AAOS Comprehensive Orthopaedic Review

Section 6 - Trauma

Chapter 59. Foot Trauma

I. Epidemiology

A. Fractures of the foot are uncommon but often devastating injuries.

 

B. Calcaneal fractures are the most common tarsal bone fractures; many involve the subtalar joint.

 

C. Fractures of the talus and fracture-dislocations of the midfoot are uncommon but also have the potential to result in severe functional limitation.



II. Anatomy

A. Bones

 

1. The foot has 26 bones and numerous joints.

 

2. The hindfoot includes the talus and calcaneus.

 

3. The midfoot includes the navicular, cuboid, and cuneiforms and their articulations with the proximal metatarsals.

 

4. The forefoot includes the phalanges and the distal metatarsals.

 

B. Joints

 

1. The key joints to maintain mobility in the foot are the hindfoot joints, including the tibiotalar, subtalar, and talonavicular articulations.

 

2. The lateral fourth and fifth tarsometatarsal joints are also important for normal foot function.

 

3. The remaining hindfoot and midfoot joints, including the calcaneocuboid and the first, second, and third tarsometatarsal joints, do not require full range of motion to maintain function.

 

4. The most important forefoot joints are the metatarsophalangeal (MTP) joints. Interphalangeal joint motion is not critical for normal functioning.



III. Fractures of the Talus

A. Anatomy and blood supply of the talus

 

1. The talus is divided into a head, neck, and body. The talus has five articulating surfaces, with 70% covered by cartilage. The only muscle attachment is the extensor digitorum brevis.

 

2. The talus relies on direct extraosseous blood supply because of the lack of soft-tissue attachments.

 

3. The limited blood supply to the talus places the talar body at risk for osteonecrosis following talar neck fractures.

 

a. Most of the blood supply to the body is from the artery of the tarsal canal, a branch of the posterior tibial artery.

 

b. Most of the blood supply to head and neck is from the artery of the tarsal sinus, a branch of both the anterior tibial artery and peroneal artery.

 

c. The deltoid artery in the deep portion of the deltoid ligament also supplies blood to the body.

 

B. Talar neck fractures

 

1. Mechanisms of injury

 

a. These fractures occur with dorsiflexion against the tibia, usually the result of a motor vehicle accident or fall.

 

b. Associated inversion can lead to medial malleolar fracture, whereas eversion may be associated with lateral malleolar fractures.

 

2. Radiographic evaluation

 

a. Imaging studies should include three plain radiographic views of the foot.

 

b. CT is indicated if displacement cannot be ruled out on plain radiographs.

 

c. MRI can be used postoperatively to detect osteonecrosis.

 

3. Hawkins fracture classification (

Figure 1)

 

a. Guides treatment decisions and is useful in predicting the risk of osteonecrosis

 

b. Types are based on displacement of the fracture and articulations of the talus.

 

c. Displaced type II, III, and IV fractures can injure the arteries of the tarsal canal and tarsal

 

[Figure 1. Hawkins classification. A, Type I: nondisplaced talar neck fractures. B, Type II: displaced talar neck fractures, with subluxation or dislocation of subtalar joint. C, Type III: displaced talar neck fractures with associated dislocation of talar body from both subtalar and tibiotalar joints. D, Canale and Kelly type IV: displaced talar neck fracture with associated dislocation of talar body from subtalar and tibiotalar joints and dislocation of head/neck fragment from talonavicular joint.]

   sinus, placing the talar body at risk of osteonecrosis.

 

4. Nonsurgical treatment

 

a. Closed reduction can be attempted by using plantar flexion with varus or valgus of the heel, depending on the direction of displacement.

 

b. Type I fractures can be treated with casting and non-weight bearing. Alternatively, fixation with 6.5-mm posterior-to-anterior lag screws may be used.

 

5. Surgical treatment

 

a. Urgent surgical treatment is required when subluxation or dislocation leads to soft-tissue compromise.

 

b. Open reduction and internal fixation (types II, III, IV)

 

i. An anteromedial approach is combined with an anterolateral approach (with medial malleolar osteotomy when necessary) for adequate exposure. The anteromedial approach is between the posterior and anterior tibial tendons. A crossed-screw construct is commonly used with this approach.

 

ii. The posterior approach does not allow for open reduction of displaced fractures and is reserved for type I injuries.

 

iii. Care is needed to avoid injury to the sural nerve with a posterolateral approach through the interval of the peroneus brevis and flexor hallucis longus (FHL).

 

c. The talonavicular joint incongruity seen in type IV injuries should be reduced and pinned.

 

d. Medial plating may be useful for comminuted fractures that would collapse with compression screws.

 

e. Titanium screws are sometimes advocated to allow MRI evaluation of postoperative osteonecrosis.

 

[

Table 1. Complications of Talar Neck Fractures]

6. Complications (Table 1)

 

a. Osteonecrosis

 

i. The limited blood supply at the talar neck places patients at risk for osteonecrosis.

 

ii. The risk of osteonecrosis increases by Hawkins fracture type. Restricted weight bearing beyond that needed for fracture healing has not been shown to decrease the risk of osteonecrosis.

 

iii. The Hawkins sign, subchondral osteopenia seen at 6 to 8 weeks on plain radiographs, is considered a good prognostic sign because it indicates revascularization of the body. This may occur only medially if the deltoid artery is the only intact blood supply.

 

iv. Osteonecrosis may be seen as early as 3 to 6 months postoperatively with sclerosis on plain radiographs. MRI is sensitive for osteonecrosis, with decreased signal on T1-weighted images.

