congenital COXA VARA

ByDr. Tejaswi Dussa

Post Graduate In Ms OrthoGH, Sec-bed

Coxa Vara

• Coxa vara is a complex 3-Dimensional deformity includes varus and retroversion of prox.femur• Normal neck shaft angle

120-140 deg• Neck shaft angle of <120deg

is called coxa vara• at birth it is 160 deg

decreasing to 125deg in adult life

• Congenital/Developemental coxa vara -Infancy -Childhood• Acquired

Congenital Coxa Vara

• INFANCY: -rare -at birth -asso.with prox.femoral focal deficiency cleido cranial dysostosis other conginital anomolies • CHILD HOOD: -more common -not discovered until the child is walking during 2nd -3rd yr of age -asso.with cong.short femur

• PATHOLOGICALLY IT CONSISTS OF :

-Progressive increasing acuteness of neckshaft angle -shortness of the femoral neck -A vertical direction of the epiphyseal plate -relative over growth of gr.trochanter• An oblique defect in the neck ‘proximal medial’ to

‘distal lateral border’• Triangular bony defect in inferior medial corner of the

neck (this is compare to salter harris type-II physeal defect)

• Due to a defect of enchondral ossification in the medial part of the femoral neck

• When child starts to crawl or stand, the femoral neck bends or get fractured because of stress forces• With continued wieght bearing it colapses

increased in to varus and retroversion• There will be -varus -Retroversion -shortening & bowing of shaft

2 yrs old pt with congenital coxa vara

Developmental Coxa Vara

• Developmental coxa vara is a descriptive term referring to the angular relation between the femoral head or neck, or both, and the femoral shaft, which is less than the normal value for the patient's age.

Developmental Coxa Vara

• Not present at birth• Not asso.with other sk.manifestations• Present after walking age 2nd-3rd yr• Present with painful limb• b/l cases progressive waddling gait/ trendelenberg gait• Limitation of hip abduction & internal

rotation

epidimiology• Developmental coxa vara is rare; • 1 in 25,000 live births • There is no racial predilection.• occurrence is equal in males to females and left to right • bilateral involvement is note in 1/3of patients • recent reports have shown increase incidence in black

population compared with whites • reports have also shown a familial pattern with an

autosomal dominant form of transmission • There are reports of the condition in families and in both

homozygous and heterozygous twins• Bilateral cases may be more likely to be associated with a

generalized skeletal dysplasia.

ETIOLOGY • Idiopathic• Congenital• Infections• Trauma• Tumors• Scfe• Epiphyseal Dysplasia• Secondary To Vascular Insult

Other Causes:

• Metabolic bone disorders-paget’s ds• Post perthes deformity• Osteomyelitis• Post traumatic• Shepherd crook deformity-severe form of coxa vara neck shaft

angle <90deg -osteogenesis imperfecta -paget’s ds -osteomyelitis -tumours -tumour like conditions (fibous dysplasia)

• Exact Etiology: – Currently remains unknown

– The most popular theory, proposed by Dylkkanes in 1960, states that the deformity is caused by a defect of enchondral ossification of the femoral neck.

Weight bearing causes shearing stresses which result in fatigue of the dystrophic one and progressive varus deformity results

– Other proposed theories include: Metabolic abnormalities cause a deficiency or delay in the ossification process

CLINICAL PRESENTATION• most commonly seen between when the child begins to

ambulate and age six

• most common complaint is a progressive gait abnormality

in unilateral involvement this is due to both abductor muscle weakness and limb length inequality

• patients with bilateral involvement have a waddling gait and increased lumbar lordosis (similar to that seen in bilateral DDH)

• abduction and internal rotation of the affected hip are limited.

• With increasing coxa vara, the tip of the greater trochanter translates proximally relative to the center of the femoral head, and the origin and insertion of the hip abductors approach each other.

• The Trendelenburg test is positive

• In contradistinction to developmental dysplasia of the hip, no telescoping of the hip or other signs of instability, such as Ortolani's sign, are present.

