Orthopediatrics EPOS 2016 Symposium Proceedings

EPOS INDUSTRIAL SATELLITE SYMPOSIUM PROCEEDINGS

Friday, April 8, 201635th EPOS Congress, Waldorf Astoria, Rome, Italy

Torsional disorder of the femur in cerebral palsy patients

TORSIONAL DISORDER OF THE FEMUR IN CEREBRAL PALSY PATIENTS

2

About the Satellite Symposium:Femoral anteversion in children with cerebral

palsy is a leading cause of internal rotation

gait amongst this important population. This

comprehensive satellite symposium, held during

the 35th European Paediatric Orthopaedic

Society (EPOS) Congress in Rome, Italy,

outlined not only the natural histories of femoral

anteversion and other potential causes of

internal rotation gait, but also the importance of

careful and precise diagnosis when planning any

intervention. Importantly, the logic and reasoning

behind the choice of any particular intervention,

be it a proximal, diapheseal or distal derotation

osteotomy were carefully and thoroughly

examined and discussed.

OrthoPediatrics, Leading Innovation in Pediatric Orthopedics


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OPENING STATEMENTS 2Dr Peter F. Armstrong

CHAIRMAN’S WELCOME 3Prof. Pierre Lascombes

HIP INTERNAL ROTATION IN PATIENTS 4 WITH CEREBRAL PALSY Prof. Reinald Brunner

PROXIMAL OSTEOTOMY OF THE FEMUR AND 6 BLADE-PLATE FIXATION Prof. Guy Molenaers

DIAPHYSEAL FEMORAL DEROTATION OSTEOTOMY USING IM NAIL FIXATION 8Prof. Tim Theologis

DISTAL OSTEOTOMY OF THE FEMUR 10 AND IMLN FIXATION Prof. Franck Accadbled

BIOGRAPHIES 12

TABLE OF CONTENTS


2

Dr Peter Armstrong, the Chief Medical Officer

for OrthoPediatrics, welcomed all participants

and faculty to the OrthoPediatrics Satellite

Symposium at the 35th EPOS Annual Meeting in

Rome.

Dr Armstrong highlighted OrthoPediatrics

passion for helping children with orthopaedic

conditions through the provision of the

broadest spectrum of paediatric implants and

instruments: “In addition,OrthoPediatrics has a

very strong commitment, and we’re proud of that

commitment, to be supporters and providers of

excellent paediatric orthopaedic education”

The OrthoPediatrics satellite symposium is a

good example of that commitment. A panel of

world class key opinion leaders in management

of femoral anteversion were assembled to

freely share their experience and opinions with

the sizeable audience. Following this opening

statement, Dr Armstrong then introduced

the Chairman of the symposium, Prof. Pierre

Lascombes, and the expert faculty.

OPENING STATEMENTS

Dr Peter F. Armstrong Chief Medical Officer,

OrthoPediatrics

“OrthoPediatrics has a very strong commitment, and we’re

proud of that commitment, to be supporters and providers of

excellent paediatric orthopaedic education.”

Rome, Italy


3

Professor Pierre Lascombes welcomed attendees

to the 2016 OrthoPediatrics Satellite Symposium

on Femoral Derotation in Children with Cerebral

Palsy on Friday, April 8, at the 35th EPOS Annual

Conference, in Rome, Italy.

In his opening address, Prof. Lascombes

highlighted that there was a range of techniques

and opinions with respect to derotation

osteotomy: from the choice of device used in

effecting the surgery, such as nails, flexible

nails, plates and screws, to the position of the

osteotomy: proximal, middle or distal, and even

the absolute necessity to perform a derotation

osteotomy in some cases. Following his

introduction of the four experienced speakers,

Prof. Lascombes presented the assembled

attendees with two multiple choice questions, to

gauge the general temper of the audience with

respect to femoral derotation.

Posing the situation that, should one be

presented with a patient who unequivocally

displayed a large anteversion and internal

rotation gait, would one perform a proximal,

middle, or distal derotation osteotomy? An

overwhelming majority of the audience indicated

that a proximal osteotomy would be their

preference, with very few choosing distal, and no

one opting for the mid-diaphyseal solution.

Additionally, when asked their preference on

device style to perform a proximal osteotomy, a

large majority indicated a preference for plates

and screws compared with the few attendees

who would use an intramedullary nail - either

locking or flexible.

In rounding up his opening comments, Prof.

Lascombes highlighted the fact that before

beginning or planning any surgery, it is

crucially important to understand the causes

of any rotational deformity that exists. A full

understanding of the causes of any rotational

disorder and effective prediction of the effects

of any intervention are the cornerstone to

successful and long-lasting deformity correction.

With the scene set, Prof. Lascombes offered

up the lectern to Prof. Reinald Brunner from

Kinderspital Basel, Switzerland.

CHAIRMAN’S WELCOME

Prof. Pierre Lascombes Chef de Service, Orthopédie

Pédiatrique

Hôpitaux Universitaires de

Genève


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Professor Reinald Brunner, a leading neuro-

orthopaedics consultant in the Orthopaedics

Department, Kinderspital Basel, Switzerland,

began the scientific satellite symposium.

As a world leading expert in paediatric

neuromuscular conditions, especially cerebral

palsy and gait correction, Prof. Brunner was

well positioned to give expert insight into not

only deformity correction in children, but also

into understanding the underlying causes of hip

internal rotation in children with cerebral palsy.

Prof. Brunner began by questioning

preconceptions and assumptions regarding hip

internal rotation and underlying anteversion as

the cause, and asked us to consider that there

maybe other causes, which are not accounted for

in a perhaps and often overly simplified view of

the problem - “Is the femoral anteversion really

the most important factor for internal rotation

during gait? Are there other factors which

produce hip internal rotation and anteversion,

and maybe there’s another cause?”

