T&O: Paediatric Hip Pain

Question 1

What are the 4 main causes of paediatric hip pain? What age ranges an gender do they usually affect?

Answer 1

1. Transient synovitis (3-8 yrs), more common in males
2. Septic arthritis (0-6 yrs)
3. Slipped capital femoral epiphysis (10-17 yrs), more common in obese M
4. Perthes disease (4-7 yrs), M:F = 5:1

Question 2

What is transient synovitis?

Answer 2

Inflammation of the synovium of the hip joint capsule. Self-limiting. Exact cause unknown but may be associated with URI.

Question 3

What is septic arthritis? What is the most common causative organism?

Answer 3

Intra-articular infection as a result of trauma, recent instrumentation of joint or haematogenous seeding.
S. aureus is most common organism.

Question 4

How would you clinically differentiate between septic arthritis and transient synovitis?

Answer 4

Have similar early symptoms with spontaneous onset of hip, groin or thigh pain.

Pain

• TS: usually mild, allowing weight bearing, absent at rest
• SA: severe, prevents weight bearing

Fever

• TS: absent to mild, systemically well
• SA: high, appears ill, irritable

ROM

• TS: restricted abduction
• SA: rests in external rotation, refuse movement

Labs

• TS: CRP <20
• SA: WBC >12,000, ESR >40

Question 5

How are transient synovitis and septic arthritis diagnosed?

Answer 5

TS: diagnosis of exclusion
- USS often shows fluid inside joint capsule (Fabella sign)

SA: arthrocentesis
- shows raised WBCs and lactate
- perform gram stain and culture
(Treatment should not be delayed for the results of culture but should be based on Gram stain and polarising microscopy (exclude crystal arthropathy) results)

Question 6

What is the management for transient synovitis and septic arthritis?

Answer 6

TS: rest, analgesia and NSAIDs

SA: surgical drainage and lavage of joint, and high-dose IV antibiotics

Question 7

What is the prognosis of transient synovitis an septic arthritis?

Answer 7

TS: usually resolves within 7-10 days. Recurrence rate is 4-17%, mostly within 1st 6mths.

SA: 90% recovery with treatment, but if unrecognised and untreated can cause:

• irreversible joint damage within 48hrs of infection onset due to proteolytic enzymes of WBCs that flood infected synovial space
• osteonecrosis due to effuson and increased intra-articular pressure compromising blood circulation

Question 8

What is Perthes disease? How does it present?

Answer 8

Idiopathic osteonecrosis of femoral epiphysis seen in children.

Most children present with atraumatic hip pain or limp. Blood tests typically normal.

Question 9

Describe the 4 stages of Perthes disease.

Answer 9

1. Disruption of blood supply to femoral head, causing necrosis (several mths).
2. Fragmentation of femoral head, with replacement of dead bone by soft woven bone (1-2 yrs).
3. Reossification with stronger cortical bone (several yrs).
4. Healing/completed bone growth.

Question 10

Describe the management options for Perthes disease.

Answer 10

Goal of treatment is to relieve pain, protect shape of femoral head and restore normal hip movement, preventing early onset arthritis.

Conservative:

• observation
• NSAIDs
• limiting activity
• physiotherapy
• casting and bracing (Petrie casts)

Surgical (>8yrs, >50% femoral head damage, unsuccessful conservative therapy):
- osteotomy - cut and reposition femur to replace femoral head within acetabulum

Question 11

What is SCFE? Name 3 risk factors. How does it present?

Answer 11

Relatively common condition affecting the physis of the proximal femur – type I Salter-Harris epiphyseal fracture due to repeated trauma on background of mechanical and probably hormonal predisposing factors.

Risk factors:

• male
• afro-carribean
• obesity

Pts present with hip pain progressing to a limp and even leg length discrepancy.

Question 12

What is the management for SCFE?

Answer 12

surgical pinning +/- prophylactic pinning of contralateral side

Question 13

Name 4 possible complications for SCFE.

Answer 13

1. long term degenerative OA (90%)
2. AVN (10-15%)
3. chondrolysis (10%) - acute cartilage necrosis
4. deformity/leg length discrepancy

Question 14

What is developmental dysplasia of the hip? Name 3 risk factors.

Answer 14

Aberrant development of hip joint, usually occuring from ligamentous laxity and abnormal presentation in utero. Affects 1-3% newborns.

Risk factors:

• female gender (1:8)
• breech presentation
• oligohydramnios

Question 15

How is DDH diagnosed?

Answer 15

USS prior to ossification of proximal femoral epiphysis, X-ray after

Question 16

Describe the management of DDH.

Answer 16

• <6mths: Pavlik harness
• older children: closed reduction
• older Pts or unsuccessful closed reduction: open reduction

Question 17

What is the main long-term complication of DDH?

Answer 17

premature degenerative joint disease requiring joint replacement