Perthes’ Disease (Coxa plana)

Legg-Calve- Perthes

Perthes’ Disease (Coxa plana)

Painful disorder of childhood characterized by necrosis of the femoral head.

Boys: Girls = 4:1

Age: 4-8 years

PATHOGENESIS

3 sourses of blood supply to femoral head

1- Metaphyseal vessels: Disappear at 4 years age

2- Ligamentum teres vessels: develop fully at 7 years age

3- Lateral epiphyseal vessels: All the ages

Between 4-7 y. the only sourse is lateral epiphyseal

Trauma OR Non-specific synovitis →effusion →stretching of retinaculum→ obstruction of vessels→ necrosis

PATHOLOGY2-4 years3 stages: 1- Bone Death 2- Revascularization and repair New bone is laid down on the dead trabeculae if: (a) Part of the head is involved (b)Repair process is rapidRestoration of the bony architecture 3- Distortion and remodeling if: (a) A large piece is damaged (b) Repair process is slow.The head and neck are distorted

XRAY(A)Early changes :(1) ↑density of the bony

epiphysis (2) ↑joint space (apparent)(B)Later changes :(1) flattening(coxa plana) (2) fragmentation (3) coxa magna (4) mushroom like head (5) lateral displacement of the

epiphysis (6) sagging rope sign (7) rarefaction and broadening

of the metaphysis(neck)

http://www.nwhealth.edu/conted/distlear/Avn/ropesag.html

CLINICAL FEATURESBoys: Girls = 4:14-8 yearsPain in the groin ± kneeLimpingLittle wasting of quadriceps ±Early stage: The hip is irritable. i.e.: All movements are diminished Their extremes are painfulLater on (after the irritable state): All movements are full except Abduction

and Internal rotation

TREATMENT(A)Irritable state: Skin traction till pain subsides (3

weeks)

(B) Further treatment depends on the assessment of prognosis

(a) Favourable prognostic signs (1) Onset< 6 years (2) Partial involvement of the femoral head (3) Normal shape of the femoral head (4) Absence of metaphyseal rarefactionTREATMENT: Supervised Neglect

(b)Unfavourable prognostic signs

(1) >6 years age

(2) Whole femoral head involved

(3) Lateral displacement of the head

(4) Severe metaphyseal rarefaction

TREATMENT: Containment of the femoral head (Keeping the femoral head well seated within the acetabulum to retain its normal shape during the period of healing). This is achieved by 2 methods:

Conservative: Holding the hips widely abducted in POP or by a removable splint for 1 year.

.

Surgery(a) Varus osteotomy of the femur

(b) Innominate osteotomy of pelvis

NOTE: Those with very worse Xray changes, treatment is useless.