FRACTURES OF THE MIDFOOT

AND FOREFOOT

MIDTARSAL (CHOPART) JOINT

Epidemiology

Injuries to the midfoot are relatively rare.

The annual incidence of midfoot fractures is 3.6 per 100,000 population per year.

The most commonly fractured bone was the cuboid (50%), followed by the navicular (44%) and the cuneiform (6%).

The male-to-female ratio is 1:1.2.

Anatomy

The midfoot is the section of the foot distal to Chopart joint line and proximal to Lisfranc joint line (Fig. 41.1).

Five tarsal bones comprise the midfoot: These are the navicular, cuboid, and the medial, middle, and lateral cuneiforms.

The midtarsal joint consists of the calcaneocuboid and talonavicular joints, which act in concert with the subtalar joint during inversion and eversion of the foot.

The cuboid acts as a linkage across the three naviculocuneiform joints, allowing only minimal motion.

Ligamentous attachments include the plantar calcaneonavicular (spring) ligament, bifurcate ligament, dorsal talonavicular ligament, dorsal calcaneocuboid ligament, dorsal cuboideonavicular ligament, and long plantar ligament (Fig. 41.2).

Mechanism of Injury

High-energy trauma: This is most common and may result from direct impact from a motor vehicle accident or a combination of axial loading and torsion, such as during impact from a fall or jump from a height.

Low-energy injuries: This may result in a sprain during athletic or dance activities.

Clinical Evaluation

Patient presentation is variable, ranging from a limp with swelling and tenderness on the dorsum of the midfoot to nonambulatory status with significant pain, gross swelling, ecchymosis, and variable deformity.

Stress maneuvers consist of forefoot abduction, adduction, flexion, and extension and may result in reproduction of pain and instability.

Plantar ecchymosis is usually indicative of midfoot injury.

A careful neurovascular examination should be performed. In cases of extreme pain and swelling, serial examinations may be warranted to evaluate the possibility of foot compartment syndrome.

Radiographic Evaluation

Anteroposterior (AP), lateral, and oblique radiographs of the foot should be obtained.

Stress views or weight-bearing x-rays may help to delineate subtle injuries.

Computed tomography (CT) may be helpful in characterizing fracture-dislocation injuries with articular comminution.

Magnetic resonance imaging (MRI) may be used to evaluate ligamentous injury and/or more subtle injuries.

Classification

Medial Stress Injury

Inversion injury occurs with adduction of the midfoot on the hindfoot.

Flake fractures of the dorsal margin of the talus or navicular and of the lateral margin of the calcaneus or the cuboid may indicate a sprain.

In more severe injuries, the midfoot may be completely dislocated, or there may be an isolated talonavicular dislocation. A medial swivel dislocation is one in which the talonavicular joint is dislocated, the subtalar joint is subluxed, and the calcaneocuboid joint is intact.

Longitudinal Stress Injury

Force is transmitted through the metatarsal heads proximally along the rays with resultant compression of the midfoot between the metatarsals and the talus with the foot plantarflexed.

Longitudinal forces pass between the cuneiforms and fracture the navicular typically in a vertical pattern.

Lateral Stress Injury

“Nutcracker fracture”: This is the characteristic fracture of the cuboid as the forefoot is driven laterally, crushing the cuboid between the calcaneus and the fourth and fifth metatarsal bases.

Most commonly, this is an avulsion fracture of the navicular with a comminuted compression fracture of the cuboid.

In more severe trauma, the talonavicular joint subluxes laterally, and the lateral column of the foot collapses because of comminution of the calcaneocuboid joint.

Plantar Stress Injury

Forces directed at the plantar region may result in sprains to the midtarsal region with avulsion fractures of the dorsal lip of the navicular, talus, or anterior process of the calcaneus.

Treatment

Nonoperative

Sprains: Nonrigid dressings are used with protected weight bearing for 4 to 6 weeks; prognosis is excellent. For severe sprains, midfoot immobilization may be indicated.

Nondisplaced fractures may be treated with a short leg cast or fracture brace with initial non–weight bearing for 6 weeks.

Operative

High-energy mechanisms resulting in displaced fracture patterns often require open reduction and internal fixation (ORIF; e.g., with Kirschner wires or screws) and/or external fixation.

Prognosis is guarded, depending on the degree of articular incongruity.

Bone grafting of the cuboid may be necessary following reduction of lateral stress injuries.

Severe crush injuries with extensive comminution may require arthrodesis to restore the longitudinal arch of the foot.

Complications

Posttraumatic osteoarthritis may occur as a result of residual articular incongruity or chondral injury at the time of trauma. If severe and debilitating, it may require arthrodesis for adequate relief of symptoms.

TARSAL NAVICULAR

Epidemiology

Isolated fractures of the navicular are rare and should be diagnosed only after ruling out concomitant injuries to the midtarsal joint complex.