 

v. Osteonecrosis usually does not involve the entire talar body and often does not require further surgery. Tibiotalar fusion is an option when nonsurgical treatment is not successful.

 

vi. Extensive osteonecrosis may require excision of the body with tibiotalocalcaneal fusion or Blair fusion. Blair fusion involves resection of the talar body with fusion of the talar head to the tibia and bone grafting of the defect to maintain overall limb length.

 

b. Degenerative arthritis is the most common complication and can affect the subtalar and/or tibiotalar joints.

 

c. Varus malunion also can occur and limit eversion. This may be treated with osteotomy.

 

C. Talar body fractures

 

1. Fractures involving large portions of the talar body are usually the result of high-energy injuries.

 

2. CT provides the best visualization and is used to identify fractures in the transverse, coronal, and sagittal planes.

 

3. Open reduction and internal fixation using a dual lateral and medial approach is required when the articular surfaces are displaced more than 2 mm. Medial and/or lateral malleolar osteotomy may be required for adequate visualization.

 

4. Complications include osteonecrosis.

 

D. Osteochondral fractures of the talus

 

1. Osteochondral fractures can be seen in association with ankle injuries, including sprains or chronic ankle instability.

 

2. Medial osteochondral fractures often are deep and located posterior in the talus.

 

3. Lateral osteochondral fractures are more commonly associated with traumatic injuries.

 

a. Lateral fractures generally are more shallow and located either in the central or anterior portion of the talus.

 

b. Lateral fractures also are more often displaced and symptomatic. Symptoms include pain, swelling, and clicking.

 

4. CT or MRI may be useful in imaging these fractures.

 

a. MRI is useful as a screening test.

 

b. CT is more useful in delineating the extent of lesions already identified by plain radiographs or MRI.

 

5. Treatment is guided by symptoms, fragment size, and chronicity of the lesion.

 

a. Nonsurgical treatment with non-weight-bearing casting is indicated for nondisplaced fractures.

 

b. Open reduction and internal fixation may be indicated for displaced fractures with large fragments (>5 mm).

 

c. Arthroscopic debridement and drilling or microfracture is required for acute fractures with large fragments that are not amenable to fixation and for fractures with small fragments. This approach also is indicated for chronic fractures.

 

d. Postoperatively, the patient generally is non-weight bearing for up to 6 weeks.

 

e. If drilling and microfracture techniques fail, mosaicplasty or autologous chondrocyte transplantation may be options, but the efficacy of these procedures is not well established.

 

E. Lateral process fractures

 

1. These fractures occur with dorsiflexion-external rotation injuries. A common mechanism is a snowboarding injury.

 

2. Plain radiographs typically do not show these fractures, but they may be seen on the AP view of the ankle.

 

3. CT may be required to adequately visualize these injuries in patients with anterolateral ankle pain and normal plain radiographs following a snowboarding injury.

 

4. Nondisplaced fractures can be treated with cast immobilization and non-weight bearing.

 

5. Open reduction and internal fixation is indicated for fractures displaced more than 2 mm. Comminuted fractures not amenable to open reduction and internal fixation can be treated with casting. Excision is an option if symptoms persist.

 

F. Posterior process fractures

 

1. The posterior process includes a posteromedial and a posterolateral tubercle. Because plain radiographs may not clearly visualize the area, CT is useful to identify these fractures.

 

2. Posteromedial tubercle fractures occur as a result of avulsion of the posterior talotibial ligament or posterior deltoid ligament.

 

a. Small fragments are treated with immobilization followed by late excision if symptoms persist.

 

b. Large displaced fragments are treated with open reduction and internal fixation.

 

3. Posterolateral tubercle fractures occur as a result of avulsion of the posterior talofibular ligament. Pain is aggravated by FHL flexion and extension.

 

[

Figure 2. Essex-Lopresti classification of calcaneal fractures and their mechanism of injury. A, Joint depression fracture. B, Tongue-type fracture.]

a. Initial nonsurgical management with late excision for symptomatic lesions is indicated with no subtalar involvement.

 

b. Open reduction and internal fixation is indicated for fractures with subtalar involvement.

 

4. Nonunion is difficult to distinguish from symptomatic os trigonum. Both conditions can be treated with excision.

 

G. Talar head fractures

 

1. Talar head injuries are less common than other areas of the talus.

 

2. Nonsurgical treatment consisting of immobilization and non-weight bearing is indicated for nondisplaced fractures.

 

3. For displaced fractures, the talonavicular joint should be reduced and the fracture fragments stabilized using screws or pins, depending on fragment size. Small fragments can be excised.

 

4. Late talonavicular arthritis can be treated with fusion.



IV. Fractures of the Calcaneus

A. Intra-articular fractures

 

1. Mechanisms of injury

 

a. The calcaneus is the most frequently fractured of the tarsal bones. Most calcaneus fractures (75%) are intra-articular.

 

b. Axial loading is the primary mechanism, with falls from a height and motor vehicle accidents the most common causes.

 

c. Oblique shear results in a primary fracture line and two primary fragments: a superomedial fragment and a superolateral fragment.

 

i. The superomedial fragment includes the sustentaculum, which is stabilized by strong ligamentous and capsular attachments. This is called the constant fragment because it remains in a stable position, which makes it a useful reference point for anatomic reduction.

 

ii. The superolateral fragment has an intraarticular component through the posterior facet.

 

d. Secondary fracture lines signal whether there is joint depression or a tongue-type fracture, depending on whether the superolateral fragment and posterior facet are separate from the tuberosity. Fractures in which the superolateral fragment and posterior facet remain attached to the tuberosity posteriorly are tongue-type fractures (Figure 2).

