Ankle fractures account for 5% and foot fractures account for approximately 8% of fractures in children. Some complications are evident early in the treatment or natural history of foot and ankle fractures. Other complications do not become apparent until weeks, months, or years after the original fracture. The incidence of long-term sequelae like posttraumatic arthritis from childhood foot and ankle fractures is poorly studied because decades or lifelong follow-up has frequently not been accomplished. This article discusses a variety of complications associated with foot and ankle fractures in children or the treatment of these injuries.
Key points
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Phalangeal fractures that are at the highest risk for complications include intraarticular phalangeal fractures of the hallux, distal phalangeal physeal fractures that extend through the nail matrix, and phalangeal fractures with severe flexion/extension displacement.
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Foot fractures that are at the highest risk for complications include Jones fifth metatarsal fractures, Lisfranc, talus, and calcaneus fractures.
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Ankle fractures that are at the highest risk for complications include high-energy fractures, articular displacement greater than 2 mm or physeal widening greater than 3 mm after final reduction.
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Children with chronic regional pain syndrome type I (CRPSI) have a higher preponderance of foot and ankle injuries than adults with CRPSI.
Introduction
Ankle fractures account for 5% and foot fractures account for approximately 8% of fractures in children. Although there is abundant literature discussing adult treatment and outcomes (including complications) of foot and ankle trauma, there is a paucity of literature specifically discussing certain risks and treatments of ankle, and especially foot, injuries in children. Some complications, including compartment syndrome (CS), extensor retinaculum syndrome, reflex sympathetic dystrophy (RSD)/complex regional pain syndrome, infection, neurovascular injuries, and cast complications, are evident early in the treatment or natural history of foot and ankle fractures. Other complications, such as osteonecrosis (ON), missed injuries, premature physeal closure (PPC), malunion, nonunion, and arthrofibrosis, do not become apparent until weeks, months, or years after the original fracture. The incidence of long-term sequelae like posttraumatic arthritis from childhood foot and ankle fractures is poorly studied because decades or lifelong follow-up have not been accomplished to date. This article discusses a variety of complications associated with foot and ankle fractures in children or the treatment of these injuries. Foot fractures, including those of the phalanges, metatarsals, Lisfranc complex, talus, and calcaneus, and pediatric ankle fractures, including physeal, triplane, and Tillaux fractures, are described with a brief overview of each type followed by the complications unique to each fracture type. General complications associated with any pediatric foot or ankle injury are reviewed at the end of the article.
Introduction
Ankle fractures account for 5% and foot fractures account for approximately 8% of fractures in children. Although there is abundant literature discussing adult treatment and outcomes (including complications) of foot and ankle trauma, there is a paucity of literature specifically discussing certain risks and treatments of ankle, and especially foot, injuries in children. Some complications, including compartment syndrome (CS), extensor retinaculum syndrome, reflex sympathetic dystrophy (RSD)/complex regional pain syndrome, infection, neurovascular injuries, and cast complications, are evident early in the treatment or natural history of foot and ankle fractures. Other complications, such as osteonecrosis (ON), missed injuries, premature physeal closure (PPC), malunion, nonunion, and arthrofibrosis, do not become apparent until weeks, months, or years after the original fracture. The incidence of long-term sequelae like posttraumatic arthritis from childhood foot and ankle fractures is poorly studied because decades or lifelong follow-up have not been accomplished to date. This article discusses a variety of complications associated with foot and ankle fractures in children or the treatment of these injuries. Foot fractures, including those of the phalanges, metatarsals, Lisfranc complex, talus, and calcaneus, and pediatric ankle fractures, including physeal, triplane, and Tillaux fractures, are described with a brief overview of each type followed by the complications unique to each fracture type. General complications associated with any pediatric foot or ankle injury are reviewed at the end of the article.
Foot injuries
Phalangeal Fractures
The incidence of phalangeal fractures in children is not reported in the literature. The mechanism of injury is usually a stubbing injury or an object dropped on the toe. There have been a few recent case series specifically discussing skeletally immature patients with intraarticular hallux phalangeal fractures.
The generally accepted threshold for choosing operative fixation of an intraarticular proximal phalanx fracture of the hallux is involvement of more than 30% of the articular surface or articular displacement greater than 3 mm.
To avoid certain phalangeal fracture complications (even rare ones), treating providers should not always just assume that all toes fractures in children will do well. The phalangeal fractures listed in Table 1 (and discussed later) should be approached with appropriate caution.
| Type of Phalangeal Fracture | Complication |
|---|---|
| Intra-articular phalangeal fractures of hallux | Posttraumatic arthritis |
| Distal phalangeal physeal fractures that extend through nail matrix (Pinckney fracture) | Infection |
| Phalangeal fracture with severe flexion/extension displacement | Malunion |
Posttraumatic arthritis/hallux rigidus
Damaging any joint (intraarticular injury) increases the chances of developing arthritis 7-fold, according to the American Academy of Orthopaedic Surgeons (AAOS). Kramer and colleagues reported on a series of 10 patients with intraarticular hallux fractures occurring at an average age of 12.6 years, who were followed for a median 50.5 months (longest follow-up was 123 months); there was a 10% rate of posttraumatic arthritis requiring fusion.