Anatomy

The navicular is the keystone of the medial longitudinal arch of the foot.

It is wider on its dorsal and medial aspect than on its plantar and lateral aspect.

The medial prominence known as the navicular tuberosity provides the attachment point for the posterior tibialis on its medial inferior surface.

An accessory navicular may be present in 4% to 12% of patients and should not be confused with an acute fracture.

Proximally, the articular surface is concave and articulates with the talus. This joint enjoys a significant arc of motion and transmits the motion of the subtalar joint to the forefoot. It is the point from which forefoot inversion and eversion are initiated.

The distal articular surface of the navicular has three separate broad facets that articulate with each of the three cuneiforms. These joints provide little motion; they mainly dissipate loading stresses.

Laterally, the navicular rests on the dorsal medial aspect of the cuboid with a variable articular surface.

Thick ligaments on its plantar and dorsal aspect support the navicular cuneiform joints. The spring ligament and superficial deltoid provide strong support to the plantar and medial aspects of the talonavicular joint.

Anatomic variants to be aware of when viewing the navicular involve the shape of the tuberosity and the presence of an accessory navicular (os tibiale externum). They are present up to 15% of the time, and bilateral 70% to 90%.

Mechanism of Injury

Direct blow, although uncommon, can cause avulsions to the periphery or crush injury in the dorsal plantar plane.

More often, indirect forces of axial loading either directly along the long axis of the foot or obliquely cause navicular injury.

Injury may result from a fall from a height or a motor vehicle accident. Stress fractures may occur in running and jumping athletes, with increased risk in patients with a cavus foot or calcaneal navicular coalition.

Clinical Evaluation

Patients typically present with a painful foot and dorsomedial swelling and tenderness.

Physical examination should include assessment of the ipsilateral ankle and foot, with careful palpation of all bony structures to rule out associated injuries.

Radiographic Evaluation

AP, lateral, medial oblique, and lateral oblique views should be obtained to ascertain the extent of injury to the navicular as well as to detect associated injuries.

If possible, the initial films should be weight bearing to detect ligamentous instability.

Medial and lateral oblique x-rays of the midfoot will aid in assessing the lateral pole of the navicular as well as the medial tuberosity.

CT may be obtained to better characterize the fracture.

MRI or technetium scan may be obtained if a fracture is suspected but not apparent by plain radiography.

Classification

The most commonly used classification of navicular fractures is composed of three basic types with a subclassification for body fractures (Sangeorzan) (Fig. 41.3).

• Avulsion-type fracture can involve either the talonavicular or naviculocuneiform ligaments.

• Tuberosity fractures are usually traction-type injuries with disruption of the tibialis posterior insertion without joint surface disruption.

• Type I body fracture splits the navicular into dorsal and plantar segments.

• Type II body fractures cleave into medial and lateral segments. The location of the split usually follows either of the two intercuneiform joint lines. Stress fractures can usually be included in this group.

• Type III body fractures are distinguished by comminution of the fragments and significant displacement of the medial and lateral poles.

  Orthopaedic Trauma Association Classification of Navicular Fractures

  See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

  Anatomic Classification

  Cortical Avulsion Fractures (Up to 50%)

Excessive flexion or eversion of midfoot results in a dorsal lip avulsion of the navicular by the talonavicular capsule and the anterior fibers of the deltoid ligament. This is seen as a part of ankle

sprain continuum.

Symptomatic, small, nonarticular fragments may be excised. Large fragments (>25% articular surface) may be reattached with a lag screw.

Body Fractures (30%)

Tuberosity Fractures (20% to 25%)

Forced eversion injury causes avulsion of the tuberosity by the posterior tibial tendon insertion or deltoid ligament.

This is often part of the “nutcracker fracture,” so concomitant midtarsal injury must be excluded.

One must rule out the presence of an accessory navicular, which is bilateral in 70% to 90% of cases.

If symptomatic, small fragments can be excised and the posterior tibial tendon reattached; larger fragments require ORIF with lag screw fixation, especially if posterior tibial tendon function is compromised.

Stress Fractures

These occur primarily in young athletes.

They frequently require bone scan or MRI for diagnosis.

The fracture line is usually sagittally oriented in the middle third and may be complete or incomplete.

Owing to increased incidence of persistent problems with pain and healing, screw fixation with autologous bone grafting should be used with comminuted fractures.

Treatment

The two most important criteria in obtaining a satisfactory outcome are maintenance or restoration of the medial column length and articular congruity of the talonavicular joint.

Nonoperative

Nondisplaced fractures of the navicular should be treated in a short leg cast or fracture brace with restricted weight bearing for 6 to 8 weeks.

Repeat radiographs should be obtained at 10 to 14 days after the initial injury to confirm the absence of bony or soft tissue instability. If instability appears or other injuries become apparent, appropriate surgical intervention should be considered.

