Hip pain

Question 1

What is the most common cause of a limp in childhood?

Answer 1

The most common cause of limp in childhood is a hip problem.
Children with hip pathology may present with pain, refusal to bear weight, a limp, or decreased movement of the lower extremity

Question 2

What is the most common cause of hip pain in a child aged 3 years or over?

Answer 2

Transient synovitis is one of the most common causes in children over 3 years of age but it has similar early symptoms to septic arthritis.

Question 3

What should you ask in the history of a child presenting with hip pain?

Answer 3

History should include pain characteristics (location, character, onset, duration, change with activity or rest, aggravating and alleviating factors, night pain), together with any mechanical symptoms (catching, clicking, snapping, worse during or after activity).

If pain is present it is important to determine the origin:

• Pain in the hip area may originate from any part of the hip joint or from the femur. Intra-articular hip pathology is usually localised to the groin.
• Pain in the hip area may be referred from the knee joint or from structures in the inguinal canal, testis (including torsion) and lower abdomen, or from the lower back.
• Hip pathology often causes referred thigh or knee pain.

History should include previous injury (acute macrotrauma, repetitive microtrauma), surgery, neurological disorder, inflammatory joint disease or bleeding diathesis, as well as conditions associated with arthropathies, including psoriasis, acute uveitis and inflammatory bowel disease.

Any other underlying developmental conditions (eg, Down’s syndrome).

Establish whether there is any possibility of tick exposure.

Ask about developmental history, particularly noting late onset of walking, unusual gait or clumsiness in very young children. These might suggest developmental or degenerative conditions.

Ask about family history of hip problems.

Ask about systemic symptoms (fever, irritability); inflammatory symptoms (morning stiffness); neurological symptoms (weakness, altered sensation); and the current level of function of the child.

Ask about previous treatments and response (including antibiotics, analgesics, anti-inflammatories, physiotherapy, steroid treatment).

Question 4

What should you examine in a child presenting with hip pain?

Answer 4

Hip examination
Most causes of hip pain are unilateral, allowing comparison to the unaffected side.
The lumbar spine, sacroiliac joint, knee and abdomen should also be examined.
A complete musculoskeletal examination to look for joint swelling should be done if there is a history of inflammatory symptoms.
Examine the corresponding knee, inguinal canal, abdomen and testes.
Systemic examination should include temperature and vital signs.

Question 5

Which investigations should be done for a child presenting with hip pain?

Answer 5

If infection is suspected, urgent assessment in secondary care is required and FBC, ESR, CRP, blood and joint cultures will form part of the evaluation. Cultures of joint and synovial fluid may be needed.

Arthritis is a clinical diagnosis; anti-nuclear antibody (ANA), rheumatoid factor and HLA-B27 are helpful in classification and treatment.

Radiographs, ultrasound and magnetic resonance imaging (MRI) are the most common imaging tools used to assess the paediatric hip.

Children and adolescents with hip pain, referred pain to the thigh or knee or a limp require visualisation of the proximal femur in two planes. Anterior posterior (AP) plain films of both hips, preferably taken with the patient standing and ‘frog leg’ view are standard.

Technetium bone scan identifies areas of increased osteoblastic activity and can help localise infection and subtle areas of bone injury such as early stress fracture.

Question 6

What are the common causes of hip pain in children?

Answer 6

The most common and significant causes of hip pain in children are:

• Transient synovitis (irritable hip) peaking at 3-8 years.
• Septic arthritis - any age (peaking at 0-6 years).
• Perthes’ disease (3-12 years peaking at 5-7 years).
• SCFE (early adolescence - usually in obese children).

Question 7

Why is it possible to diagnose septic arthritis as transient synovitis?

Answer 7

Transient synovitis and septic arthritis have similar early symptoms with spontaneous onset of:

• Progressive hip, groin, or thigh pain.
• Limp or inability to bear weight.
• Fever.
• Irritability.

This significant clinical overlap means that there are no absolute criteria for definitive diagnosis of either condition.

