PRESENTERS: DR. MAINA/DR. ONDARIFACILITATOR: DR. T. MOGIRE

01/08/2013

Legg-Calve-Perthes Disease

FIRM 1 GRANDROUND

Georg Perthes (1869-1927)

First described by Karel Maydl

Epidemiology

Incidence 1-4/10,000

Age 4 - 10years; average 7 yrs As early as 2yrs as late as teens

Boys : girls 4:1

Bilateral 10-12%

No evidence of inheritance

Common in Caucasians; rare in black races

Etiology

Idiopathic

Past theories Infection, inflammation, trauma, congenital

Most theories involve vascular compromise

Pathophysiology

Rapid growth occurs in relation to devt of blood supply

Interruption of blood supply results in necrosis, removal of necrotic tissue, and its replacement with new bone.

Bone replacement may be so complete and perfect that completely normal bone may result

The adequacy of bone replacement depends on Age of the patient Congruity of the involved joint

Sources of blood supply

Up to 4years Metaphyseal vessels Retinacular vessels Ligamentum teres – scanty

4 to 7 years Metaphyseal vessels ceases

Above 7years Vessels in ligamentum teres have developed

Pathology Goes through stages which may last 3 to 4 years

Stage1 Ischaemia and bone death, cartilage thickens

Stage 2 Revascularization and repair

Dead marrow replaced by granulation tissue Bone revascularized and new bone laid down Dead bone resorbed, replaced by fibrous tissue,

fragmentation Stage 3

Distortion and remodelling Restoration of femoral archtecture or collapse Femoral head displaces laterally in relation to

acetabulum

Classification Waldenstrom classification

Catterall classification

Salter and thompson classification

Herring classification

Caterall classification

Based on amt of involvement of femoral epiphysis

Group I <1/2 of head involved ,

Group II Up to half of head. Some collapse of

central portion Group III

>1/2 of head involved with sclerosis, fragmentation and collapse of head

Group IV Entire epiphysis involved

Caterall “head-at-risk” signs Associated with poor results

lateral subluxation (most important)

calcification lateral to the epiphysis

Gage's sign: V shaped defect laterally

metaphyseal cysts

horizontal growth plate

Caterall “head-at-risk” signs

metaphyseal cysts

Gage's sign

Salter and thompson classification

Describes extent of subchondal fracture in the superolateral portion of femoral head

Type A - <50% of femoral head Type B - >50% of femoral head

can be observed radiographically earlier and more readily tan caterall classification

Can be applied early in course of dz to determine management

Herring classificatin/lateral pillar

Based on degree of collapse of lateral pillar during fragmentation stage

Goup A No collapse, no progressive flattening

Group B <50% collapse

Group C >50% collapse

Ritterbusch 1993 Has the highest predictive value and

interobserver reliability

Bilateral involvement

More severe dz than unilateral

Boys and girls equally affected

Independent event

Bone age delayed in perthes disease

Examination

Short stature Delayed bone age

Early Decreased ROM Antalgic gait

Late Decreased ROM of motion from acetabular

impingement Disuse atrophy of thigh muscles Leg lenght descrepancy Trendelenburg gait

Investigations Blood tests

haemogram, ESR, CRP Imaging

Plain X-rays Hip U/S Bone scintigrpahy MRI

Dynamic arthrography Assess spherity of femoral head Hinge abduction

Bilateral perthes Skeleta survey as part of work-up

Song et al MRI findings on widened medial joint space Initial stage

Overgrowth of cartilage Fragmentation stage

Overgrown cartilage with widened true medial joint space

Healing stage Widened true medial joint space

Treatment Goals of tratment

Maintain femoral head spherity – containment

Avoid severe degenerative arthritis

Guided by Age Severity Limitation in ROM

Treatment cont.

Initial Mx determined by sympts severity

Analgesia

Modification of activities

Bedrest and short period of traction

Wheelchair/crutch walking discouraged

Preserve abduction

Determine bone age

Treatment: Two main choices Conservative

Pain control Gentle exercises Regular re-assessment Avoid sport and strenous activities

Containment Hold hips widely abducted in

cast/brace >1yr Operation

Varus osteotomy of femur Innominate osteotomy of pelvis Both

Herring Guidelines to treatment

Children <6years Symptomatic treatment

Children >6years; bone age more imp than chronological age Bone age at or <6yrs

Lateral pillar A or B/ caterall I and II Symptomatic treatment

Lateral pillar C/ Caterall III and IV Bone over 6years

Herring A and B/Caterall I and II Abduction brace or osteotomy

Herring C/Caterall III and IV Outcome unaffected by treatment

Children 9yrs and older Except in very mild cases, operative containment is

the treatment of choice

oseoclast-osteoblat interaction

Prognostic features Age

<6yrs; good regardless of treatment 6-9years; not always satisfactory with

containment >10yrs; questionable benefit from containment,

poor prognosis Gender

Girls have worse prognosis Classification grade

Herrings lateral pillar classification Salter and thompson grade B worse prognosis Caterral classification grade

Caterral “head-at-risk” signs The five signs carry worse prognosis

Others Body weight, decreased ROM