Operative

Surgical indications

• Any unstable injury or fracture resulting in loss of position or articular congruity should be treated surgically.

• Because the joint is concave, a 2-mm separation in any plane is considered incongruent. Most

  authors agree these injuries need to be managed aggressively with operative reduction.

• Cortical avulsion fractures found to involve a significant portion of the dorsal anterior surface

  should be considered for operative treatment.

Surgical management

• Individual fragments are stabilized using K-wires or mini-fragment screws.

• Bone graft should be considered for crushed areas requiring elevation.

• If anatomic restoration of 60% or more of the talonavicular surface can be achieved, an effort should be made to salvage the joint.

• If more than 40% of the articular surface cannot be reconstructed, an acute talonavicular fusion

  should be considered.

Postoperative management

• Cast or brace immobilization with non–weight bearing is recommended for 12 weeks.

   

  Complications

These include nonunion, arthritic degeneration, late instability, loss of normal foot alignment through bony resorption or collapse, and osteonecrosis.

Osteonecrosis: The risk is increased with significantly displaced, markedly comminuted fractures. It may result in collapse of the navicular, with need for bone grafting and internal fixation.

Posttraumatic osteoarthritis may occur as a result of articular incongruity, chondral damage, or free osteochondral fragments.

NAVICULAR DISLOCATION

Isolated dislocation or subluxation of the navicular is rare.

The mechanism is hyperplantar flexion of the forefoot with subsequent axial loading.

Open reduction is usually necessary to restore both navicular position and articular congruity.

CUBOID FRACTURES

Epidemiology

Injury to the cuboid can occur as an isolated entity but is usually seen in association with injuries to the talonavicular joint or other midfoot structures or in conjunction with Lisfranc injuries.

Anatomy

The cuboid is part of the lateral support column of the foot.

The cuboid articulates with the calcaneus proximally, the navicular and lateral cuneiform medially, and the lateral two metatarsals distally.

Its plantar aspect forms a portion of the roof of the peroneal groove through which the peroneus longus tendon runs; scarring and irregularity of the peroneal groove caused by cuboid fracture may compromise function of peroneus longus tendon.

Mechanism of Injury

Direct: This is uncommon; trauma to the dorsolateral aspect of the foot may result in fractures of

the cuboid.

Indirect: This accounts for most cuboid fractures.

• “Nutcracker injury”: Torsional stress or forefoot abduction may result in impaction of the cuboid between the calcaneus and the lateral metatarsals.

• Extreme plantar flexion may cause isolated sprain or dislocation of calcaneocuboid joint in

  high-velocity trauma, dance injuries, or patients with Ehlers–Danlos syndrome.

Stress fractures may occur in athletic individuals.

Clinical Evaluation

Patients typically present with pain, swelling, and tenderness to palpation at the dorsolateral aspect of the foot.

Palpation of all bony structures of the foot should be performed to rule out associated injuries.

Pain on the lateral aspect of the foot may be confused with symptoms of peroneal tendonitis in cases of stress fractures of the cuboid.

Radiographic Evaluation

AP, lateral, and oblique views of the foot should be obtained.

Multiple medial oblique radiographic views may be needed to see the articular outlines of both the calcaneocuboid and cuboid metatarsal joints.

As with other potential midfoot problems, weight-bearing or stress views should be obtained to rule out interosseus instability of surrounding structures.

A small medial or dorsal avulsion fracture of the navicular is considered a sign of possible cuboid injury.

A CT scan may be necessary to assess the extent of injury and instability.

An MRI or bone scan may be used for diagnosing a stress fracture.

Classification

Orthopaedic Trauma Association Classification

See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html

Treatment

Nonoperative

Isolated fractures of the cuboid with no evidence of loss of osseous length or interosseus instability can be treated in a cast or removable boot.

Non–weight bearing for 4 to 6 weeks is recommended.

Operative

ORIF is indicated if there is more than 2 mm of joint surface disruption or any evidence of longitudinal compression.

Severe comminution and residual articular displacement may necessitate calcaneocuboid arthrodesis for proper foot alignment and to minimize late complications.

Complications

Osteonecrosis: This may complicate severely displaced fractures or those with significant comminution.

Posttraumatic osteoarthritis: This may result from articular incongruity, chondral damage, or free osteochondral fragments.

Nonunion: This may occur with significant displacement and inadequate immobilization or fixation. If severely symptomatic, it may necessitate ORIF with bone grafting.

CUNEIFORM FRACTURES

These usually occur in conjunction with tarsometatarsal injuries.

The usual mechanism is indirect axial loading of the bone.

Localized tenderness over the cuneiform region, pain in the midfoot with weight bearing, or discomfort with motion through the tarsometatarsal joints can signify injury to these bones.

AP, lateral, and oblique views should be obtained. These should be weight bearing if possible.

Coronal and longitudinal CT scan of the midfoot can be used to better define the extent of the injury.