Noting that it was important to ask these

questions given that correction of anteversion

can be unreliable in correcting internal rotation

gait, and that it is known that femoral inversion

can recur if it is corrected too early in childhood.

Prof. Brunner illustrated his point with video of

a patient from the gait laboratory, who showed

relatively good gait correction post-intervention.

Pointing out that with anteversion there is

an offset of the normal range of hip motion

towards internal rotation but there was often

poor correlation between the position of the hip

during gait and angle of anteversion. Citing data

from his own studies1, Prof. Brunner illustrated

the good correlation of all clinical and radiological

assessments, but the still very poor correlation

to the internal rotation gait. Expanding the

discussion to consider other factors that may

cause internal rotation, he introduced the roles of

the capsule and ligaments.

“If the anterior capsule is short ... then you get

a similar shift of the range of motion towards

internal rotation without changing anteversion.”

Muscles that are active might also play a role in

the production of internal rotation, and although

there was the hypothesis that adductors and

hamstrings may be involved, this was proven

not to be so, but there is the possibility that

long muscles, e.g. long hip external rotators, are

involved. This phenomenon has not yet been

studied but again would shift the range of motion

toward hip internal rotation without changing

anteversion.

After covering a range of internal factors, which

may play a role, Prof. Brunner then highlighted

three important external factors which may

also play a role: Midfoot break, toe walking and

rocking on the rotated foot.

Illustrating midfoot break with a video and

animation, Prof. Brunner explained that if one

tests dorsiflexion in a foot that shows midfoot

HIP INTERNAL ROTATION IN PATIENTS WITH CEREBRAL PALSY

Prof. Reinald BrunnerConsultant of

Neuro-Orthopaedics

Kindersspital Basel,

Switzerland

“Is the femoral anteversion really the most important factor for internal rotation

during gait? Are there other factors which produce hip internal rotation and

anteversion, and maybe there’s another cause?”


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break, the foot goes into external rotation with

the shank being stable. However, as a patient

walks the foot is stable to the floor, and cannot

rotate, so the motion in the mid and rear of the

foot is translated into an internal rotation of the

leg without altering anteversion. Furthermore,

gait analysis data shows that foot rotation

correlates well with hip internal rotation so the

foot goes out and the hip goes in at the same

moment in time.

The second external factor to consider is

toe walking. Prof. Brunner highlighted the

importance of this factor by showing again the

patient shown in his initial video and pointing

our that if one walks on their toes, they push

their foot down and the hip is being flexed,

adducted, and internally rotated because the

pelvis is pushed back. He continued by pointing

out that the internal rotation and gait correction

of the patient we see in the video was mostly

due to correction of equinus and limited bilateral

adductor and hamstring lengthening, and that

she received no femoral derotation.

Thirdly, if a patient with already severe internal

rotation rocks on their foot when walking, it

increases the range of motion towards internal

rotation and decreases the range of motion

towards external rotation. This point was

illustrated with a video showing a patient who

with every step increases the amount of internal

rotation.

Based on Wolff’s Law2, Prof. Brunner then

explained that we know that form follows

function and that the growth plate tried to

be perpendicular with the forces acting up in.

Further, a multi-element modelling study by

Shefelbine3 explored the effect of various forces

on a growth plate in the proximal femur in a

paediatric setting. Applying the forces derived

from gait analyses of cerebral palsy patients

to the model resulted in anteversion. These

factors, Prof. Brunner suggested, indicate that

anteversion is probably a secondary rather than

primary phenomenon causing internal rotation

gait.

Placing this in the context of paediatric

development, in a normal heel-toe gait in the first

half of stance phase we have the hip externally

rotated and flexed and the pelvis pushes from

the back side against the femoral head, which

causes the inverse force on the femur and then

the growth plate would rotate and derotate

which is the spontaneous derotation that we all

know. However, with toe walking, the hip remains

in inflexion, the pelvis now does not press from

the back side but rather from the front side

against the femoral head and femoral anteversion

increases.

In conclusion, there are several factors that

produce an internal rotation gait: Femoral

anteversion, ligaments and capsule, muscles – all

internal factors, and external factors acting on

the leg. If we undertake an intervention on only

one of this whole list of active factors, one should

not assume a good and lasting correction will

result.

All the factors that can cause anteversion and

internal rotation must be considered to have

a long lasting and good correction, regardless

of whether a femoral derotation is undertaken

proximally, diaphyseally or distally.

Ultimately, anteversion may not be the only

factor causing internal rotation gait, and

correcting anteversion in isolation may not be

sufficient.

1. Brunner et al., 2016, in

preparation.

2. Wolff, J. (1892) Das Gesetz

der Transformation der

Knochen. Hirschwald, Berlin

3. Shefelbine, S.J. and Carter,

D.R. Ann Biomed Eng. 2004

Feb;32(2):297-305.


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Following Prof. Brunner’s introduction into

causes of internal hip rotation, Prof. Guy

Molenaers, the Medical Head of the Department

of Orthopaedic Surgery at University Hospital

Leuven, Belgium, took up the baton and explained

at a biomechanical level what happens when

one has a real femoral inversion, and how one

can best correct the imbalance of forces with a

proximal derotation osteotomy.

Explaining initially that the prerequisite for

improvement in femoral anteversion is hip

extension, regardless of the multiple internal

and external factors that caused the malrotation,

Prof. Molenaers highlighted that a high femoral

anteversion, results in a malrotated lever arm,

and out-of-plane moment (torque). Out of plane

moments lead to a functional weakening of

important muscles.

