Foot, Ankle, and Calf

Joseph M. Bestic

Jeffrey J. Peterson

Thomas H. Berquist

▪ FRACTURES/DISLOCATIONS: ANKLE FRACTURES—PEDIATRIC

KEY FACTS

Image features of ankle fractures depend on age (growth plate development), relationship of ligaments to epiphyses, and mechanism of injury.
Metaphyseal and diaphyseal fractures are frequently incomplete.
Fractures of the distal tibia and fibula frequently involve the growth plate.
Fracture of the distal tibial physis is the second most common growth plate injury.
The Salter-Harris classification is frequently used for growth plate fractures:
- Type I: Separation of epiphysis, fracture confined to growth plate (6%)
- Type II: Fracture through growth plate extending into the metaphysis (75%)
- Type III: Fracture through growth plate extending through epiphysis (8%)
- Type IV: Extends from articular surface of epiphysis through growth plate and metaphysis (10%)
- Type V: Compression of growth plate (1%)
- Complications are more significant with Types III to V

FIGURE 5-1. The five Salter-Harris fracture patterns.

FIGURE 5-2. Anteroposterior (AP) (A) and lateral (B) radiographs demonstrate marked swelling with a Salter-Harris Type IV (white arrows) tibial fracture and Type II fibular fracture (black arrow) as the result of an inversion injury.

FIGURE 5-3. Anteroposterior (AP) (A) and lateral (B) radiographs of an eversion injury with opening of the tibial physis and a Salter-Harris Type III fracture (white arrows).

SUGGESTED READING

Blackburn EW, Aronsson DD, Rubright JH, et al. Ankle fractures in children. J Bone Joint Surg Am. 2012;94(13):1234-1244.

Rogers LF. Radiology of epiphyseal injuries. Radiology. 1970;96:289-299.

Wuerz TH, Gurd DP. Pediatric physeal ankle fracture. J Am Acad Orthop Surg. 2013;21(4):234-244.

▪ FRACTURES/DISLOCATIONS: ANKLE FRACTURES—PEDIATRIC: TRIPLANE FRACTURE

KEY FACTS

Triplane fractures are the result of external rotation forces, and account for 6% of physeal fractures.
The fracture consists of three fragments instead of two seen with most growth plate fractures.
Fracture fragments include (1) anterior lateral tibial epiphysis (Salter-Harris Type III); (2) remainder of the tibial epiphysis with metaphyseal attachment (looks like Salter-Harris Type II); and (3) tibial metaphysis.
Complication rates are similar to those for a Salter-Harris Type IV fracture.
Computed tomography (CT) may be required to properly characterize the injury.

FIGURE 5-4. Triplane fracture seen from the front and side (A) and from the articular surface and with fragments separated (B).

FIGURE 5-5. Anteroposterior (AP) (A) and lateral (B) radiographs demonstrate a triplane fracture (white arrows). Coronal (C) and sagittal (D) reformatted computed tomography (CT) images define the fractures (black arrows) and degree of displacement.

SUGGESTED READING

Cone RO III, Nguyen V, Flournoyr JG, et al. Triplane fracture of the distal tibial epiphysis: radiologic and CT studies. Radiology. 1984;153:763-767.

Schnetzler KA, Hoernschemeyer D. The pediatric triplane ankle fracture. J Am Acad Orthop Surg. 2007;15(12):738-747.

▪ FRACTURES/DISLOCATIONS: ANKLE FRACTURES—PEDIATRIC: JUVENILE TILLAUX

KEY FACTS

Distal tibial epiphysis fuses from medial to lateral, placing the lateral physis at risk in adolescents.
Distal tibial physis fuses at approximately age 15 in females and age 17 in males.
Juvenile Tillaux fracture is a Salter-Harris Type III fracture of the lateral tibial physis.
The fracture is displaced by the distal tibiofibular ligament when the foot is externally rotated.

FIGURE 5-6. Mechanism of injury for juvenile Tillaux fractures.