Orthopaedic Trauma Association Classification of Cuneiform Fractures See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html

TARSOMETATARSAL (LISFRANC) JOINT

Epidemiology

These are generally considered rare.

Approximately 20% of Lisfranc injuries may be initially overlooked (especially in polytraumatized patients).

Anatomy

In the AP plane, the base of the second metatarsal is recessed between the medial and lateral cuneiforms. This limits translation of the metatarsals in the frontal plane.

In the coronal plane, the middle three metatarsal bases are trapezoidal, forming a transverse arch that prevents plantar displacement of the metatarsal bases. The second metatarsal base is the keystone in the transverse arch of the foot (Fig. 41.4).

There is only slight motion across the tarsometatarsal joints, with 10 to 20 degrees of dorsal plantar motion at the fifth metatarsocuboid joint and progressively less motion medially except for the first metatarsocuneiform (20 degrees of plantar flexion from neutral).

The ligamentous support begins with the strong ligaments linking the bases of the second through fifth metatarsals. The most important ligament is Lisfranc ligament, which attaches the medial cuneiform to the base of the second metatarsal.

Ligamentous, bony, and soft tissue support provides for intrinsic stability across the plantar aspect of Lisfranc joint; conversely, the dorsal aspect of this articulation is not reinforced by structures of similar strength.

There is no ligamentous connection between the base of the first and second metatarsals.

The dorsalis pedis artery dives between the first and second metatarsals at Lisfranc joint and may be damaged during injury, approach, or reduction.

Mechanism of Injury

Three most common mechanisms include:

Twisting: Forceful abduction of the forefoot on the tarsus results in fracture of the base of the second metatarsal and shear or crush fracture of the cuboid. Historically, this was seen in equestrian accidents when a rider fell from a horse with a foot engaged in a stirrup. It is commonly seen today in motor vehicle accidents.

Axial loading of a fixed foot may be seen with (1) extrinsic axial compression applied to the heel, such as a heavy object striking the heel of a kneeling patient, or (2) extreme ankle equinus with

axial loading of the body weight, such as a missed step off a curb or landing from a jump during a dance maneuver.

Crushing mechanisms are common in industrial-type injuries to Lisfranc joint, often with sagittal plane displacement, soft tissue compromise, and compartment syndrome.

Clinical Evaluation

Patients present with variable foot deformity, pain, swelling, and tenderness on the dorsum of the foot. Plantar ecchymosis is pathognomonic for a Lisfranc injury.

Diagnosis requires a high degree of clinical suspicion.

• Twenty percent are misdiagnosed.

• Forty percent have no treatment in the first week.

Be wary of the diagnosis of “midfoot sprain.”

A careful neurovascular examination is essential because dislocation of Lisfranc joint may be associated with impingement on or partial or complete laceration of the dorsalis pedis artery. In addition, dramatic swelling of the foot is common with high-energy mechanisms; compartment syndrome of the foot must be ruled out on the basis of serial neurovascular examination or compartment pressure monitoring if necessary.

Stress testing may be performed by gentle, passive forefoot abduction and pronation, with the hindfoot firmly stabilized in the examiner’s other hand. Alternatively, pain can typically be reproduced by gentle supination and pronation of the forefoot.

Radiographic Evaluation

Standard AP, lateral, and oblique films are usually diagnostic.

The medial border of the second metatarsal should be colinear with the medial border of the middle cuneiform on the AP view (Fig. 41.5).

The medial border of the fourth metatarsal should be colinear with the medial border of the cuboid on the oblique view (Fig. 41.6).

Dorsal displacement of the metatarsals on the lateral view is indicative of ligamentous compromise.

Flake fractures around the base of the second metatarsal are indicative of disruption of Lisfranc joint.

Weight-bearing radiographs provide a stress film of the joint complex.

If clinically indicated, physician-directed stress views should be obtained. The forefoot is held in abduction for the AP view and in plantar flexion for the lateral view.

A CT scan can be used to assess the plantar osseous structures as well as the amount of intra-

articular comminution.

MRI scanning is useful for suspected Lisfranc sprains.

Associated Injuries

Fractures of the cuneiforms, cuboid (nutcracker), and/or metatarsals are common.

The second metatarsal is the most frequent associated fracture.

Classification

Classification schemes for Lisfranc injuries guide the clinician in defining the extent and pattern of injury, although they are of little prognostic value.

Ouenu and Kuss (Fig. 41.7)

This classification is based on commonly observed patterns of injury. Homolateral: All five metatarsals displaced in the same direction Isolated: One or two metatarsals displaced from the others

Divergent: Displacement of the metatarsals in both the sagittal and coronal planes

Myerson (Fig. 41.8)

This is based on commonly observed patterns of injury with regard to treatment.

Total incongruity: Lateral and dorsoplantar Partial incongruity: Medial and lateral Divergent: Partial and total

Treatment

Nonoperative

Injuries that present with painful weight bearing, pain with metatarsal motion, and tenderness to palpation but fail to exhibit any instability should be considered a sprain.