 

2. Radiographic evaluation

 

a. The lateral view can be used to determine the Bohler angle (normal 20° to 40°) to assess loss of height. Double density of the posterior facet indicates subtalar incongruity.

 

b. AP and oblique views can visualize the calcaneocuboid joint.

 

c. The Broden view is useful intraoperatively to evaluate reduction of the posterior facet.

 

d. The axial Harris view visualizes widening, shortening, and varus position of the tuberosity fragment.

 

e. An AP view of the ankle also may be useful to assess lateral wall extrusion with impingement against the fibula.

 

3. Sanders fracture classification (

Figure 3)

 

a. Used to guide treatment and to predict outcomes of treatment

 

b. Based on CT to visualize the subtalar joint at its widest point in the coronal plane. CT also is the most complete and reliable method of visualizing these injuries.

 

c. Types are based on the number of articular fragments.

 

i. Type I fractures: nondisplaced

 

ii. Type II fractures: the posterior facet is in two fragments.

 

iii. Type III fractures: the posterior facet is in three fragments.

 

iv. Type IV fractures: comminuted, with more than three articular fragments

 

[Figure 3. Schematic diagram of Sanders classification.]

d. Other important fracture characteristics include the degree of shortening, widening, and lateral wall impingement, which may result in peroneal tendon pathology.

 

4. Nonsurgical treatment

 

a. Type I fractures are treated nonsurgically.

 

b. Patients do not bear weight for 10 to 12 weeks.

 

c. Range-of-motion exercises are initiated early, as soon as soft-tissue swelling allows.

 

5. Surgical treatment

 

a. Treatment of type II and III fractures remains controversial. Both open reduction and internal fixation and nonsurgical management have been advocated, with nonsurgical management the same as for type I fractures. Negative prognostic factors for the treatment of these fractures include severity, advanced age, male sex, obesity, bilateral fractures, multiple trauma, and worker's compensation.

 

b. Open reduction and internal fixation generally is delayed for 10 to 14 days to allow for resolution of soft-tissue swelling.

 

i. An extensile lateral L-shaped incision is the most common approach.

 

ii. No-touch retraction techniques are used, a pin is placed in the tuberosity fragment to assist reduction, and a drain is inserted.

 

iii. Bone grafting has not been shown to have a benefit.

 

c. Type IV fractures can be treated using open reduction and internal fixation with possible primary fusion because open reduction and internal fixation alone (as well as nonsurgical treatment) is associated with poor results.

 

d. A less invasive sinus tarsi approach combined with an Essex-Lopresti maneuver has become an option recently for intra-articular calcaneal fractures. This approach involves manipulation of the heel to increase the varus deformity, followed by plantar flexion of the forefoot and valgus reduction of the heel to correct the varus deformity. The reduction maneuver can be stabilized with limited percutaneous or open fixation. The depressed posterior facet can also be elevated through the sinus tarsi approach and limited fixation placed.

 

e. Outcomes correlate with the accuracy of the reduction and the number of articular fragments. Type II fractures have better outcomes than type III fractures, whereas type IV fractures have the worst outcomes.

 

6. Complications

 

a. A complication rate of up to 40% has been reported. Factors that predict an increased risk of complications include a fall from a height, early surgery, and smoking. Approximately 10% of patients also have associated lumbar spine injuries.

 

b. Wound-related complications are the most common. Other potential complications include malunion, subtalar arthritis, and lateral impingement with peroneal tendon pathology.

 

c. Compartment syndrome develops in up to 10% of patients and may lead to a hammer toe deformity.

 

d. Malunion can also occur, resulting in loss of height, widening, and lateral impingement (

Figure 4).

 

i. The talus may be dorsiflexed, with a decrease in the talar declination angle to less than 20°, which limits ankle dorsiflexion.

 

ii. Associated lateral wall impingement may result in peroneal tendon pathology. Subtalar incongruity can also lead to subtalar arthritis. Difficulty with shoe wear also is possible.

 

e. Malunion can be classified using CT.

 

i. Type I malunion: lateral exostosis with no subtalar arthritis that can be treated with lateral wall resection

 

ii. Type II malunion: lateral exostosis with subtalar

 

[Figure 4. Stephens and Sanders classification of calcaneal malunions.]

   arthritis that is treated with lateral wall exostectomy and subtalar fusion

 

iii. Type III malunion: lateral exostosis with subtalar arthritis and varus malunion that is treated with lateral wall exostectomy and subtalar fusion. The addition of an osteotomy to correct the varus deformity is controversial and has not been proved to improve outcomes.

 

B. Extra-articular fractures

 

1. Mechanisms of injury

 

a. The mechanism of avulsion is the result of strong contraction of the gastrocnemius-soleus complex and avulsion at its insertion.

 

b. These injuries often occur in patients with osteopenic bone, making secure fixation difficult.

 

2. Treatment

 

a. Early reduction is important because displaced fractures can cause pressure necrosis of the overlying skin.

 

b. Full-thickness skin slough may require flap coverage.

 

c. Small fragments can be excised, but fractures with larger fragments require open reduction and internal fixation. Note, however, that screw fixation alone may fail in osteopenic bone but can be augmented with tension band fixation.

 

C. Anterior process fractures

 

1. Mechanism of injury

 

a. Anterior process fractures occur with inversion and plantar flexion.

 

b. They result from avulsion of the bifurcate ligament.

 

2. Treatment

 

a. Small extra-articular fragments are treated with immobilization.