FIGURE 5-7. Anteroposterior (AP) radiograph shows a Salter-Harris III fracture—juvenile Tillaux fracture (white arrows).

SUGGESTED READING

Horn BD, Crisci K, Krug M, et al. Radiologic evaluation of juvenile Tillaux fractures of the distal tibia. J Pediatr Orthop. 2001;21(2):162-164.

Mann DC, Rajmaira S. Distribution of physeal and nonphyseal fractures in 2,650 long bone fractures in children aged 10 to 16 years. J Pediatr Orthop. 1990;10:713-716.

▪ FRACTURES/DISLOCATIONS: ANKLE FRACTURES—PEDIATRIC COMPLICATIONS

KEY FACTS

Fractures not involving the growth plate generally heal without sequelae.
Growth plate fractures may heal with premature or asymmetric closure. Complications vary with Salter-Harris fracture type.
Low risk (6.7% complications): Types I and II fibular fractures; Types I, III, and IV tibial fractures with less than 2 mm of displacement.
High risk (32% complications): Types III and IV tibial fractures with more than 2 mm of displacement; juvenile Tillaux fractures, triplane fractures, comminuted epiphyseal fractures, and Type V fractures.
Complications include leg length discrepancy, rotational deformity, malunion, nonunion, and avascular necrosis.
Routine radiographs are usually adequate to define complications. CT or magnetic resonance imaging (MRI) may be required to assess growth plate involvement.

FIGURE 5-8. Prior Salter-Harris IV fracture of the distal tibia. Anteroposterior (AP) (A) and lateral (B) radiographs demonstrate premature closure and angular deformity of the anteromedial growth plate (arrow). The physis remains open laterally and posteriorly (open arrow). Standing radiographs (C) in a different patient with an old physeal fracture on the right and leg length discrepancy and angular deformity of the articular surface (lines).

SUGGESTED READING

Blackburn EW, Aronsson DD, Rubright JH, et al. Ankle fractures in children. J Bone Joint Surg Am. 2012;94(13):1234-1244.

Spiegel PG, Cooperman DR, Laros GS. Epiphyseal fractures of the distal ends of the tibia and fibula. J Bone Joint Surg. 1978;60A:1046-1050.

▪ FRACTURES/DISLOCATIONS: ANKLE FRACTURES—ADULT

KEY FACTS

The mechanism of injury for ankle fractures is rarely pure inversion (supination) or eversion (pronation). Abduction, adduction, lateral rotation, and axial loading forces are usually associated.
Fracture patterns, specifically the location and appearance of the fibular fracture and talar shift in the ankle mortise, can allow definition of the mechanism of injury and ligament involvement in more than 90% of cases.
Anteroposterior (AP), lateral, and mortise views are usually adequate for diagnosis.
The lateral view is particularly useful to define joint effusions. An effusion should raise the question of subtle osteochondral injury, which may require CT or MRI for further evaluation.

FIGURE 5-9. (A) Joint effusion (white arrow) seen on the lateral radiograph. Sagittal fat-suppressed proton density image (B) demonstrates a large effusion (white arrow). Coronal fat-suppressed proton density image (C) reveals an oblique, nondisplaced distal fibular fracture (white arrow), which was not evident radiographically.

SUGGESTED READING

Arimoto HR, Forrester DM. Classification of ankle fractures: an algorithm. AJR Am J Roentgenol. 1980;135:1057-1063.

Michelson JD. Fractures about the ankle. J Bone Joint Surg Am. 1995;77:142.

▪ FRACTURES/DISLOCATIONS: ANKLE ADULT—SUPINATION-ADDUCTION INJURIES

KEY FACTS

Supination-adduction injuries (inversion) cause traction laterally, resulting in ligament injury or a transverse lateral malleolar fracture below the ankle joint (Stage I). When force continues, a medial impaction (steep oblique) fracture of the medial malleolus occurs (Stage II) (Fig. 5-10).
Supination-adduction injuries account for approximately 20% of ankle fractures.

