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Basics ⬇

Author: Adam T.Chrusch, MD, CAQSM

The anatomy of the foot is divided into the hindfoot, the midfoot, and the forefoot:

Description

  • A metatarsal fracture can be described as being extra-articular, partial intra-articular, or articular, depending on where on the metatarsal the fracture occurs. Extra-articular fractures may be transverse (straight across the long axis), oblique, or spiral. An articular or partial intra-articular may be a simple isolated fracture extending into the joint, comminuted, or an avulsion fracture.
  • A stress injury with normal radiographs but a positive exam (pain to palpation) may be categorized as macrotrabecular (visible fracture lines on magnetic resonance imaging [MRI]) or stress reaction (T2 signal change on MRI without visible fracture lines).

Epidemiology

  • Metatarsal fractures are likely more common in athletes involved in weight-bearing exercise such as dancers, runners, or contact sport athletes.
  • Any direct trauma, however, can cause fracture, and lower risk athletes such as swimmers or bikers still may present with this injury.

Incidence

  • Metatarsal fractures are common with the 5th metatarsal constituting >50% of all metatarsal fractures (1)[A].
  • Incidence peaks in men in their 30s and in women in their 60s (1)[A].

Etiology and Pathophysiology

  • When the cortical bone’s mechanical strength is exceeded acutely by direct trauma, such as a heavy object falling on the foot, it will fracture.
  • A fracture may also occur when the bone-tendon interface is acutely stressed past its mechanical failure point.
  • An additional mechanism for fracture occurs when repetitive subthreshold forces are incompletely healed, and the additive damage eventually causes an overt fracture.

Risk-Factors

  • Those with osteopenia or osteoporosis have a greater risk.
  • Any activity that increases the likelihood of direct trauma to the foot increases the risk of metatarsal injury.
  • Twisting mechanism is associated with 5th metatarsal fractures (1)[A].
  • Excessively rapid progressions of training volume and/or stress on the foot can also increase the risk of metatarsal stress injury.
  • Alcohol abuse may increase the risk for nonunion complicating this fracture (2)[A].

General Prevention

  • Gradual increases in workload allow a bone to adapt to mechanical stress and become stronger.
  • Bone is a dynamic organ that is subject to anabolic forces tending to build it up as well as to catabolic forces tending to break it down.
  • This balance allows a bone to remodel and adapt to stress but may also cause progressive weakening if catabolic forces outweigh the anabolic ones, such as with too-rapid progression of training load.

Commonly Associated Conditions

  • The same forces that cause fracturing of the metatarsals may also injure adjacent structures such as the midfoot joint (between the row of cuneiform bones articulating with the 1st through 4th metatarsals and the cuboid articulating with the 4th and 5th metatarsal). At the other end, the metatarsophalangeal (MTP) joints may be involved when a fracture extends into the joint or when the joint capsule or ligamentous structures are disrupted.
  • Other injuries to consider:
    • Midtarsal joint injury (calcaneocuboid or talonavicular): can include lateral process of talus or anterior process of calcaneus
    • Navicular or cuboid contusion/fracture
    • Metatarsocuneiform (MTC)/cuboid injury: Lisfranc joint injury may include ligamentous disruption and/or fracture of surrounding bone.
    • MTP injury: can include capsular or ligamentous sprain (turf toe) or fracture of adjacent bone
    • Phalangeal fracture
    • Sesamoid contusion or fracture
  • Predisposing conditions:
    • Hallux valgus/hallux rigidus: Altered mechanics at the 1st MTP joint leads body weight shifting laterally over the lesser caliber 2nd metatarsal.
    • Osteopenia/osteoporosis: Decreased mechanical strength of the bone increases susceptibility to stress fracture and acute fracture.
    • Diabetes mellitus puts one at risk for a poorer outcome (3)[C].

Diagnosis ⬆ ⬇

  • Diagnosis of overt metatarsal fracture is by radiograph.
  • Standard views include the anteroposterior (AP), lateral, and oblique views.
  • Addition of weight-bearing views may help identify subtle lesions as well as Lisfranc injuries if the patient tolerates them.
  • Point of care ultrasound may be an alternative imaging modality because it is quick and sometimes more readily available. Radiography is still the standard of care (4)[A].
  • Diagnosis of radiographically negative stress injury is via a technetium-99 bone scan or by MRI:
    • Advantages of MRI over bone scan include differentiation of stress reaction without fracture lines versus macrotrabecular fracture.
  • Prehospital:
    • Prehospital/on-field care includes minimizing weight-bearing on the affected extremity as well as icing to reduce swelling and inflammation.
    • If there is no evidence for open fracture or vascular compromise, plain radiographs may be obtained at the patient’s convenience.
    • If there is visible bone penetrating the skin or the extremity is cool indicative of vascular compromise, immediate transport to the emergency room is advisable.

History

  • With acute injury, the patient will usually be able to point to the area of direct trauma to the foot or a twisting injury causing pain.
  • More subtle stress injuries will typically have a history of recent increases in training volume or impact load and possibly a prior history of other stress fractures, disordered eating, or menstrual irregularities.