Referencing the work of Delp1, from the late

1990s, Prof. Molenaers explained that the

gluteus medius acts as a strong internal rotator

and flexor of the femur when the child walks with

excessive hip flexion. Furthermore, he called

for surgeons not to lengthen hamstrings again

calling on the work of Delp et al. to illustrate this

point that if one has all medial hamstrings and the

adductors included the moment arm is not even

half of the moment arm created by the flexed hip

and activity of the gluteus medius.

The ultimate goal of the intervention should be to

improve the moment arm of the gluteus medius

and maximus thereby creating greater pelvic

stability and helping to prevent recurrence.

Prof. Molenaers then showed how one can

examine the effect of a proximal derotation

osteotomy on a patient’s moment generating

capacity, using the work of Arnold and Skodel,

and Prof. Molenaers, own research group to

illustrate. A patient was evaluated in the clinic

and a 3D MRI scan of the whole lower body

was made so that not only the skeleton - clearly

showing the anteversion and the combined

valgus of the neck shaft angle, but also the origin,

the insertion, the size and volume of all the

muscles were documented. In this way the real

strengths, forces, and moments acting at any time

could be calculated.

This patient specific modelling allows potential

interventions to be evaluated. In his example,

Prof. Molenaers showed that a proximal

intertrochanteric derotation osteotomy would

increase the extension moment of the gluteus

maximus, and that if the osteotomy were to

be performed lower than the insertion of the

gluteus maximus then there would be very little

improvement. (Figure 1)

Furthermore, when modelling the effect of

the hamstrings and psoas major on extension

moment generation, it could be seen that in this

case, there was no difference in effect between

a proximal or diaphyseal derotation. Increase in

extension moment due to the hamstrings was

the same for proximal or diaphyseal derotation,

and importantly neither intervention would

PROXIMAL OSTEOTOMY OF THE FEMUR AND BLADE-PLATE FIXATION

Prof. Guy MolenaersMedical Head of the Department

of Orthopaedic Surgery,

University Hospital Leuven,

Belgium

Figure 1. Patient specific modelling evaluation showing hypothetical effects of distal (green) or

proximal (red) derotation osteotomy compared with the original deformity (blue) on moment

generating capacity of the gluteus maximus relative to hip flexion angle. The modelled curve for

the original deformity sits perfectly underneath the curve for the distal osteotomy.

Gluteus MAX

9 29 49 69 89-11

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2

8

10

12

Hip flexion angle (°)

proxDVO

distDVO

FemDef

Mo

men

t ge

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atin

g ca

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(Nm

)

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have a marked effect on effect on the hip flexion

moment generation of the psoas major.

Finally, potential improvements in pelvic stability

were modelled in the context of abduction

moment. In the example situation the moment arm

of the gluteus medius could be seen not to improve

with only a proximal osteotomy. However, addition

of a varus osteotomy – ultimately resulting in a 45°

proximal derotation and a neck shaft angle of 130°

was noted to improve the moment generating

capacity of the gluteus medius in hip abduction.

After his elegant explanation of the biomechanics

of proximal derotation osteotomy and the value

of careful and thorough patient specific modelling,

Prof. Molenaers then described his preferred

techniques for performing the osteotomy.

After careful calculation of the varus angle, a pin

is inserted, and the value of newer devices comes

to the fore as the chisel can be easily slid over the

pin, simplifying even osteomotic work. A cut is

made proximally then, perpendicular to the shaft,

[1] Delp, J Biomech. 1999

May;32(5):493-501.

[2] Ruwe PA, J Bone Joint Surg

Am. 1992 Jul;74(6):820-30.

Figure 2. X-ray of completed proximal derotation osteotomy

showing good alignment and combination of compression

principles with locked screws.

“The advantages of

newer devices such as the

OrthoPediatrics plates are

evident here because they afford

a good grip on the plate thereby

allowing the extension of the

hip that is essential to improve

the moment arm of the gluteus

maximus, which is the goal.”

a second cut allows the possibility to derotate

and achieve a good fit. (see picture sequence 1).

The advantages of newer devices, such as the

OrthoPediatrics plates, are evident here because

they afford a good grip on the plate thereby

allowing the extension of the hip that is essential

to improve the moment arm of the gluteus

maximus, which is the goal.

With the patient draped in the prone position,

one can perform a Ruwe test2 intra-operatively

for optimal derotation.

Prof. Molenaers illustrated his description with

some intra-operative photographs. These also

showed the use of a lift under the knee to put

the femur in extension to ensure that not only

the varus and derotation are achieved but also

extension of the proximal femor. Finally, Prof.

Molenaers showed X-ray images (Figure 2) of the

procedure in both planes to ensure correct

alignment and again highlighted the benefits

of the newer plates as one can combine

compression principles with locked screws and

get a very solid outcome.


8

Professor Tim Theologis, Consultant

Orthopaedic Surgeon at Oxford University

Hospitals in the United Kingdom, took the lectern

and prefaced his presentation by announcing

that although he would speak primarily about

diaphyseal derotation osteotomy, it is imperative

to remain flexible as a surgeon and that deformity

corrections should be undertaken only after

considering all factors. A major consideration

in practice with children with cerebral palsy is

that such deformity correction is always part of

multilevel surgery, and as such are associated

with the negative impacts that long procedures,

high blood loss, and large dissections have on

children and the necessarily long rehabilitations

afterwards. In particular, any of the femoral

osteotomies that require extensive muscle

dissection and periosteal stripping carry

heightened risks.

An additional and major impact of extensive

multilevel surgery is the loss of muscle strength.