• Shortening is present in unilateral cases but seldom exceeds 3 cm at skeletal maturity, even in untreated patients.

Physical Examination: - prominent and elevated greater trochanter

- positive Trendelenburg test

- limb-length inequality (usually less 2.5 cm)

- decreased ROM with restrictions noted with abduction and internal rotation

Quantification of the extent of radiographic deformity of the proximal femur in developmental coxa vara. A, The neck–shaft angle is the angle between the axis of the femoral shaft and the axis of the femoral neck. B, The head–shaft angle is the angle between the axis of the femoral shaft and a perpendicular line drawn to the base of the capital femoral epiphysis. C, The Hilgenreiner–epiphyseal angle is the angle between Hilgenreiner's line and a line drawn parallel to the capital femoral physis

Clinical Evaluation

Radiographs• AP- radiographs demonstrate a - decreased neck–shaft angle of the affected hip, - a widened radiolucent line corresponding to the proximal femoral physis, - characteristically, but not universally, a triangular metaphyseal fragment in inferior femoral neck surrounded by radiolucent bands traversing the neck and forming an inverted Y

• The superior, more horizontal radiolucent line is the capital femoral physis;

• The inferior, more vertical line is an abnormal area of faulty maturation of cartilage and irregular ossification

This Radiograph Shows –

relative overgrowth of the greater trochanter,

shortening of the femoral neck, varus deformity of the femoral head and neck,

vertical orientation of the capital physis,

a radiolucent inverted V isolating a segment of the medial superior femoral neck.-

• Histologic studies have shown that there are abnormalities in both cartilage production and metaphyseal bone formation. These findings are similar to those found in the proximal tibia in patients with Blount's disease.

• mechanical abnormalities may occur during development and early ambulation

• partial vascular insult to the inferior aspect of the femoral neck

• developmental abnormality which causes faulty cartilage formation and maturation

• Coxa vara because of short femoral neck

Biomechanics Of Congenital Coxa Vara

• Because of decreased neck shaft angle there will be -decreased joint reaction forces -Increased shearing forces across the neck -altered mescle tension because of shortened leg -Altered resting length of hip abductors may cause persistant limp• Increased abductor lever arm• There is decreased joint forces across the hip during one

leg stance as less muscle force is required to keep the pelvis horizontal position

• To Achieve Optimal Biomechanical Reconstruction Of Hip Joint In Coxa Vara-

‘’lateral Transposition Of Abductors,tenotomy of psoas And Adductors Tendon, Shortening of femur’’ Is Required

• So valgus osteotomy my move trochanter laterally, -improving the strength of abductor contraction but joint forces may increase -Adducted position restores improved wieght bearing area to the diseased hip joint -Shortening of abductor lever arm -Lengthening of limb

COMPLICATIONS OF UNTREATED COXA VARA

• Acetabular dysplasia• Hip subluxation• Degenerative arthritis• In b/l cases increased lordosis suggests

dislocation of hip

• b/l developmental coxa vara at age of 3yrs and 16 yrs who received no treatment

-gait was extraordinarliry good

• At the age of 40yrs with out treatment• Marked deformity with secondary osteoarthritis

Indications For Surgery• Progressive varus deformity• Painful limp • Trendelenberg gait• Unilateral progressive shortening• Asso.leg length discrepancy• Neck shaft angle <110deg• HE angle >60deg

• TREATMENT : – aimed at the prevention of the secondary deformities caused

by the disease's natural history on the proximal femur

Goals Of Surgery• Correction of femoral varus and retroversion• Restoration of articulotrochantric distance (abductor lever arm)• Create HE angle of <40 deg• Converting the abnormal shearing streses to compressive forces

at femoral neck• Efficiency of g.medius muscle has been improved by lowering

gr.trochanter• Rapidly progressive coxa vara is best treated by proposed

surgery• Surgery can be delayed until the child 4-5yrs old to make

internal fixation easier

• HILGENREINER’S EPIPHYSEAL ANGLE• Normal is 30-40 deg• Increased on abnormal side• IncreasedHE angle 45-60deg calls for careful

followup• HE angle >60deg, proggresive shortening

indication for surgery

TIMING OF SURGERY

• The timing of surgery remains controversial. Several authors recommend delay surgery until 5 6 years of age. Others state that surgery may be performed after 18 months if the below criteria are met.