 

b. Larger fragments (>1 cm) can involve the calcaneocuboid joint and require open reduction and internal fixation if joint displacement is present.

 

c. Late excision is used for chronically painful nonunions.



V. Midfoot Fractures

A. Navicular fractures

 

1. Anatomy

 

a. The navicular articulates with the cuneiforms, cuboid, calcaneus, and talus.

 

b. The talonavicular articulation is critical to maintaining inversion and eversion range of motion.

 

c. The blood supply is limited in the central portion of the navicular, making this area susceptible to fractures.

 

2. Radiographic evaluation

 

a. Plain radiographs including AP, lateral, internal oblique, and external oblique images of the foot are used for initial evaluation.

 

b. CT is useful for characterizing the fracture pattern. MRI can be used for detection of stress fractures.

 

3. Avulsion fractures of the navicular

 

a. Plantar flexion injury is the principal mechanism of injury.

 

b. Acute treatment consists of immobilization with delayed excision of painful fragments.

 

c. Open reduction and internal fixation is required for fractures with fragments involving more than 25% of the articular surface.

 

4. Tuberosity fractures

 

a. The principal mechanism is eversion and posterior tibial tendon contraction that may result in diastasis of a preexisting accessory navicular.

 

b. An oblique radiograph at 45° of internal rotation best visualizes the injury.

 

c. Most tuberosity avulsions can be managed with immobilization.

 

d. Acute open reduction and internal fixation is indicated with more than 5 mm of diastasis or with large intra-articular fragments.

 

[

Figure 5. Navicular fractures. A, Lateral view of a type I navicular fracture (axial plane fracture line). B, AP view of a type II navicular fracture (sagittal plane fracture line). The arrows indicate the direction of applied force. Note also subluxation of the talonavicular joint and proximal migration of the first ray, a common component of type II fractures. C, AP view of a type III navicular fracture. Note the comminution, displacement, and incongruity of the talonavicular and naviculocuneiform joints. Arrow indicates the direction of applied force.]

e. Symptomatic nonunions are treated with late excision.

 

5. Body fractures (Figure 5)

 

a. The mechanism of injury is axial loading.

 

b. The Sangeorzan fracture classification is based on the plane of the fracture and degree of comminution (

Table 2).

 

c. Minimally displaced type I and II fractures are treated nonsurgically.

 

d. Open reduction and internal fixation through a medial incision is used for displaced type I and II fractures or with disruption of the talonavicular joint.

 

e. Type III fractures require open reduction and internal fixation with external fixation or primary fusion as needed to maintain lateral column length. Comminution often requires fixation of fragments independently to the cuneiforms if the navicular fragments are too small for open reduction and internal fixation.

 

[Table 2. Sangeorzan Classification of Navicular Fractures]

6. Stress fractures

 

a. These fractures are most common in runners and basketball players.

 

b. MRI is a useful screening tool, but CT better visualizes bone when the fracture is visible on plain radiographs.

 

c. When acute, these injuries can be treated either nonsurgically or surgically. Nonunions require open reduction and internal fixation. Bone grafting may be used to encourage healing.

 

B. Tarsometatarsal (Lisfranc) fracture-dislocations

 

1. Anatomy

 

a. The bones of the midfoot include the navicular, cuboid, cuneiforms, and bases of the metatarsals.

 

b. The midfoot has osseous stability due to the recessed articulation of the base of the second metatarsal. The trapezoidal shape of the first three metatarsal bases contribute to stability, as do the plantar ligaments. The Lisfranc ligament runs from the base of the second metatarsal to the medial cuneiform.

 

c. The lateral tarsometatarsal joints (fourth and

 

[

Figure 6. Classification of Lisfranc joint injuries.]

   fifth metatarsal-cuboid joints) have 10° to 20° of sagittal plane motion. The medial three tarsometatarsal joints have limited motion.

 

2. Mechanisms of injury

 

a. Direct injuries occur with dorsal force and may result in soft-tissue injuries and compartment syndromes. Both bony and soft-tissue components are common in direct injuries.

 

b. Indirect injuries occur with axial loading and twisting on a loaded, plantar flexed foot. Patients commonly report a history of a fixed foot with rotation of the body around the midfoot.

 

3. Radiographic evaluation

 

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

 

b. Normal anatomic relationships should be maintained.

 

i. The medial aspect of the second metatarsal should be aligned with the medial cuneiform.

 

ii. The medial aspect of the fourth metatarsal should be aligned with the medial cuboid.

 

iii. Diastasis of >2 mm between the base of the first and second metatarsals is pathologic.

 

iv. There should be no dorsal subluxation of the metatarsal bases on the lateral view.

 

c. The fleck sign is a small avulsed fragment of bone in the interval between the first and second metatarsal bases. This represents avulsion of the Lisfranc ligament from its insertion on the base of the second metatarsal.

 

d. Weight-bearing or stress radiographs can be ordered when the results of physical examination and plain radiographs are equivocal.

 

e. A 30° internal rotation oblique view best visualizes cuboid compression (nutcracker injury).

 

4. Fracture classification (Figure 6)

 

a. Tarsometatarsal injuries are divided into three categories.

 

i. Type A injuries: total incongruity of the midfoot joints. The most common direction is lateral, and homolateral injuries may be associated with cuboid compression fractures.

 

ii. Type B injuries: partial incongruity of the midfoot joints. Common patterns include medial dislocation of the first metatarsal or lateral dislocation of some or all of the lateral rays.

 

iii. Type C injuries: divergent incongruity of the midfoot joints in which the first metatarsal and some or all of the lateral rays displace in opposite directions.