It has been demonstrated in previous studies that

even a year after multilevel surgery a majority

of children have not regained their preoperative

muscle strength.

For these reasons, Oxford surgeons have

developed a minimally invasive, strength

preserving, programme of surgery that includes

doing some of the soft tissue procedures using

less invasive techniques, including some of the

hamstring lengthening. Prof. Theologis illustrated

this point with photographs of the patient’s leg

being held in the popliteal angle measurement

position with multiple small incisions being made

in the muscular tendonous junction for the

medial hamstrings and gradually correcting the

popliteal angle. This results in minimal scarring

and minimal postoperative pain.

A similarly less-invasive technique has been

developed for derotational osteotomy of the

femur and the tibia, however, Prof. Theologis was

careful to point out that if there is a need for a

sagittal or coronal plane deformity correction

at the same time one should not be doing the

rotational correction on the diaphysis. So if one

needs to varise the femur because the femoral

head is uncovered, or if there is a need to do

an extension supracondylar osteotomy at the

knee due to severe flexion contraction, then the

minimally invasive technique does not apply.

The minimally invasive technique, is usually only

used in younger children who simply require

derotation and no sagittal or coronal plane form

correction.

Prof. Theologis explained that in their minimally

invasive technique the flexible nails are inserted

distally to proximally. The osteotomy is effected

and a closed corticotomy at the isthmus is made.

The insertion is done distally because that’s

where the flexible nails would sit and provide

the major stability (Figure 3). The osteotomy

is completed and the nails advanced and fixed

proximally. Additionally, an anteversion wire is

inserted into the femoral neck to control rotation

during the process by measuring its angle to the

transcondylar axis at the knee with a goniometer.

DIAPHYSEAL FEMORAL DEROTATION OSTEOTOMY USING IM NAIL FIXATION

Prof. Tim TheologisConsultant Orthopaedic Surgeon

Oxford University Hospitals,

Oxford, UK

“A major consideration in practice with children with cerebral palsy is that

such deformity correction is always part of multilevel surgery, and as such are

associated with the negative impacts that long procedures.”


9

The flexible intramedullary nails have proven

to be surprisingly stable, perhaps because of

the corticotomy. They interdigitate when the

patient stands and walks a little. Also, they heal

very quickly - usually within the first four weeks.

It is recommend to remove the nails for the

same reasons they are removed when used for

fractures. Furthermore, for children who are

above 40 kg, locking nails are recommended.

In terms of rehabilitation, the children go through

a very rigorous programme focussing on post-

operative muscle strengthening. Prof. Theologis

showed some preliminary results of a 2-year

follow-up study and indicated that a 5-year

follow-up study is currently being undertaken.

A cohort of 18 children were compared to a

matched cohort of 20 children undergoing

conventional multilevel surgery. The types of

surgery were similar in the two groups – both

groups were undergoing multiple procedures

– with an average of six per leg. Clinical

measurements were made including X-ray, gait

analysis (Vicon MX40), Isometric Dynamometry

(MIE Medical Research Ltd.), and multifunctional

measurements (GMFM 88).

In terms of correction of gait index as measured

by gait analysis, the amount of correction

achieved post operatively, and foot progression

angle at 24 months, the cohorts were relatively

similar. However, when comparing operative

time, blood loss, and time to mobilise then

the minimally invasive approach was better.

Additionally, significant achievements in strength

preservation, particularly, in the knee and hip

extensors and in the hamstrings have been

demonstrated in the minimally invasive group.

Overall, the take home message from Prof.

Theologis was that his team achieved the same

result by doing less surgery - an achievement

with clear benefits for appropriate patients.

Figure 3. X-ray images showing

the advancement of the flexible

nails, first one and then the other,

across the femoral osteotomy.

An X-ray image of the completed

intervention shows where the

nails are fixed proximally.


10

Following Prof. Theologis, Franck Accadbled gave

the final scientific presentation on the benefits

of distal derotation osteotomy. Prof. Franck

Accadbled is an orthopaedic surgeon at Hôpital

des Enfants, Toulouse University Hospital,

France.

He began his presentation by citing a recently

published paper from the Journal of Pediatric

Orthopedics1 wherein the results of a preliminary

study and the technique of using a locking nail

in adolescent femoral antetorsion have been

published.

The rationale for the distal osteotomy, explained

Dr Accadbled, is to do with biomechanics.

The maximum varus forces are located in the

proximal third of the femur, as evidenced by a

number of examples of implant failure in this

region. Additionally, deformity correction in the

horizontal plane, such as derotation, may result

in induced deformities in the coronal and sagittal

planes because of the curve of the femur, and the

narrowness of the shaft, as depicted in Paley’s

book “Principles of deformity correction”2, and

demonstrated mathematically by Pailhé et al.3

Finally, bone healing is best at the distal

metaphysis of the femur, as demonstrated in leg

lengthening by Fischgrund et al.,4 and Aaronson

and Shen,5 and there is a strong correlation

between derotation osteotomy of over 30° and

poor post-operative consolidation.6

Prof. Accadbled pointed out that technique

planning is very important before commencing

any deformity correction, it is critical to

undertake gait analysis, and identify exactly

the indication for any particular procedure. “In

our experience, bone torsion is best evaluated

with EOS system,” and our radiologist has

validated this method over the gold standard CT

scan. However, the use of CT scans is still very

important for those patients who are unable to

stand still in the EOS machine.

Not dwelling longer on the theoretical details of

procedure choice, Prof. Accadbled moved quickly

into a detailed practical explanation illustrated

with numerous intraoperative photographs and

images.