Question 8

How does transient synovitis present?

Answer 8

Transient synovitis typically has an acute onset, followed by spontaneous recovery with no systemic upset. It is a benign condition with a small amount of fluid in the joint.

It is the most common cause of hip pain in children between the ages of 3-10 years (peaking between 5 years and 6 years) and is more common in boys, often preceded by viral infection.

Question 9

What is the management of transient synovitis?

Answer 9

It is a self-limited condition with no long-term sequelae. It can be managed with oral analgesics such as ibuprofen/paracetamol and observation.
Transient synovitis recurs in up to 15% of children.

Question 10

What are the complications of transient synovitis?

Answer 10

It may affect the same or the opposite hip:

• Pain is usually not severe but may prevent weight-bearing.
• Usually there is no pain at rest and passive movements are only painful at the extreme range of movement.
• The child is usually systemically well and the ESR is either normal or slightly raised.
• Management includes rest and analgesia, with mobilisation once the pain has settled.

Question 11

What is juvenile idiopathic arthritis?

Answer 11

Juvenile idiopathic arthritis (JIA) is defined as joint inflammation presenting in children under the age of 16 years and persisting for at least six weeks, with other causes excluded.

There are seven subsets of JIA with oligoarticular JIA most common.

Question 12

What is the presentation of JIA?

Answer 12

It affects the hips in 30-50% of cases and is usually bilateral. It is very uncommon for hip monoarthritis to be the initial manifestation.

Children typically present with groin pain but may have referred thigh or knee pain.

There is often morning stiffness, with gradual resolution of pain with activity.

There is painful or decreased range of motion, especially in internal rotation.

Question 13

What are the differentials of JIA?

Answer 13

Septic arthritis 
Osteomyelitis
Reactive arthritis 
Trauma 
Mechanical pain
IBD 
Malignancy 
Connective tissue disease

Question 14

What are the investigations of JIA?

Answer 14

It is a clinical diagnosis,

Aspirate the joint if septic arthritis is suspected.

Question 15

What is the management of JIA?

Answer 15

Treatment includes physiotherapy and anti-inflammatory therapies.

All children suspected of having chronic inflammatory arthritis should be referred to a paediatric rheumatologist.

Patients should be encouraged to participate in physical activity.

NSAIDs provide symptom relief

Methotrexate is the first-line treatment

Etanercept is second-line in polyarticular JIA

Surgery such as joint replacement

Question 16

What are the complications of JIA?

Answer 16

Joint deformities such as contractures, swan-neck/ boutonniere deformities

Uveitis which can lead to blindness

Osteoporosis

Growth restriction

Restriction of sports

Psychosocial, behavioural and educational difficulties may occur.

Question 17

What is Perthes disease?

Answer 17

This is an idiopathic avascular necrosis/osteonecrosis of the femoral epiphysis (usually affecting those aged 4-10 years and peaking between 5 and 7 years). It affects more boys for each girl affected and is bilateral in 10%.

Question 18

What is the pathogenesis of Perthes disease?

Answer 18

The primary event is avascular necrosis of the femoral epiphysis, which results in delayed ossific nucleus:

• The articular cartilage is nourished by synovial fluid and continues to grow.
• The cartilage columns become distorted with some loss of their cellular components.
• They do not undergo normal ossification, which results in excess of calcified cartilage in the primary trabecular bone.
• Revascularisation proceeds from peripheral to central.
• Symptoms occur with subchondral collapse and fracture.

Question 19

What is the presentation of Perthes disease?

Answer 19

Onset is usually over weeks with no hx of trauma.
Usually unilateral.
Child is systemically well.
Children usually present with a limp or pain in the hip, thigh or knee.
There is limited and painful rotation and abduction of the ipsilateral hip.
Internal rotation is usually affected more than external rotation.
Antalgic gait due to pain and a Trendelenburg gait is seen in the late phase.

Question 20

What are the investigations of Perthes disease?

