Legg Calve PerthesDr.Aftab Qadir

Osteochondritis• Osteochondritis is a disease of epiphyses,

beginning as necrosis and followed by healing

Osteochondritis of the femoral capital epiphysisSynonym:Coxa plana,Waldenstrom“Characterized by idiopathic avascular osteonecrosis of the capital femoral epiphysis of the femoral head”

Legg Calve Perthes

Epidemiology

• Disorder of the hip in young children

• Usually ages 4-8 years

• Boys:Girls= 4:1

• Usually unilateral

ETIOLOGY Idiopathic

• Common in low socioeconomic group

• Parents of the effected children are often elderly

• Low birth weight babies

• Associated congenital anomalies

Pathology

Ischemia

Epiphysis necrosis

Growth arrest

Dense necrotic bone

Replaced by Vital bone

Clinical Presentation

•Patients usually limp while walking•Knee pain, constant pain in groin or thigh•Limited range of movement•Hip stiffness, which limits motion in the hip•Atrophy of muscles in the upper thigh•Shortening of the leg or unequal length of legs

Four phases of Legg-Calve Perthes Disease

Waldenstrom stages:• 1) Initial stage• 2) Fragmentation stage• 3) Re ossification 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 

Re ossification 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

Perthes' disease. A series of radiographs showing the stages of healing. (A) The initial radiograph shows a flattened, sclerotic femoral head. (B) An osteotomy is performed. (C, D) Later films show resorption of the sclerotic dead bone and its replacement with vital bone, resulting in a mushroom shaped femoral head.

Imaging

•Plane radiography (AP pelvis and Frog leg lateral)

•Ultrasound•Arthrography•CT •Radionuclide•MRI

Early radiographic signs of LCPD

•Small femoral epiphysis•Sclerosis of the femoral head with

sequestration and collapse•widening of the joint space

The flattened appearance on the affected side, compared to the smooth curve of the femoral head on the normal side.

Late signs of LCPD on radiographs

•A radiolucent crescent line representing a subchondral fracture

•Femoral head fragmentation and femoral neck cysts and coxa plana

Coxa magna, or remodeling of the femoral head, which becomes wider and flatter, similar in appearance to a mushroom

The left femoral neck is broadened, the metaphysis sclerotic with focal areas of lucency, the growth plate irregular and the femoral head flattened and sclerotic. It is uncovered laterally. The joint space appears widened.

ultrasound

•Assess hip joint for effusions.•Assessment of epiphyseal cortex•Articular cartilage assessment

• Normal anatomy of the anterior hip joint capsule. fce = femoral capital epiphysis; fm = femoral metaphysis; between cursors = both layers of joint capsule (hyperechoeic to muscle); I = iliopsoas muscle; small arrows = echogenic interface between joint capsule layers.

• Normal right hip compared to the left hip with an effusion. Hyperaemia of the soft tissues is evident on the left side. The machine settings are kept the same for comparison.

• Transverse image of both hips at the level of the neck of femur. Fluid distends the joint capsule on the left side (as marked by calipers).

• Perthes disease in a 4 year old boy with fragmentation of the femur epiphysis

• Perthes disease with irregular flattened epiphysis and joint effusion

Arthrography

Does not diagnose LCPD but determine:•Size and shape of the articular cartilage•Presence or absence of congruity

(A) Gross Perthes' disease of the femoral head. (B) The outline of the cartilaginous epiphysis is somewhat dome shaped with slight flattening and broadening laterally. The lateral aspect of the femoral head is uncovered but in the neutral position is in congruity. (C) In abduction there is pooling of contrast agent medially within the joint.

COMPUTED TOMOGRAPHY

Early signs of LCPD on CT scans include:•Bone collapse•Curvilinear zones of sclerosis•Subtle changes in bone trabecular pattern

Late signs of the disease on CT scans include:•Central or peripheral areas of decreased attenuation•Intraosseous cysts•Coronal reconstructions can show subchondral fractures, or collapse of the articular surface.

• Legg-Calvé-Perthes disease. Axial nonenhanced CT scan through the hip joints shows the loss of structural integrity of the right femoral head.

• Legg-Calvé-Perthes disease. Nonenhanced axial CT section through the hip joints obtained at a different level in the same patient. The scan shows the loss of structural integrity of the right femoral head, with acetabular subchondral sclerosis

• Legg-Calvé-Perthes disease. Coronal reconstruction shows flattening, sclerosis, and early fragmentation of the right femoral head

Radionuclide scan

•Technetium scan images of bone depend in part on blood flow to bone•Avascular areas are seen as scan defects(photopenic void)

Magnified pinhole views from a bone scan show decreased accumulation of radiopharmaceutical in the lateral aspect of the left femoral head (arrow), caused by disruption of the blood supply to the femoral head. The normal right femoral head is shown for comparison.

MRI

•Irregular foci of low signal intensity or linear segments.

•an intra-articular effusion•small, laterally displaced ossification

nucleus •femoral head deformity.

• Legg-Calvé-Perthes disease. Axial T1-weighted MRIs through the femoral heads show low signal intensity in the left femoral head.

• Legg-Calvé-Perthes disease. Coronal T2-weighted MRIs show irregularity and flattening of cortical margins of the left femoral epiphysis. A mild joint effusion

Differential Diagnosis• rule out infectious etiology (septic arthritis, toxic synovitis)

Others:• Sickle Cell anemia• Osteomyelitis • Traumatic AVN• Neoplasm   • Medication-steroid

Few Cases

The left capital femoral epiphysis is seen collapsed and sclerotic with low signal in all sequences and irregular contour as well as metaphyseal cystic lesion. Thickening of the articular cartilage is also noted with subsequent widening of the joint space. Bilateral hip joint effusions is seen, more on the left side. Relative loss of girth of left gluteal and thigh muscles with no abnormal signal within. 

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