Patients with nondisplaced ligamentous injuries with or without small plantar avulsion fractures of the metatarsal or tarsal bones should be placed in a well-molded short leg cast or removable boot.

Patients with fractures of the bases of the first through third metatarsals may be treated nonoperatively as bony healing is reliable.

Initially, the patient is kept non–weight bearing with crutches and is permitted to bear weight as comfort allows.

Once swelling decreases, repeat x-rays are necessary to detect osseous displacement.

Operative

This should be considered when displacement of the tarsometatarsal joint is >2 mm.

The best results are obtained through anatomic reduction and stable fixation.

The most common approach is using two longitudinal incisions. The first is centered over the first/second intermetatarsal space, allowing identification of the neurovascular bundle and access to the medial two tarsometatarsal joints. A second longitudinal incision is made over the fourth

metatarsal.

The key to reduction is correction of the fracture-dislocation of the second metatarsal base. Clinical results suggest that accuracy and maintenance of reduction are of utmost importance and correlate directly with the overall outcome.

Once reduction is accomplished, screw fixation is advocated for the medial column.

The lateral metatarsals frequently reduce with the medial column, and Kirschner wire fixation is acceptable.

If intercuneiform instability exists, one should use an intercuneiform screw.

Stiffness from ORIF is not of significant concern because of the already limited motion of the tarsometatarsal joints.

Postoperative Management

The foot is immobilized in a non–weight-bearing cast or boot for 6 to 8 weeks.

Progressive weight bearing is then permitted as comfort allows.

Advancement out of cast immobilization is done once pain-free, full weight bearing is achieved.

Lateral column stabilization can be removed at 6 to 12 weeks.

Medial fixation should not be removed for 4 to 6 months.

Some advocate leaving screws indefinitely unless symptomatic.

Complications

Posttraumatic arthritis

• Present in most, but may not be symptomatic

• Related to initial injury and adequacy of reduction

• Treated with orthotics initially and arthrodesis late for the medial column

• Possibly treated with interpositional arthroplasty for the lateral column

Compartment syndrome

Infection

Complex regional pain syndrome (CRPS, RSD)

Neurovascular injury

Hardware failure

FRACTURES OF THE FOREFOOT

The forefoot serves two purposes during gait

• As a unit, it provides a broad plantar surface for load sharing. Weight-bearing studies show that the two sesamoids and the four lesser metatarsal heads share an equal amount of the forefoot load in normal gait.

• The forefoot is mobile in the sagittal plane. This enables the forefoot to alter the position of the individual metatarsal heads to accommodate uneven ground.

  Metatarsals

  Epidemiology

This is a common injury; however, the true incidence of metatarsal shaft fractures is unknown, owing to the variety of physicians treating such injuries.

Anatomy

Displaced fractures of the metatarsals result in the disruption of the major weight-bearing complex of the forefoot.

Disruptions produce an alteration in the normal distribution of weight in the forefoot and lead to problems of metatarsalgia and transfer lesions (intractable plantar keratoses).

Mechanism of Injury

Direct: This most commonly occurs when a heavy object is dropped on the forefoot.

Twisting: This occurs with body torque when the toes are fixed, such as when a person catches the toes in a narrow opening with continued ambulation.

Avulsion: This occurs particularly at the base of the fifth metatarsal.

Stress fractures: These occur especially at the necks of the second and third metatarsals and the proximal fifth metatarsal.

Clinical Evaluation

Patients typically present with pain, swelling, and tenderness over the site of fracture.

Neurovascular evaluation is important, as well as assessment of soft tissue injury and ambulatory capacity.

Radiographic Evaluation

In isolated injuries to the foot, weight-bearing films should be obtained in the AP and lateral planes.

The lateral radiographic view of the metatarsals is important for judging sagittal plane displacement of the metatarsal heads.

Oblique views can be helpful to detect minimally displaced fractures.

Except in the case of an isolated direct blow, initial films should include the whole foot to rule out other potential collateral injuries that may also require attention.

MRI has replaced technetium bone scan to aid in the diagnosis of an occult stress fracture.

Classification

Orthopaedic Trauma Association Classification

See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

Specific Metatarsal Injuries

First Metatarsal Injuries

This bone is larger and stronger than the lesser metatarsals and is less frequently injured.

The lack of interconnecting ligaments between the first and second metatarsal bones allows independent motion.

The first metatarsal head supports two sesamoid bones, which provide two of the six contact points of the forefoot.

Injuries usually relate to direct trauma (often open and/or comminuted).

Anatomic reduction and stable fixation are important.

The best way to determine operative or nonoperative treatment is with stress radiographs. Manual displacement of the position of the first metatarsal through the joint or fracture site represents instability that requires fixation.

