eMedicine Specialties > Radiology > Musculoskeletal

Metatarsals, Fractures

Prabhakar Rajiah, MD, MBBS, FRCR, Registrar, Department of Radiology, Central Manchester and Manchester Children's University Hospitals, UK
Shanmugam Karthikeyan, MBBS, MD, Dip Ortho, MRCS, Clinical Research Fellow in Orthopaedics, University Hospitals Coventry and Warwickshire NHS Trust, UK

Updated: Oct 7, 2009

Introduction

Background

Fractures of the foot are common, and the metatarsals are among the bones most commonly fractured. Acute foot fractures of normal bones are usually caused by the dropping of heavy objects on the foot or as a result of stress associated with abnormal repetitive trauma. In deficient bones, insufficiency fractures may result from normal stress. (See Images 1-25 in the Multimedia Section.)

Acute fractures may be transverse, oblique, or comminuted (see Images below); they are easily recognized. Stress fractures are difficult to recognize in the early stages, when they are manifested only by a periosteal reaction. Bone scans are helpful in this situation. Recognition of fracture is crucial for guiding appropriate management and for preventing complications.^1,2

$Fractured metatarsals. Transverse frac...$

Fractured metatarsals. Transverse fracture at the base of the fifth metatarsal in a male adolescent.

$Fractured metatarsals. Oblique fractur...$

Fractured metatarsals. Oblique fracture of the metaphysis of the distal shaft of the fifth metatarsal.

$Fractured metatarsals. Comminuted frac...$

Fractured metatarsals. Comminuted fracture of the base of the fifth metatarsal bone.

Recent studies

Abisetti et al reported on the diagnosis and treatment of stress fractures at the base of the second and third metatarsal bones in 150 trainee ballet dancers from the ballet school of Teatro Alla Scala in Milan, Italy, from 2005 to 2007. Stress fractures of the base of the metatarsal bones were identified in 19 of the dancers. The fractures were treated with external shockwave therapy in 18 of the patients; one was treated with low-intensity ultrasound. The authors found that the best approach to diagnosis was early clinical examination followed by radiography and MRI studies. All patients recovered and were able to return to dancing with no pain.³

Banal et al evaluated the sensitivity and specificity of ultrasonography versus dedicated MRI (0.2 Tesla), taken as the gold standard, in early diagnosis of metatarsal bone stress fractures in 41 feet of 37 patients between November 2006 and December 2007. All the patients had mechanical pain and swelling of the metatarsal region for less than 3 months and normal radiographs. MRI detected 13 fractures in 12 patients. Sensitivity of US was 83%, specificity 76%, positive predictive value 59%, and negative predictive value 92%. Positive likelihood ratio was 3.45, and negative likelihood ratio was 0.22. The authors concluded from their findings that in cases of normal radiographs, US is indicated in the diagnosis of metatarsal bone stress fractures because of its low cost; because it is a noninvasive, rapid, and easy technique; and because it has good sensitivity and specificity.⁴

Raikin et al assessed MRI for diagnosing injuries to the Lisfranc and adjacent ligaments; manual stress radiographic evaluation under anesthesia along with surgical findings were used as the reference standard in 21 feet of 20 patients. Intraoperatively, 17 unstable and 4 stable Lisfranc joints were identified. Of the 21 Lisfranc joint complexes, 19 were correctly classified on MRI; in 1 case, a stable Lisfranc joint complex was interpreted as unstable on MRI, and in another, an unstable joint complex was interpreted as stable. The authors concluded that MRI is accurate for detecting traumatic injury of the Lisfranc ligament and for predicting Lisfranc joint complex instability when the plantar Lisfranc ligament bundle is used as a predictor.⁵

For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education articles Broken Foot, Broken Toe, and Crutches.

Pathophysiology

Types of metatarsal injuries

Jones and pseudo-Jones, or tennis, fractures

A Jones fracture (see Image below) is caused by inversion of the foot, which produces tension on the peroneus brevis tendon and on the lateral cord of the plantar aponeurosis.^6,7 In this type of fracture, significant displacement is absent. This type of fracture is more prone to nonunion.

$Fractured metatarsals. Transverse fractur...$

Fractured metatarsals. Transverse fracture at the base of the fifth metatarsal; this is a Jones fracture.

A fracture of the metatarsal tuberosity is an avulsion fracture. This is also called a pseudo-Jones fracture or a tennis fracture. The mechanism of injury is forcible inversion of the foot in plantar flexion, which may occur when one steps on a curb or when one falls while climbing stairs. A direct blow to the tuberosity can cause a comminuted fracture.

