Painful hip in childhood

Imaging approaches and findings

(an overview)

M. Mearadji International Foundation for Pediatric Imaging Aid

Introduction

• Painful hip is a common clinical symptom in

all ages.

• Patient history and clinical findings are the

first step in diagnosis of painful hip.

• Because of the large number of acute and

chronicle conditions different imaging

procedures are indicated.

Conditions associated with

painful hip in different age groups

Years Diagnosis

0-3 Accidental and non accidental trauma

Coxarthritis and osteomyelitis

3-10 Transient synovitis (most frequent)

Perthes disease

Primary or metastatic malignancies

10-15 SCFE

Secondary osteonecrosis

Osteoid osteoma

Osteomyelitis and coxarthritis

Bone and soft tissue malignancies

Others and pitfalls

Imaging modalities in diagnosis

of painful hip

• Sonography

• Plain film

• MRI

• CT

• Radionuclide studies

Flow chart of painful hip in childhood

Sonographic screening

of hip

Normal Abnormal

Plain film

Trauma?

Joint effusion without

muscle atrophy or bone

changes

Muscle atrophy or bone

changes with or

without effusion

Transient synovitis

Sonographic follow up

within 6 weeks

Plain film

Sufficient finding for diagnosis

Perthes, SCFE, osteoarthritis

Secondary avascular necrosis

Rheumatoid arthritis

Insufficient finding for diagnosis

Neoplastic disease and other

soft tissue and bone changes

MRI CT

Bone scan MRI rarely indicated

Sonographic technique in

evaluation of painful hip • Examination in supine position

• Anterior approach along the long axis of femoral neck

• Use of high frequency (7-12 MHZ) linear array transducer

• Identical evaluation of asymptomatic hip as the normal references

• Identification of the anterior joint capsule

• Visualization of m. iliopsoas and m. rectus femoris

• Search for echogenic or non-echogenic joint effusion

• Symmetric imaging of both femoral head and neck

• Sonographic measurements of the quadriceps muscle at both sides

Symmetric normal sonogram of both hips and m. quadriceps

Spiral fracture tibia by a limping and crying three year old child.

Normal sonography of the hip

Transient synovitis

• Most frequent disease of hip in children 3 - 10 years

• Boys more affected than girls 2 : 1

• Unilateral sudden onset of pain radiating to knee

• Clinical findings: decreased rotation and abduction

• No fever and normal laboratory findings

• Possible etiology: antibody response to infections or

traumatic

• Treatment: rest, spontaneous cure

Sonographic features in transient

synovitis

• Anechoic effusion in anterior recess

• No measurable thickening of joint capsule

• No or small amount of joint fluid in asymptomatic hip

• Symmetric thickness of quadriceps muscle both-sided without sign of atrophy

Left-sided transient synovitis

Transient synovitis

Note the symmetrical aspect of epiphysis and cartilage

Not affected side Affected side

Perthes disease

• Mean age of children 5 (2 - 11) years

• Boys more affected than girls (4 : 1)

• In 15 % bilateral

• The onset is usually more insidious with longer history

• Clinical findings: abnormal gait, reduced rotation and

abduction

• No fever and normal laboratory findings

• Possible etiology: recurrent trauma, hypovascularity,

coagulation disturbances

• Treatment: rest, bracing, osteotomy

Imaging features of Perthes disease

Sonography Hip effusion in initial stage

Cartilage thickening

Epiphyseal deformation

Muscle atrophy

Plain film First few days normal

Osteopenia

Widening of joint space

Flattening of the femoral head

Condensation

Initial phase of Perthes disease.

Note fluid collection, flat epiphysis, hypertrophy of

cartilage and atrophy of iliopsoas muscle.

Right-sided Perthes disease with effusion

Note asymmetric epiphysis and atrophic iliopsoas muscle

Muscle waste of quadriceps left-sided in Perthes disease

Normal and atrophic rectus muscles

Initial stage of Perthes disease left-sided. Note hypo-intensity of affected

epiphysis on MRI and fluid collection.