If no evidence of instability can be seen on stress films, and no other injury of the midfoot or metatarsals is evident, isolated first metatarsal fractures can be adequately treated with a short leg cast or removable boot with weight bearing as tolerated for 4 to 6 weeks.

Malunion, nonunion, and arthritic degeneration of the tarsometatarsal and metatarsophalangeal (MTP) joints are all possible complications of first metatarsal fractures. Transfer metatarsalgia to the lesser toes can occur with shortening of the metatarsal length.

Second, Third, and Fourth Metatarsal Injuries

The four lesser metatarsals provide only one contact point each on the plantar weight-bearing surface.

Significant ligamentous structures link each of the bones to their adjacent neighbors.

Fractures of the central metatarsals are much more common than isolated first metatarsal fractures. Central metatarsal fractures may be isolated injuries or part of a more significant injury pattern.

Indirect twisting mechanisms may result in a spiral pattern. One must be wary of Lisfranc injury with involvement of base of second metatarsal.

Most isolated individual central metatarsal fractures can be treated closed with hard-soled shoes and progressive weight bearing as tolerated.

The surgical criterion most often mentioned is any fracture displaying more than 10 degrees of deviation in the dorsal plantar plane or 3- to 4-mm translation in any plane.

Complications of treating central metatarsal fractures usually stem from incomplete restoration of plantar anatomy.

Fifth Metatarsal Injuries

These usually result from direct trauma.

Fractures are separated roughly into two groups, proximal base fractures and distal spiral fractures.

Proximal fifth metatarsal fractures are further divided by the location of the fracture and the presence of prodromal symptoms (Fig. 41.9).

• Zone 1: Cancellous tuberosity (93%)

  • Insertion of the peroneal brevis and plantar fascia

  • Involvement of the metatarsocuboid joint

• Zone 2: Distal to the tuberosity (4%)

• Zone 3: Distal to the proximal ligaments (3%)

  • Extension to the diaphysis for 1.5 cm

  • Usually stress fractures

     

     

     

Zone 1 injury (pseudo-Jones)

• This results from avulsion from lateral plantar aponeurosis.

• Treatment is symptomatic, with a hard-soled shoe.

• Healing is usually uneventful.

Zone 2 injuries are considered Jones fractures.

• They result from adduction or inversion of the forefoot.

• The fracture is caused by tensile stress along the lateral border of the metatarsal.

• Treatment is controversial: Advocates recommend both weight bearing and non–weight bearing in a short leg cast as well as ORIF.

• Union is frequently a concern.

Zone 3 injuries are now referred to as proximal diaphyseal stress fractures.

• These are relatively rare and seen mainly in athletes.

• They occur in the proximal 1.5 cm of the diaphyseal shaft of the metatarsal.

• Patients usually present with prodromal symptoms before complete fracture.

• This particular entity poses problems because of its tendency to nonunion.

• Initial treatment is between casted non–weight bearing for up to 3 months and surgical intervention with grafting and internal compression.

The remainder of the fifth metatarsal fractures not resulting from a direct blow have been termed

dancer’s fractures.

• The usual pattern is a spiral, oblique fracture progressing from distal–lateral to proximal–medial.

• The mechanism of injury is a rotational force being applied to the foot while axially loaded in a

  plantar flexed position.

• Treatment is symptomatic, with a hard-soled shoe.

   

  Metatarsophalangeal Joints

Mobility of the MTP joints is essential for forefoot comfort in normal gait; attempts should thus be made to salvage any motion at this level.

First Metatarsophalangeal Joint

Epidemiology

Injuries to the first MTP joint are relatively common, especially in athletic activities or ballet.

The incidence in US football and soccer has risen because of the use of artificial playing surfaces as well as lighter, more flexible shoes that permit enhanced motion at the MTP joint.

Anatomy

The MTP joint is composed of a cam-shaped metatarsal head and a matched concave articulation on the proximal phalanx. These contours contribute little to the overall stability of the joint.

Ligamentous constraints includes dorsal capsule reinforced by the extensor hallucis longus tendon, plantar plate (capsular ligament) reinforced by the flexor hallucis longus tendon, flexor hallucis brevis tendon, and medial and lateral collateral ligaments.

The plantar capsule is a thick, weight-bearing structure with strong attachments to the base of the proximal phalanx. There is a thinner, more flexible attachment to the plantar aspect of the metatarsal head proximally. Imbedded in this plantar structure are the two sesamoids.

Mechanism of Injury

“Turf toe”: This is a sprain of the first MTP joint. It reflects hyperextension injury to the first MTP joint as the ankle is in equinus, causing temporary subluxation with stretching on plantar capsule and plate.

In ballet dancers, injury may occur as a dancer “falls over” the maximally extended first MTP joint, injuring the dorsal capsule. Forced abduction may result in lateral capsular injury with possible avulsion from the base of the proximal phalanx.

