Comprehensive Column on Freiberg Infarction: Etiology, Pathophysiology, Imaging, and Management

on

Introduction

Freiberg infarction, also known as Freiberg disease or osteochondrosis of the metatarsal head, is a relatively rare yet clinically significant condition affecting the forefoot. It is characterized by avascular necrosis and subchondral bone collapse, predominantly involving the second and third metatarsal heads. Its understanding is crucial for clinicians, radiologists, and orthopedic surgeons due to its subtle early presentation and progressive impact on foot biomechanics if untreated. 

Case Overview (Reference Case)
A 63-year-old active woman presented with severe left forefoot pain following running. She had a notable history of a healed fifth metatarsal base fracture. Initial weight-bearing X-ray showed no acute fractures ([Figure 1]). MRI without intravenous contrast revealed pronounced bone marrow edema of the third metatarsal head consistent with Freiberg infarction ([Figure 2]).

Cause and Etiology
Freiberg infarction is multifactorial, involving repetitive mechanical stress, microtrauma, and potential vascular compromise leading to subchondral bone necrosis. Key etiologic contributors include:

  • Mechanical overload due to high-impact activities such as running or dancing.

  • Anatomical predisposition, like a long second metatarsal.

  • Vascular insufficiency resulting in compromised blood flow to the metatarsal head.

  • Systemic factors such as corticosteroid use, collagen vascular diseases, or metabolic conditions.

Pathophysiology
The condition starts with microvascular compromise and localized ischemia of the metatarsal head. Progressive stress results in trabecular microfractures and collapse of the subchondral plate. Over time, the articular cartilage loses support, causing pain, stiffness, and eventual degenerative joint changes. MRI is highly sensitive for early detection, identifying bone marrow edema before radiographic changes appear ([Figure 2]).

Epidemiology

  • Age and sex: Most commonly affects adolescents and young adults, though older active patients may present with atypical cases. Women are affected more frequently (3:1 ratio).

  • Incidence: Rare but important among athletes and active individuals.

  • Location: The Second metatarsal head accounts for 68% of cases; the third metatarsal involvement occurs in approximately 27%.

Clinical Presentation
Symptoms typically include:

  • Forefoot pain exacerbated by weight-bearing.

  • Localized tenderness over the affected metatarsal head.

  • Occasional swelling or stiffness of the metatarsophalangeal joint.

  • Limp or altered gait in chronic cases.

Imaging Features

[Figure 1] X-ray: Early stages may appear normal; later findings include flattening and fragmentation of the metatarsal head.

[Figure 2] MRI: Gold standard for early detection, demonstrating bone marrow edema, subchondral fractures, and cartilage involvement.

  • Bone Scan: Increased tracer uptake in the affected metatarsal head.

Differential Diagnosis
Includes Morton neuroma, metatarsal bursitis, plantar plate tears, rheumatoid arthritis, and stress fractures.

Treatment and Management
Conservative:

  • Rest and activity modification.

  • Offloading using orthotics or supportive footwear.

  • Nonsteroidal anti-inflammatory drugs (NSAIDs).

  • Physical therapy and gradual return to activity.

Surgical (advanced cases):

  • Debridement and synovectomy.

  • Osteotomies to redistribute pressure.

  • Joint replacement or arthroplasty for end-stage disease.

Prognosis
With early detection and conservative measures, prognosis is generally favorable. Chronic or late-stage disease may progress to degenerative arthritis, necessitating surgical intervention.

Quiz

  1. Which metatarsal head is most commonly affected in Freiberg infarction?
    a) First
    b) Second
    c) Third
    d) Fifth

  2. Which imaging modality is best for early detection?
    a) X-ray
    b) MRI without contrast
    c) CT angiography
    d) Bone scan

  3. Primary etiology of Freiberg infarction?
    a) Infectious arthritis
    b) Autoimmune vasculitis
    c) Repetitive microtrauma with vascular compromise
    d) Gout

Answer & Explanation

1. Answer: b) Second. Explanation: The Second metatarsal head accounts for the majority (68%) of cases.
2. Answer: b) MRI without contrast
Explanation: MRI can reveal marrow edema before radiographic findings appear.
3. Answer: c) Repetitive microtrauma with vascular compromise. Explanation: Mechanical overload and vascular factors are key contributors.

References
[1] A. Hodes and H. Umans, "Metatarsalgia," Radiol Clin North Am., vol. 56, no. 6, pp. 877-892, 2018.
[2] S. Lee and A. Saifuddin, "Magnetic resonance imaging of subchondral insufficiency fractures of the lower limb," Skeletal Radiol., vol. 48, no. 7, pp. 1011-1021, 2019.
[3] P.G. Talusan, P.J. Diaz-Collado, and J.S. Reach Jr., "Freiberg’s infraction: Diagnosis and treatment," Foot Ankle Spec., vol. 7, no. 1, pp. 52-56, 2014.
[4] M. J. Blitz and A. Schweitzer, "MRI of the Foot," Clin Sports Med., vol. 31, no. 1, pp. 139-161, 2012.
[5] R. Torg and F. Pavlov, "Overuse injuries in athletes," Am J Sports Med., vol. 15, no. 1, pp. 25-38, 1987.
[6] M. Raikin and S. Ahmad, "Osteochondroses of the foot and ankle," Foot Ankle Clin., vol. 10, no. 1, pp. 125-143, 2005.
[7] H. Nyska, E. Margulies, and M. Mann, "Pathogenesis and classification of Freiberg's infraction," Foot Ankle Int., vol. 14, no. 5, pp. 282-289, 1993.

Comments

Post a Comment