What is the typical mechanism of injury for a Jones fracture?

Mechanism of Injury for Jones Fracture

A Jones fracture occurs through repetitive weight-bearing and pivoting on the involved foot, creating stress at the metaphyseal-diaphyseal junction of the fifth metatarsal approximately 1.5-2 cm distal to the tuberosity. 1

Biomechanical Mechanism

The injury results from repetitive submaximal stress on the proximal fifth metatarsal during activities involving pivoting and lateral foot loading. 1 This mechanism differs fundamentally from the avulsion-type fractures that occur more proximally at the tuberosity. 2

• The fracture occurs at the junction between the metaphysis and diaphysis, where inherent poor blood supply makes this region particularly vulnerable to stress injury 3
• The repetitive loading leads to accelerated bone remodeling that exceeds the rate of new bone formation, resulting in microtrabecular disruption and eventual cortical break 4

Patient Demographics and Activity Patterns

Acute Jones fractures occur equally in both sexes, typically in nonathletes over age 21, while chronic stress-type Jones fractures predominantly affect male athletes between 15-21 years of age. 1

• The acute variant results from a single higher-energy pivoting event on the lateral foot 1
• The chronic or fatigue variant develops from cumulative repetitive stress in athletes participating in activities requiring running, jumping, and cutting movements 4, 1

Anatomical Location and Imaging Characteristics

The fracture appears as a transverse fracture line at the metaphyseal-diaphyseal junction, approximately 1.5-2 cm distal to the fifth metatarsal tuberosity. 5, 1

• On radiographs, the fracture line is transverse and located at this specific junction, distinguishing it from more proximal avulsion fractures 5
• MRI demonstrates bone marrow edema patterns when radiographs are negative or inconclusive 5

Clinical Pitfall

Do not confuse Jones fractures with more proximal avulsion fractures at the tuberosity—these are entirely different injuries with different mechanisms, prognosis, and treatment requirements. 2 The proximal avulsion injuries result from acute inversion stress causing pull of the peroneus brevis tendon, while Jones fractures result from repetitive pivoting stress at the watershed vascular zone. 1, 3