Brachymetatarsia

What is Brachymetatarsia?

Brachymetatarsia is a congenital or acquired condition characterized by shortening of one or more metatarsal bones, leading to cosmetic and functional foot deformities. The condition most commonly affects the fourth metatarsal and is more prevalent in females, with an estimated incidence of 1 in 1,900 live births.

Causes and Pathophysiology

Brachymetatarsia results from premature closure of the metatarsal growth plate, preventing normal bone elongation. The underlying causes include:

• Idiopathic (isolated cases)
• Genetic factors (autosomal dominant inheritance in some cases)
• Syndromic associations:
  • Turner syndrome
  • Pseudohypoparathyroidism
  • Multiple epiphyseal dysplasia
  • Down syndrome
• Post-traumatic: Damage to the growth plate due to fractures or infections
• Iatrogenic: Following surgery or radiation therapy affecting bone growth

Clinical Features

• Shortened toe (most often the fourth toe, but can affect multiple toes)
• Floating toe appearance due to lack of proper weight-bearing
• Pain and discomfort, particularly with shoe wear
• Cosmetic concerns, often leading to psychosocial distress
• Metatarsalgia or adjacent toe deformities due to altered weight distribution

Evaluation and Diagnosis

• Clinical examination: Assessing foot structure, gait, and any pain complaints
• Radiographic imaging (X-rays): Confirming metatarsal shortening and ruling out other skeletal abnormalities
• MRI or CT scans (rarely needed): Evaluating soft tissue and joint involvement in complex cases

Treatment Options

The treatment of brachymetatarsia depends on the severity of the deformity and patient concerns.

Non-Surgical Management

• Shoe modifications: Wide, soft footwear to accommodate toe shortening
• Orthotics: Custom insoles to redistribute pressure and reduce metatarsalgia
• Physical therapy: Strengthening and stretching exercises to improve foot mechanics

Surgical Treatment

Surgery is often required for functional or cosmetic correction in severe cases. Options include:

1. Distraction osteogenesis: Gradual lengthening of the metatarsal using an external fixator (Ilizarov technique) over several weeks.
2. One-stage bone grafting: Immediate lengthening using an autograft or allograft to bridge the gap.
3. Shortening of adjacent metatarsals: In cases with significant weight distribution imbalance.

Prognosis

The prognosis is generally excellent with surgical correction, particularly when performed by experienced surgeons. Complications may include stiffness, nonunion, or toe misalignment, but most patients achieve satisfactory functional and cosmetic outcomes.

References

1. Masada K, et al. Brachymetatarsia: Clinical features and treatment. J Bone Joint Surg Am. 2007;89(1):50-58.
2. Jung HG, et al. Distraction osteogenesis for brachymetatarsia: Clinical outcomes and complications. Foot Ankle Int. 2014;35(2):162-170.
3. Lee HS, et al. One-stage bone lengthening in brachymetatarsia: Long-term outcomes. J Orthop Surg Res. 2019;14(1):198.