Freiberg disease

Dr Henry Knipe ◉ ◈ and Dr Jeremy Jones ◉ et al.

Freiberg disease, also known as Freiberg infraction, is osteochondrosis of metatarsal heads. It typically affects the 2^nd metatarsal head, although the 3^rd and 4^th may also be affected. It can be bilateral in up to 10% of cases.

A traumatic insult in the form of either acute or repetitive injury and vascular compromise, perhaps due to an elongated 2^nd 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 characterised 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 orthopaedic 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