Dislocation of the first MTP joint is usually the result of high-energy trauma, such as a motor vehicle accident, in which forced hyperextension of the joint occurs with gross disruption of the plantar capsule and plate.

Clinical Evaluation

Patients typically present with pain, swelling, and tenderness of the first MTP joint.

Pain may be reproduced with range of motion of the first MTP joint, especially at terminal dorsiflexion or plantar flexion.

Chronic injuries may present with decreased range of motion.

Most dislocations are dorsal with the proximal phalanx cocked up and displaced dorsally and proximally, producing a dorsal prominence and shortening of the toe.

Radiographic Evaluation

AP, lateral, and oblique views of the foot may demonstrate capsular avulsion or chronic degenerative changes indicative of long-standing injury.

Classification

Bowers and Martin

Grade I: Strain at the proximal attachment of the volar plate from the first metatarsal head

Grade II: Avulsion of the volar plate from the metatarsal head

Grade III: Impaction injury to the dorsal surface of the metatarsal head with or without an avulsion or chip fracture

Jahss Classification of First Metatarsophalangeal Dislocations

This is based on the integrity of the sesamoid complex.

Type I: Volar plate avulsed off the first metatarsal head, proximal phalanx displaced dorsally; intersesamoid ligament remaining intact and lying over the dorsum of the metatarsal head

Type IIA: Type IIA

Type IIB: Longitudinal fracture of either sesamoid

Treatment

First MTP sprains

• Rest, ice, compression, and elevation (RICE) and nonsteroidal anti-inflammatory medication are used.

• Protective taping with gradual return to activity is recommended; the patient may temporarily

  wear a hard-soled shoe with a rocker bottom for comfort.

• Pain usually subsides after 3 weeks of treatment, but an additional 3 weeks are usually necessary to regain strength and motion for return to competitive activity.

• Operative intervention is rarely indicated except in cases of intra-articular fractures or

  significant discrete instability. The presence of avulsion fragments and significant valgus instability may need to be addressed by ORIF or debridement and ligamentous repair.

• Displaced intra-articular fractures or osteochondral lesions should be fixed or debrided depending on their size.

Dislocations

• Jahss type I fracture: Closed reduction may be initially attempted. However, if irreducible by closed means, it will require open reduction.

• Jahss type IIA and type IIB fractures: These are easily reduced by closed means

  (longitudinal traction with or without hyperextension of the first MTP joint).

• After reduction, the patient should be placed in a short leg walking cast with a toe extension for 3 to 4 weeks to allow capsular healing.

• Displaced avulsion fractures of the base of the proximal phalanx should be fixed with either lag

  screws or a tension band technique. Small osteochondral fractures may be excised; larger fragments require reduction with Kirschner wires, compression screws, or headless screws.

  Complications

Hallux rigidus and degenerative arthritis complicate chronic injuries and may prevent return to competitive activity.

Posttraumatic osteoarthritis: This may reflect chondral damage at the time of injury or may result from abnormal resultant laxity with subsequent degenerative changes.

Recurrent dislocation: This is uncommon, although it may occur in patients with connective tissue disorders.

Fractures and Dislocations of the Lesser Metatarsophalangeal Joints

Epidemiology

“Stubbing” injuries are very common.

The incidence is higher for the fifth MTP joint because its lateral position renders it more vulnerable to injury.

Anatomy

Stability of the MTP joints is conferred by the articular congruity between the metatarsal head and the base of the proximal phalanx, the plantar capsule, the transverse metatarsal ligament, the flexor and extensor tendons, and the intervening lumbrical muscles.

Mechanism of Injury

Dislocations are usually the result of low-energy stubbing injuries and are most commonly displaced dorsally.

Avulsion or chip fractures may occur by the same mechanism.

Comminuted intra-articular fractures may occur by direct trauma, usually from a heavy object dropped onto the dorsum of the foot.

Clinical Evaluation

Patients typically present with pain, swelling, tenderness, and variable deformity of the involved digit.

Dislocation of the MTP joint typically manifests as dorsal prominence of the base of the proximal phalanx.

Classification

Descriptive

Location

Angulation

Displacement

Comminution

Intra-articular involvement

Presence of fracture-dislocation

Treatment

Nonoperative

Simple dislocations or nondisplaced fractures may be managed by gentle reduction with longitudinal traction and buddy taping for 4 weeks, with a rigid shoe orthosis to limit MTP joint motion, if necessary.

Operative

Intra-articular fractures of the metatarsal head or the base of the proximal phalanx may be treated by excision of a small fragment, by benign neglect of severely comminuted fractures, or by ORIF with Kirschner wires or screw fixation for fractures with a large fragment.

Complications

Posttraumatic arthritis: This may result from articular incongruity or chondral damage at the time of injury.

Recurrent subluxation: This is uncommon and may be addressed by capsular imbrication, tendon transfer, cheilectomy, or osteotomy, if symptomatic.