 

5. Treatment

 

a. Open reduction and internal fixation is indicated for displaced midfoot fractures and dislocations.

 

i. One or two dorsal incisions can be used. The neurovascular bundle is lateral to the first interspace.

 

ii. Fully threaded cortical screws usually are used because compression across the joint is not necessary.

 

iii. Percutaneous pins are commonly used in the fourth and fifth tarsometatarsal joints, but screw fixation may be used.

 

b. Plate fixation or external fixation may be used for cuboid compression (nutcracker injury) to maintain lateral column length.

 

c. Reduction and screw fixation is indicated to stabilize intercunieform instability.

 

d. Screws generally are not removed for at least 3 months.

 

e. Primary fusion has been advocated as an option, particularly in purely ligamentous injuries, which have worse outcomes. However, this option requires further investigation.

 

f. Late reconstruction of missed injuries (up to 30% of tarsometatarsal injuries) may include fusion of the first three tarsometatarsal joints.

 

g. Resection arthroplasty with tendon interposition has been advocated in the fourth and fifth tarsometatarsal joints to avoid stiffness and abnormal gait. It is more critical to maintain motion in these joints, and they typically are not symptomatic.

 

6. Complications

 

a. Late posttraumatic osteoarthritis is common, occurring in up to 58% of patients. Anatomic reduction, open injury, and comminution predict outcomes.

 

b. More than 2 mm or 15° of displacement results in a worse prognosis.

 

c. Purely ligamentous injuries also may have a worse prognosis, leading some to advocate primary fusion as an alternative treatment.

 

C. Cuboid fractures

 

1. Compression fractures from a nutcracker mechanism can be part of a Lisfranc fracture-dislocation, whereas isolated cuboid fractures are uncommon.

 

2. Cuboid fractures with significant compression can result in collapse of the lateral column.

 

a. External fixation can be used to restore lateral column length and disimpact fragments.

 

b. Fixation and bone grafting may be required for impacted fractures.

 

c. Avulsion fractures are treated symptomatically.

 

D. Cuneiform fractures

 

1. Isolated cuneiform fractures are uncommon. Avulsion fractures are treated symptomatically.

 

2. Displaced fractures and intercunieform instability can occur as part of a Lisfranc fracture-dislocation. These injuries should be reduced and stabilized during fixation of the tarsometatarsal injuries.



VI. Metatarsal and Phalangeal Fractures

A. Metatarsal shaft fractures

 

1. Mechanisms of injury include a direct blow, avulsion, twisting, or inversion. Repetitive stress also can be a cause.

 

2. The plantar flexors are the deforming force. A prominent plantar fragment can result in callus formation. A dorsiflexion malunion can result in transfer metatarsalgia.

 

3. Nonsurgical treatment is appropriate for fractures of the second, third, and fourth metatarsal shafts when there is <3 mm of displacement or <10° of angulation.

 

4. Indications for surgical treatment

 

a. Displaced fractures of the first metatarsal. Patients do not tolerate these fractures well because the first ray bears more weight than the lesser metatarsals.

 

b. Fractures of the second through fourth metatarsals if there is 3 to 4 mm of displacement or >10° of sagittal displacement.

 

c. Multiple metatarsal fractures

 

5. Fixation options include Kirschner wires (K-wires), screws, or plates.

 

B. Metatarsal neck and head fractures

 

1. Most metatarsal neck fractures can be treated nonsurgically. Metatarsal neck fractures with severe angulation with plantar prominence may require reduction and fixation. Dorsal angulation also may require either closed or open reduction with fixation to prevent transfer metatarsalgia.

 

2. Metatarsal head fractures are rare and generally can be treated nonsurgically; however, severely displaced fractures may require closed or open reduction and fixation.

 

[

Figure 7. Fifth metatarsal base fractures. A, Drawing showing the fracture zones: 1, tuberosity avulsion fracture; 2, zone of metaphyseal-diaphyseal junction; 3, shaft stress fracture zone. B, Radiographs showing a displaced tuberosity avulsion fracture: zone 1. C, Radiograph showing a displaced metaphyseal-diaphyseal junction fracture: zone 2. D, Radiograph showing a diaphyseal shaft stress fracture: zone 3.]

C. Fractures of the fifth metatarsal base (Figure 7)

 

1. Type I fractures

 

a. Avulsion of the long plantar ligament, the lateral band of the plantar fascia, or contraction of the peroneus brevis may result in these fractures.

 

b. Treatment consists of weight bearing as tolerated in a stiff-soled shoe.

 

c. Surgery may be necessary, although rarely, for fractures with large displaced intra-articular fragments.

 

d. Nonunions also are uncommon but can be treated by excision and repair of the peroneus brevis, as needed.

 

2. Type II fractures

 

a. The metadiaphyseal region is an area of circulatory watershed resulting in limited blood supply. Fractures that occur at the metadiaphy-seal junction, approximately 1.5 to 2.5 cm distal to the metatarsal base, are commonly called Jones fractures.

 

b. Because of the compromised blood supply in this area, the fracture is at risk of nonunion. Therefore, patients should not bear weight for 6 to 8 weeks.

 

c. Acute open reduction and internal fixation using screws is often used in athletes to minimize the possibility of nonunion and prolonged restriction from activity.

 

d. Development of postoperative nonunion is associated with a return to activity before evidence of radiographic union and is more common in high-demand athletes.

 

3. Type III fractures

 

a. These are diaphyseal stress fractures. Cavovarus foot deformities increase first tarsometatarsal joint mobility, increasing stress in the lateral column of the foot.

