The “limping child” is commonly encountered in the ED, and while we may consider the common entities like Osgood Schlatter’s Disease, the potential issues that lead to a child limping are vast. Certainly we concern ourselves with weighing Toxic Synovitis versus Septic Arthritis. Some kids would be at risk for osteomyelitis, while others may be suffering from Legg-Calve-Perthes Disease. Obviously, we cannot forget fractures (ex, Toddler’s Fracture) or SCFE… while also considering issues “outside” of the leg – Appendicitis, PID, Epididymitis, Ovarian Torsion, Testicular Torsion, or Acute Cerebellar Ataxia. After an extensive review of your Ddx list, you may be inclined to call it “Growing Pains,” but before you do, consider avascular necrosis in the foot… and Kohler’s Disease:

Avascular Necrosis

• Also called “osteonecrosis.”
• Lack of blood circulation in a bone leading to cellular death.
  • Can be due to occlusion of arterial or venous flow.
  • Can be from anatomic disruption of the blood vessel.

• Most often related to trauma, particularly in the foot. [DiGiovanni, 2007]
• Other conditions / behaviors increase the risk for it:
  • Sickle Cell Disease
  • Corticosteroid use
  • Alcohol use
  • Gaucher’s Disease

• Radiographically, osteonecrosis can appear as: [DiGiovanni, 2007]
  • Increased radiodensity
  • Bony collapse
  • Loss of trabecular pattern
  • Fragmentation
  • Flattening
  • Sclerotic bone

• Osteonecrosis can occur in any bone, but some are more prone than others, particularly in the foot. [DiGiovanni, 2007]
  • Talus
  • 1st metatarsal
  • 2nd metatarsal
  • Navicular

Navicular Avascular Necrosis

• The Navicular is the last tarsal bone to ossify. [Alhamdani, 2017]
  • Susceptible to mechanical compression by the adjacent ossified talus and cuneiform bones.
  • The perichondral blood supply gets compressed and leads to ischemia of the central bone.

• The Navicular has vulnerable vascular supply. [DiGiovanni, 2007]
  • Doralis pedis artery provides several perforating branches.
  • Medial plantar artery supplies the plantar surface of the bone.
  • Intraosseous blood flow is centripetal and has a central watershed area [DiGiovanni, 2007]

• Avascular necrosis of the navicular can be related to trauma.
  • Feet are poorly protected in high-speed MVCs.
  • Injury may not be apparent at first.
  • Persistent pain following trauma warrants consideration for this.

• Avascular necrosis of the navicular can also be idiopathic. [DiGiovanni, 2007]
  • Or… the trauma was remote and just not considered significant at the time.
  • Termed Kohler’s Disease in children and Muller-Weiss disease in adults.

Kohler’s Disease

• Relatively rare.
• Self-limited condition, although therapy hastens improvement.
• Kohler’s Disease presents between ages of 2 and 9 years.
• More common in males, but females often present at younger age compared to male counterparts.
• May present with:
  • Sudden onset of pain and limping
  • Can also be insidious.
  • Midfoot pain
  • Child may favor walking on lateral aspect of affected foot. [Gillespie, 2010]
  • Tenderness and swelling over dorsal mid foot.
  • Occasionally, even redness

• The radiographic findings of slcerosis, fragmentation, and flattening can also be a NORMAL VARIANT, so need to be found in the appropriate clinical setting. [DiGiovanni, 2007]
• Treatment:
  • Generally, conservative management is used.
    • Rest
    • Pain control
    • Limited weight bearing
    • Soft arch supports or medial heal wedge [Shastri, 2012]
  • Short leg cast applied for a brief period (a few weeks), can help reduce duration of symptoms. [Alhamdani, 2017]
  • Overall prognosis is good!

Moral of the Morsel

• Don’t just look at the leg! Think “outside” of the leg as a possible source for a child’s limp.
• Don’t forget the foot! We commonly consider the knee and hip, but foot pain can be difficult to discern in young children, so actively look for it.
• Midfoot pain? Think about avascular necrosis of the navicular bone!

References