Physical Exam

  • Point-tenderness directly over the metatarsal is the typical finding on exam.
  • The foot will usually show some swelling in comparison to the unaffected foot and possibly some bruising as well.
  • Gross displacement is not common. Open fractures will present with bone penetrating through the skin.
  • Focal tenderness and/or swelling over the metatarsals after an injury is a clear indication for plain radiographs to rule out a fracture.
  • Chronic symptoms of foot pain with weight-bearing and negative radiographs warrant further imaging such as bone scan or MRI.
  • An urgent need for a clear diagnosis after an acute injury and negative radiographs also suggests the need for further imaging.
  • Tuning fork testing is a quick and easy sideline/clinic test which can provide some reassurance if negative but is widely variable for accuracy and specificity.

Differential Diagnosis

  • MTP joint synovitis: inflammation of the joint rather than stress reaction in the bone itself. Bone scan will show distal uptake around MTP joint. MRI is diagnostic. Claw toe may also cause synovitis with plantar displacement of metatarsal head or a metatarsal stress reaction.
  • MTP capsular strain and/or chip fracture of 1st metatarsal head (turf toe)
  • Lisfranc sprain/fracture: injury to the 2nd MTC articulation. Any pain at the proximal 2nd metatarsal in association with a twisting injury in plantar flexion should raise concern for this injury.
  • Midfoot sprain: injury to MTC ligamentous structures
  • Forefoot mass (ganglion or tumor)
  • Metatarsalgia
  • Morton neuroma (interdigital neuroma)
  • Freiberg infarction: osteonecrosis of 2nd metatarsal head; more common in adolescent athletes with unilateral (usually) pain in 2nd metatarsal head

Diagnostic Tests & Interpretation

  • Plain radiographs will show cortical disruption if a significant fracture has occurred.
  • The findings may be subtle with mild injury.
  • A stress fracture may show subtle sclerotic borders/periosteal elevation or be entirely normal.
  • Plain films only become positive once healing has progressed enough to produce visible bony callus. In the interim, an MRI should show changes on T2 images, and a bone scan should be positive for focal hot spot over the painful area.
  • A computed tomography (CT) scan may be indicated for an intra-articular fracture to delineate any articular step-off.
  • Ultrasound will show a cortical irregularity and fracture hematoma (4)[A].

Treatment ⬆ ⬇

The goal of treatment is to stabilize the fracture such that normal length, rotation, and declination of the metatarsal is maintained, and the area is protected from further injury until healing has occurred:

  • Prehospital:
    • If possible, the foot should be elevated and cooled with ice as soon as possible after injury.
    • Limited or crutch-assist weight-bearing is advisable until emergency department (ED) or physician evaluation has occurred.
    • Chronic complaints can be evaluated in a physician’s office rather than an ED.
  • ED treatment:
    • Evaluation of acute injury to the foot in the ED includes AP, lateral, and oblique plain radiographs. Good neurovascular status must be verified, as compartment syndrome can occur with a forefoot crush injury. The need for closed or open reduction is then assessed. Multiple metatarsal fractures with >4 mm of displacement or an apical angulation of the metatarsal head of >10 degrees on the lateral view could require open/closed reduction to ensure a normal weight-bearing position of the metatarsal head.
    • Open reduction of metatarsal, phalangeal, and MTP joint injuries can cause scarring and stiffness in addition to the original trauma. It is used largely to maintain a plantigrade foot for normal weight-bearing. An open fracture requires surgical intervention for débridement and stabilization.
    • Nondisplaced fractures of the metatarsal neck and shaft may be treated with a short leg cast, fracture brace, or a cast shoe. Weight-bearing is permitted as tolerated on discharge from ED. The minimum amount of immobilization necessary for comfort should be used. Fractures at the base of the 5th metatarsal may be treated with an ankle stirrup brace, cast shoe, or fracture brace to maintain comfort.

Medication

  • Depending on the severity of the injury, nonsteroidal anti-inflammatory drugs (NSAIDs) are first-line drugs to treat pain.
  • Acetaminophen is also used.
  • More severe pain may require narcotic pain relief.

First Line

  • NSAIDs
  • Acetaminophen

Second Line

  • Oral low- to mid-potency narcotics such as hydrocodone
  • Tramadol and codeine are also options but should be avoided in patients age <12 yr as well as breast feeding women (5).
  • Tramadol should also be avoided in patients taking selective serotonin reuptake inhibitors (SSRIs) due to the risk of serotonin syndrome.

