Legg Calve Perthes Disease

Definition.  

• It is degenerative disease of the hip joint, where growth/loss of bone mass that leads to some degree of collapse of the hip joint and to deformity of the ball of the femur and the surface of the hip socket
• The disease is characterized by idiopathic avascular osteonecrosis of the capital femoral epiphysis of the femoral head leading to an interruption of the blood supply of the head of the femur close to the hip joint 

Epidemiology

• Disorder of the hip in young children
• Usually ages 4-8 years
• Boys:Girls= 4:1
• Usually unilateral

Blood supply

Age related changes in blood supply to Epiphysis

Age < 4

Receives blood from the metaphyseal vessels

Age 4-8

Blood from separate epiphyseal vessels as the physis is barrier to blood flow

Age > 8

The ligamentum teres has increasing significance in supply (20%)

Radiographic Stages

Four Waldenstrom stages:

1) Initial stage

2) Fragmentation stage

3) Reossification stage

4) Healed stage

Initial Stage

Early radiographic signs:

• Failure of femoral ossific nucleus to grow
• Widening of medial joint space
• Irregular physeal plate
• Blurry/ radiolucent metaphysis

Fragmentation Stage

• Bony epiphysis begins to fragment
• Areas of increased lucency 

Reossification Stage

• Normal bone density returns
• Alterations in shape of femoral head and neck evident

Healed Stage

• Left with residual deformity from disease and repair process
• Differs from AVN(avascular necrosis) following Fx or dislocation

Presentation

• Often insidious onset of  limp
• C/O pain in groin, thigh, knee
• The typical patient has a flexion contracture of 0-30 degrees, loss of abduction compared with the opposite side and loss of internal rotation of the hip.
• Can have an acute onset
• Patients frequently have younger skeletal age than cohorts

Physical Exam

• Decreased ROM, especially abduction and internal rotation
• Trendelenburg test often positive
• Adductor contracture
• Muscular atrophy of thigh/buttock/calf
• Limb length discrepency

• Imaging

AP pelvis

Frog leg lateral

Key= view films sequentially over course of dz

Arthrography

Differential Diagnosis

• Important to rule out infectious etiology (septic arthritis, toxic synovitis)

Others:

-JRA

-Sickle Cell

-Osteomyelitis

-Traumatic AVN

-Neoplasm  

-Medication-steroid

Non-operative Tx

• Improve ROM 1st
• Bracing:

-casts

-Hips abducted and internally rotated for containment

• Wean from brace when improved x-ray healing signs

Bracing

Operative Tx

• If non-op tx cannot maintain containment

Surgical options:

• Excise lat extruding head portion to stop hinging abduction
• Acetabular (innominate) osteotomy to cover head
• Varus femoral osteotomy
• Arthrodesis 

Varus Osteotomy

Late Effects of LCP

• Physeal arrest patterns 
• Irregular head formation