 

b. Hereditary sensorimotor neuropathy and diabetic neuropathy may result in a patient's inability to sense overload of the bone.

 

c. Nonsurgical treatment consisting of non-weight-bearing status is used for proximal fractures in the area of the watershed. Pulsed electromagnetic bone stimulators may accelerate healing.

 

d. Screw fixation is indicated in patients with established sclerosis and nonunion or in athletes.

 

e. Bone grafting and/or structural correction may be needed to achieve healing and prevent recurrence, particularly in atrophic nonunions.

 

D. Phalangeal fractures

 

a. The mechanism of injury is a crush injury or axial loading.

 

b. Painful subungual hematoma can be evacuated through a hole in the nail.

 

c. Nonsurgical treatment consisting of closed reduction and buddy taping for 4 weeks generally is indicted for lesser toe injuries. Distal phalanx fractures of the hallux are treated nonsurgically.

 

d. Surgical treatment is indicated for displaced articular injuries or angulated proximal phalanx fractures of the hallux if closed reduction and percutaneous pinning fail. A failed closed reduction can be converted to open reduction and internal fixation performed through an L-shaped incision dorsally.

 

E. Sesamoid injuries

 

a. Injuries can occur by direct impact with compression, through hyperdorsiflexion with a transverse fracture, or with repetitive trauma.

 

b. Plain radiographs can include a sesamoid view to evaluate the articulation of the sesamoid with the plantar aspect of the metatarsal head. MRI is useful in determining the presence of stress reaction or stress fracture.

 

c. Acute fractures or stress fractures are treated with padding and immobilization in a hard-soled shoe for 4 to 8 weeks.

 

d. Excision of the sesamoid is used for chronic symptomatic nonunions. The potential complication of medial sesamoidectomy is hallux valgus, whereas lateral sesamoidectomy may result in hallux varus.



VII. Dislocations of the Foot

A. Subtalar dislocation

 

1. Mechanism of injury

 

a. These are high-energy injuries but are closed in 75% of patients.

 

b. Most dislocations (65% to 80%) are medial, with the talus translated medially. The remaining dislocations generally are lateral; anterior or posterior dislocation is rare.

 

2. Radiographic evaluation—CT is necessary following reduction to rule out associated fractures, which can occur in up to 44% of patients.

 

3. Treatment

 

a. Closed reduction is performed by flexing the knee, recreating the deformity, plantar flexing the foot, and then pushing the talar head; however, up to 32% of dislocations cannot be reduced.

 

b. Medial dislocations that cannot be reduced are the result of buttonholing of the talus through the extensor digitorum brevis, inferior extensor retinaculum, or talonavicular capsule and/or interposition of the peroneal tendons.

 

c. Lateral dislocations that cannot be reduced are the result of interposition of the posterior tibial tendon or a bony fragment, with the FHL and flexor digitorum longus less commonly interposed.

 

d. Open reduction with tendon relocation and stabilization with transarticular pins, as needed, is indicated for dislocations that cannot be reduced.

 

B. Midtarsal dislocation

 

1. Midtarsal dislocation involving the talonavicular and calcaneocuboid articulations (Chopart joint) can occur through axial loading (longitudinal), medial stress, lateral stress, plantar stress, or crush injuries.

 

2. Plain radiographs should be obtained, with CT used if associated fractures are suspected.

 

3. The prognosis depends largely on the severity of the original injury.

 

4. Treatment involves prompt reduction to avoid skin necrosis.

 

a. Nondisplaced and stable injuries can be treated with immobilization and protected weight bearing.

 

b. Displaced or subluxated joints should be reduced and pinned with K-wires.

 

C. Isolated tarsal dislocations

 

1. Isolated dislocations of the talonavicular joint, navicular bone, calcaneocuboid joint, cuboid bone, and cuneiforms are uncommon.

 

[

Figure 8. Dorsal (A) and medial (B) approaches for foot fasciotomies. These approaches can be combined to facilitate decompression.]

2. Treatment involves prompt closed or open reduction to avoid skin necrosis. K-wires may be required to secure anatomic reduction.

 

D. Forefoot dislocations

 

1. First MTP joint

 

a. Dislocations usually are dorsal.

 

b. Closed reduction usually is attempted first, but may not be possible if the first metatarsal buttonholes through the sesamoid-short flexor complex.

 

c. A dorsal approach is used for open reduction if necessary.

 

2. Lesser MTP joints

 

a. Dislocations usually are dorsal.

 

b. Closed reduction usually is attempted first but may not be possible if the metatarsal head buttonholes through the plantar plate mechanism.

 

c. A dorsal incision is used for open reduction if necessary.

 

3. Interphalangeal joints

 

a. Dislocations are uncommon and usually dorsal.

 

b. Closed reduction usually is attempted first but may not be possible if the proximal phalanx buttonholes through the plantar plate.

 

c. Open reduction is performed through a dorsal approach if necessary.



VIII. Compartment Syndromes

A. Anatomy/pathophysiology

 

1. The foot has a total of nine compartments divided into four main groups: medial (one compartment), lateral (one compartment), interosseous (four compartments), and central (three compartments, including the deep central, or calcaneal, which communicates with the deep posterior compartment of the leg).

 

2. Acute trauma to the foot, including calcaneus fractures, Lisfranc injuries, crush injuries, and other high-energy mechanisms can result in compartment syndromes.

