BASICS

• Transient hip pain presenting with unilateral limp

EPIDEMIOLOGY

Incidence

• Most common in school-aged children (ages 3-10)

Prevalence

• 3% of all children
• Male preponderance

RISK FACTORS

• Usually preceded by a non-descript viral infection

PATHOPHYSIOLOGY

• Hip pain caused by autoimmune synovial irritation

ETIOLOGY

• Post-viral autoimmune inflammation

COMMONLY ASSOCIATED CONDITIONS

DIAGNOSIS

HISTORY

• Preceding history of viral infection
• No history of trauma

PHYSICAL EXAM

• Pain with external rotation and flexion at the hip joint or with compression of the hip joint.
• Absence of fever favors transient synovitis
• Pain with weight bearing.
• Patient relatively well-appearing when seated, difficulty only when bearing weight or flexing/rotating at the hip

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial Lab Tests

• CBC
• ESR, CRP

Imaging

• Hip xray will be normal
• Hip ultrasound will reveal effusion

Diagnostic Procedures / Other

• Synovial fluid aspiration if concern for septic arthritis

Pathological Findings

• Non-specific synovial inflammation

DIFFERENTIAL DIAGNOSIS

• Septic arthritis
• Fracture (Hip, knee, foot)
• SCFE, avascular necrosis
• Arthritis

TREATMENT

MEDICATION

First Line

• Ibuprofen
• Naproxen

Second Line

COMPLEMENTARY & ALTERNATIVE THERAPIES

SURGERY / OTHER PROCEDURES

• None

DISPOSITION

Admission Criteria

• Unable to ambulate
• High risk for septic arthritis

Discharge Criteria

• Able to ambulate, or young enough to be carried easily
• If non-ambulatory, laboratory studies argue against septic arthritis and Xrays without evidence of fracture

Issues For Referral

• If high concern for septic arthritis, requires consultation with orthopedist

FOLLOW UP

FOLLOW-UP RECOMMENDATIONS

• Discharge instructions and medications
• NSAIDs around the clock x 3 days, with follow up in 1-2 days
• Activity
• Return to activity as tolerated. Weight bearing not harmful.

DIET

• Normal, with precautions for gastric irritation caused by high-dose NSAID use

PROGNOSIS

• Self resolves with no residual deficits in 7-10 days

COMPLICATIONS

• More likely to recur in patients who have already suffered one episode

REFERENCES

1. Kocher, MS, Zurakowski D, Kasser JR. “Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm. J Bone Joint Surg Am. 1999 Dec; 81(12):1662-80.

ADDITIONAL READING

See Also (Topic, Algorithm, Electronic Media Element)

• Kocher criteria
  1. Fever >38.5
  2. WBC> 11,000
  3. ESR>40
  4. Unable to bear weight on affected side

# of criteria met	Likelihood of septic arthritis
1	3%
2	40%
3	93%
4	99%

PEARLS AND PITFALLS

• Can be difficult to differentiate between transient synovitis and septic arthritis.