Pediatric Ankle Fractures: Types and Treatment

Introduction

Pediatric ankles have biological and mechanical attributes that form fracture patterns different from adults and create treatment dilemmas. The primary goals of treating pediatric fractures in young children include physis protection and maintenance, prompt arthritis (joint disorder) prevention, and articular congruence maintenance.

What Is a Pediatric Ankle Fracture?

These are common injuries affecting the growth plates of the distal tibia and fibula near the ankle. Direct trauma, excessive use, or twisting injuries are the causes of the fractures. It accounts for 5 percent of all pediatric fractures and 25 to 40 percent of physical fractures. Distal tibial physis supplies 45 percent of the tibia and is the third most common growth plate injury. Any injury to distal tibial physis has a greater risk for growth arrest. The fracture is common among children between 8 to 15 years old and has a slight male prevalence. Children's ligaments are stronger than adults; therefore, traumas that would result in sprains in adults instead produce physeal fractures in children. Children with higher BMI (body mass index) or sports injuries are common causes of pediatric ankle fractures.

How Is Pediatric Ankle Fracture Classified?

Salter-Harris classification based on anatomical location is commonly used. The severity of growth plate injury increases progressively with an increased risk for premature physeal closure. The classification is:

• Type I (SH I): This type of fracture extends transversely across physis and forms 15 percent of all fractures.

• Type II (SH II): This type of fracture extends transversely across physis, changes direction to exit metaphyseal, and forms a Thurston-Holland fragment accounting for 45 percent of all fractures.

• Type III (SH III): The fracture line begins in epiphysis, travels across physis, and exits through physis. It is associated with medial malleolus fracture and Tillaux fracture. There is an increased risk of physeal arrest with this fracture. It forms almost 25 percent of all pediatric fractures.

• Type IV (SH IV): Fracture extends vertically across physis, metaphysis, and epiphysis. The fractures are associated with lateral malleolus, medial malleolus shearing injury, and triplane fracture. This fracture accounts for 25 percent of ankle fractures and has a risk for physeal arrest.

• Type V (SH V): Crush injuries to physis occur, which are difficult to diagnose initially but have an increased risk for physeal arrest. When growth is stopped, the fractures are visible on subsequent radiographs. The fractures form 1 percent of ankle fractures.

• Type VI (SH VI): Due to the fracture, perichondral ring injury develops. These uncommon fractures are caused by open wounds or iatrogenic surgical dissections in which part of the growth plate is absent.

Dias and Tachdjian have categorized pediatric ankle fractures based on the foot's location concerning the applied force.

• Supination inversion injury causes SH-1 injury of the fibula and SH-IV injury of the medial malleolus.

• Supination and external rotation forces cause distal metadia-physeal fracture that does not involve a growth plate.

• Pronation-aversion and external rotation cause high fibular fracture and SH II fracture of the distal tibia with Thurston-Holland fragment located posterolaterally.

• Supination and plantar flexion cause classic SH II fracture of the distal tibia with Thurston-Holland fragment posteriorly, with or without fibular involvement.

There is the possibility of transitional fractures in pediatric ankles. These fractures occur at a certain time when the distal tibial physis is gradually closing. In girls, distal tibial physis is close by 12 to 15 years, but in boys, it is 14 to 18. Distal physeal fracture has a distinct closure pattern that begins centrally, extends to the medial aspect, and completes in the lateral, which takes 18 months to complete. Any trauma to the region causes a distinct fracture pattern. During the early phase of closure, trauma causes triplane fractures. If only lateral physis is involved, it produces Tillaux fracture. Both these fractures do not have the risk of physeal arrest.

What Are the Signs and Symptoms of Pediatric Ankle Injury?

Children with ankle fractures experience excruciating pain, cannot bear weight, and their limb pain is worsened. On inspection, there is ecchymosis (bruise) and swelling of the affected leg, and deformity appears if the broken bone is displaced and interferes with foot vasculature. If there is tenderness in the distal fibula's physical region, it causes a non-displaced ankle fracture.

How Are Pediatric Ankle Fractures Diagnosed?

• To check for open fractures, the skin of the injured foot must be inspected. Feel the tibialis posterior and dorsalis pedis and foot pulses to assess blood flow. The foot's distal and plantar surfaces need to undergo a neurological examination away from the area of damage.

• A palpatory examination must be carried out to discriminate between ankle sprains or other related fractures. While ligament sensitivity is typically associated with a sprain, tenderness on bony prominences suggests physeal damage or bone fractures.

• Normal radiographs help visualize a full-length tibia that rules out Maisonneuve-type fracture. CT (computed tomography) scan of the ankle can help assess fracture displacement, articular step-off, and treatment plan. An MRI (magnetic resonance imaging) of the ankle can reveal further details on its soft tissue architecture and cartilage health.

How Are Pediatric Ankle Fractures Treated?

Treatment for ankle fractures includes operative and nonoperative procedures.

Nonoperative Procedures:

• Removable Walking Boots or Non-weight-Bearing Short-Leg Casts for Four Weeks: It is recommended for distal fibula fractures that are not displaced, minimally displaced (<2 millimeters), or isolated distal fibular fractures.

• Closed Reduction and Non-weight-Bearing Cast for 6 Weeks: The procedure benefits distal fibula displaced more than 2 mm and can undergo closed reduction. Distal tibial fracture with acceptable closed reduction can also be treated.

Operative Procedures:

• Closed reduction percutaneous pinning (CRPP) is indicated for distal fibula fractures that are more than 2 mm displaced, cannot be closely reduced, and have more than two years of growth remaining. Additionally, distal tibial fractures that cannot be closed or minimized are treated with CRPP.

• Open reduction internal fixation is used for distal fibula fracture that is more than 2 mm displaced or isolated distal fibula fracture that cannot be closed reduced and has less than two years of growth remaining. Additionally, it is advised for fractures of the distal tibia with higher displacement and less than two years of growth left.

What Are the Complications Associated With Pediatric Ankle Fractures?

The following complications are associated with pediatric ankle fractures:

• Ankle pain and degeneration.

• Growth arrest.

• Exterior retinaculum syndrome typically occurs in posteriorly displaced fractures. It develops when the excessive translation of fragments causes compression of structures in the anterior aspect of the ankle.

• Malunion (fracture not healed in optimal position).

• Reflex sympathetic dystrophy is a common complication in girls.

• Compartment syndrome is a rare phenomenon after ankle fractures.

Conclusion

Pediatric fractures are common and carry the risk of physeal arrest. The fractures must be accurately diagnosed and classified. Closed reduction or operative procedures are performed for correcting fractures whenever required. A prompt diagnosis and early intervention can reduce the risk of developing complications.