FIGURE 5-10. Inversion (supination)-adduction injury. The forces cause a transverse fracture below the joint line (Stage I) or ligament tear. With continued stress, a steep oblique fracture of the medial malleolus occurs (Stage II).

FIGURE 5-11. Supination-adduction injury with a transverse fracture of the lateral malleolus (white arrow) below the level of the ankle joint.

FIGURE 5-12. Supination-adduction Stage II injury with an oblique fracture (arrow) of the medial malleolus and avulsed fragments from the lateral malleolus (arrow).

SUGGESTED READING

Funk, JR. Ankle injury mechanisms: lessons learned from cadaveric studies. Clin Anat. 2011;24(3):350-361.

Lauge-Hansen N. Fractures of the ankle. II. Combined experimental-surgical and experimental-roentgenologic investigations. Arch Surg. 1950;60:957-985.

Okanobo H, Khurana B, Sheehan S, et al. Simplified diagnostic algorithm for Lauge-Hansen classification of ankle injuries. Radiographics. 2012;32(2):E71-E84.

▪ FRACTURES/DISLOCATIONS: ANKLE ADULT—SUPINATION LATERAL ROTATION INJURIES

KEY FACTS

Supination lateral rotation injuries cause medial tension, with the talus causing posterior displacement of the lateral malleolus.
The anterior distal tibiofibular ligament is injured (Stage I). If force continues, a spiral fracture of the lateral malleolus occurs just above the joint (best seen on the lateral view). This Stage II injury is the most common ankle fracture. With continued force, a posterior tibial fracture or distal tibiofibular ligament tear occurs (Stage III), and eventually a transverse medial malleolar or medial (deltoid) ligament injury occurs (Stage IV) (Fig. 5-13).
Supination lateral rotation injuries account for 55% to 58% of ankle fractures.
All supination or inversion injuries account for 75% to 78% of ankle fractures.

FIGURE 5-13. Supination lateral rotation injuries. The talus causes posterior fibular displacement with disruption of the anterior distal tibiofibular ligament (Stage I). If force continues, a spiral fracture of the fibula occurs just above the joint line (best seen on the lateral view) (Stage II). Continued force results in a posterior tibial fracture or tear in the posterior distal tibiofibular ligament (Stage III) and, finally, a transverse medial malleolar fracture or deltoid ligament tear (Stage IV).

FIGURE 5-14. Supination lateral rotation Stage II injury. Anteroposterior (AP) (A), mortise (B), and lateral (C) radiographs. The fracture is clearly demonstrated only on the AP and lateral views (white arrows).

FIGURE 5-14. (continued)

SUGGESTED READING

Berquist TH. Radiology of the Foot and Ankle, 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2000:171-280.

Funk, JR. Ankle injury mechanisms: lessons learned from cadaveric studies. Clin Anat. 2011;24(3):350-361.

Okanobo H, Khurana B, Sheehan S, et al. Simplified diagnostic algorithm for Lauge-Hansen classification of ankle injuries. Radiographics. 2012;32(2):E71-E84.

▪ FRACTURES/DISLOCATIONS: ANKLE ADULT—PRONATION-ABDUCTION INJURIES

KEY FACTS

Pronation-abduction (eversion) injuries result from medial tension leading to deltoid ligament injury or a transverse medial malleolar fracture (Stage I). Continued force results in tears of the anterior and posterior distal tibiofibular ligaments or a posterior tibial fracture (Stage II) followed by an oblique lateral malleolar fracture near the joint level (best seen on AP view) (Stage III) (Fig. 5-15).
When displaced, internal fixation is necessary to reduce the ankle mortise.

FIGURE 5-15. Pronation (eversion)-abduction injuries. Medial tension causes a transverse malleolar fracture or deltoid ligament tear (Stage I). Continued force results in disruption of the distal anterior and posterior tibiofibular ligaments or a posterior tibial fracture (Stage II) followed by an oblique fibular fracture near the joint line best seen on the anteroposterior (AP) radiograph (Stage III).

