Freiberg disease
Freiberg disease, also known as Freiberg infraction, is osteochondrosis of metatarsal heads. It typically affects the 2nd metatarsal head, although the 3rd and 4th may also be affected. It can be bilateral in up to 10% of cases.
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Epidemiology
It is most common in females aged 10-18 years (male to female ratio of 1:3).
Clinical presentation
Clinically they present with pain on weight-bearing with swelling and tenderness.
Pathology
The cause of Freiberg infraction is controversial and is probably multifactorial.
A traumatic insult in the form of either acute or repetitive injury and vascular compromise, perhaps due to an elongated 2nd metatarsal, are the most popular theories, and as it is more commonly seen in women, particularly during adolescence, high-heeled shoes have been postulated as a possible causative factor.
Histologically, Freiberg infraction is characterized by the collapse of the subchondral bone, osteonecrosis, and cartilaginous fissures 1.
Radiographic features
Plain radiograph
These can be split into early and late features:
Early
- flattening and cystic lesions of the affected metatarsal head
- widening of the metatarsophalangeal joint
Late
- osteochondral fragments
- sclerosis and flattening of the bone
- increased cortical thickening
Some publications advocate the use of the Bragard staging classification 10, which requires two views/planes of the forefoot:
- I - metatarsal head flattening and decreased subchondral bone density
- II - metatarsal head sclerosis, fragmentation and deformation, with cortical thickening
- III - metatarsophalangeal osteoarthrosis with intra-articular loose bodies
MRI
Early MR imaging findings include low-signal-intensity changes in the metatarsal head on T1-weighted images with increased signal intensity on corresponding T2-weighted and STIR images.
With disease progression, flattening of the metatarsal head occurs, and low-signal-intensity changes develop on T2-weighted images as the bone becomes sclerotic.
History and etymology
Albert H Freiberg (1868-1940), was an American orthopedic surgeon, who first described his eponymous condition in 1914 8,9,11.
Differential diagnosis
On imaging consider
- normal variant: metatarsal head flattening is described in ~10% of the asymptomatic population
- fracture of metatarsal head or neck
- including subchondral insufficiency fracture
- unstable metacarpus (only identified on MRI)
- torn metacarpophalangeal collateral ligaments