Paediatrics

Developmental Dysplasia of the Hip

DDH represents a spectrum of conditions affecting the proximal femur and acetabulum. It involves dislocation or subluxation of the femoral head during the perinatal period which affects the subsequent development of the hip joint.

Risk Factors

• Female gender

• Positive FHx

• Breech position delivery

Pathophysiology

In true DDH, the femoral head has a persistently abnormal anatomical relationship with the acetabulum, which leads to abnormal bony development that can ultimately result in premature arthritis and significant disability. If left untreated the acetabulum becomes very shallow and in more severe cases a false acetabulum occurs proximal to the original one with a shortened lower limb.

Investigation and Examination

• Shortening, asymmetric groin/thigh skin creases and a click or clunk on the Ortolani or Barlow manoeuvres.

Ortolani Manoeuvre:

• Flex hip at 90° and abducted

• Place fingers laterally over the greater trochanter or hip joint

• Use anterior pressure over the trochanter in an attempt to identify a dislocated hip that is relocatable.

Barlow Manoeuvre:

• Flex hip at 90°and adducted

• Placed hand on the knee and use posterior pressure through the hip in an attempt to identify dislocatable hips.

Diagnosis

• Ultrasound (when the patient is aged 6 weeks to 6 months)

• X-ray (beyond the age of 6 months of age)

Management

< 6months of age

• 1^st line: Observation with normal physical examinations and mild dysplasia without instability on ultrasound

• 2^nd line: hip adduction in orthosis (typically Pavlik harness) and follow up at 6 months of age

6-18 months of age

• 1^st line: Closed reduction and spica casting

• 2^nd line: Open reduction and spica casting

References

• BMJ Best Practice: https://bestpractice.bmj.com/topics/en-gb/742/history-exam

• Youtube: https://hipdysplasia.org/for-physicians/pediatricians-and-primary-care-providers/infant-examination/

• Shaw BA, Segal LS. Evaluation and referral for developmental dysplasia of the hip in infants. Pediatrics. 2016 Dec;138(6): pii:e20163107.

• Cortex: Paediatric Orthopaedics

Transient Synovitis

Transient synovitis (or reactive arthritis) of the hip is the most common cause of hip pain in children and is a self-limiting condition.

Children may be able to walk more manageably later in the day and symptoms will be worse in the morning. Typically, the child will have their hip in flexion, abduction and external rotation (similar to the cross-legged position but on the affected side only) since this is the position with least intracapsular pressure and is therefore most comfortable. Internal rotation of the hip is most painful.

Referral to orthopaedics is warranted after 1 week of no improvement in a child with suspected transient synovitis of the hip.

2-3% of cases go on to develop Perthes disease.

Risk Factors

• Recent viral infection

• Recent bacteria infection (post streptococcal synovitis)

• Trauma

• Allergic reaction

• Male gender

Epidemiology

Children between the ages of 2 and 10 are most affected. Boys are affected more commonly than girls.

Pathophysiology

Usually one hip is impacted in transient synovitis of the hip and this typically develops after an upper respiratory tract infection. Infection in another part of the body leads to autoimmune cross-reactivity between viral and self-antigens.

The condition does not cause systemic upset, yet the patient may present with a low-grade fever. Transient synovitis of the hip is self-limiting and usually resolves in a few days to 2-3 weeks. The rate of recurrence can be as high as 20%.

Investigations

Since there can be other more severe conditions with similar symptoms such as septic arthritis or Perthes disease it may be appropriate to x-ray the hip (to rule out Perthes disease) and take blood tests to measure inflammatory markers such as CRP and ESR (low/normal levels make septic arthritis unlikely).

The diagnosis of transient synovitis of the hip is made clinically.

Management

• Rest

• Analgesia if required

References and Useful Links

• Kumar and Clarks Clinical Medicine 8^th Edition pg 546

• Coretext – Paediatric orthopaedics – 7.2 Transient synovitis of the hip

• Eureka Paediatrics pg 280

• https://www.orthobullets.com/pediatrics/4030/transient-synovitis-of-hip

• https://cks.nice.org.uk/topics/acute-childhood-limp/background-information/causes/#transient-synovitis

Slipped Upper Femoral Epiphysis (SUFE)

Patients symptoms are characterised with pain and limping with either acute, chronic or acute-to-chronic onset. Pain may be felt in the groin however, it can also present purely with pain in the knee due to impingement of the obturator nerve. A predominant clinical sign is loss of internal rotation at the hip.

The condition can also be called slipped capital femoral epiphysis (SCFE).

Risk Factors

• Obesity

• Obesity is intimately involved with idiopathic SUFE with more than 63.2% of patients within the 90^th percentile for weight for their age

• Puberty onset

• Circulating gonadotrophins are thought to be positively correlated with the weakening of the physis occurring at the onset of puberty.

• Endocrine disorders

• Hypothyroidism, panhypopituitarism, renal osteodystrophy, and growth hormone deficiency

Pathophysiology

The growth plate is intrinsically weak. Factors that induce stress at the hip joint (obesity, rapid growth and endocrine disorders) apply shear force at the growth plate. Failure at the growth plate causes the metaphysis to shift anterior and angularly in relation to the epiphysis.

Investigations

Bilateral antero-posterior x-ray

• Diagnosis: Klein's line does not intersect the femoral head

Management

The purpose of SUFE treatment is to restore functional long-term hip function.

Percutaneous pin fixation should ensure the patient regains anatomical alignment and fusion of the physis without jeopardising the longitudinal growth of the femur.

References

• BMJ Best Practice: https://bestpractice.bmj.com/topics/en-gb/757

• Ortho bullets: https://www.orthobullets.com/pediatrics/4040/slipped-capital-femoral-epiphysis-scfe

Patient Presentation 1

A 12-year-old boy presents with right hip, groin and medial knee pain. He is overweight and recently experienced an adolescent growth spurt. On physical examination, the right leg is externally rotated and there is restricted range of motion in the hip joint. He is unable to bear weight on the affected leg.

Patient Presentation 2

Johnny, 5, presents with his mother to the GP complaining of pain in his hip on his left side and a limp. His mother describes that he has been far less mobile and is reluctant to walk around the house if given the choice, however she thinks he may be slightly better in the evenings. When asked if Johnny has been unwell recently, she notes that he had a cough and sore throat about 1 week ago. Johnny does not appear systemically unwell, yet on examination of the hip there is slight erythema and swelling.

Patient Presentation 3

An infant is seen for a routine examination at 2 weeks of age. He was born at term with no pregnancy or delivery complications. A screening examination of the hips, using the provocative tests of Ortolani and Barlow, reveals laxity of the left hip joint. A characteristic 'clunk' is felt as the femoral head shifts out of the acetabulum with pressure applied directly posteriorly in the adducted hip, as well as when it shifts back into the acetabulum with the hip abducted and anterior pressure applied.