FIGURE 5-16. Pronation-abduction Stage III injuries. (A) There is a transverse medial malleolar fracture (white arrow), tibiofibular ligament tears with separation of the tibia and fibula (open arrows), and an oblique fibular fracture (black arrows). (B) Widening of the medial ankle mortise (white arrow) caused by a ligament tear with increased tibiofibular distance (open arrows) and oblique fibular fracture (black arrows).

SUGGESTED READING

Arimoto HR, Forrester DM. Classification of ankle fractures: an algorithm. AJR Am J Roentgenol. 1980;135:1057-1063.

Funk, JR. Ankle injury mechanisms: lessons learned from cadaveric studies. Clin Anat. 2011;24(3):350-361.

Okanobo H, Khurana B, Sheehan S, et al. Simplified diagnostic algorithm for Lauge-Hansen classification of ankle injuries. Radiographics. 2012;32(2):E71-E84.

▪ FRACTURES/DISLOCATIONS: ANKLE ADULT—PRONATION LATERAL ROTATION INJURIES

KEY FACTS

Pronation lateral rotation injuries cause medial tension as the talus rotates laterally.
The medical malleolus (low transverse fracture) or medial ligaments are injured initially (Stage I). As force continues, the anterior tibiofibular and interosseous membranes are torn (Stage II), followed by a high fibular fracture (more than 5 to 6 cm above the joint) (Stage III). Posterior tibial avulsion or distal tibiofibular ligament tears occur with continued force (Stage IV) (Fig. 5-17).
Pronation injuries account for 22% to 25% of ankle fractures.
Treatment of these fractures usually requires internal fixation of the fibular fracture and screw fixation of the medial malleolus.

FIGURE 5-17. Pronation lateral rotation injuries. Medial tension results in a low transverse medial malleolar fracture or deltoid ligament tear (Stage I), followed by tearing of the distal anterior tibiofibular ligament and interosseous membrane (Stage II). With continued force, a high (>6 cm) fibular fracture occurs (Stage III) followed by a posterior distal tibiofibular ligament tear or avulsion fracture (Stage IV).

FIGURE 5-18. Pronation lateral rotation Stage IV injury with a transverse medial malleolar fracture (white arrow), disruption of the tibiofibular and interosseous ligaments (black arrowheads), and a high fibular fracture (black arrow).

SUGGESTED READING

Arimoto HR, Forrester DM. Classification of ankle fractures: an algorithm. AJR Am J Roentgenol. 1980;135:1057-1063.

Funk, JR. Ankle injury mechanisms: lessons learned from cadaveric studies. Clin Anat. 2011;24(3):350-361.

Okanobo H, Khurana B, Sheehan S, et al. Simplified diagnostic algorithm for Lauge-Hansen classification of ankle injuries. Radiographics. 2012;32(2):E71-E84.

▪ FRACTURES/DISLOCATIONS: ANKLE ADULT—PLAFOND FRACTURES (PILON)

KEY FACTS

Plafond fractures do not fit neatly into other fracture classifications. Tibial plafond fractures account for less than 10% of lower extremity fractures.
Fractures are the result of axial loading; 72% occur in patients less than 50 years of age.
Up to 20% of plafond fractures are open, resulting in increased incidence of infection.
Treatment of these fractures is difficult, because the articular surface needs to be anatomically reduced.
CT and MRI may be required to clearly demonstrate the extent of injury for surgical treatment planning.

FIGURE 5-19. Mortise view of a tibial plafond fracture reduced with external fixateur and tibial screws. Note the residual articular deformity (arrow).

SUGGESTED READING

Bonar SK, Marsh JL. Tibial plafond fractures: changing principles of treatment. J Am Acad Orthop Surg. 1994;2:297-304.

