EM@3AM: 5th Metatarsal Fractures

Author: Brit Long, MD (@long_brit, EM Attending Physician, San Antonio, TX) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)

Welcome to EM@3AM, an emDOCs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.

A 23-year-old female presents with left foot pain after rolling her ankle in volleyball. She is able to bear weight, but with pain. She has some minor ankle pain, but her lateral foot is painful to touch or with weight-bearing. She has no PMH or PSH. Her VS are normal. On exam, her ankle is normal. The base of her 5^th metatarsal is tender to palpation, with swelling and ecchymosis.

What are your next steps, and what is the likely diagnosis?

Answer: Proximal 5^th Metatarsal Fracture

• Background: Due to fracture of the 5^th metatarsal base, broken into 3 separate zones, primarily on mechanism and fracture site. Location matters!
  • Zone 1: inversion
  • Zone 2: forefoot adduction
  • Zone 3: repetitive minor trauma (stress)
• Epidemiology:
  • Fractures of the 5^th metatarsal account for 68% of metatarsal fractures and are the most common.
  • Zone 1 is more common (>70%), followed by Zone 2 (20%).
• History and Exam:
  • Patients often present with history of inversion, forefoot adduction, or chronic pain.
  • Present with pain, edema, bruising over lateral forefoot, with tenderness to palpation at the base of the 5th metatarsal.
  • Patients often have pain with weightbearing or are unable to bear weight.
• Diagnostics:
  • Patients will meet criteria for imaging per Ottawa foot rules (pain at base of 5^thmetatarsal).
  • Obtain foot (AP, lateral, oblique) and ankle X-rays.
    • Zone 1: Pseudo-Jones fracture or avulsion involving the proximal tubercule. Result of bony fragment detachment by ligament. X-ray will show fracture line into metatarsocuboid joint.
    • Zone 2: Jones fracture is a fracture of the metaphysial-diaphysial junction, or 4^th-5^th metatarsal articulation. This is a vascular watershed area and is at high risk of non-union due to poor blood supply.
    • Zone 3: Proximal diaphyseal fracture distal to 4^th-5^th metatarsal articulation. This fracture is associated with foot deformities and sensory neuropathy. X-ray typically does not demonstrate a clean fracture line, but rather widened fracture site with cortical thickening.
      • Management
        • Provide analgesia and recommend elevation and ice for swelling.
        • Management revolves around specific diagnosis:
          • Zone 1: weightbearing as tolerated, hard-sole shoe or walking boot, 1-2 weeks of shoe/boot for comfort.
          • Zone 2: non-weightbearing for minimum 6 weeks, place in short leg posterior splint or boot, ensure orthopedic follow up within 1 week.
          • Zone 3: non-weightbearing for minimum 6 weeks, place in short leg posterior splint or boot, ensure orthopedic follow up within 1 week.
          • If unsure, treat as a Zone 2 or 3 injury: splint and ensure orthopedic follow up!
        • Prognosis
          • Zone 1 fractures heal well, and patients can resume activities as tolerated.
          • Zone 2 and 3 fractures are at high risk of complication, even with immobilization and non-weightbearing. Athletes may be treated with intramedullary screw fixation. Non-union is associated with pain, poor ambulation, and potential need for surgery.

A 22-year-old man presents to the emergency department with foot pain after landing on his foot improperly while playing basketball last night. His X-ray is shown above. What is the correct diagnosis in this patient?

A. Chopart’s fracture

B. Jones fracture

C. Lisfranc fracture

D. Pseudo-Jones fracture

Answer: B

Fractures of the proximal fifth metatarsal pose an important diagnostic challenge. A difference in millimeters of location can lead to a vastly different prognosis and treatment plan. Suboptimal treatment can lead to delayed union, re-injury and chronic disability. The fifth metatarsal can be divided into three parts: the tuberosity, the metaphysis and the proximal diaphysis. There are three basic types of fractures including tuberosity avulsion fractures, acute proximal diaphyseal fractures, and stress fractures of the proximal diaphysis. The easiest way to distinguish among the fractures is to locate the medial tip of the fracture line and compare its location to the intermetatarsal joint. Styloid avulsion fractures exit proximal to the intermetatarsal joint. These are called pseudo-Jones fractures. Acute proximal diaphyseal fractures extend into or towards the intermetatarsal joint. These are called Jones fractures. Stress fractures typically exit or extend distal to the intermetatarsal joint. The patient in this question has an acute proximal diaphyseal fracture, or Jones fracture. In comparison to an avulsion fracture, or pseudo-Jones injury, the Jones fracture is more likely to fail conservative management. Therefore, immobilization in a posterior splint and quick referral to an orthopedist within three to five days is indicated.

Chopart’s fracture (A) and dislocation is a dislocation of the midtarsal joints of the foot including the talonavicular and calcaneocuboid joints and associated fractures of the calcaneus, cuboid and navicular bones. The radiograph in this question does not show fractures of the calcaneus, cuboid and navicular bones. A Lisfranc fracture (C) is an injury of the foot in which one or more of the metatarsal bones are displaced from the tarsus. The radiograph in this question does not show a Lisfranc injury. As already mentioned, a pseudo-Jones fracture (D) is a styloid avulsion fracture of the fifth metatarsal. These fractures generally heal very well and do not require surgical intervention. The fracture line in this patient is more distal and is consistent with a Jones fracture rather than a pseudo-Jones fracture.

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Rosh Review Website Link

FOAMed:

• WikEM Overview – Fifth Metatarsal Fracture
• OrthoBullets – 5th Metatarsal Base Fracture 
• Ped EM Morsels – Metatarsal Fractures in Children
• Life in the Fastlane – Jones Fracture
• emDOCs – Foot Injuries in the ED
• emDOCs – Diagnostic accuracy of ankle x-rays: How often do we miss fractures? How can we improve?
• http://www.emdocs.net/em-in-5-5th-metatarsal-fractures/

References:

1. Bowes J, Buckley R. Fifth metatarsal fractures and current treatment. World J Orthop. 2016;7(12):793-800.
2. Dameron TB. Fractures of the Proximal Fifth Metatarsal: Selecting the Best Treatment Option. J Am Acad Orthop Surg. 1995;3(2):110–4.
3. Kane JM et al. The epidemiology of fifth metatarsal fracture. Foot Ankle Spec 2015; 8: 354–9.
4. Lutter LD, Mizel MS, Pfeffer GB, Orthopaedic Knowledge Update: Foot and Ankle. Rosemont IL: AAOS 1994.
5. Petrisor BA, Ekrol I, Court-Brown C. The epidemiology of metatarsal fractures. Foot Ankle Int. 2006;27:172-174.
6. Thordarson DB. Orthopaedic Surgery Essentials: Foot & Ankle. Philadelphia, PA: Lipincott: 2004.