Distal, or dancer's, fractures

Distal fractures, also called dancer's fractures, are caused by a rotational force resulting from axial loading with the foot in a plantigrade position.

Lisfranc dislocation

The Lisfranc joints are the tarsometatarsal joints. A Lisfranc fracture-dislocation (see Image below) is caused by falling from a height, falling down stairs, or stepping off a curb.

Fractured metatarsals. Image shows a Lisfranc fracture-dislocation: a fracture of the base of the second metatarsal and a lateral dislocation of the second metatarsal.

Mechanisms of injury are (1) rotation around a fixed forefoot (eg, falling from a horse with the foot caught in the stirrup) or (2) longitudinal compression of the foot. In this second mechanism, the metatarsal head is fixed. The weight of the body is on the hindfoot against the base of the metatarsals during rotation; these forces result in a distal dorsal dislocation of the metatarsal.

Stress fractures

Stress fractures (see Images below) are the result of abnormal stress on a normal bone. Stress fractures of the foot are also called marcher's foot because of the high incidence of occurrence in military recruits and in those who engage in heavy exercise for prolonged periods. This fracture is also common in ballet dancers, gymnasts, and athletes.³ Other predisposing factors include surgery, stress fractures in adjacent bones, neuropathic disease, and rheumatoid arthritis.

When a normal step is initiated, maximum force is placed on the head of the second or the third metatarsal. With increased activity, microinfarction takes place in the bones, resulting in a fracture.

Fractured metatarsals. Image shows a thin layer of subtle, solid periosteal reaction on the medial side of the shaft of the second metatarsal bone. This is an early stage of a stress fracture.

Fractured metatarsals. Image shows a stress fracture more florid than that shown in the image of the stress fracture above (Image 22 in the Multimedia Section), with extensive periosteal reaction on either side of the third and fourth metatarsals.

Insufficiency fractures

Insufficiency fractures are the result of normal stress on a weakened bone. Such injuries are seen in people with osteoporosis; postmenopausal women are commonly affected.

Classification systems

Simple classification

Many classifications apply to fracture of the fifth metatarsal.

In a simple classification for fractures of the proximal end of the fifth metatarsal, fractures are classified as (1) those of the tuberosity and (2) those of the proximal metatarsal within 1.5 cm of the tuberosity.

Acute fractures, Jones fractures, and stress fractures may be described as (1) early fractures, (2) delayed union fractures, or (3) nonunion fractures.

Torg classification

The Torg classification is used for fractures within 1.5 cm of the metatarsal tuberosity. Type I includes fractures with sharp margins and no widening, sclerosis, periosteal reaction, or cortical hypertrophy. Type II includes fractures with widening, periosteal reaction, sclerosis, or both. Type III fractures involve widening, periosteal reaction, complete sclerosis at the fracture line, or both.

Stewart classification

The Stewart classification of fifth metatarsal fractures is as follows: type I, extra-articular fracture between the metatarsal base and diaphysis; type II, intra-articular fracture of the metatarsal base; type III, avulsion fracture of the base; type IV, comminuted fracture with intra-articular extension; and type V, partial avulsion of the metatarsal base with or without a fracture.

Zonal classification

The zonal classification, reported by Dameron, Lawrence, and Botte, categorizes metatarsal fractures by the region affected: zone 1 corresponds to the tuberosity, zone 2 corresponds to Jones fractures, and zone 3 is the diaphysis.

Mortality/Morbidity

Early diagnosis and avoidance of weight bearing are essential to prevent the complications of metatarsal fractures.
Complications of metatarsal fractures include nonunion (more common in Jones fractures than in other types), delayed union, malunion, secondary osteoarthritis, and reflex sympathetic dystrophy.

Race

Metatarsal fracture has no racial predilection.

Sex

Metatarsal fracture has no particular sexual predilection.

Age

Stress fractures are more common in adults involved in prolonged exercises, especially military recruits, runners, dancers, and gymnasts, than in other groups.

Anatomy

Fractured metatarsals. Normal anteroposterior view of the foot. Note the alignment of (1) the lateral border of the first metatarsal with the lateral border of the medial cuneiform and (2) the medial border of second metatarsal with the medial border of the middle cuneiform.

Fractured metatarsals. Oblique view of a normal foot shows that the medial and lateral borders of the third metatarsal are aligned with the corresponding borders of the lateral cuneiform bone. The medial border of the fourth metatarsal is aligned with the medial border of the cuboid bone. The lateral border of fifth metatarsal projects a few centimeters beyond the cuboid bone.

