This Little Piggy Went to the Hospital

Author: Chia-Yuan Michael Lee, DO

Peer-Reviewer and Final Editor: Mark Hopkins, MD

A 74-year-old female presents with right foot pain after tripping on a shoe. She reports discomfort on the lateral side of her foot with weightbearing.

Image 1: X-Ray of the Right Foot (Author's own image)

What is your diagnosis?
What is your management in the emergency department?
What complications may arise?
What is your disposition?
What is another associated injury that needs to be considered?

-- see below for answers --

What is your diagnosis?

This is a Jones fracture, a fracture of the proximal 5th metatarsal at the metaphyseal-diaphyseal junction. The exact mechanism of injury is unclear but the fracture is likely the result of an applied adduction force on the forefoot when the ankle is in plantarflexion, such as when one missteps on the lateral part of the foot [1].

Pearl: Fractures of the proximal 5th metatarsal are most frequently classified based on the location and mechanism of injury as described by Lawrence and Botte [2].

Zone I: Pseudo-Jones fractures. These involve the tuberosity and are typically avulsion injuries due to forces applied to the peroneus brevis tendon or the lateral portion of the plantar fascia during inversion of the foot [2].

Zone II: Jones fractures (as detailed above)

Zone III: Stress fractures. These involve the proximal 1.5 cm of the diaphysis and are typically due to repetitive load or stress [3].

Image 2: Zones of the 5th metatarsal as described by Lawrence and Botte (Annotations and image by author).

What is your management in the emergency department?

Jones fractures are typically managed non-operatively. They should be placed in a short leg splint and made non-weight bearing for at least 6 weeks [1].

Patients with Zone I fractures can remain weight-bearing as tolerated with a hard-soled shoe or walking boot [3]. Zone III fractures should be managed similarly to Zone II, although these may take up to 20 weeks to heal [1].

Pearl: If there is uncertainty about the zone, err on the conservative side by initially placing a short-leg splint until they can receive follow-up.

What complications may arise?

Delayed union or non-union and refracture are common complications for all fifth metatarsal fractures. Zone I has been shown to have a much lower rate of non-union (~1%) when compared to Zone II and Zone III (~25%) [2].

Pearl: Jones fractures are particularly at risk for delayed union or non-union because the metaphysis-diaphysis junction is a watershed area [2].

What is your disposition?

After splint placement, the patient can be discharged home and instructed to follow-up with an orthopedic surgeon or primary care sports medicine physician.

Pearl: While Zone I fractures rarely require surgical intervention, surgical management for Zone II and Zone II fractures may be considered for athletes, patients who decline conservative treatment, or those who wish to return to activity earlier [3]. Displaced Zone II fractures may also require operative intervention [1].

What is another associated injury that needs to be considered?

When evaluating fifth metatarsal fractures, it is also important to confirm there is not an associated Lisfranc injury (where the metatarsal base is displaced from the tarsus) because a Lisfranc injury requires early operative management, and delay or failure to treat may lead to post-traumatic arthritis [2].

References

1. Lawrence SJ, Botte MJ. Jones' fractures and related fractures of the proximal fifth metatarsal. Foot Ankle. 1993;14(6):358-365. doi:10.1177/107110079301400610

2. Cheung CN, Lui TH. Proximal fifth metatarsal fractures: anatomy, classification, treatment and complications. Arch Trauma Res. 2016;5(4):e33298. doi:10.5812/atr.33298

3. Dameron TB. Fractures of the proximal fifth metatarsal: selecting the best treatment option. J Am Acad Orthop Surg. 1995;3(2):110-114.