Some of the most common fractures in the foot are to the proximal aspect of the 5th metatarsal.1 The approach to fractures in this region may be confusing and difficult to know how to manage. Depending on the exact location and fracture pattern, the prognosis and treatment varies significantly. This variation is mainly attributed to the unique blood supply to this aspect of the bone. The blood supply to the proximal diaphysis is a watershed area and therefore has a higher risk of delayed union or nonunion if vascularity is disrupted.1-2 Whereas more proximally at the tuberosity, there is increased sources of vascularity and less likelihood of complication. The 5th metatarsal tuberosity is also an attachment site for the plantar fascia and the peroneus brevis tendon laterally.1,3 Inversion injuries may lead to avulsion fractures at the styloid.
Injuries to the proximal 5th metatarsal present with pain along the lateral border of the foot. Since the vast majority of these injuries are caused by forceful inversion, the patient may present with concerns of a lateral ankle sprain. The patient may or may not be able to weightbear initially but attempts to weightbear will often aggravate the pain.
Physical exam is key to identifying fractures in the foot. Fractures will often have a maximal point of tenderness at the fracture site. Bony tenderness should be differentiated from pain associated with soft tissue. The physical exam should also assess skin integrity, neurovascular function, and evaluate for other associated injuries of the ankle or foot. Bony tenderness to the base of 5th metatarsal is an indication for plain radiographs to determine the type of fracture.1
Radiographs are the most useful initial diagnostic test for identifying a fracture of the 5th metatarsal and determining the location and pattern.4,5 The proximal metatarsal is divided into 3 zones, classified proximal to distal. Zone 1 is the tuberosity, zone 2 is the metadiaphysis, and zone 3 is the proximal diaphysis.2–4 These zones help in diagnosing and predicting possible complications.3,4 Standard radiographs of the foot include AP, oblique, and lateral views. Additional ankle radiographs may also be indicated depending on the clinical presentation and mechanism of injury.
Pseudo-Jones fractures result from an avulsion fracture at the 5th metatarsal tuberosity and are located in zone 1. These fractures may be intra-articular at the cubometatarsal joint or extra-articular if more proximal. 2-3,5 Avulsion fractures may be confused with normal variants of growth including an accessory bone or the apophysis in skeletally immature patients.1,5 These findings are typically smoother in appearance, but clinical correlation is important since these are still susceptible to injury.
A transverse fracture in zone 2 at the junction of the metaphysis and diaphysis is considered a Jones fracture.2-4 This often involves extension into the 4th/5th metatarsal joint but no articular extension is seen to the cubometatarsal joint.4 Due to the location and blood supply, these fractures are particularly concerning for delayed union or nonunion.
Stress fractures also occur at the 5th metatarsal in zone 3.3,4 These are typically at the proximal diaphysis, distal to the Jones fracture zone. This fracture should be considered in athletes with a prodrome of pain or when cortical thickening is noted on radiographs to the surrounding bone.4,5 Stress fractures of the 5th metatarsal are more rare but also have a higher likelihood of nonunion compared to acute avulsion injuries.
Treatment of avulsion fractures typically require conservative measures based on the symptoms and severity of the injury. Rest, ice, elevation, over-the-counter pain medication, and use of either a rigid shoe or boot is recommended.1,3-5 These injuries are often managed by an orthopaedic provider but could also be followed by primary care if appropriate or necessary. This fracture pattern typically heals well but should still be observed for symptom improvement and evidence of healing on radiographs.3-5 Surgery is not often necessary.
Jones fractures require rest, ice, elevation, immobilization, non-weightbearing, appropriate analgesics as indicated, and referral to an orthopaedic provider. Conservative treatment may continue to be recommended but with signs of fracture displacement or delayed union, operative management may become necessary.1,3,5 Weightbearing will increase the risk of either of these occurring so strict non-weightbearing is recommended initially.1,3
Stress fractures often present late and may require prolonged non-weightbearing immobilization which should be guided by an orthopaedic specialist. Surgical intervention may become indicated, particularly in athletes.3,4
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1. Ramponi DR. Proximal fifth metatarsal fractures. Adv Emerg Nurs J. 2013;35(4):287-292. doi:10.1097/TME.0b013e3182aa057b
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. Egol KA, Koval KJ, Zuckerman JD, eds. Handbook of Fractures. 6th ed. Wolters Kluwer; 2020.
4. Steffes MJ, Weatherford B. 5th metatarsal base fracture. OrthoBullets. Updated August 20, 2021. Accessed January 29, 2022. https://www.orthobullets.com/foot-and-ankle/7031/5th-metatarsal-base-fracture
5. Gaillard F, Hacking C. Avulsion fracture of the 5th metatarsal styloid. Radiopaedia. May 2, 2008. Updated December 27, 2021. Accessed January 29, 2022. https://doi.org/10.53347/rID-952