips
1. Pre-bending of plates should take into consideration
the anatomic configuration of the targeted epiphysis.
2. Choose the appropriate plate size for the epiphysis.
A small for size plate may make it difficult to avoid
physeal injury during screw insertion.
3. Drill the first few millimeters of the screw track only.
This helps achieve better screw purchase (Fig.).
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39. Assessing Outcomes of Surgery?
• Restoration of the mechanical axis deviation so as to
intersect the central one third (yellow) of the widest
diameter of the proximal tibial metaphysis.
• Restoration of the mechanical axis is confirmed by
measuring the clinical tibio-femoral angle
• Resolution of gait difficulties experienced before surgery.
• Tibial derotation according to the clinical measurement of
bimaleolar axis.
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 39

40. Accepted Versus Optimal Alignment?
• Both the yellow and green areas represent central one
third of the widest diameter of the proximal tibial
metaphysis.
• A mechanical axis bisecting the yellow area of the central
one third this is considered accepted alignment.
• A mechanical axis bisecting the green area of the central
one third is considered optimal alignment.
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 40

41. When to Remove the Implants?
• In a clinical setting the plates can be removed once the clinical
alignment (Tibio-femoral) angle is judged satisfactory.
• In a research setting plates can be removed once both the clinical and
radiologic parameters are restored.
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42. Beware!
• Beware! Physeal plate is also liable to damage during plate removal.
• Beware! Recurrence of rickets can occur at any point in time during the
whole management period. Recurrence of rachitic activity may lead to
deformity recurrence.
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43. Results Of Guided Growth In Nutritional Rickets
• The overall radioclinical results were satisfactory.
• The incidence of screw loosening/implant disassembly in our study was
basically related to severe deformities (TFA of ≥30°) which resulted in
overall longer duration of implant retainment from insertion to removal
(see Treatment Algorithm).
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44. Clinical Assessment of Knee Alignment (Left Genu Valgum)
Preoperative 6 Months
44
9 Months

45. Preoperative 12 Months
45
20 Months
Clinical Assessment of Knee Alignment (Bilateral Genu Varum)

46. 46
Final PostoperativePreoperative
Radiologic Assessment of Knee Alignment (same patient)

47. 47
Final PostoperativePreoperative
Clinical Assessment of Knee Alignment (Left Genu Valgum)

48. 48
Final PostoperativePreoperative
Left severe
genu valgum.
Note mild
right genu
valgum.
Note optimal
clinical
alignment of both
knees. Only the
left knee was
operated. The
mild residual
valgus of right
knee remodeled
spontaneously.
Clinical Assessment of Knee Alignment (Genu Valgum)

49. Radiologic Assessment of Knee Alignment (Genu Valgum)
49
Final PostoperativePreoperative
Left severe genu
valgum. Note mild
right genu valgum
(mechanical axis
outside the central
1/3 but still
bisecting the lateral
femoral condyle
(zone 1)
Note optimal
alignment of both
mechanical axes
(bisecting the
lateral half of the
central 1/3. Only
the left knee was
operated
(femoral). The
right remodeled
spontaneously.

50. Complications
• The complications were tolerable i.e. did not impact the final outcome
negatively.
• Most complications (failure of guided growth) necessitated a redo of
guided growth surgery or simply observation till full correction.
50https://doi.org/10.5435/JAAOSGlobal-D-19-00009

51. Complications: Broken Screw/Failure of
Correction
• Only one patient/one physis in the current
study.
• Note that the screw failure is metaphyseal and
at the interface of screw shaft and cortex.
• This is consistent with the literature.
• Rescheduled for repeat guided growth.
51

52. Complications: Implant Disassembly
Despite Full Correction
• Patient was simply observed until full
correction was achieved.
52

53. Discussion
• These results expand the range of pathologies in which guided growth can
be used effectively.
• Experimental studies reported success with the use of guide growth to
correct pure rotational long bone deformities in animal models.
• The current study demonstrated that tibial rotational guided growth occurs
simultaneously with coronal plane correction in a clinical setting.
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54. Conclusion
• The homogenous patient and disease demographics of the current study
allow for reasonable generalizability of the conclusions.
• The current study showed that guided growth surgery in young children
with nutritional rickets is effective in correcting coronal plane knee
deformities with an acceptable complication profile.
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 54

55. Conclusion (continued)
• Tibial intoeing derotated simultaneously with coronal plane correction
irrespective of plate/screw positioning and derotation osteotomies are
NOT regarded mandatory unless there is a significant functional
impairment.
• The outcome measures and treatment algorithm used in the current
study may be considered as a roadmap to help physicians plan treatment of
angular knee deformities in None-rachitic children.
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56. Recommendations
• Natural history studies are recommended because they may better
demonstrate the prognosis of such deformities in regard to patient’s age,
deformity type and severity.
• They may narrow the indications of surgery and help treating physicians
and surgeons take more informed decisions.
https://doi.org/10.5435/JAAOSGlobal-D-19-00009 56

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59. Presenter
Tamer A. El-Sobky
Department of Orthopedic Surgery, Faculty of Medicine,
Ain Shams University, Cairo, Egypt
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