Osteonecrosis of the lesser metatarsal heads

• Freiberg's infraction is a condition of cartilage degeneration (osteonecrosis) of the lesser metatarsal heads -
  • first described in 1914 by Alfred H. Freiberg
  • adolescent females are the "textbook" patients - however both males and females may present with this condition later in life
  • second and third metatarsals are the most commonly affected, while involvement of the fourth and fifth is rare
    • more common in patients whose first metatarsal is shorter than the second metatarsal, which increases the weight on the second metatarsal head
  • incidence is higher in females than in males
    
    
• pathophysiology is unknown, but studies suggest a combination of vascular compromise, genetic predisposition, and altered biomechanics
  
  
• diagnosis is made clinically and imaging is used to confirm
  • clinical presentation
    • forefoot pain - generally affecting head of the second metatarsal
    • there is irritation of the joint
    • generally associated with physical activity
    • the head of the metatarsal is palpable and tender
    • may be localised swelling and stiffness in the metatarsophalangeal joint
    • patient may have an antalgic gait
    • conditions in the differential include stress fracture, synovitis, Morton's neuroma and osteosarcoma
  • early in the process, radiographs are normal however bone scans may demonstrate a photopenic center with a hyperactive collar
    • as Freiberg's infraction progresses, radiographs show a flattened and fragmented metatarsal head
  • magnetic resonance imaging can reveal hypointensity of the metatarsal head
    
    
• management
  • nonoperative treatment is based on decreasing foot pressure and unloading the affected metatarsal. Spontaneous healing with remodeling may occur in early stages of the disease
  • operative options are dorsal closing wedge osteotomies, osteochondral transplant, and resection arthroplasty
    
    
• outcomes of nonoperative and operative management are good to excellent and most patients are able to return to previous activity (1)

Reference:

• Talusan PG et al. Freiberg's infraction: diagnosis and treatment. Foot Ankle Spec. 2014 Feb;7(1):52-6.
• Freiberg AH; Infraction of the second metatarsal bone, a typical injury, Surg Gyn Ob, 1914, 19:191.