He explained that he prefers to drape the patient

in a supine manner so the whole limb is accessible

to allow for concomitant associated procedures

such as tendon transfer or lengthening, or other

surgery. Additionally, a bag around the other

limb is beneficial as it allows free passage for the

imaging arm.

To ensure accurate rotational correction Prof.

Accadbled uses 2 rotation landmarks consisting

of 4mm Steinmann pins, one positionned rather

posterior at the level of the lesser trochanter,

the other at the posterior aspect of the distal

metaphysis. Pin position should be posterior

enough to avoid interference with the nail and

leave the approach clear for reaming and nail

positioning.

DISTAL OSTEOTOMY OF THE FEMUR AND IMLN FIXATION

Prof. Franck AccadbledOrthopaedic surgeon

Hôpital des Enfants, Toulouse

University Hospital,

France

“It is a percutaneous surgery, which provides an accurate correction, and stable

fixation using a locked nail - we don’t have an immobilization and we get early

weight bearing as well.”


11

The two pins are very useful to assess the angle

between the two segments, both before the

osteotomy, and again during to check that the

planned degree of correction is achieved. To help

in assessing this, Prof. Accadbled’s team have

developed a special goniometer that is fitted

sequentially on the proximal pin and then the

distal pin, thereby allowing the angular difference

between the pins to be determined.

Prof Accadbled begins by performing a

percutaneous post stamp osteotomy, with just

the holes to start with acting as venting holes

to reduce the risk of fatty embolism. Moving to

the entry point, which is lateral regardless of the

implant and brand that is used.

Prof. Accadbled stressed the importance of

using narrow shaft deep fluted reamers, as

these next-generation reamers are very sharp.

Reaming is conducted in 0.5 mm increments and

should be carried out until 1.5 mm overeaming is

achieved. The guidewire is then pulled back and

the osteotomy is completed using an osteotome,

and the nail is inserted with gentle taps - sledging

should be strictly avoided. Additionally, it is

important to check the progression of the nail

using the image intensifier until the narrowest

(diaphyseal) part of the femur has been passed.

To fix the nail in position, two locking screws

should be used proximally and two screws distally

(Figure 4). This provides greater stability, and

gives a lower chance of error should a screw

be out of the nail simply by giving the surgeon

two chances rather than just one. Additionally,

blocking screws can prove to be very useful in

providing more stability or to perform further

deformity correction. Prof. Accadbled prefers to

bone graft percutaneously, using the products of

reaming in a tube.

[1] Pailhé R., J Pediatr Orthop B.

2014 Nov;23(6):523-8.

[2] Paley, D. Principles of

deformity correction, 200

Springer-Verlag, Berlin.

[3] Pailhé R., J Pediatr Orthop B.

2015 Mar;24(2):171.

[4] Fischgrund J, Paley D, Suter

C.. Clin Orthop Relat Res.

1994;301:31–37.

[5] Aronson, J. and Shen, X.,

Clin Orthop Relat Res. 1994

Apr;(301):25-30.

[6] Donnan LT, Saleh M, Rigby

AS. J Bone Joint Surg Br.

2003;85:254–260

In the case that Prof. Accadbled showed, which

was a bilateral procedure, he used a staged

procedure with at least 2 days between separate

interventions, again to reduce the risk of fat

embolization. Ultimately, no post-operative

immobilisation is required and weight bearing is

encouraged after the third week.

In conclusion Prof. Accadbled emphasised the

importance of preoperative planning and nail

diameter selection, finishing by stating “It is

a percutaneous surgery, which provides an

accurate correction, and stable fixation using a

locked nail - we don’t have an immobilization and

we get early weight bearing as well.”

Figure 4. X-ray image showing the

positioning of the intramedulary

nail (left) and distal and proximal

fixation each with two screws

(right)


12

Following the faculty presentations, Prof.

Lascombes invited questions from the audience.

Dr Paulo Selber, consultant orthopedic surgeon

at the Royal Children’s Hospital, Victoria,

Australia, commented on the range of techniques

to achieve a femoral derotation osteotomy and

the contrasting levels of invasiveness shown,

from minimally invasive to reaming out the entire

femur. More importantly, Dr Selber enquired as

to the experts’ opinions on the importance of the

level at which the osteotomy is done, if above or

below the lesser trochanter.

However, Prof. Brunner considered the insertion

of the gluteus maximus, not the lesser trochanter,

to be the relevant point in the position of the

osteotomy. Dr Selber enquired if the were aware

of what he calls “the fate of the hamstrings and

the Achilles tendons”, which, he pointed out,

are are known to be very superficial hence the

most frequently operated muscles in cerebral

palsy. Prof. Molenaers agreed that this was an

important consideration stating, “If you have

knee flexion pressure, then of course you change

the moment arm of the hamstrings too, and that

if you want to get to the real problem you have to

address it proximally.”

Dr Selber suggested that the fate of the

hamstrings and the Achillies could be that they

are too superficial, and the fate of the psoas is

that it is too deep and hence very rarely treated.

He further suggested that, “We derotate in the

inter trochanteric region, not only to improve the

abductor moment through gluteus medius, but

also to relax the iliopsoas.”

A further question was raised regarding a video

of Prof. Brunner’s patient, shown during the

presentations, and that the patient appeared

to walk with excessive anterior pelvic tilt. Prof.

Brunner responded that the patient’s anterior

pelvic tilt was due to long hamstrings and

because she was walking in equinus. If you walk

on your toes you get more hip flexion so you have

a tendency to lean forward and this is not due to

psoas activity in my opinion but rather related to

less activity of the hip extensors.