Ovadia DN, Beals RK. Fractures of the tibial plafond. J Bone Joint Surg. 1986;68A:543-551.

Topliss CJ, Jackson M, Atkins RM. Anatomy of pilon fractures of the distal tibia. J Bone Joint Surg Br. 2005;87(5): 692-697.

▪ FRACTURES/DISLOCATIONS: ANKLE ADULT—COMPLICATIONS

KEY FACTS

Complications resulting from ankle fractures may be related to injury or treatment.
Loss of reduction occurs more commonly with closed techniques (casting) than internal fixation.
Degenerative arthritis is the most common long-term complication, occurring in 30% to 40% of cases.
Complications are summarized as follows:
- Loss of reduction (up to 26% treated by casting alone)
- Osteoarthritis
- Chronic instability
- Loss of motion
- Nonunion
- Malunion
- Reflex sympathetic dystrophy
- Infection
- Adhesive capsulitis
- Tendon rupture
- Neurovascular injury

FIGURE 5-20. Anteroposterior (AP) (A) and lateral (B) radiographs demonstrate severe posttraumatic arthritis with osseous fragments in the joint and marked tibiotalar joint asymmetry.

SUGGESTED READING

Chen SH, Wu PH, Lee YS. Long-term results of pilon fractures. Arch Orthop Trauma Surg. 2007;127(1):55-60.

Pettrone FA, Gail M, Pee D, et al. Quantitative criteria for prediction of results of displaced fracture of the ankle. J Bone Joint Surg. 1983;65A:667-677.

▪ FRACTURES/DISLOCATIONS: TALAR FRACTURES—TALAR NECK

KEY FACTS

Fractures of the talar neck are common in adults and rare in children.
Talar neck fractures account for 6% of foot and ankle injuries and 30% of talar fractures.
The mechanism of injury is abrupt dorsiflexion of the foot during a fall or motor vehicle accident.
Talar neck fractures may be undisplaced or displaced. The latter are associated with subtalar subluxation/dislocation.
Displaced fractures usually require internal fixation.
Complications include avascular necrosis (usually evident by 6 to 8 weeks), osteoarthritis (97%), and malunion or nonunion (15%).

FIGURE 5-21. Lateral radiograph of the foot shows a comminuted talar neck fracture (arrows).

FIGURE 5-22. Hawkins sign. Anteroposterior (AP) radiograph after fixation of talar neck and medial malleolar fractures. The lateral talus is sclerotic, indicating loss of flow. There is normal subchondral osteopenia (arrow) medially.

SUGGESTED READING

Daniels TR, Smith JW. Talar neck fractures (review). Foot Ankle. 1993;14:225-234.

Hawkins LG. Fractures of the neck of the talus. J Bone Joint Surg. 1970;52A:991-1002.

Melenevsky Y, Mackey RA, Abrahams RB, et al. Talar fractures and dislocations: a radiologist’s guide to timely diagnosis and classification. RadioGraphics. 2015;35(3):765-779.

▪ FRACTURES/DISLOCATIONS: TALAR FRACTURES—BODY, HEAD, PROCESS FRACTURES

KEY FACTS

Fractures of the talar body and posterior or lateral processes are uncommon in adults and rare in children.
Most fractures are the result of significant falls or motor vehicle accidents with axial compression.
Lateral talar process fractures (“snowboarder’s fracture”) are easily missed on radiographs (40% are overlooked initially).
CT is important to detect and manage talar body and process fractures.
Treatment is anatomic reduction, which requires internal fixation for displaced fractures.
Complications are the same as with talar neck fractures. Malunion and avascular necrosis occur in 16%.

FIGURE 5-23. Lateral radiograph of a talar body fracture (arrow).

FIGURE 5-24. Sagittal computed tomography (CT) image demonstrates talar body fracture (arrow) entering the posterior subtalar joint.

SUGGESTED READING

Boack DH, Manegold S. Peripheral talar fractures. Injury. 2004;35(S2):B23-B25.

