The rapid diagnosis of hip pain in important to rule out joint or bone infection that left undiagnosed may lead to joint destruction.

Important Questions to Ask in the History

1. Has there been fever, and how high has it been?
2. Has there been a recent viral illness?
3. Has there been any trauma?
4. Has there been knee pain?
5. Acute onset more suggestive of trauma or infection. How long has there been symptoms?
6. Are there any underlying conditions? Sickle cell disease, rickets, SLE, Anorexia Nervosa, medications such as steroids.
7. Is there a family history of hip disease?

1. Observe gait
2. Check for leg length discrepancy
3. Evaluate for muscle atrophy. This may suggest chronic disuse. 
4. Is there point tenderness or evidence of joint swelling?
5. Check range of motion.
6. Examine the back

1. Septic hip joint
1. Rapid diagnosis is imperative because increased pressure within joint may lead to decreased blood supply to the femoral head
2. The majority of the children are less than four years of age. Present with acute onset of fever, pain, ill appearance, refusal to stand, limp. Infants may present with irritability and poor feeding. 
3. Hip usually held in flexed and abducted position.
4. Diagnosis is by combination of suspicion, physical findings, radiographic changes with widening of joint space, and obtaining fluid from a joint tap. Fluid will have low glucose, usually > 50,000 WBCs and a predominance of polys. Gram stain and culture will be positive in about 80% of the cases. 
5. Blood culture positive in 20% of the cases. Most cases will have increased WBC count, CRP, and ESR.
6. Treatment.- Surgical drainage and antibiotics to cover susceptible S. aureus. Further treatment determined by the organisms isolated and their sensitivity to antibiotics. 
2. Osteomyelitis
1. May have history of trauma
2. Fever and ill appearing, limp or refusal to stand, point tenderness.
3. Increased ESR, CRP, and WBCs 
4. Diagnosis by radiographs, bone scan, and needle aspiration obtaining organism
5. Most common organism is S. aureus
3. Toxic Synovitis
1. Most common between 2-8 years of age. It is a benign condition with the presence of small amount of fluid in the joint. Often follows viral illness. Etiology speculated to be post infectious reactive arthritis. It is important to rule out a bacterial infection of the joint and bone. 
2. Child may refuse to stand and limp. There may be pain on maneuvering the hip joint. The child does not usually appear ill, only low grade fever, and the ESR, CRP, and WBC count are normal or slightly elevated. 
3. Radiograph is normal or only small effusion present. Fluid is sterile. 
4. Treatment is reassurance and following carefully to be sure that there is no septic process, analgesics, and rest as needed. Lasts for a few days. 
4. Slipped Capital Femoral Epiphysis
1. Males > females and most common 10 -16 years of age. May be bilateral and present at different times. This is a fracture of the growth plate leading to a slipping of the femoral epiphysis off the femoral neck.
2. Patient often overweight and there is an association with hypothyroidism.
3. Patient complains of pain in hip or knee and holds the extremity externally rotated. Resists internal rotation.
4. Radiograph positive. The femoral head is displaced medially in relation to the femoral neck. 
5. Treatment is surgical with pinning of the joint.
5. Legg Calve Perthe’s Disease
1. This is an avascular necrosis of the femoral head. Common between the ages of 4-9 years and greater incidence in males. 10% are bilateral 
2. The onset is insidious with painless limp and then development of hip, groin, lateral thigh, or knee pain. Physical examination will demonstrate leg length discrepancy, decreased abduction and internal rotation. 
3. Radiographic diagnosis. There is a flattening and fragmentation of the femoral head.
4. Treatment is bracing or surgery.
6. Osteoid Osteoma
1. These are benign bone tumors, most common in the femur and tibia prior to adolescence.
2. Pain is worse at night and responds dramatically to aspirin. Failure to respond to ASA usually rules out the diagnosis.
3. May require CT scan or bone scan to demonstrate
4. Surgical removal 
7. Malignancy
1. Neuroblastomas, leukemias, osteosarcomas, and Ewing’s sarcomas, Eosinophilic granulomas
8. Rheumotologic Disorders
9. Trauma
10. Functional hip pain

1. Hollingsworth,P Differential Diagnosis and Management of Hip Pain in Childhood. British Journal of Rheumatology. 1995; 34: 78-82
2. Elyn Palermo Theophilopoulos and Douglas Barnett. Get a grip on the pediatric hip. Contemporary Pediatrics November 1998