• goal of surgical treatment is to produce an overcorrection of valgus angle to >150 - 160 degrees, as well as, correction of epiphyseal angle to less than 30 degrees

OPERATIVE TREATMENT • The presence of symptoms and the extent of proximal

femoral deformity as quantified by the H-E angle are the primary determinants of the need for surgical correction of the deformity.

• Normal HE angle is 30-40 deg that is increased on abnormal side

• Valgus osteotomy of is recommended in hips with an H-E angle of 60 degrees or greater

• is not usually required in patients with an angle less than 45 degrees,

• and may or may not be required in patients with angles between 45 and 59 degrees

• F I X AT I O N O P T I O N S include - Steinmann pins to the proximal and distal fragments incorporated in

plaster; - transfixing crossed Steinmann pins; - external fixation with monolateral half-pin fixators;- hybrid circular external fixation with wires and half-pins,- bifid plates (as described in Muller, Allgower, and Willenegger),- vitallium mold arthroplasty for degenerative disease- standard blade plates, - dynamic hip compression plates. – - pauwels valgus osteotomy- subtrochantric valgus osteotomy- inter trochantric valgus osteotomy

The latter forms provide the most secure forms of internal fixation in a child with adequate bony development.

CORRECTIVE VALGUS OSTEOTOMIES

• Valgus osteotomy of the upper femur at the intertrochanteric or subtrochanteric level is the most effective way to correct the varus deformity,

- to rotate the proximal femoral physis from a vertical to horizontal position (relieving shear stress on it),

- to enhance ossification of the defect

• The amount of valgus correction clearly plays an important role in the recurrence of deformity with growth, which has been estimated to occur in 30% - 70% of cases

• Treatment of coxa vara in chindren with cervico trochantric #

a closing wedge osteotomy just distal to gr.trochanter using a pediatric lag screw with a side plate for internal fixation

COMPLICATIONS:

• Recurrence of proximal femoral varus deformity-many feel that this is due to undercorrection at surgery while others feel that it is due to failure to place the osteocartilaginous defect into a compressive mode

• Premature physeal closure-the incidence may be as high as 89% and has not been found to be related to physeal injury at the time of surgery

• Greater trochanteric overgrowth-associated with premature capital femoral physeal closure and is commonly treated by greater trochanter transfer or epiphysiodesis

• Acetabular dysplasia-found to be increase in patients with premature physeal closure and inpatients who have had an undercorrection of the neck-shaft angle less than 140 degrees

• other complications have included pseudarthrosis, avascular necrosis, leg-length discrepancy, and degenerative arthritis

• Vitallium mold arthroplasty done on right side for degenerative changes

• Valgus osteotomy and Fixed angle blade plate on left side

WAGNER FIXATION• It is performed with a bifurcated plate

driven through the intramedullary surface of the proximal fragment and secured to the distal fragment with screws

• A variation of this technique is to perform the osteotomy slightly more proximally after insertion of an appropriate-sized screw of a dynamic compression hip screw device,

• insert the lateral distal edge of the proximal fragment into the medullary canal of the distal fragment, and secure the distal fragment to the plate portion of the device

CONTRAINDICATIONS TO OSTEOTOMY

• Neuropathic arthropathy• Inflammatory arthropathy• Active infections• Severe osteopenia• Advanced arthritis/ankylosis• Advanced age• *smoking, obesity

