Osteotomy around the knee in children: when and why?

F. Moungondo ,R. ElbaumService d’orthopédie

Hôpital Erasme

Introduction• In young children or

adolescent,most of frontal knee defformity can be correct without osteotomy only by simple epiphysiodesis (staple,scews or growth plate).

• In some cases when the deformity is too complex or when the patient is too old , knee osteotomy is the only solution to restaure anatomy.

Just a little remind

The variation of the normal pattern

Physiologic evolution in the frontal plane

ligament laxity

weight-bearing

Variation of the measurements

10 cm 4 cm

VARIATIONS Obese adolescents = False knock-knee

Abnormal fat distribution

10cm

Axe diaphysaire F et T en charge

Use of the metaphyseal-diaphyseal angle in the evaluation of bowed legs.J Bone and Joint surg. 1993 Nov;75(11):1602-9.Feldman MD1, Schoenecker PL.

- 5°

0°

+ 5°

2 Y 4 Y 12 Y 15 Y

G. Varum

G. Valgum

M

EVOLUTION OF THE TF ANGLE IN THE FRONTAL PLANE

F

Normal femoral and tibial torsion

Torsion :

Is the turning of a bone on its longitudinal axes.

As a result the upper andthe lower epiphysis are not in the same plane

Femoral anteversion angle :

Fabry (1973)

Tibial torsion angle :

Dupuis ( 1951)

Jend (1981)

ROTATIONAL NORMS IN HEALTHY CHILDREN

Rotational angles vary with age

5 Y 1O Y 15 Y

30°

15°

10°

5°

40°

20°

10°

FA

Lat. T.T.

EVOLUTION OF THE NORMAL FEMORAL AND TIBIAL TORSION /

AGE

Consequences of constitutional angular deformities

Do severe angular deformities induce osteoarthritis of the knee ?Modifications of TF angle

Alteration of distribution of loads on the knee

Osteoarthritis

No prospective study on the long term

of angular deformities

However

Consequences of constitutional rotational deformities

Do severe rotational deformities induce osteoarthritis of the knee and hip ?

Exaggerated torsion

Alteration of the loads on hip or knee

osteoarthritis

No prospective and longitudinal study

on the long term of rotational deformities

However

Knee growth potential

Indication of osteotomy around the knee in children and adolescent

FEMORAL OSTEOTOMY• Post acquired epiphysiodesis

(septic,traumatic…)• Posttraumatic deformity• Idiopathic malalignement (Genu

Valgum,Genu Varum; Femoral hyperantetorsion)

• Flexion contracture arthrogryppotic,IMOC,Polio

• Congenital deformity (PFFD,neurofibromatosis,OI…)

• Acquired deformity (Rickets,blount disease…)

• ….

TIBIAL OSTEOTOMY• Tibia vara (Blount disease)• Postraumatic deformity• Idiopathic Malalignement

(Excessive tibial torsion, genu varum or valgum)

• Congenital (Tibial hypoplasia, hemielia,OI, CPT…)

• Aquired Genu varum (Rickets,Blont disease…)

• Postraumatic • Focal chondrodyspalsia• ….

Mechanical axis

But we know that mechanical axis is a little bit medial to center of the knee

Normal : 9±7mm (Paley et al 2004)

4±4mm (Bhave et al)

Anatomical Axis (Paley 1994)

What about the frontal plane?

« Pathological » constitutional frontal deformities

« Pathological » constitutional angular deformities :

Should be related to the natural history

Frequently found in other members of family

They can be corrected in late chilhood

They must be differentiated from secondary deformities

TF angle exceeding 2 SD around the mean for age and sex

Constitutional angular deformityPatients < 3 years old

24 months

Constitutional genu varum

ITT

Bow legs

Spontaneous correction

Boy 16 years oldBilat genu varum

Girl 12 years oldGenu valgum I M D : 12 cm

Constitutional angular deformities in preadolescents

Rickets :Nutritional Vitamin D resistantHypophosphatasia

Infantile tibia vara (Blount)

Metaphyseal chondrodysplasia

Focal fibrocartilaginous dysplasia

Secondary angular deformities in patients less than 3 Y

Focal Chondrofibrodysplasia

Blount disease • Black ,carribean• infantile bilat• adolescent unilat

Rickets

Genu varum

X ray : widening of the physis+++

3 YGenu varum

ICd = 9cm

Metaphyseal chondrodysplasia

Secondary to :

Trauma

Infection

M.. l. 15 YFemoral Epiphysiodesis

Unilateral genu valgum or varum

Secondary angular deformities in patients more than 10 Y

Secondary to

CarentielNeuroPolyepiphyseal dysplasiaBone Tumor…

Late onset tibia vara (12Y)

Courtesy PL Docquier

AND WHAT ABOUT THE ROTATIONNAL PLANE??

Relationships between rotational malalignment and the patella

Eckhoff (1997) : « the patellar tracking pattern is determinedby the femoral and tibial torsion ».

The patella is subjected to increased stress due to malalignment syndrome.

Anterior knee pain is associated with triple deformity sd :Delgado (1996)Bruce (2004)

Patella instability is related to torsional problems :Turner ( 1994)Cameron (1996)

TreatmentOutward femoral osteotomy

+ Inward tibial osteotomy

(Delgado 1996)

AND WHAT ABOUT THE SAGITTAL PLANE??

flessum defformity

Extension deformity (genu recurvatum)

Iatrogenic (post épiphysiodèse TTA) Post trauma Post septic

Technique de l’ostéotomie tibiale de flexionpour le recurvatum d’origine tibiale

LECUIRE F, LERAT JL et al.Le genu recurvatum et son traitement par ostéotomie tibiale Revue de Chirurgie Orthopédique, 198O

Complications of osteotomies about the knee in children.

“On Sixty-five procedures were performed by a variety of techniques with the majority being on the proximal tibia.Postoperative complications were numerous with 63% of the patients having one or more. These complications included loss of alignment, vascular complications, pathologic fractures, wound infection, anterior and posterior angulation at the osteotomy site, tibial tubercle prominence and patellofemoral malalignment.”

Myckosie J.P. Orthopedics 1981 Sep 1;4(9):1005-15.

CONCLUSION

• In children ,most of pathological knee deformity can be corrected by simple procedure if some principles are respect

• If a knee osteotomy is planned ,it has to be decide after a good explanation to the child and his parents.

• Type of procedure depends on the surgeon habits• Be very carefull because complications rate are

not so rare.

THANK YOU