Sesamoids

Epidemiology

The incidence is highest with repetitive hyperextension at the MTP joints, such as in ballet dancers and runners.

The medial sesamoid is more frequently fractured than the lateral owing to increased weight bearing on the medial side of the foot.

Anatomy

The sesamoids are an integral part of the capsuloligamentous structure of the first MTP joint.

They function within the joint complex as both shock absorbers and fulcrums in supporting the weight-bearing function of the first toe.

Their position on either side of the flexor hallucis longus forms a bony tunnel to protect the tendon.

Bipartite sesamoids are common (10% to 30% incidence in the general population) and must not be mistaken for acute fractures.

• They are bilateral in 85% of cases.

• They exhibit smooth, sclerotic, rounded borders.

• They do not show callus formation after 2 to 3 weeks of immobilization.

  Mechanism of Injury

Direct blows such as a fall from a height or a simple landing from a jump as in ballet can cause acute fracture.

Acute fractures can also occur with hyperpronation and axial loading seen with joint dislocations.

Repetitive loading from improper running usually gives rise to the more insidious stress fracture.

Clinical Evaluation

Patients typically present with pain well localized on the plantar aspect of the “ball” of the foot.

Local tenderness is present over the injured sesamoid, with accentuation of symptoms with passive extension or active flexion of the MTP joint.

Radiographic Evaluation

AP, lateral, and oblique views of the forefoot are usually sufficient to demonstrate transverse fractures of the sesamoids.

Occasionally, a tangential view of the sesamoids is necessary to visualize a small osteochondral or avulsion fracture.

Technetium bone scanning or MRI may be used to identify stress fractures not apparent by plain radiography.

Classification

Descriptive

Transverse versus longitudinal

Displacement

Location: Medial versus lateral

Treatment

Nonoperative management should initially be attempted, with soft padding combined with a short leg walking cast for 4 weeks followed by a bunion last shoe with a metatarsal pad for 4 to 8 weeks.

Sesamoidectomy is reserved for cases of failed conservative treatment. The patient is maintained postoperatively in a short leg walking cast for 3 to 4 weeks.

Complications

Sesamoid excision may result in problems of hallux valgus (medial sesamoid excision) or transfer pain to the remaining sesamoid owing to overload.

Phalanges and Interphalangeal Joints

Epidemiology

Phalangeal fractures are the most common injury to the forefoot.

The proximal phalanx of the fifth toe is the most often involved.

Anatomy

The first and fifth digits are in especially vulnerable positions for injury because they form the medial and lateral borders of the distal foot.

Mechanism of Injury

A direct blow such as a heavy object dropped onto the foot usually causes a transverse or comminuted fracture.

A stubbing injury is the result of axial loading with secondary varus or valgus force resulting in a spiral or oblique fracture pattern.

Clinical Evaluation

Patients typically present with pain, swelling, and variable deformity of the affected digit.

Tenderness can typically be elicited over the site of injury.

Radiographic Evaluation

AP, lateral, and oblique views of the foot should be obtained.

If possible, isolation of the digit of interest for the lateral radiograph may aid in visualization of the injury. Alternatively, the use of small dental radiographs placed between the toes has been described.

MRI may aid in the diagnosis of stress fracture when the injury is not apparent on plain radiographs.

Classification

Descriptive

Location: Proximal, middle, distal phalanx

Angulation

Displacement

Comminution

Intra-articular involvement

Presence of fracture-dislocation

Treatment

Nondisplaced fractures irrespective of articular involvement can be treated with a stiff-soled shoe and protected weight bearing with advancement as tolerated.

Use of buddy taping between adjacent toes may provide pain relief and help to stabilize potentially unstable fracture patterns.

Fractures with clinical deformity require reduction. Closed reduction is usually adequate and stable (Fig. 41.10).

Operative reduction is reserved for those rare fractures with gross instability or persistent intra-articular discontinuity. This problem usually arises with an intra-articular fracture of the proximal phalanx of the great toe or multiple fractures of lesser toes.

A grossly unstable fracture of the proximal phalanx of the first toe should be reduced and stabilized with percutaneous Kirschner wires or mini-fragment screws.

Unstable intra-articular fractures of any joint despite adequate reduction should be reduced and percutaneously pinned in place to avoid late malalignment.

Complications

Nonunion: This is uncommon.

Posttraumatic osteoarthritis: This may complicate fractures with intra-articular injury, with resultant incongruity. It may be disabling if it involves the great toe.

Dislocation of the Interphalangeal Joint

This is usually due to an axial load applied at the terminal end of the digit.

Most such injuries occur in the proximal joint, are dorsal in direction, and occur in exposed, unprotected toes.

Closed reduction under digital block and longitudinal traction comprise the treatment of choice for these injuries.

Once reduced, the interphalangeal joint is usually stable and can be adequately treated with buddy taping and progressive activity as tolerated.