Answer 20

FBC and ESR.
Early X-rays may show widening of the joint space (the best view is frog lateral), or may be normal.
Technetium bone scan or MRI scanning can be used to identify pathology (seen as an area of reduced perfusion)[
Later, there is a decrease in the size of the nuclear femoral head with patchy density on X-ray.
Later still, there may be collapse and deformity of the femoral head with new bone formation. Severe deformity of the femoral head risks early arthritis.
An arthrogram and/or MRI scan are often needed to assess congruency throughout full range of movement. A flat-topped incongruent head has the worst prognosis. It can rule out hinge abduction where the enlarged femoral head impinges on the acetabular rim.
Hip aspiration if a septic joint is suspected.

Question 21

What are the differentials of Perthes disease?

Answer 21

Transient synovitis 
Fracture or soft tissue injury
Septic arthritis 
Sickle cell disease 
Gaucher’s disease

Question 22

What is the management of Perthes disease?

Answer 22

Treatment consists of rest from aggravating activities and range of exercises. Orthoses or surgery may be required.
NSAIDs for pain relief.
Operative treatments include:
-Femoral or pelvic osteotomy.
-Valgus or shelf osteotomies.
-Hip arthroscopy.
-Hip arthrodiastasis (controversial).

Question 23

What is slipped capital femoral epiphysis?

Answer 23

This is displacement of the proximal femoral epiphysis off the femoral neck, usually in those aged 11-14 years. It is more common in obese children and boys and is bilateral in 20-40%.

Question 24

What is the classification of SCFE?

Answer 24

Stable (90% of cases): the patient is able to walk and osteonecrosis is very rare.

Unstable (10% of cases): the patient is unable to walk (even with crutches) and there is a 50% incidence of osteonecrosis

Question 25

What are the risk factors of SCFE?

Answer 25

Mechanical: local trauma, obesity. More than 80% of children diagnosed with SCFE are obese. Inflammatory conditions: neglected septic arthritis. Endocrine: -Hypothyroidism, hypopituitarism, growth hormone deficiency, pseudohypoparathyroidism, vitamin D deficiency. Previous radiation of the pelvis, chemotherapy, renal osteodystrophy-induced bone dysplasia.

Question 26

What is the presentation of SCFE?

Answer 26

Adolescents usually present with a limp and may have hip, groin or knee pain. The hip is often held in abduction and external rotation with decreased internal rotation, flexion and abduction.

Question 27

What are the differentials of SCFE?