Prof. Brunner further explained that if the psoas

were to contract during stance one would bend

forward and fall. However, the iliopsoas is needed

as an accelerator for swing, so after stance

phase we need swing phase. The psoas is needed

because in most CP patients the plantar flexors

are weak or kept in ankle foot orthoses, so their

effect is known considering acceleration, and so

the only muscle remaining to get that forward in-

swing is the iliopsoas muscle, therefore it may be

lengthened slightly but should not be released.

Back to stance phase and it is a different

situation because it is necessary to preserve

hamstring strength, because they are active as

hip extensors, and they help to extend the hip. At

this point in time that has nothing to do with the

iliopsoas.

This explanation was not universally accepted

and a counter explanation for the patient case

seen in Prof. Brunner’s video was put forward.

Dr Selber considered that the patient was most

likely a GFMCS 2 patient and would then have

much better selective motor control than a

GFMCS 3 patient. So, when they have a lot of

femoral torsion, because they have very good

selective motor control, they can adopt one of

two patterns of strategies; one, they go into

equinus if they have a little bit of spasticity down

there, or two, they tilt their pelvis forward to

improve the lever arm. Dr Selber considered that

for the patient shown, the second situation was

likely - that the patient still had femoral torsion

- and that patient was just adopting a different

pattern, to cover for and to produce a better

fulcrum, in the hip.

Prof. Brunner pointed out that he had shown the

patient only to illustrate that deformity and gait

OPEN DISCUSSION


13

may be considerably modified by interventions

other than a derotation osteotomy. In this case

just correcting the toe walking may have an

influence on the rotational position of the leg

during gait, the patient does not otherwise

change muscle activity, and does not develop an

obligate pattern but does, however, adjust and

has the same gait as before if one were to view

the whole gait cycle.

Nowadays [video is 25y old] the patient would

also undergo femoral derotation because one

believes that this is a need. However, in modelling

studies you see that the typical gait approach

that the patient shows may derive only from toe

walking, and one needs no further muscle activity

in the leg.

Prof. Theologis added that the opposite can also

be true, “because there are children who walk on

their toes because they have a quite excessive

internal rotation of the hip. When you try and

walk with your hips fully internally rotated you

will be on your toes to achieve that, but arguably

sometimes the assessment of which comes first is

a challenge.”

Prof. Molenaers felt it should encourage people

and it is a clear indication to do what he does

- dynamic muscle length assessment, as that

reveals a lot of problems that can then be avoided

e.g. over lengthening the modular hamstrings,

because of the importance of the hamstrings

and most of the paediatric CP patients don’t

have enough motor control to control the

muscles. On the other hand, often we do have to

lengthen and and with full imaging assessment

this can be determined, e.g. the psoas muscle

intramuscularly, because everything has to do

with the balance across the joints as too much

inflexion is not good but we need enough.

A question directed towards Prof. Brunner

regarding what to do at the leg below the knee,

if faced with external rotation of the femur in

crouch patients. Prof. Brunner clarified that

if one operates on a patient with a multi level

problem he would first make a list of all the

deformities present and then would decide

whether correcting each one is of importance or

not. Following this prioritization, he would then

correct everything at once. “So if I have a foot

which is unstable or a tibia which is externally

or internally rotated, I would correct these

deformities at the same time [as a derotation].”

Professor Theologis was then asked about

how he could be sure of the accuracy of the

surgery when performing the percutaneous

lengthening of the hamstrings. He responded

that in the context of accurately cutting only

the hamstring and nothing else, or only the

fascia etc., the location of the surgery at the

margin of lower and middle thirds of the thigh

is important. In this area there should be

muscle overlapping the fascia, therefore this

is an intramuscular lengthening. In the context

of cutting the hamstrings and nothing else,

Prof. Theologis professed to not having had

any complications. Finally, in the context of the

“If you walk on your toes

you get more hip flexion

so you have a tendency to

lean forward and this is not

due to psoas activity in my

opinion but rather related

to less activity of the hip

extensors.”


14

accuracy of correction, the aim is to correct a

mild contracture, which he would do gradually,

until sufficient correction is achieved.

When asked if there was a risk of muscle injury,

Prof. Theologis continued that they have done

ultra sound checks of the hamstrings in a

subgroup of children in order to see exactly what

is cut, and that they hadn’t found any significant

muscle injury in this group.

A question was raised as to how one avoids

coronal knee malalignment at the distal

osteotomy because the distal part of the canal is

very large and when the distal part of the femur

is derotated and because the nail is very thin,

about 7-9 mm, one can induce varus or valgus

deformity.

Prof. Accadbled responded that he likes to do

the distal reaming first then the derotation over

the guide wire which maintains the general

alignment, and if he is not satisfied once the

nail is in, he checks the mechanical axis with

a radiolucent plate including a metal grid. If

unsatisfactory, Prof. Accadbled uses blocking

(Poller) screws to reroute the nail and thus

correct the alignment. The use of blocking screws

is a fast technique for intramedulary nail use and

is good for deformity correction or trauma.

Prof. Lascombes asked the panel to comment on

the role of the adductor muscles. Prof. Molenaers

highlighted the ongoing problem of severe

adductor involvement. However, by using the

evaluation tools, the clinical evaluation, and the

data from the gait lab, one can determine, in

much the same way as for the hamstrings, that

for example, in a diplegic child there is often over

lengthening from the adductors. Another thing is

the pelvic stability because pelvic stability is the

key to a good result in cerebral palsy patients.

So it is something one should be careful not to

destroy, and that if you have 15° of abduction in

the flexed knee stay away from the adductors.