Infection
Pinckney fractures are distal phalangeal physeal fractures that extend through the nail matrix. These fractures usually occur in the hallux. If they are not recognized or treated appropriately as open fractures, osteomyelitis can occur. In Pinckney and colleagues’ original article describing this injury in 6 children, the first 4 presented with cellulitis or osteomyelitis, but the last 2 were given antibiotics and did not develop infection caused by this open fracture type. To minimize the infection risk, treatment can be extrapolated from the hand literature describing appropriate treatment of Seymour fractures, Salter-Harris (SH) I or II fractures of the distal phalanx of the hand with associated nailbed laceration. Timely (within 24 hours) treatment involves irrigation and debridement, fracture reduction to ensure that there is no interposed periosteum in the fracture site, and antibiotic administration. In the study by Reyes and Ho, there were 0 out of 11 infections in the group treated within 24 hours of sustaining a Seymour fracture, and there were 5 out of 11 (45%) infections in the delayed treatment group.
Rare phalangeal fracture complications
Phalangeal fractures in children can, rarely, result in ON and malunion. ON is a rare complication of intraarticular hallux phalangeal fractures that usually occurs if there is disruption of the vascularity of small fragments attached to the collateral ligament. Fig. 1 shows an example of ON of a phalangeal fracture treated with open reduction with Kirschner (K) wire fixation. Phalangeal fractures (except border toes) can tolerate some varus/valgus and rotation, but can create abnormal pressure/callus on the plantar surface of the foot or difficulty with shoe wear if they heal in flexion or extension. Fig. 2 shows a case that could have healed in excessive extension if treated without reduction and fixation.
Metatarsal Fractures
A British epidemiologic study of pediatric fractures showed that the incidence of foot fractures was 10.5 per 10,000 children less than 18 years old and that they occurred most commonly in both boys and girls around age 13 years. Metatarsal fractures in children account for 60% to 90% of pediatric foot fractures. Foot fractures at high risk for complications are discussed later and in Table 2 .
| Type of Foot Fracture | Complication |
|---|---|
| Jones fracture (metaphyseal-diaphyseal fifth metatarsal fracture) | Nonunion |
| Lisfranc fracture | Arthritis |
| Talus fracture | ON, concurrent injury, OCD |
| Calcaneal fracture | Associated injury, arthritis |
Nonunion
Similar to adults, the most common site of metatarsal fracture nonunion in children is the proximal metaphyseal-diaphyseal junction of the fifth metatarsal (Jones fracture). Risk of nonunion at this site is most common in children more than 13 years of age and in patients with preceding stress injury indicated by pain at that site before traumatic injury. Knowledge of which patients are at highest risk of nonunion with nonoperative cast treatment can expedite operative treatment with an intramedullary screw when indicated. Fig. 3 shows an example of a healthy 10-year-old girl with painful nonunion of her fifth metatarsal base Jones fracture, which failed multiple attempts at both non–weight-bearing and weight-bearing cast immobilization before having successful union after open reduction and internal fixation (ORIF) with a cannulated screw.
Compartment syndrome of the foot
High-energy crush injuries to the foot with or without multiple foot fractures can result in excessive swelling within the 9 compartments of the foot. CS presents differently in children than in adults; usually an increasing analgesia requirement is the primary sign. It is also harder to differentiate between direct foot injury pain and foot CS pain, whereas foot symptoms that indicate a CS with a more proximal injury such as a tibia fracture are at least easier to differentiate. There should be a low threshold in children to check compartment pressure measurements, usually under anesthesia. Measurements of any compartment greater than 30 mm Hg or less than 30 mm Hg less than patient’s diastolic blood pressure are the accepted thresholds for performing fasciotomies through 2 dorsal longitudinal incisions and a medial incision along the arch. The most sensitive of the 9 compartments for measuring compartment pressures is the calcaneal compartment. The incidence of pediatric foot CS is unknown, but a recent article by Wallin and colleagues included a systematic literature review from 1990 to 2012 and found 8 studies, including 59 pediatric patients between the ages of 1.5 and 18 years, with traumatic foot CS. There were not many long-term outcomes presented in these studies, but a follow-up study of 7 pediatric patients treated with fasciotomies for foot CS for an average of 41 months all had good or excellent results. Late sequelae of missed foot CS reported in different a publication include pain, claw toes, paresthesias, and cavus foot.
