Hip Pain in the Child (Singapore Guide 2023)

Description

• Hip pain is a term used to describe discomfort in the groin, which receives sensory innervation provided by the obturator and femoral nerves.
• This pain can be produced by a lesion anywhere in the region of the hip joint, such as:
  • Capsule and synovial lining
  • Bone of the pelvis or proximal femur
  • Muscles, nerves, and vascular structures in the region of hip, buttock, groin, or pelvis
• Regardless of cause, hip pain usually is localized to the region of the anterior groin, the greater trochanter, or the anterolateral thigh down to the knee.
• Because many of the causes of hip pain need urgent treatment or carry a poor prognosis if left untreated, hip pain must be evaluated thoroughly.

Epidemiology

• Transient synovitis is reported to be the most common cause of hip pain in children.
• Male predominance:
  • Septic arthritis, slight; transient synovitis, 2:1; SCFE, 2.5:1; osteomyelitis, 4:1; Legg-Calve-Perthes disease, 6:1.

Risk Factors

• Juvenile rheumatoid arthritis
• Closed trauma
• Impaired host immune defense
• Obesity, trauma, and age (all shown to be related to the development of SCFE)

Etiology

• The 2 most common causes are transient synovitis and septic arthritis.
  • Transient synovitis:
    • Average age of onset of symptoms is 6 years, with most cases occurring in children 3-8 years old.
    • Associated with current or recent illness, trauma, or allergic reaction
  • Septic arthritis:
    • ~2/3 of all cases occur in children <3 years old.
    • Mechanism of onset: Direct extension of osteomyelitis from the proximal metaphysis of the femur into the hip joint or hematogenous dissemination of organisms through the blood supply of the synovial membrane
    • During a child’s first 12-18 months, little resistance exists to the extension of infection across the physis in the proximal femur because of vascular channels in the growth plate, so osteomyelitis and septic arthritis are more common in this group than in others.
    • In newborns, most commonly caused by Staphylococcus, Streptococcus, or Haemophilus influenzae type B
    • In those >6 months old, predominantly caused by Staphylococcus aureus
    • In adolescents, possibly caused by Neisseria gonorrhoeae
  • Legg-Calve-Perthes disease: Cause unknown, although trauma, hypercoagulability, and thrombosis have been postulated
  • SCFE:
    • Physeal weakness during adolescent growth spurt and trauma probably are related.
    • ~80% of patients are obese; hormonal factors most likely are involved.
• Other types of hip pain:
  • Infectious
  • Traumatic
  • Neoplastic
  • Idiopathic

Associated Conditions

Signs and Symptoms

• Pain referred to the groin, trochanter, anterolateral thigh, or knee
• Involuntary guarding or spasm of muscles around the hip joint
• Limitation of active and passive hip motion (i.e., loss of internal rotation and abduction in Legg-Calve-Perthes disease or hip dysplasia; external rotation of the hip with attempted flexion pathognomonic for SCFE)
• Refusal to walk or bear weight on the affected extremity
• Limp, possibly antalgic or painless
• Atrophy of the thigh or buttock muscles
• Fever in septic arthritis, osteomyelitis

Tests

Differential Diagnosis

• Transient synovitis (although the most common cause of hip pain) should be a diagnosis of exclusion only.
• Infections of the hip joint, proximal femur, pelvis, intervertebral discs, SI joint
• Legg-Calve-Perthes disease (AVN of the femoral head)
• SCFE
• Juvenile rheumatoid arthritis, early osteoarthritis
• Tumors of the pelvis, spine, or proximal femur
• Bursitis of psoas or trochanter
• Sickle cell crisis
• Nonarticular processes
• SI joint septic arthritis
• Pyomyositis around the hip
• Psoas septic bursitis
• Leukemia or lymphoma

General Measures

• Transient synovitis:
  • Rapidly resolve underlying inflammation with rest and anti-inflammatory agents.
  • Prescribe bed rest and no weightbearing on the involved joint until pain resolves and full motion returns.
  • Spontaneous resolution is the natural course: This condition usually is self-limiting.
• Septic arthritis:
  • Perform immediate surgical drainage and administer antibiotic therapy.
  • Antibiotics:
    • Give broad-spectrum antibiotic coverage until culture results are available.
    • Oral antibiotics, if appropriate, usually are given for 3 weeks, until the clinical examination and/or ESR has returned to normal.
    • Splint hips in abduction if capsular distention has occurred.
    • After infection is controlled and drainage has ceased, begin ROM exercises.
• Legg-Calve-Perthes disease:
  • Prevent subluxation.
  • Preserve the sphericity of the femoral head.
  • Order bed rest, if needed, and traction to reduce spasms and synovitis.
  • Surgical reconstruction sometimes is necessary to maintain the femoral head within the acetabulum.
• SCFE:
  • Prevent additional slipping while minimizing the risk of AVN or chondrolysis.
  • Provide the necessary immobilization for acute slips with prompt in situ pin fixation with threaded screws.

Special Therapy

Medication

Surgery

• An anterior or posterior approach to the hip may be used, with irrigation, debridement, and insertion of drain.
• For osteomyelitis:
  • A small window is cut in the bone for curettage of material for culture and open drainage.
  • Chronic osteomyelitis, although rare, often requires surgical debridement.
• Legg-Calve-Perthes disease may require surgical reconstruction of the femur or acetabulum for severe cases.
• In situ percutaneous pinning is required for SCFE to prevent additional slips and the associated complications.

Prognosis

• Septic arthritis and osteomyelitis:
  • Early detection, may have good prognosis
  • Chronic osteomyelitis often results in residual deformity.
• Legg-Calve-Perthes disease:
  • The smaller the amount of avascular bone and the younger the child at the onset of disease, the better the prognosis, although some residual deformity always is seen on radiographs.
  • Other good prognostic signs include lack of lateralization or extrusion and adequate ROM.
• SCFE:
  • Long-term prognosis depends on the amount of displacement.
  • Patients with more severe slips have a greater likelihood of developing degenerative arthritis later in life.

Complications

• Untreated septic arthritis and osteomyelitis can be devastating for a growing child and can result in limb shortening, joint-surface irregularities, stiffness, and early degenerative changes. (Cartilage destruction begins as early as 8 hours after the onset of infection.)
• SFCE:
  • Either the slip itself or reduction attempts may result in AVN or chondrolysis, a condition in which the cartilage of the femoral head degenerates and produces joint narrowing, stiffness, contracture, pain, and limping.
  • Patients with SCFE have a higher-than-normal risk of developing degenerative arthritis.

Patient Monitoring

• ESR or C-reactive protein value:
  • Shown to be a reliable marker to guide the length of antibiotic therapy after surgical management for septic arthritis and osteomyelitis
  • Should return to within normal limits before antibiotics are discontinued.
• Observation only is appropriate for all patients with transient synovitis and for patients with Legg-Calve-Perthes disease with minimal involvement of the femoral head (<50%).

Miscellaneous

Codes

Patient Teaching

• The parents of a patient who is presumed to have synovitis of the hip should be able to observe the child and ensure that improvement continues.
• They should maintain regular follow-up and should contact the physician if the child’s status worsens.

FAQ