Issues for Referral

  • Multiple metatarsal fractures
  • Single metatarsal fracture with >4 mm of displacement
  • Single metatarsal fracture with >10 degrees of dorsal angulation of distal segment
  • Possible compartment syndrome
  • Displaced/comminuted fracture of the 1st metatarsal
  • Open fracture
  • Proximal 5th metatarsal fracture nonunion after 12 wk of conservative care

Additional Therapies

  • Proximal 5th metatarsal avulsion fracture (pseudo-Jones fracture):
    • Mechanism is usually due to an acute inversion injury to the ankle in plantar flexion. This can cause avulsion of the peroneus brevis or lateral plantar aponeurosis at the metatarsal tuberosity. May be a stress injury. They tend to be nondisplaced and experience relatively rapid union with symptomatic treatment. More distal injuries (without being a Jones fracture) may require short leg casting with non–weight-bearing (NWB) status for up to 6 to 8 wk. Use open reduction and internal fixation (ORIF) for delayed union or nonunion, significant displacement, or if cuboid 5th metatarsal joint involved.
  • Jones fracture (proximal shaft of 5th metatarsal):
    • The metaphyseal/diaphyseal junction is a watershed zone for blood flow and is susceptible to delayed union or nonunion. Consider ORIF in higher level athletes primarily and if nonunion occurs as well as displaced acute Jones fractures. Treat initially with short leg cast/fracture brace with no weight-bearing until evidence of bony callus formation is seen. Progress to weight-bearing at that point; may present with preinjury symptoms similar to stress fracture exacerbated by inversion injury
  • Spiral fracture of 5th metatarsal (dancer’s fracture):
    • This is typically treated nonsurgically with a fracture brace or cast shoe. Weight-bearing is allowed as tolerated. Radiographic healing may take up to 12 wk.

Surgery/Other Procedures

  • Proximal 5th metatarsal fracture/Jones fracture: ORIF with malleolar screw Kirschner wires
  • Bone grafting may be required with a nonunion.
  • Lisfranc fracture/dislocation: involves 2nd through 5th MTC joints; ORIF with cortical screws and Kirschner wires

Admission, Inpatient, and Nursing Considerations

  • Metatarsal fractures rarely require inpatient care.
  • Open fractures and multiple traumatic injuries that include a metatarsal likely require intravenous (IV) antibiotics and observed care.

Ongoing Care ⬆ ⬇

  • Upon discharge from the ED or after initial diagnosis, a patient with a metatarsal fracture should be seen in the office for follow-up radiographs in 1 wk to document correct bony alignment and adequacy of the treatment mode. Assuming radiographs show stability, follow-up films can be obtained at 6 wk, when full healing should be expected.
  • The least-limiting form of immobilization should be considered. With the exception of a Jones fracture, most metatarsal fractures tolerate weight-bearing with use of a cast shoe/wooden-soled shoe fairly quickly, if not at the time of diagnosis. If fracture brace/controlled ankle motion (CAM) boot use is required initially, transition to a stiff-soled or cast shoe should be considered when tolerated. A steel shank insert into a gym shoe may also be used.
  • Restriction from full weight-bearing stress without protection should continue for at least 4 wk for a stress fracture and for 4 to 6 wk for a nondisplaced metatarsal fracture. Pain to palpation and forefoot swelling should subside as the fracture heals. Evidence for radiographic healing, resolution of edema, and pain-free direct palpation are needed for return to sports.
  • Jones fracture:
    • Once diagnosis is made, an NWB fracture brace/cast is used for 6 wk to allow for healing to occur. Repeat radiographs are done at this point to assess progress, but up to 12 wk may be needed. Nonunion at 12 wk may require ORIF. The decision to pursue ORIF for a Jones fracture in a competitive athlete may occur at the time of initial diagnosis.

Patient Education

The patient should be advised to:

  • Elevate the leg frequently to minimize forefoot edema.
  • Use ice up to 20 min/hr to control swelling.
  • Notify the physician if there is any significant increase in pain/swelling during the recovery process.
  • Reduce activity level to remain pain free and use stiff-soled shoe for all weight-bearing activity until healing is complete.

Prognosis

Good

Complications

  • Nonunion
  • Malunion with painful plantar calluses under the metatarsal head
  • Dorsal corns secondary to friction over prominent metatarsal head

References ⬆ ⬇

  1. Kane JM, Sandrowski K, Saffel H, et al. The epidemiology of fifth metatarsal fracture. Foot Ankle Spec. 2015;8(5):354–359.
  2. Thorud JC, Mortensen S, Thorud JL, et al. Effect of obesity on bone healing after foot and ankle long bone fractures. J Foot Ankle Surg. 2017;56(2):258–262.
  3. Bowes J, Buckley R. Fifth metatarsal fractures and current treatment. World J Orthop. 2016;7(12):793–800.
  4. Kozaci N, Ay MO, Avci M, et al. The comparison of radiology and point-of-care ultrasonography in the diagnosis and management of metatarsal fractures. Injury. 2017;48(2):542–547.
  5. Jin J. Risks of codeine and tramadol in children. JAMA. 2017;318(15):1514.

Clinical Pearls ⬆

  • The 1st metatarsal carries a large amount of load, and fractures of it are often surgical.
  • Fracture-dislocations involving the Lisfranc joint are often missed on NWB films.
  • Dancer’s fractures, even displaced, will usually heal with conservative nonoperative management, whereas Jones fracture has a higher rate of nonunion and more often needs surgical fixation.