There are 5 metatarsal bones in the foot. Each bone has a base, a shaft, and a head. The base is situated proximally and articulates with the distal row of tarsal bones. This articulation is called the Lisfranc joint. The first metatarsal articulates with the medial cuneiform bone; the second metatarsal, with the intermediate cuneiform bone; the third, with the lateral cuneiform bone; and the fourth and fifth metatarsals, with the cuboid bone.

The base of the fifth metatarsal has a tuberosity that projects inferiorly in the plantar direction and attaches to the peroneus brevis tendon and the lateral band of the plantar fascia. The heads of the metatarsals articulate with the proximal phalanges of the corresponding digits.

The second metatarsal is the longest of all metatarsal bones; the first metatarsal is the shortest. Two sesamoid bones are present in the tendon of the flexor hallucis brevis, posterior to the first metatarsal bone.

Development of metatarsal bones

The primary centers of ossification of the metatarsal shaft appear by 9-10 weeks of intrauterine life. The epiphysis for the heads of the metatarsals appears by 3-4 years of postnatal life. The epiphysis at the base of the first metatarsal also appears by 3-4 years and unites by 18 years. Occasionally, the base of the fifth metatarsal has a separate secondary ossification center; this may be confused with a fracture.

Radiologic anatomy

The metatarsal bones and tarsal bones are connected by strong ligaments. Soft tissue support for the joints in the plantar aspect of foot is better than that in the dorsal aspect.

On the anteroposterior view, the lateral border of the first metatarsal should be aligned with the lateral border of the medial cuneiform. The medial border of the second metatarsal should be aligned with the medial border of the intermediate cuneiform bone.

On the oblique view, the medial and lateral border of the third metatarsal should be aligned with the medial and lateral borders of lateral cuneiform bone. The medial border of the fourth metatarsal should be aligned with the medial border of the cuboid bone. The fourth and fifth metatarsals are aligned with the cuboid bone, but the lateral part of the fifth metatarsal may project beyond the margin of the cuboid bone by up to 3 mm.

The distance between the base of the first and second metatarsals and the medial and intermediate cuneiform is more than the distance between other corresponding joints.

If a lateral image is obtained, a line drawn through the long axis of talus bone and the long axis of first metatarsal bone should be straight if there is no dislocation.

Presentation

Signs, symptoms, and treatment

In a fracture of the fifth metatarsal (see Images below), pain and tenderness are present at the base of fifth metatarsal, along with swelling and ecchymosis; in addition, the patient experiences difficulty with weight bearing. This fracture is sometime hard to differentiate from an ankle injury because the swelling can be near the lateral malleolus.

$Fractured metatarsals. Spiral fracture...$

Fractured metatarsals. Spiral fracture through the distal shaft of the fifth metatarsal.

$Fractured metatarsals. Another fracture o...$

Fractured metatarsals. Another fracture of the fifth metatarsal, oblique, in the shaft.

The head of the second metatarsal head is most commonly affected, though other bones may be involved as well.

Management depends on whether the injury is an acute fracture or a stress fracture and on whether it is displaced or not.

Avulsion fractures of the tuberosity are managed conservatively with non – weight bearing casts. Jones fractures are managed according to their Torg classification: Type I fractures are managed conservatively. Type II fractures are managed conservatively or with surgery. Type III fractures are associated with more complications and are usually managed surgically.

Preferred Examination

For patients with symptoms, proper history taking is essential to identify a suggestive mechanism of injury.

Physical examination commonly reveals signs and symptoms of swelling, tenderness, warmth, ecchymosis, limitation of movements, and an inability to bear weight.

Radiography is the first and often the only investigation required for the diagnosis of fractures. Radiographs may be used to diagnose all acute fractures, dislocations, and established stress fractures (see Images 1-25).

Bone scanning is more sensitive than plain radiography; it is indicated when a stress fracture or an acute fracture is suspected and radiographs are negative. Bone scanning is not a specific investigation.

Although MRI is more sensitive than radiography and bone scanning, it is used only for the assessment of soft tissue structures and ligamentous injuries. MRI is the most sensitive technique for imaging stress fractures of the foot; MRI may depict bone marrow edema even before increased uptake is seen on bone scans.

CT scanning is useful for finding avulsion fractures and comminuted fractures and to assess for intra-articular extension.

Limitations of Techniques

Small avulsions may be missed on radiographs. In the early stages of stress fracture, radiographs may be normal, or they may show only subtle periosteal reaction, which can be easily missed. Radiography cannot be used to assess soft tissue and ligamentous disruption.

Although CT and MRI are more sensitive than radiography, they are not cost-effective and are not indicated for the diagnosis of fractures.