Slipped capital femoral epiphysis

(SCFE)

• Moderate male prediction (2 : 1)

• Mean age boys 11,5 and girls 13,5 years. High incidence in obesity

• 16 to 49 % bilateral

• Clinical findings: severe pain in the groin, buttocks or thigh

• No fever and normal laboratory findings

• Possible etiology: epiphyseal plate weakening due to endocrine factors. Trauma

• Treatment: fixation with cannulated hip screws

Imaging features of slipped capital

femoral epiphysis (SCFE)

Sonography Small amount of hip effusion

Dislocated epiphysis

Muscle atrophy

Plain film Widening of physis compared with

asymptomatic contralateral side

Dislocated epiphysis on frog lateral

film

Slipped epiphysis on right side. Note the atrophy of m. iliopsoas and

quadriceps, the femoral epiphysis is displaced

Slipped epiphysis of the left side. Diagnosed primary by ultrasound.

Note dislocated femoral epiphysis and broad epiphysial line.

Septic osteoarthritis of hip

• Categorization in 6 different types in different

age groups, more acute and frequently in

infancy

• Unilateral in hip with mostly sudden onset

• Clinical findings:

– immobility

– painful hip

• Etiology: hematogenous, pathogenic bacteria

Bacterial coxarthritis on the left side with huge effusion of the hip and

periostal apposition. This finding is confirmed on plain film with

lateralization of caput femoris.

Girl with fever: fluid collection in anterior recess, the cause of

effusion was bacterial coxarthritis (Staphylococcus aureus) left-

sided.

2 year old boy with right-sided osteo-

arthritis.

Juvenile rheumatoid arthritis

• Annual incidence of 14 : 100.000 new cases in

child population

• Affects girls more often than boys

• Clinical sign is different, mostly affects large

rather than small joints

– Transitory pain

– Immobility

• Fever only in case of Still disease (10%) mostly

positive laboratory findings

Imaging features of juvenile

rheumatoid arthritis

Sonography Joint effusion

Synovial proliferation

Muscle atrophy

Loss of joint space

Plain film Negative in early stage

Loss of joint space

Erosion, subchondral cysts

MRI Joint effusion

Acetabular and femoral head edema

Juvenile idiopathic

arthritis. Note the

muscle atrophy,

loss of joint space

and structural

changes of femur

head.

Secondary osteonecrosis of femoral

head

• One of the most frequent cause of painful hip

in children with acute lymphoblastic leukemia,

sickle cell anemia, a history of trauma, steroid

therapy or organ transplantation

• Gender M:F = 4:1

• Sonographic screening, plain film, MRI, CT or

nuclear scanning

Imaging features of secondary

avascular necrosis Sonography Joint effusion

Femoral head deformity

Muscle atrophy

Plain film

Femoral head sclerosis with or

without deformity

CT Osteoporosis and sclerosis

MRI Joint effusion

Hypo-intense bone marrow

Double line sign

11 year old boy with leukemia.

Note: corresponding hip changes

on plain film, sonography and

MRI.

2 januari 2007

7 year old boy with painful hip.

Note the osteoid osteoma of

femur and the right-sided,

muscular atrophy on plain film

without skeletal changes on

the first film

7 year old boy with a Brodie abscess of right

acetabulum

Multi-imaging of

painful hip

A boy with painful hip caused by Ewing sarcoma of os

ilium.

Note the finding on plain film and MRI.

Patient admitted with a clinical diagnosis of transient synovitis. On

sonogram the hip was normal. In right lower quadrant a perforated

appendicitis with pus is found.

Pitfall

Conclusions

• Patient history, clinical findings and age category are

important in diagnostic work up of painful hip in

children.

• Sonographic screening is the first modality of choice

in diagnostic of painful hip.

• Transient synovitis is the most common cause of

painful hip in the age of 3-10 years.

• Sonographic recognition of muscle atrophy is an

important sign of serious disorders of hip joint or

surrounding bone and soft tissue.

Conclusions

• Hip effusion and cartilage thickening can be the first initial signs of Perthes disease.

• Synovial thickening, echogenic effusion with or without bone destruction are frequent findings of cox arthritis.

• Perthes disease, SCFE, osteo-arthritis as well as secondary avascular necrosis with bone deformities on sonograms should be confirmed by plain film or in complicated cases with MRI.

• MRI, CT or bone scan are indicated by persistent painful hip with a normal sonogram or plain film.