Freiberg Disease or Osteochondrosis of Metatarsal Head

Freiberg disease is an uncommon condition which was described by Alfred H. Freiberg in 1914.

Freiberg disease or infraction is a painful collapse of the articular surface of the metatarsal head. Second or third metatarsal heads are most commonly involved. First and fifth metatarsals show least common involvements. Bilateral involvement has been reported to occur in less than 10% of patients.

Most of the cases of infraction are not symptomatic or may resolve spontaneously.

The disease affects females five times more commonly than males.

It most commonly occurs in adolescence through the second decade of life through the disease has been reported in as early as 8 years and as old as 77 years.

Causes of Freiberg Disease

In adolescents, Freiberg disease is thought to be a growth disturbance and belongs to the group of the disease called osteochondrosis.  Though Freiberg thought trauma as the cause of the condition exact etiology has still not been explained.

Freiberg disease in adults is thought to represent a different process though they have similar radiological features. The primary cause may be vascular or traumatic

Vascular

In this theory, the primary event is an injury to the blood supply of metatarsal either direct or repetitive. Some patients may have a greater risk due to their anatomic variances of blood supply.

Trauma

The other theory believes trauma to be a predominant etiological factor. Again, it may be a single instance of trauma or multiple repetitive micro-injuries.

Long metatarsals have been recorded as a factor for these diseases. Certain patients may be anatomically predisposed due to local, mechanical, vascular, and developmental factors.

Presentation of Freiberg Disease

The patient usually complains of pain in the forefoot which is related to activity and is also present on the passive motion of metatarsophalangeal joints. There could be associated with stiffness and limp on walking.

The patient may or may not give a history of trauma.

The patient might also present with chronic pain in the forefoot area with frequent exacerbation.

On examination, the area involved would be tender and might reveal some swelling as well. The range of motion of the affected joint would be decreased.

A few patients are completely asymptomatic and noted only on radiographs taken for other purposes.

Imaging Studies

Radiographs

Anteroposterior and oblique views are routinely done for foot afflictions and are basic x-rays for Freiberg disease too. Early radiographs may show only sclerosis and widening of the joint space but radiographs in a later stage show with the collapse of the metatarsal head. Fragmentation of the head and osteochondral loose bodies may be visible in further stages.

Special Investigations

Use of bone scintigraphy in early stages may show a cold lesion or decreased uptake in early stages and an increased uptake in the later stage when the head gets revascularized. The diagnostic or prognostic significance of bone scintigraphy is not known.

Magnetic resonance imaging has been advocated for preoperative evaluation, especially if an osteotomy is planned.

Staging of Freiberg Disease

Smillie classification

It is most widely used and is based on radiological changes.

I – Fissure develops in the ischemic epiphysis.  Opposing cancellous bone on either side of the fissure appears sclerotic.

II –    Collapse. central resorption of bone within the metatarsal head causes the subchondral bone to subside.

III – Peripheral irregularities present. Continued resorption allows the subchondral bone to sink further centrally into the head, creating peripheral irregularities of the intact joint surface.

An isthmus of the articular cartilage on the plantar aspect of the metatarsal head remains intact.

IV –  Osteochondral Loose body.

V – Flattening deformity and arthrosis. Only the plantar aspect of the metatarsal head where the final isthmus of cartilage fractured retains its original contour. The shaft of the metatarsal becomes thickened and dense.

Treatment of Freiberg Disease

Quite a number of patients in stage I-III  may resolve spontaneously or with conservative treatment. The patients who do not respond to conservative treatment in the above-listed stages as well those who fall in stage IV & V  require surgery.

The goal of therapy is to rest the joint to allow inflammation and mechanical irritation to resolve.

In acute presentations, a simple below knee non-weight-bearing cast may be sufficient. In nonacute presentations, weight bearing cast may be given.

Shoe modifications in the form of inserts with metatarsal bars or pads, rigid shanks, or a rocker bottom, may be helpful. Activity modification during exacerbations may help to prevent the aggravating symptoms of pain and swelling.

Symptomatic analgesic drugs might be taken. Few physicians recommend steroid injections too.

In patients who do not respond to the medical treatment or those who are in stage IV and V, the following options can be considered –

• Simple debridement – It can be done alone or combined with other procedures including excision of the metatarsal head, hemiphalangectomy, and loose body excision.

• Bone grafting
• Dorsal closing wedge osteotomies – Reorienting the intact cartilage on the plantar surface to articulate with the base of the proximal phalanx.
• Shortening osteotomy – To shorten the second metatarsal
• Resection arthroplasty  – Involves resection of the base of the proximal phalanx or of the metatarsal head. Not done nowadays
• Total small joint arthroplasty using  a silicone prosthesis
• Core decompression – Multiple drill holes with Kwire
• Osteochondral plug transplantation

In stage I or II grafting and elevation of the collapsed articular surface is recommended.

For advanced lesions, the treatment needs to be individualized.