 

B. Clinical evaluation

 

1. The primary method of diagnosis is clinical.

 

2. Loss of pulses and capillary refill are unreliable signs.

 

3. Loss of two-point discrimination and light touch sensation are more reliable than loss of pinprick sensation.

 

4. Pain with passive dorsiflexion results from stretch of the intrinsic muscles. This decreases compartment volume and increases pressure.

 

5. Pressure measurements can be helpful in clinically equivocal cases. Pressure thresholds greater than 30 mm Hg or within 30 mm Hg of diastolic blood pressure have been advocated as indications for compartment release.

 

C. Treatment (Figure 8)

 

1. Fasciotomy is indicated when clinical symptoms are consistent with compartment syndrome.

 

2. Medial and/or dorsal incisions can be used to release all nine compartments.

 

a. Two dorsal incisions are commonly used.

 

i. The medial incision is used to release the first and second interosseous, medial, and deep central compartments.

 

ii. The lateral incision is used to release the two lateral interosseous, superficial and middle central, and lateral compartments.

 

b. Medial incisions

 

i. A single medial incision can be used to release all nine compartments but is technically more difficult.

 

ii. A medial incision is sometimes used in conjunction with two dorsal incisions to ensure release of the deep central compartment.

 

3. Delayed closure should be used because skin closure can increase compartment pressures. A split-thickness skin graft may be required.



Bibliography

Buckley R, Tough S, McCormack R, et al: Operative compared with nonoperative treatment of displaced intraarticular calcaneal fractures: A prospective, randomized, controlled multicenter trial. J Bone Joint Surg Am 2002;84:1733-1744.

Canale ST, Kelly FB: Fractures of the neck of the talus: Long-term evaluation of seventy-one cases. J Bone Joint Surg Am 1978;60:143-156.

Kelly IP, Glisson RR, Fink C, Easley ME, Nunley JA: Intramedullary screw fixation of Jones fractures. Foot Ankle Int 2001;22:585-589.

Kuo RS, Tejwani NC, Digiovanni CW, et al: Outcome after open reduction internal fixation of Lisfranc joint injuries. J Bone Joint Surg Am 2000;82:1609-1618.

Larson CM, Almekinders LC, Taft TN, Garret WE: Intramedullary screw fixation of Jones fractures: Analysis of failure. Am J Sports Med 2002;30:55-60.

Myerson MS: Experimental decompression of the fascial compartments of the foot: The basis for fasciotomy in acute compartment syndromes. Foot Ankle 1988;8:308-314.

Quill GE: Fractures of the proximal fifth metatarsal. Orthop Clin North Am 1995;26:353-361.

Sanders R, Fortin P, DiPasquale T, Walling A: Operative treatment in 120 displaced intraarticular calcaneal fractures: Results using a prognostic computed tomography classification. Clin Orthop Relat Res1993;290:87-95.

Schulze W, Richter J, Russe O, Ingelfinger P, Muhr G: Surgical treatment of talus fractures: A retrospective study of 80 cases followed for 1-15 years. Acta Orthop Scand 2002;73: 344-351.

Shah SN, Knoblich GO, Lindsey DP, Dreshak J, Yerby SA, Chou LB: Intramedullary screw fixation of proximal fifth metatarsal fractures: A biomechanical study. Foot Ankle Int 2001;22:581-584.

Teng AL, Pinzur MS, Lomansney L, Mahoney L, Havey R: Funtional outcome following anatomic restoration of tarsalmetatarsal fracture-dislocation. Foot Ankle Int 2002;23:922-926.

Thordarson DB, Triffon MJ, Terk MR: Magnetic resonance imaging to detect avascular necrosis after open reduction and internal fixation of talar neck fractures. Foot Ankle Int 1996; 17:742-747.

 

Top Testing Facts

 

Fractures of the Talus

1. The talus is 70% covered by cartilage and the extensor digitorum brevis is the only muscle attachment.

 

2. The blood supply to the body is mostly from the artery of the tarsal canal, a branch of the posterior tibial artery.

 

3. The blood supply to the neck is mostly from the artery of the tarsal sinus, a branch formed from the anterior tibial and peroneal arteries.

 

4. The deltoid artery supplies the medial body.

 

5. Posttraumatic osteoarthritis is the most common complication of talar neck fracture.

 

6. Osteonecrosis occurs with increasing frequency as the Hawkins classification for a talar neck fracture increases in severity.

 

7. Open reduction and internal fixation is required for all displaced talar neck fractures. Open reduction and internal fixation is usually performed through a combined anterolateral and anteromedial approach.

 

8. The Hawkins sign is subchondral osteopenia seen at 6 to 8 weeks postoperatively after fixation of a talar neck fracture and indicates revascularization and a better prognosis.

 

9. Varus malunion after a talar neck fracture can lead to loss of eversion.

 

10. Lateral process fractures of the talus are commonly seen in snowboarders as a result of a dorsiflexion-external rotation mechanism.

 

Fractures of the Calcaneus

1. Approximately 10% of patients with an intra-articular calcaneal fracture have an associated lumbar spine injury.

 

2. Approximately 10% of patients with an intra-articular calcaneal fracture have an associated foot compartment syndrome.

 

3. A superomedial fragment containing the sustentaculum is seen with intra-articular fractures of the calcaneus. This constant fragment is stabilized by ligaments and capsular attachments, making it a useful reference during open reduction and internal fixation.

 

4. The management of Sanders type II, III, and IV fractures remains controversial.

 

5. Negative prognostic factors for the surgical treatment of Sanders type II and III fractures include severity, advanced age, male sex, obesity, bilateral fractures, multiple trauma, and worker's compensation.

