Basics
Description
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Freiberg infraction is an eponym for osteonecrosis of the 2nd metatarsal head.
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The most common presentation is in a young or middle-aged adult with a history of well-localized pain to the 2nd MTP joint that is aggravated with activities and relieved with rest.
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It primarily affects the 2nd metatarsal head.
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Rarely, the 3rd or other metatarsal heads may be involved.
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It may be unilateral or bilateral.
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Stages of involvement:
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Early stages may show mottling of the metatarsal head or central collapse on radiographs.
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Moderate disease shows flattening or collapse of the metatarsal head along with osteophytes or loose ossicles.
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Late stages include loss of joint space and arthritis.
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Epidemiology
Occurs more often in females than in males
Incidence
The true incidence is unknown because many cases are asymptomatic and discovered incidentally on radiographs.
Prevalence
Most common in 13-18-year-olds, with symptoms occasionally persisting into adulthood
Risk Factors
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Running
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Dancing
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Long 2nd metatarsal
Etiology
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This disorder is characterized by AVN of the involved metatarsal head.
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Impaired microcirculation to bone
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Acute trauma
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Repetitive microtrauma or overuse
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The fact that the 2nd metatarsal is the longest metatarsal and is relatively immobile subjects it to increased stress.
Diagnosis
Signs and Symptoms
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Pain about the 2nd MTP joint is aggravated with activity and alleviated by rest.
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Running or sports often is associated with increased pain.
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Tenderness and soft-tissue thickening about the MTP joint may occur.
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Stiffness of affected MTP joint may develop.
Physical Exam
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Decreased joint ROM
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Tenderness to palpation
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Swelling after activity
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Pain on toe-raising
Tests
Imaging
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Radiography: Standing foot radiographs:
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AP, oblique, and lateral views
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Early findings include osteopenia and mild subchondral lucency.
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Later stages show enlargement and flattening of the metatarsal head, sclerosis, cystic changes, and osteophytes.
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End-stage disease shows arthritic narrowing and destruction of the joint.
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Occasionally, in early or occult cases, radiographs may be unremarkable and technetium bone scan or MRI may help confirm the diagnosis.
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Bone scan shows focal intense uptake at the involved metatarsal head.
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MRI shows bony edema with osteonecrosis of head.
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Pathological Findings
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Typical findings include:
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Synovitis, loose bodies, osteophytes
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Metatarsal head osteonecrosis, with fibrosis of the marrow space, spicules of dead bone, resorption, and collapse
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Arthritic changes with loss of cartilage
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Differential Diagnosis
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Idiopathic synovitis
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Inflammatory arthritides
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Acute fracture
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Sprain of MTP joint
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Metatarsal stress fracture
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Morton neuroma
Treatment
General Measures
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Patients should avoid or limit activities that cause pain, especially running, jumping, and dancing.
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Early disease may be treated with a hard-soled shoe, fracture boot brace, or a walking cast.
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Symptoms may be relieved by using a metatarsal pad just proximal to the involved metatarsal head.
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Taping or strapping the toe can help to immobilize the joint.
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Judicious use of intra-articular corticosteroid injections may relieve synovitis.
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Late stages of the disease may require surgery.
Medication
NSAIDs may alleviate swelling and pain.
Surgery
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Surgery is indicated if nonoperative measures are unsuccessful.
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Treatment options include:
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Synovectomy
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Joint debridement, including removal of fibrosis, loose bodies, and osteophytes
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Bone grafting of the metatarsal head if no flattening or joint surface collapse is present
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Dorsiflexion osteotomy of the involved metatarsal to rotate healthier plantar cartilage to articulate with the phalanx
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Metatarsal head resection arthroplasty
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Prosthetic joint replacement is not recommended because of transfer metatarsalgia, bony resorption, and implant failure.
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Follow-up
Prognosis
In most patients, symptoms abate after the acute period and are replaced by an occasional ache.
Complications
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Collapse of joint surface
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Arthritis of the second MTP joint
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Mechanical unloading of the joint with transfer metatarsalgia
Miscellaneous
Codes
ICD9-CM
732.5 Freiberg disease (osteochondrosis, metatarsal head)
Patient Teaching
Activity
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Explain the concept of AVN, including the slow process of revascularization, and warn that joint collapse may occur if weight is borne prematurely.
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Describe activities likely to exacerbate the disorder, such as running and jumping.
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Suggest substitute activities such as swimming.
FAQ
Q: What are the possible causes of Freiberg infraction (osteonecrosis of metatarsal head)?
A: Overuse, trauma, vascular impairment, inflammatory disease, increased 2nd metatarsal length, and immobility of 2nd metatarsal leading to increased stress.
Q: How is Freiberg infraction treated?
Rest, unloading or protection of the MTP joint, NSAIDs, and corticosteroid injections are standard nonoperative measures. Surgery is considered after failure of these methods.