Prof. Brunner added that in the case of a

complex problem, like in CP, then he likes to play

with “toys” – “toys” being modelling. Through

modelling, one can change the situation slightly

and see what happens. Prof. Brunner’s team

have done this and modelled the outcome if

one were to take away hip extensors. The result

is that that the hip adductors became more

active, especially the adductor minimus. This

means that if the hip extensors get weak, as a

compensatory mechanism, the hip adductors

become more active – that is to increase hip

stability. This in turn means, but not necessarily,

they produce internal rotation and Skodol has

shown that the hip adductors are not powerful

hip internal rotators. Prof. Brunner added that

in his experience at least, he gets good results

and increased hip abduction if he does adductor

lengthenings, but hardly ever gets a major

influence on hip internal rotation. Therefore,

he doesn’t think the focus should be on the hip

adductors, nor even on the hamstrings, as he

feels they influence rotation only to a minor

degree. The rotation derives from the psoas and

anatomy, you have origin and insertion and if that

has a little twist you get rotation – “I think that

this simple principle of deriving muscle activity

from this anatomical structures and position

“So if I have a foot which is unstable or a tibia which is externally or internally rotated, I would correct these deformities at the same time [as a derotation].”


15

that we have on a dead body, does not mean

that these muscles really work that way during

function and gait.”

When one does gait analysis to understand what

happens when we export these gait data to more

complex models then we see that Skodol is right,

we don’t see a major influence of rotation from

the adductors.

A final question was raised wherein the

panel were asked to address the leg extensor

mechanism and power. When discussing tiptoe

gait, it is necessary to see whether it’s a true

equinus or masked one from the knee.

Discussion about the hip and the importance

of the hip extensor should also address the

importance of the knee extensor mechanism,

especially as lengthening the so called strong

hamstrings can result in weak extensor and weak

hamstrings and there is risk that the gait could be

ruined.

Prof. Molenaers commented that one at balance

across joints, and that we should all remember

that there is no “strong” in CP because they

are all weak – all muscles are weak. Too much

spasticity doesn’t mean that the muscles are

too strong, because if you look at the muscle

structure they are all weak. Ultimately, we have

to work strength in those patients rather than

weakening muscles even more. Prof. Molenaers’

sentiments were echoed by Prof. Brunner who

indicated that it is a complex problem, and

for that reason he aimed to show during his

presentation that we should not focus on just

one part, the femur, because you have to have

a summary of all possible structures in the leg

which may produce part of or the complete

internal rotation that we see during gait.

The second thing is that we usually consider only

the effects of the muscles being active in our

joints. However, this is not true, because on earth

we have gravity. If we talk about muscle balance

this is actually an erroneous concept because

we do not only have muscles acting on the joints,

there are external forces like gravity and inertia,

which all together have another influence.

The term “balance of forces” is a far more

comprehensive and therefore correct expression.

Having balance between all forces, internal and

external, acting on the joint. The problem is we

have only little idea which external forces are

contributing, and that’s why we concentrate on

the muscles.

“This simple principle of deriving muscle activity from the anatomical structures

and position on a cadaver, does not really reflect how muscles work during

function and gait.”


16

(French Society of Paediatric Orthopaedics)

including the redaction of medical books: Imaging

of the hip in children (1985), Benign bone tumors

(1996), Fractures in children (2005), Long bone

deformities and their correction (2009).

He contributed to the development of the

instrumentation and implants “Legacy®”

(Medtronic Spine) for the surgical treatment of

scoliosis, and implants and instruments for “T2

Kids®” as flexible intramedullary nails.

He is currently Past President of The European

Pediatric Orthopedic Society (EPOS), as well

as The French Paediatric Orthopedic Society

(SOFOP).

In January of 2013, Dr Armstrong joined

OrthoPediatrics as the first, full-time Chief

Medical Officer of the company.

Prof. Pierre Lascombes Chef de Service, Orthopédie Pédiatrique,

Hôpitaux Universitaires de Genève, Switzerland

Professor Pierre Lascombes is a paediatric

orthopaedic surgeon and Chairman of the

Division of Paediatric Orthopaedic Surgery

and Professor of Orthopaedics in Geneva,

Switzerland. Prior to this appointment, he

was Head of the Department of Paediatric

Orthopaedics and Professor of Anatomy at the

University of Nancy, France.

Professor Lascombes has a vast experience

in scoliosis in children and adolescents, bone

deformity correction and limb lengthening,

as well as neuromuscular orthopaedics. He

has published more than 130 peer reviewed

papers and book chapters, and extensively on

traumatology in children. He has organized

several educational courses with the SOFOP

Dr Peter F. Armstrong Chief Medical Officer

OrthoPediatrics

Dr Armstrong received his medical degree from

the University of Western Ontario, Canada in

1972. His orthopaedic residency was undertaken

at the University of Toronto followed by a

paediatric orthopaedic fellowship with Toronto’s

Hospital for Sick Children.

Subsequently, he became chief of staff of Shriners

Hospitals for Children, Intermountain (Salt Lake

City, USA). In 2000, he was selected as Chief

Medical Officer of the 22 Shriners Hospitals and

moved to the Headquarters in Tampa.

BIOGRAPHIES


17

and spine deformities. His research interests are

focused on spine biomechanics.

He is currently the treasurer and president of

the scientific committee of SOFOP, the French

Paediatric Orthopaedics Association.

Disclosures: Consultant, OrthoPediatrics

Prof. Dr. med. Reinald Brunner, FRCS Consultant of Neuro-Orthopaedics

Kindersspital Basel, Switzerland

Professor Reinald Brunner is Professor of

Orthopaedics and a Consultant of Neuro-

Orthopaedics at the Orthopaedic Department,

Children’s University Hospital Basel, Switzerland.