 

6. Malunion of calcaneal fractures can result in shortening, widening, and varus position. The symptoms include difficulty with shoe wear and peroneal tendon symptoms.

 

7. Malunions that result in talar dorsiflexion with loss of talar declination angle to less than 20° can limit ankle dorsiflexion.

 

8. Malunions of the calcaneus are treated with lateral exostectomy. Fusion is also added for subtalar arthritis.

 

9. Tension band fixation can be used to avoid failure of screw fixation in avulsion fractures of the calcaneal tuberosity.

 

10. Anterior process fractures occur with inversion and avulsion of the bifurcate ligament.

 

Midfoot Fractures

1. The central navicular has limited blood supply and is susceptible to stress fractures.

 

2. The tarsometatarsal joints are constrained by the recessed articulation of the second metatarsal.

 

3. The Lisfranc ligament runs from the base of the second metatarsal to the medial cuneiform.

 

4. The lateral fourth and fifth tarsometatarsal joints have 10° to 20° of sagittal motion, whereas the medial three tarsometatarsal joints have little motion.

 

5. Lisfranc fracture-dislocations can occur with direct application of force or indirectly through axial loading and twisting on a fixed, plantar flexed foot.

 

6. Plain radiographs may show a fleck of bone in the proximal first metatarsal interspace. This fleck sign represents the avulsed Lisfranc ligament.

 

7. Homolateral dislocation of the tarsometatarsal joints may be associated with a compression injury to the cuboid.

 

8. Intercuneiform instability can be associated with Lisfranc injuries and should be reduced and fixed.

 

9. Up to 30% of Lisfranc injuries are missed acutely. Weight-bearing or stress radiographs can be used to rule out injury.

 

10. Fusion of the fourth and fifth tarsometatarsal joints is poorly tolerated, and resection arthroplasty is used in conjunction with fusion of the medial tarsometatarsal joints for missed or late reconstruction of Lisfranc injuries.

 

Metatarsal and Phalangeal Fractures

1. Displacement of first metatarsal fractures is poorly tolerated and is an indication for reduction and fixation.

 

2. More than 3 mm of displacement, 10° of angulation, or multiple metatarsal fractures are indications for fixation of second, third, or fourth metatarsal fractures.

 

3. Plantar displacement of metatarsal fractures can lead to callosity.

 

4. Dorsal displacement of metatarsal fractures can lead to transfer metatarsalgia under adjacent metatarsals.

 

5. The proximal fifth metatarsal has poor blood supply at the metadiaphyseal junction 1.5 to 2.5 cm distal to the base. Jones fractures occur at this metadiaphyseal junction.

 

6. High-level athletes may undergo acute fixation of Jones fractures with a screw to avoid delay in the return to activity because of nonunion.

 

7. Diaphyseal stress fractures of the fifth metatarsal can be caused by cavovarus foot deformities or peripheral neuropathies.

 

8. Proximal phalanx fractures of the hallux are treated surgically for angulation or displaced intra-articular injuries.

 

9. Medial sesamoidectomy for nonunion may result in hallux valgus deformity.

 

10. Lateral sesamoidectomy for nonunion may result in hallux varus deformity.

 

Dislocations of the Foot

1. Medial subtalar dislocations may be irreducible if the talar head buttonholes through the extensor digitorum brevis, inferior extensor retinaculum, or talonavicular capsule, or with interposition of the peroneal tendons.

 

2. Lateral subtalar dislocations may be irreducible if the posterior tibial tendon, flexor digitorum longus, or FHL is interposed.

 

3. Subtalar dislocations are close-reduced by flexing the knee to relax the gastrocnemius-soleus complex, recreating the deformity, plantar flexing the foot, and pushing the talar head.

 

4. CT is indicated for subtalar dislocations, given the high rate of associated fractures.

 

5. First MTP joint dislocations may be irreducible because of buttonholing through the sesamoid-short flexor complex.

 

6. Irreducible first MTP joint dislocations are treated through a dorsal approach.

 

7. Lesser MTP joint dislocations may be irreducible because of buttonholing through the plantar plate.

 

8. Irreducible lesser MTP joint dislocations are treated through a dorsal approach.

 

9. Chopart joints are the talonavicular and calcaneocuboid joints. These joints should be reduced promptly to avoid skin necrosis.

 

10. Isolated tarsal dislocations are rare but are treated with prompt reduction to avoid skin necrosis.

 

Compartment Syndromes

1. The foot has a total of nine compartments that comprise four main groups: the medial, lateral, four interosseous, and three central compartments.

 

2. The central compartment includes the deep central, or calcaneal compartment, which communicates with the deep posterior compartment of the leg.

 

3. Compartment syndromes result from bleeding and edema that increase the tissue interstitial pressures.

 

4. Interstitial pressures above the capillary pressure lead to venous occlusion.

 

5. Irreversible myoneural necrosis and fibrosis occur after 8 hours.

 

6. Loss of two-point discrimination and light touch are more sensitive signs of compartment syndrome than loss of pinprick sensation. Loss of pulses and capillary refill are unreliable signs.

 

7. Pain with passive dorsiflexion results from stretch of the intrinsic muscles, resulting in decreased compartment volume and increased pressure.

 

8. Clinical symptoms are the main indication for compartment release. Pressures greater than 30 mm Hg or within 30 mm Hg of diastolic pressure have been advocated as indications for release in equivocal cases.

 

9. Two dorsal incisions can be used to release all nine foot compartments.

 

10. Alternatively, a medial approach can be used to release all nine compartments. The medial approach is more commonly used in conjunction with dorsal incisions to ensure release of the deep central compartment.