Lisfranc Fractures
In adults, Lisfranc injuries account for less than 1% of all fractures. Lisfranc injuries are even more rare in children and the patients tend to do well. The largest published case series of pediatric Lisfranc injuries comprises 18 patients 16 years old and younger (average age 12 years) with a range of injuries from mild displacement to frank tarsometatarsal (TMT) joint dislocation. The most common mechanism of injury was falling with the foot in equinus position and the fractures in this series were treated very differently from the standard adult treatment of ORIF or primary TMT arthrodesis. Most were treated with closed reduction and casting or closed reduction and K-wire fixation, 14 out of 18 patients were asymptomatic at final follow-up 3 to 8 months after injury, and 4 out of 18 patients had only minor pain 1 year postinjury. In a series of 41 patients with pediatric Lisfranc (average age, 11 + 4 years), 13 of whom completed outcomes questionnaires an average of 5 years after injury, nonoperative treatment resulted in excellent long-term function and quality of life. Operative treatment was performed in older patients (>12 years old) with more complicated and displaced injuries and resulted in worse but still good function and quality of life. The preferred method of treatment of Lisfranc injuries in children is unclear, but most Lisfranc injuries in children, especially those less than 12 years of age, are treated nonoperatively with a short-leg cast for about a month.
Malunion/posttraumatic arthritis
In the Wiley study, 2 out of 18 patients had angular deformity (malunion) from incomplete reduction, but long-term follow-up was lacking so the rate of posttraumatic arthritis is unknown. In the Buoncristiani and colleagues study, one of the 8 patients in the series had radiograph evidence of arthritis across the TMT joint at 39 months after Lisfranc injury and the investigators concluded that the patient should have been treated with ORIF instead of short-leg casting alone. In the Denning and colleagues study, 21% of patients had residual angulation, displacement, or malunion and 38% of patients had radiographic evidence of TMT and/or other midfoot arthritis at final radiographic follow-up. The rates of malunion and arthritis were not significantly different between operatively and nonoperatively treated groups.
Missed injury
The rate of missed Lisfranc injuries in children is unknown, but in the adult literature up to 20% of these injuries are missed on initial anteroposterior (AP) and lateral radiographs. Weight-bearing radiographs should be performed if there is suspicion of a Lisfranc injury and initial injury films do not show any injury. MRI is capable of showing ligamentous tears if the radiographs are inconclusive.
Talus Fractures
Talus fractures account for less than 0.1% of all pediatric fractures, which makes them more rare than adult talus fractures, which make up 0.3% of fractures. In biomechanical studies, it takes nearly twice the force to fracture a child’s talus than to fracture the ankle or other tarsal bones. The usual mechanism of injury is a fall from a height with the ankle in forced dorsiflexion.
Osteonecrosis
In the pediatric population, the rate of ON is lower than that of adults with talus fractures in some studies. Other studies conclude that the ON rate in children with talus fractures equals or exceeds that of adults. From the literature review in the Rammelt and colleagues article, there was a 16% incidence of ON in nondisplaced talus fractures in children. Half of the fractures going on to ON were initially missed on radiograph at the time of injury and all of the children with these nondisplaced fractures that went on to ON were less than 9 years old. The Hawkins sign is a radiographic finding of subchondral lucency that occurs by 1 to 2 months postinjury and indicates adequate blood flow to the talar body following talus fracture in adults. Ogden suggests that the Hawkins sign is not reliable in children because the talar dome is cartilaginous. The Hawkins classification is a classification system from I to IV based on degree of displacement of the talar neck fracture, and, although it bears the same name, is different from the Hawkins sign described earlier. This classification system is predictive of ON rate in adults, but it does not correlate in with risk of ON in children. The literature regarding children with talar fractures indicates that ON seems to be unpredictable, so the treating clinician should follow children closely after all talus fractures, including nondisplaced injuries.
Posttraumatic arthritis
Because much of the talus is covered in articular cartilage, the rule of striving for anatomic reduction of an intraarticular fracture is applicable in 3 separate joints during talus fracture reduction: the tibiotalar, subtalar, and talonavicular joints. Posttraumatic arthritis occurred in 3 out of 12 patients in a study with an average 11-year follow-up after pediatric talus fractures. One patient had to be treated with pantalar arthrodesis and 2 patients with ankle arthrodesis. The average American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score at 1 to 22 years postinjury was 85 (range, 65–100).
Talar malunion
The most common malunion either from incomplete reduction or loss of fixation after surgical treatment of talus fractures is hindfoot varus malalignment and forefoot adduction and supination from medial column shortening. Subtalar joint incongruity is also common. Even in pediatric patients, the remodeling potential of the talus is not good.
Concurrent injury
Because talus fractures tend to be high-energy injuries, concurrent injuries with talus fractures in children are common. To prevent the possibility of a missed injury, treating providers should have a high index of suspicion to look for concomitant injuries with talar fractures. In the Meier and colleagues study, there were 7 out of 15 pediatric patients with talus fracture with concurrent injuries to the same extremity and 4 of those patients had more than 1 associated injury. Fig. 4 shows an example of a skeletally immature patient with talar neck fracture/dislocation with concurrent medial and lateral malleolus fractures.
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