Melenevsky Y, Mackey RA, Abrahams RB, et al. Talar fractures and dislocations: a radiologist’s guide to timely diagnosis and classification. RadioGraphics. 2015;35(3):765-779.

Sneppen O, Christensen SB, Krogsoe O, et al. Fracture of the body of the talus. Acta Orthop Scand. 1977;48:317-324.

▪ FRACTURES/DISLOCATIONS: TALAR FRACTURES—TALAR DOME FRACTURES

KEY FACTS

Most common talar fracture.
Talar dome fractures are difficult to detect (50% missed), and prognosis is more guarded compared with nonarticular chip or avulsion fractures.
Fractures are most common in adults. Only 8% occur in patients less than 16 years of age.
Acute lesions are most often lateral. Ten percent involve both the lateral and medial talar dome.
CT or MRI is important for detection, localization, and measurement of lesion size and displacement.
Displaced lesions should be resected or arthroscopically removed.
Arthrosis is the most common complication (50%).

FIGURE 5-25. Coronal (A) and sagittal fat-suppressed T2-weighted (B) images demonstrate marrow edema and a subtle nondisplaced talar dome fracture (arrows).

FIGURE 5-25. (continued)

FIGURE 5-26. Mortise view of a slightly displaced lateral talar dome fracture fragment (arrow).

SUGGESTED READING

Clark TWI, Janzen DL, Kendall H, et al. Detection of radiographically occult ankle fractures following acute trauma: positive predictive value of ankle effusion. AJR Am J Roentgenol. 1995;164:1185-1189.

Melenevsky Y, Mackey RA, Abrahams RB, et al. Talar fractures and dislocations: a radiologist’s guide to timely diagnosis and classification. RadioGraphics. 2015;35(3):765-779.

▪ FRACTURES/DISLOCATIONS: TALAR AND SUBTALAR DISLOCATIONS

KEY FACTS

The majority of eversion and inversion motion occurs in the subtalar joint.
Talar dislocations account for only 1% of all dislocations.
Fifteen percent of talar injuries are caused by dislocation.
Subtalar dislocations may be medial (56%), lateral (34%), posterior (6%), or anterior (4%).
Associated talar or calcaneal fractures occur in 75% of lateral and 45% of medial dislocations.
Total dislocation is rare. There is a high incidence of infection, which may require talectomy. Avascular necrosis is also common.
Postreduction CT with coronal and sagittal reformatting is essential to assess reduction and detect associated fractures.

FIGURE 5-27. Subtalar and talonavicular dislocation. (A) Anteroposterior (AP) view of the ankle shows the talus (T), calcaneus (C), and navicular (N). The calcaneus is rotated under the talus. (B) Oblique view shows the talus lateral to the calcaneus.

SUGGESTED READING

Detenbeck LC, Kelly PJ. Total dislocation of the talus. J Bone Joint Surg. 1969;51A: 283-288.

Melenevsky Y, Mackey RA, Abrahams RB, et al. Talar fractures and dislocations: a radiologist’s guide to timely diagnosis and classification. RadioGraphics. 2015;35(3):765-779.

▪ FRACTURES/DISLOCATIONS: CALCANEAL FRACTURES—INTRA-ARTICULAR

KEY FACTS

The calcaneus is the most commonly fractured bone in the adult foot, accounting for 60% of foot fractures, but only 2% of all skeletal fractures.
Calcaneal fractures in children account for only 5% of foot fractures.
Pediatric fractures are usually extra-articular (63%), whereas adult fractures are usually intra-articular (70% to 75%).
Most adult fractures are the result of axial loading resulting from falls or motor vehicle accidents. Ten percent are bilateral. Associated vertebral fractures occur in 10%.
CT with coronal and sagittal reformatting is required to classify the injury and assess articular involvement and fracture complexity.
Treatment goals are to reestablish articular alignment, calcaneal width, and the posterior facet (Böhler’s angle).
Complications include
- Prolonged pain and disability
- Lower extremity fractures (20%-46%)
- Soft tissue injury
- Neurovascular injury

FIGURE 5-28. Lateral radiograph in a patient with a comminuted calcaneal fracture. Böhler’s angle measures 10 degrees.