Answer 27

``` Acute hip fracture Perthes’ disease Osteomyelitis Septic arthritis DDH ```

Question 28

What are the investigations for SCFE?

Answer 28

Anteroposterior and 'frog-leg' lateral X-rays show widening of epiphyseal line or displacement of the femoral head. - Earliest findings include globular swelling of the joint capsule, irregular widening of the epiphyseal line and decalcification of the epiphyseal border of the metaphysis. - Epiphysis normally extends slightly cephalad to the upper border of the femoral neck. - Small amounts of slippage can be detected by the epiphyseal edge becoming flush with the superior border of the neck. - Sometimes, however, the only evidence of epiphyseal injury is a slight widening of the growth plate. Ultrasound can detect the presence of an effusion but is rarely indicated.

Question 29

What is the management of SCFE?

Answer 29

Treatment includes non-weight-bearing, and surgery Provide analgesia and immediate orthopaedic referral if the diagnosis is suspected. The short-term goal of surgery is to prevent further progression of the slip and the longer-term goal is to prevent femoroacetabular impingement (FAI); residual abnormal morphology of the proximal femur is thought to be the cause of labral and cartilage damage leading to osteoarthritis of the hip.

Question 30

What are the complications of SCFE?

Answer 30

Chondrolysis Avascular necrosis of the epiphysis Recurrence or progression OA of hips

Question 31

What is DDH?

Answer 31

DDH refers to a spectrum of severity ranging from mild acetabular dysplasia with a stable hip, through more severe forms of dysplasia with neonatal hip instability, to established hip dysplasia with or without later subluxation or dislocation.

Question 32

What are the risk factors for DDH?

Answer 32

A sibling with DDH Females (Probably due to circulating maternal hormone relaxin on ligamentous laxity) Vaginal delivery of babies with breech presentation Firstborn child Oligohydramnios (causes restriction of movement) Multiple pregnancy Common in cerebral palsy and arthrogryposis

Question 33

How do you screen for DDH?

Answer 33

Screening for DDH is part of the physical examination of newborn and 6- to 8-week-old babies. Ultrasound screening is not currently recommended as a screening tool for all babies.

Question 34

When is USS screening fo DDH done?

Answer 34

USS screening is done within 6 weeks if: - There is a first-degree FH of hip problems in early life - Breech presentation

Question 35

How do you examine for DDH?

Answer 35

Observe for asymmetry: -Asymmetrical gluteal or thigh skin folds. -Limb length discrepancy (Galeazzi sign used in 3-6 months babies). -Limitation and asymmetry of hip abduction when the hip is flexed to 90°. The Ortolani and Barlow tests are the most common clinical tests for newborn babies (becomes difficult after 2-3 months) -Both Barlow and Ortolani tests detect an unstable hip but do not detect an irreducible dislocated hip, which is best detected by identifying limited abduction of the flexed hip. Nor do they detect a stable hip with abnormal anatomy - eg, acetabular dysplasia.

Question 36

What is the presentation of DDH?

Answer 36

There is limited abduction when fully flexed. They may walk on toes on the affected side or present with a painless limp.

Question 37

What are the investigations for DDH?

Answer 37

Dynamic USS to assess hip stability CT and MRI scan

Question 38

What is the management of DDH?

Answer 38

Early diagnosis and treatment of those most severely affected are important for a good outcome. Most unstable hips stabilise spontaneously by 2-6 weeks of age and any hip that remains dislocatable or pathologically unstable after this time requires prompt treatment. Bracing is first-line treatment in children younger than 6 months. Surgery is an option for children in whom non-operative treatment has failed and in children diagnosed after 6 months of age.

Question 39

What are the other causes of hip pain?

Answer 39

``` Lyme disease Osteomyelitis Reactive arthritis Kawasaki disease Psoas abscess Appendicitis Pyomyositis Muscle strains Benign and malignant tumours ```

Question 40

What are the causes of hip pain at any age?

Answer 40

``` Transient synovitis. Septic arthritis of the hip Trauma Acute osteomyelitis of the proximal femur. Tuberculous arthritis. Lyme disease. Juvenile idiopathic arthritis. Bone malignancy. Non-accidental injury. Secondary avascular necrosis ```

Question 41

What are the causes of hip pain in a child aged 0-3 years?

Answer 41

``` Septic arthritis NAI Osteomyelitis DDH Kawasaki disease Fractures ```

Question 42

What are the causes of hip pain in a child aged 3-10 years?

Answer 42

``` Transient synovitis. Septic arthritis. Osteomyelitis. Perthes' disease. Fracture or soft tissue injury (stress fracture). Kawasaki disease. Subluxation in Down's syndrome. ```

Question 43

What are the causes of hip pain in a child aged 10-16 years?

Answer 43

``` SCFE Septic arthritis Osteomyelitis Idiopathic chondrolysis Fractures ```

Question 44

What is the management of hip pain in children?

Answer 44

Management of hip pain in children depends on the underlying cause. In primary care, however, the most pressing question is which children need urgent assessment in secondary care. Arrange urgent assessment if the child: - Is less than 3 years of age. - Is older than 9 years of age with painful or restricted hip movements (in particular internal rotation) - to exclude SCFE. This does not exclude younger children: a younger child with risk factors would also need urgent assessment. - Is unable to weight-bear. - Has a fever and/or red flags suggesting serious pathology, such as pain causing waking at night, fatigue, anorexia, weight loss, or night sweats. - Is in severe pain, agitated, or has reduced peripheral pulses or muscle weakness which may indicate neurovascular compromise or impending compartment syndrome. - Has an injury which you suspect to be non-accidental.