Base of 5th Metatarsal Fractures: Avulsion, Jones, Stress

Written by: Jonathan Jong, DO; Edited by: Timothy Khowong, MD, MSEd

 
 

Fracture Classification

Fracture location can be divided into 3 zones at the base of the 5th metatarsal. Blood supply to these 3 regions vary, dictating healing outcomes and management. The tuberosity, designated as Zone 1, receives blood supply from multiple branches of metaphyseal arteries. Zone 2 and 3 injuries receive blood supply solely from the Nutrient artery. Fractures in these regions can thus disrupt blood supply and subsequently cause nonunion or delayed union of fractures [1].

Mechanism of injury

Fractures in zone 1 are typically sustained from forced inversion [2, 5]. Fractures in zone 2 typically occur from significant forefoot adduction while zone 3 fractures are thought to occur from repetitive microtrauma. Zone 3 injuries will usually present in younger athletes with months of pain [3, 5].

Diagnosis

Diagnosis is made with a standard, 3 view foot radiograph. Zone 1 injuries, also known as pseudojones, are avulsion fractures of the tuberosity, seen as a well-defined radiolucency usually perpendicular to the long axis of the bone. At times, the fracture line can extend medially towards the metaphysis while not clearly visualized, suggesting a Zone 2 injury [4]. Care should be taken not to mistake an accessory ossicle for a fracture. These will typically be seen as smooth and rounded structures, relatively distant from the tuberosity. 

Zone 2 fractures are also known as Jones fractures. Radiographs will reveal a fracture line at the metaphyseal-diaphyseal junction that extends medially towards the 4th-5th metatarsal joint [7]. Fractures distal to this region (Zone 3) are typically stress fractures and will display features of chronic injury [3].

Management

Patients with Zone 1 injuries can be managed conservatively as nonunion is rare. If there is displacement of the fracture >3mm, they should be referred to orthopedics. 

Patients with Zone 2 or Zone 3 fractures should be immobilized in a posterior ankle splint or CAM boot and be non-weight bearing on the extremity with orthopedic follow up.

If the diagnosis is unclear, presume an injury is present and treat accordingly. These patients should have follow-up for repeat X-ray and possible MRI if clinical suspicion is still high [5].

 
 

References

  1. Quill GE Jr. Fractures of the proximal fifth metatarsal. Orthop Clin North Am. 1995 Apr;26(2):353-61. PMID: 7724197.

  2. He W, Zhou H, Zhang Y, Yu T, Xia J, Zhao Y, Yang Y, Li B. Classification of avulsion fractures of the fifth metatarsal base using three-dimensional CT mapping and anatomical assessment: a retrospective case series study. J Foot Ankle Res. 2022 Aug 31;15(1):65. doi: 10.1186/s13047-022-00571-2. PMID: 36045449; PMCID: PMC9429432.

  3. Gaillard F, Qureshi P, Elfeky M, et al. Stress fracture of the 5th metatarsal. Reference article, Radiopaedia.org (Accessed on 27 May 2024) https://doi.org/10.53347/rID-7647

  4. Noori N, Abousayed M, Guyton GP, Coleman MM. What Is the Interrater and Intrarater Reliability of the Lawrence and Botte Classification System of Fifth Metatarsal Base Fractures? Clin Orthop Relat Res. 2022 Jul 1;480(7):1305-1309. doi: 10.1097/CORR.0000000000002131. Epub 2022 Jan 26. PMID: 35081080; PMCID: PMC9191320.

  5. Smidt KP, Massey P. 5th Metatarsal Fracture. [Updated 2023 May 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK544369/

  6. WikEM contributors. Fifth metatarsal fracture.. WikEM, The Global Emergency Medicine Wiki. April 17, 2024. Available at: https://wikem.org/wiki/Fifth_metatarsal_fracture. Accessed MAY 26, 2024.

  7. Alsobrook J, Hatch RL. Proximal fifth metatarsal fractures. In: UpToDate, Connor RF (Ed), Wolters Kluwer. (Accessed on May 26, 2024.)

 
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