Although bone scanning is sensitive, some stress fractures may go undetected in the early stages.

Differential Diagnoses

Ankle, Fractures
Metatarsals, Fractures
Stress Fracture

Radiography

Findings

Metatarsal fractures

$Fractured metatarsals. Spiral fracture...$

Fractured metatarsals. Spiral fracture through the distal shaft of the fifth metatarsal.

$Fractured metatarsals. Another fracture o...$

Fractured metatarsals. Another fracture of the fifth metatarsal, oblique, in the shaft.

Fractured metatarsals. Fracture at the base of the first metatarsal in a child.

$Fractured metatarsals. Transverse frac...$

Fractured metatarsals. Transverse fracture at the base of the fifth metatarsal in a male adolescent.

Fractured metatarsals. Fracture of the distal shaft of the third metatarsal.

$Fractured metatarsals. Transverse fractur...$

Fractured metatarsals. Transverse fracture at the base of the fifth metatarsal; this is a Jones fracture.

An acute fracture is seen as a linear lucency and a break in the cortical surface. Nondisplaced impacted fractures may appear as an opaque line; such fractures may be confirmed on a different view.

Fractures may affect any metatarsal, but the fifth metatarsal is most commonly affected. The fracture may be transverse, oblique, or comminuted. Longitudinal linear fractures are extremely rare.

The 2 most common fractures in the fifth metatarsal are a fracture at the tip of the tuberosity and a transverse fracture 1.5-2 cm from the tuberosity; the latter is called a Jones fracture. Small avulsions derived from the tip of the base of the fifth metatarsal may be seen only in the oblique projection of the ankle.⁸

Stress fractures

Fractured metatarsals. Image shows a thin layer of subtle, solid periosteal reaction on the medial side of the shaft of the second metatarsal bone. This is an early stage of a stress fracture.

Fractured metatarsals. Image shows a stress fracture more florid than that shown in the image of the stress fracture above (Image 22 in the Multimedia Section), with extensive periosteal reaction on either side of the third and fourth metatarsals.

The radiographic findings of a stress fracture depend on the bone involved and the stage of disease. Radiographs are normal in the early stages of the disease; stress fractures appear as well-defined linear lucency or fluffy periosteal reactions by 7-10 days. The periosteal reaction is variable and is occasionally florid.

The head of the second metatarsal and, occasionally, the third metatarsal are commonly affected. The first metatarsal is injured in 10% of metatarsal stress fractures; such fractures involve a different kind of reaction (the endosteal variety), with liner sclerosis. Periosteal reaction is not common in this type of injury. One third of such fractures heal with only an intramedullary callus.

The base of second metatarsals may be affected in ballet dancers. The proximal aspect of the shaft of the fourth and fifth metatarsals is affected; the pattern is that of a linear lucency, which is slow to heal. Fractures in the sesamoid bones are also seen in ballet dancers.

Lisfranc fracture-dislocation

Fractured metatarsals. Image shows a Lisfranc fracture-dislocation: a fracture of the base of the second metatarsal and a lateral dislocation of the second metatarsal.

Fractured metatarsals. Image shows a Lisfranc dislocation with a fracture of the base of the third and fourth metatarsals.

A Lisfranc fracture-dislocation is a dislocation of the tarsometatarsal joints. Two types of Lisfranc dislocation have been described: homolateral and divergent.

In the homolateral type, all of the metatarsals are dislocated to one side. Usually, the second to fifth metatarsals are dislocated, but occasionally, all of the metatarsals are affected. Lateral displacement is more common than medial displacement.

A divergent dislocation is medial displacement of the first metatarsal and lateral displacement of the second to fifth metatarsals. A variant of this type is an isolated medial dislocation of the first metatarsal.

Lisfranc dislocations are associated with fractures of the base of the second metatarsal, fractures of the cuboid bone, fractures of the shaft of the other metatarsal bones, dislocations of the middle and medial cuneonavicular joints, and fractures of the navicular bone. The base of the second metatarsal is relatively fixed compared with the other metatarsal bones. Therefore, it is involved in both types.

This dislocation is overlooked in as many as 20% of cases if the alignment is not carefully evaluated. Lisfranc dislocations should be suspected if a gap of more than 5 mm is present between the bases of first and second metatarsals or between the medial and middle cuneiforms.

Degree of Confidence

Radiography is sensitive in the diagnosis of acute fractures.

False Positives/Negatives

Radiographs may not show stress fractures in the early stages and in as many as 50% of patients. In addition, nondisplaced fractures may be difficult to visualize. Associated ligamentous injuries and soft tissue changes are not depicted.