PAUWEL’S VALGUS OSTEOTOMY

• Preoperative tracking on pelvic radiograph

• P=plane of physis• H=horizontal line drawn

below the lesser trochanter

• Deside angle of closing wedge osteotomy from the proximal femur to correct the angle of inclination of physis

• A ‘Y’ shaped osteotomy will obtain a valgus position

• By this method static forces are converted from shearing to impacting forces

• Femoral head and neck are supported by calcar femorale

• Union is more and recurrence is less likely

INTERTROCHANTRIC VALGUS OSTEOTOMY

• BORDEN AND COLLEAGUES described a technique of valgus osteotomy in which the trochanteric region and the proximal shaft of the femur are exposed through a lateral longitudinal approach[.

• Under image intensifier a guidewire is inserted into the center of the superior half of the femoral neck parallel to its upper border.

• The guide pin is used as a landmark while the blade of a blade plate of appropriate size with an angle of 140 degrees is inserted into the neck.

• The blade should be parallel to the long axis of the femoral neck.

• Predrilling a slot facilitates insertion of the blade.

• Next, an intertrochanteric transverse osteotomy is made under radiographic control.

• The level of osteotomy should be 2 to 2.5 cm distal to the angle of the blade.

• The lateral surface of the proximal fragment is roughened.

• The head and neck of the femur are adducted by using the blade as a lever, and the femoral shaft is abducted.

• The lateral cortex of the upper fragment is thus approximated to the upper end of the lower fragment.

• Adductor tenotomy or muscle release may be necessary to facilitate correction of the deformity.

• The plate of the blade plate is fixed to the shaft with screws.

• postoperative one-and-one-half-hip spica cast should be applied.

• The cast is removed when the osteotomy has healed.

SUBTROCHANTRIC VALGUS OSTEOTOMY• Here the length of the femoral head and neck doesnot

change,only the angle anf limb length changes• Determine preoperatively the amount of valgus necessary to

align the hip properly by comparing the radiograph of c/l hip• The estimted increase in leg length ‘Delta H’ is given for the

desired angle obtained by the valgus osteotomy Delta h=L(cos@1-cos@)• When the angle of correction is determined the appropriate

laterally based closing wedge osteotomy can be determined• First detrmine the diameter of the bone by drilling a guide

pin transversely through the femur w=tangant angle x the diameter W=0.02 x diameter x angle

table

Procedure

• Perform an adductor tenotomy through a small medial incision

• Expose the gr. Trochanter and prox.shaft through 8-10 cm lateral incision

• Make a transvberse osteotomy just distal to to the screw at about the level of lesser trochanter take lateral wedge of bone as per tangent formula

• Fix the side plate in the usual manner

• Drill ahole just distal to gr.trochanter and check its placement

• Place an intermediate hip compression screw

• If the child is young avoid crossing the physis

• If it is for nonunion coprerssion hip screw should cross the nonuion site, and if it is proximal, crossing the physis may be necessary for union

• If grafting is necessary,is incerted by drilling a hole the size of the graft up through the femoral neck adjacent and parallel to the fixation divice

• Bilateral subtrochanteric osteotomy and internal fixation with coventry lag screw fixation.

After Treatment:• A spica cast can be worn until union is

complete• Cast can be removed at 8-12 wks• Regardless of method of osteotomy the

deformity can recur so children should be examined periodically after surgery until their growth is complete

TAKE HOME MESSAGE• Clinical evaluation at infancy/childhood to identify coxa vara ealry and

timely intervention as per degree of severity • Non surgical interventions has got greater degree of failure and

asso.complications • Surgery can be delayed until the child 4-5yrs old to make internal

fixation easier• currently, the most effective surgical treatment is a valgus producing

proximal femoral osteotomy (subtrochanteric and intertrochanteric procedures have similar results)

• Postoperative followup is adviced in children until epiphyseal fusion is complete till adult age group

• correction of coxa vara is not itself a curative of exact cause of coxa vara… we should exclude the existance of the etiological risk before intervention.

Thank you