FIGURE 5-29. Comminuted intra-articular calcaneal fracture. Axial (A, B) and coronal (C) computed tomography (CT) images clearly show fragment position and articular involvement.

SUGGESTED READING

Badillo K, Pacheco JA, Padua SO, et al. Multidetector CT evaluation of calcaneal fractures. Radiographics. 2011;31(1): 81-92.

Crosby LA, Fitzgibbons I. Computerized tomographic scanning of acute intra-articular fractures of the calcaneus. J Bone Joint Surg. 1990;72A:852-859.

Daftary A, Haims AH, Baumgartner MR. Fractures of the calcaneus: a review with emphasis on CT. Radiographics. 2005;25:1215-1226.

▪ FRACTURES/DISLOCATIONS: CALCANEAL FRACTURES—EXTRA-ARTICULAR

KEY FACTS

Extra-articular fractures account for 25% of calcaneal fractures. This includes all fractures that do not involve the posterior facet.
Mechanism of injury: twisting, compression, or avulsion forces.
Certain fractures may present as ankle sprains: anterior calcaneal process, peroneal tubercle, lateral calcaneal process, sustentaculum tali, calcaneal tuberosity, and medial calcaneal process fractures.
CT is frequently required to detect the injury and exclude intra-articular involvement.

FIGURE 5-30. Computed tomography (CT) shaded surface display rendering of the hind foot demonstrates an anterior calcaneal process fracture (arrow).

FIGURE 5-31. Lateral radiograph of a calcaneal tuberosity avulsion fracture (arrow).

SUGGESTED READING

Badillo K, Pacheco JA, Padua SO, et al. Multidetector CT evaluation of calcaneal fractures. Radiographics. 2011;31 (1): 81-92.

Gilheany MF. Injury to the anterior process of the calcaneous. Foot. 2002;12:142-149.

▪ FRACTURES/DISLOCATIONS: MIDFOOT INJURIES

KEY FACTS

The midfoot consists of the lesser tarsal bones (navicular, cuboid, and three cuneiforms) and tarsometatarsal (Lisfranc) joints.
Injuries may be the result of medial (30%), longitudinal (41%), lateral (17%), or plantar (4%) forces, and crush injuries (5%).

Isolated tarsal fractures are uncommon.

FIGURE 5-32. Patterns of Lisfranc fracture/dislocations. (A) Type A—total incongruity. (B) Type B—partial incongruity. (C) Lateral dislocation. (D) Type C or divergent with total displacement (A) and partial displacement (B).

FIGURE 5-32. (continued)

Tarsometatarsal fracture/dislocations are Lisfranc injuries (1% of all fracture/dislocations). The mechanism of injury is forced plantar flexion of the forefoot. CT with reformatting is essential to define the extent of injury. Magnetic resonance (MR) may be able to depict subtle injuries of the Lisfranc ligament.

FIGURE 5-33. Lisfranc fracture/dislocation. (A) Anteroposterior (AP) radiograph shows a fracture/dislocation (arrow) at the tarsometatarsal joints. There is also a dislocation (arrowhead) of the second metatarsophalangeal (MTP) joint. Computed tomography (CT) images in the axial (B), sagittal and coronal (C, D) planes demonstrate widening of the 1-2 metatarsal bases (arrow) with multiple osteochondral fractures (arrowheads).

FIGURE 5-33. (continued)

SUGGESTED READING

Karasick D. Fracture and dislocation of the foot. Semin Roentgenol. 1994;29:152-175.

Makawana NK, Van Lefland MR. Injuries of the midfoot. Curr Orthop. 2005;19:231-242.

