Freiberg disease, also known as Freiberg infraction, is osteochondrosis of the metatarsal heads. It commonly affects the 2^nd or 3^rdmetatarsal head (in ~2/3 and ~1/4 of all cases, respectively) or rarely, the 4^th or 5^th metatarsal head ¹³. It can be bilateral in up to 10% of cases.

Epidemiology

Freiberg disease is most common in adolescent athletic females (M:F = 1:5) and young women. It is the fourth most common osteochondrosis and is the only osteochondrosis more common in females ¹³.

Clinical presentation

Patients typically present with localised forefoot plantar pain, especially on weight-bearing, with swelling and tenderness.

Pathology

The cause of Freiberg disease 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 2^nd metatarsal, are the most popular theories. As it is more commonly seen in women, particularly during adolescence, high-heeled shoes have been postulated as a possible causative factor.

Microscopic appearance

Histologically, Freiberg disease is characterised by the collapse of the subchondral bone, osteonecrosis, and cartilaginous fissures ¹. 

Classification

Some publications advocate the use of the Bragard staging classification ¹⁰, which requires two views/planes of the forefoot:

• stage I: metatarsal head flattening and decreased subchondral bone density

• stage II: metatarsal head sclerosis, fragmentation, and deformation, with cortical thickening

• stage III: metatarsophalangeal osteoarthrosis with intra-articular loose bodies

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

MRI

Early MRI 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.

Treatment and prognosis

In early stages of the disease, it can be managed with lifestyle modifications, immobilisation and NSAID therapy. In advanced stages, surgery can be considered. It is usually divided into joint preserving or reconstruction options ¹².

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

• lesser metatarsal head instability (only identified on MRI) due to plantar plate tear

See also

• osteonecrosis