He joined the department in 1987 and has been

its leader/director since 1992.

Prof. Brunner has had a longstanding clinical

and research interest in the biomechanics of

gait. His findings have led to the development of

biomechanically-oriented treatment approaches

that focus on the efficient correction of functional

deformities of the musculoskeletal system.

His special fields of interest also include

orthopaedics of neuromuscular diseases, gait

disturbances, hip joint problems and conservative

paediatric orthopaedics. Prof. Brunner is the

chairman of the Swiss Society for Prosthetics

and Orthotics (APO), and he also headed the

European Society for Movement Analysis in

Adults and Children (ESMAC) between 2001 and

2005.

Prof. Brunner has been a honorary member of

the Royal College of Surgeons of Edinburgh since

2013.

Prof. Franck Accadbled Orthopaedic surgeon

Hôpital des Enfants, Toulouse University

Hospital, France

Professor Accadbled qualified from Toulouse

School of Medicine in France, before completing

a clinical fellowship in paediatric orthopaedic

trauma at the Women’s and Children’s Hospital in

Adelaide, Australia.

His clinical interests are in paediatric

orthopaedics and trauma - especially of the lower

limb, sports injuries, limb lengthening and growth,


18

Prof. Guy MolenaersMedical Head of the Department of Orthopaedic

Surgery,

University Hospital Leuven, Belgium

Guy Molenaers is graduated as medical doctor

in 1982 and as an orthopaedic surgeon in 1988

at the Catholic University of Leuven, Belgium.

After his fellowship in paediatric orthopaedics,

he joined the medical staff of the Orthopaedic

Department of the University Hospitals Leuven

in 1989. He became the medical director of the

Clinical Motion Analysis Laboratory in Pellenberg

in 1996. From 2004 to 2014, he was head of the

CP Reference Centre. In 2014, he was elected

as chairman of the Department of Orthopaedic

Surgery at the University Hospitals Leuven.

In 2003, he received his PhD in Paediatric

Orthopaedics and in 2004, he was appointed as

an associate professor at the Faculty of Medicine,

Department of Orthopaedics and the Faculty of

Kinesiology and Rehabilitation Sciences at the

Tim Theologis, MSc, PhD, FRCSConsultant Orthopaedic Surgeon

Oxford University Hospitals, Oxford, UK

Tim Theologis studied medicine in Athens,

Greece, and completed his surgical and

orthopaedic training in Oxford, UK. He

completed a paediatric orthopaedic fellowship at

the Hospital for Sick Children in Toronto, Canada.

In 1996 he was appointed at the Nuffield

Orthopaedic Centre in Oxford, as a Consultant

Orthopaedic Surgeon with special interest in

children and neuromuscular disorders.

He is a Senior Clinical Lecturer at Oxford

University and a Research Professor at Oxford

Brookes University.

He has a strong clinical and research link

with the Oxford Gait Laboratory. He looks

after children with orthopaedic conditions,

primarily developmental dysplasia of the

hip and musculoskeletal tumours, as well as

neuromuscular disorders, including cerebral

palsy.

He was Editor in Chief for Gait and Posture from

2005 to 2015, and has been a board member of

the British Society for Children’s Orthopaedic

Surgery since 2009 and is now President-elect.

He has been a member of EPOS since 2001.

Catholic University of Leuven.

His main research interests include

neuropediatrics with focus on optimizing

treatment based on 3D movement analysis,

objective spasticity assessment, dynamic

muscle lengths and simulation techniques

(musculoskeletal models) with the ultimate goal

to improve quality of life in children with neuro-

orthopaedic problems.

He is a member and contributes to EPOS,

ESMAC, AACPDM, EMCPDM and an honorary

member of the ‘Gesellschaft für Neuropädiatrie’.

Besides reviewing for several journals, he

functions as editorial board member of the

Journal of Children’s Orthopaedics and Gait and

Posture.


19

NOTES/DISCUSSION

ColophonThis meeting report was written by

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© OrthoPediatrics Corp. 2016

NoteThis document is intended exclusively for experts in

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The information on the procedures contained in

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Creating QualityEnsuring Accuracy

Infusing KnowledgeInstilling Confidence

ACL Reconstruction SystemTreats the full spectrum of developing patients and utilizes ShieldLoc™ and ArmorLink™ technologies

RESPONSE™ Spine SystemFeatures Jiminy rod reducers for

versatile rod reduction and one of the lowest profile pedicle screws on

the market

PediFrag™ System 2.7/3.5 PediPlates®

®

Leading Innovation in Pediatric OrthopedicsTreatment Options for Trauma, Limb Deformity, Spine & Sports Medicine

Instructions For Use (IFU), cleaning instructions, and surgical techniques may be obtained by calling OrthoPediatrics®

Customer Service at 574-268-6379. Read and understand indications, warnings, and adverse effects explained in IFU’s prior to use.

OrthoPediatrics, Children Are Not Just Small Adults, ArmorLink, PediFlex, PediFrag, PediLoc, PediNail, PediPlates, PLEO, Response, Scwire, ShieldLoc, and

the OP and Pedi logos are trademarks of OrthoPediatrics Corp.

All-in-one fragment set, built with the entire operating staff in mind, that provides innovative instruments to facilitate all procedures

Offers multiple options for physeal tethering and is a member of the Trauma

and Limb Deformity product line that also includes PediNail, PediLoc Femur &

Tibia & PediFlex

2850 Frontier Drive • Warsaw, IN 46582 ph: 1.574.268.6379 or 1.877.268.6339 fax: 1.574.268.6302 • www.OrthoPediatrics.com

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