Siddiqui NA, Galizia MS, Almusa E, et al. Evaluation of the tarsometatarsal joint using conventional radiography, CT, and MR imaging. RadioGraphics. 2014;34:514-531.

▪ FRACTURES/DISLOCATIONS: FOREFOOT INJURIES—FIFTH METATARSAL FRACTURES

KEY FACTS

Fractures of the fifth metatarsal base are common in children and adults.
Fractures are categorized as proximal or distal.
Proximal fractures are divided into three zones (Fig. 5-34). Zone 1—avulsion fractures; Zone 2—Jones fractures caused by forefoot adduction; Zone 3—typically athletic stress fractures.
Distal fractures (Dancer’s fracture) are usually the result of a direct blow.
Treatment of fractures in Zone 1 and distal fractures is conservative. Fractures in Zones 2 and 3 may require internal fixation.

FIGURE 5-34. Oblique radiograph demonstrates the three zones of the proximal fifth metatarsal. There is an ununited Jones fracture (arrow) in Zone 2.

FIGURE 5-35. Subtle nondisplaced avulsion fracture of the fifth metatarsal base in Zone 1 (arrow).

SUGGESTED READING

Chuckpaiwong B, Queen RM, Easley ME, et al. Distinguishing Jones and proximal diaphyseal fractures of the fifth metatarsal. Clin Orthop Relat Res. 2008;466(8): 1966-1970.

Ekrol I, Court-Brown CM. Fractures of the base of the fifth metatarsal. Foot. 2004;14:96-98.

Theodorou DJ, Theodorou SJ, Kakitubata Y, et al. Fractures of the fifth metatarsal base: anatomic and imaging evidence of pathogenesis of avulsion of the plantar aponeurosis and short peroneal tendon. Radiology. 2003;226:857-865.

▪ FRACTURES/DISLOCATIONS: FOREFOOT INJURIES—METATARSOPHALANGEAL FRACTURE/DISLOCATIONS

KEY FACTS

Isolated fractures of the first metatarsal are rare.
Proximal metatarsal fractures are often associated with midfoot fracture/dislocations.
Distal metatarsal fractures are usually related to a blow from a heavy object.
Phalangeal fractures are the most common forefoot injury. Jamming or dropping a heavy object results in fracture.
Dislocations of the metatarsophalangeal (MTP) and interphalangeal joints may occur as isolated events or be associated with fractures.
- The first MTP and proximal interphalangeal joints are most commonly dislocated.

FIGURE 5-36. Crush injury. (A) Anteroposterior (AP) radiograph demonstrates complex comminuted metatarsal fractures. (B) Fractures were reduced using K-wire fixation.

FIGURE 5-37. Dislocation. Anteroposterior (AP) (A) and oblique (B) radiographs demonstrate lateral dislocation at the fifth proximal interphalangeal joint (arrow).

SUGGESTED READING

Karasick D. Fractures and dislocations of the foot. Semin Roentgenol. 1994;29:152-175.

Mizel MS, Yodlowski ML. Disorders of the lesser metatarsophalangeal joints. J Am Acad Orthop Surg. 1995;3:166-173.

▪ FRACTURES/DISLOCATIONS: STRESS FRACTURES

KEY FACTS

Most stress fractures are fatigue fractures caused by repetitive stress or muscle tension on normal bone.
Stress fractures commonly occur in military recruits or civilians engaged in a new activity such as running.
More than 80% of stress fractures involve the tibia, fibula, metatarsals, and calcaneus.
Table 5-1 summarizes the location and cause of stress fractures.
Early detection may be difficult with routine radiographs. MRI provides the most specific early diagnosis.

Table 5-1 STRESS FRACTURES

Location	Cause
Metatarsals	Marching Running Ballet Prior surgery Rheumatoid arthritis
Tarsals	Long-distance running
Calcaneus	Jumping Running
Sesamoids	Marching Standing Skiing Cycling
Distal tibia	Running
Distal fibula	Running Parachute jumping