eMedicine Specialties > Orthopedic Surgery > Trauma

Triplane Fracture

Author: John L Abt, DO, FACEP, FACFE, Clinical Associate Professor and Senior Consulting Staff, Department of Emergency Medicine, Mount Sinai Medical Center of Miami
Coauthor(s): Vinod K Panchbhavi, MD, FRCS, FACS, Associate Professor, Chief, Division of Foot and Ankle Surgery, Department of Orthopedics, University of Texas Medical Branch School of Medicine
Contributor Information and Disclosures

Updated: Jun 12, 2009

Introduction

A triplane fracture of the distal tibia is generally sustained during adolescence and occurs before complete closure of the distal tibial physis (growth plate). It represents 5-10% of pediatric intra-articular ankle injuries and typically presents in children aged 12-15 years of age. The incidence is slightly higher in boys than in girls.^{1,2,3,4,5,6,7}

The characteristic asymmetric closure of the distal tibial growth plate occurring over a period of approximately 18 months is the basis for the unique occurrence of this fracture following an ankle injury in this age group.

The classic fracture pattern is multiplanar. The fracture extends through the transverse (growth plate), sagittal (epiphysis), and coronal (distal tibial metaphysis) anatomic planes, disrupting the tibial plafond intra-articularly, resulting in 3 classically described fragments. It has, however, several variations.

History of the Procedure

What is now known as a triplane fracture is believed to have first been reported in 1957 by Johnson and Fahl.⁸ Ehalt, in 1961, and Titze, in 1967, described similar fractures of the distal lateral tibia and tibial epiphysis as transitional fractures.^9,10

In 1970, Marmor first described a fracture that involved the distal tibia and distal tibial epiphysis as having 3 separate fragments, including the anterolateral distal tibial epiphysis, the anteromedial and posterior portions of the distal tibial epiphysis with an attached posteromedial spike of the distal tibial metaphysis, and the remainder of the distal tibial metaphysis and shaft.¹¹ This fracture pattern was recognized to have fracture lines in the transverse, coronal, and sagittal anatomic planes.

In 1972, Lynn first coined the term triplane fracture in his paper describing the reduction surgery in 2 patients with distal tibial epiphyseal injuries, both of whom had fractures in the sagittal, coronal, and transverse planes.¹² In 1978, Cooperman reviewed 237 cases of distal tibial epiphyseal fractures. Fifteen (6%) were triplane fractures, of which 13 were treated by closed reduction.¹³

In 1981, Denton and Fischer reported a triplane fracture that was unusual in that it was a medial triplane fracture.¹⁴ Von Laer and, later, Etrl continued investigations into the nature of the tibial triplane fracture.^15,16

Problem

Early discussions of distal tibial fractures occurring in adolescence lacked consistent and exact descriptions of the fracture fragments because plain radiographs were used to visualize and characterize the fragments. Additionally, involvement of the tibial growth plate in these fractures was suspected but not understood completely.

With the advent of computerized axial tomography (CT) and magnetic resonance imaging (MRI), delineating the exact anatomy, fracture lines, plane analysis, and other characteristics of the triplane fracture is now possible. In particular, any disruption that occurs at the growth plate, the anterior talofibular and tibiofibular ligament, and the talotibial articular plafond is visualized on CT scans.

Frequency

A review of the literature reveals epidemiologic characteristics of the triplane fracture as follows¹ :

• Triplane fracture occurs most commonly in patients aged 12-15 years.
• It represents 5-10% of all pediatric intra-articular ankle injuries.
• Male-to-female frequency ratio varies in the literature from 1:1 to 2:1. In studies indicating a higher incidence in males, this is postulated to be caused by later closure of the lateral tibial growth plate in males than in females, thereby lengthening the period of vulnerability to injury for males.
• A higher incidence in the right ankle is reported most often. However, one report noted a preponderance in the left ankle.¹⁷
• Two-part triplane fractures occur more commonly and at a younger age than 3-part triplane fractures. This reflects the fact that relatively less closure of the tibial epiphysis exists in the 3-part group than in the 2-part group.
• Missed or incompletely diagnosed triplane fractures initially were evaluated with plain film radiography without further CT scan studies.
• Of the 8683 childhood and adolescent fractures evaluated by Landin over a 9-year study period, 4% (373) were ankle fractures.¹⁸
  • More than 50% of ankle injuries were sustained during a fall.
  • Right-sided injury predominated almost 2:1.
  • Seasonally, over the 9-year study period, peak incidence was in April and September, with the lowest frequency in July and December.
  • Males sustained more ankle fractures than did females. For males, the incidence for each of the 2-year age groups studied was highest for those aged 15-16 years. For females, incidence was highest for those aged 13-14 years.
  • During the study period, the incidence of ankle injuries progressively increased. This may reflect the increasing popularity of roller skates, skateboards, and scooters.
• Devalentine found upon review of 118 epiphyseal injuries in childhood that 25% involved the distal tibial or fibular epiphyses.¹⁹
• Mac Nealy studied 194 cases of injuries of the distal tibial epiphysis and reported that 9.8% were triplane fractures.²⁰
• The fibula is fractured in approximately 50% of triplane fractures.^16,21,22
• Although other associated injuries are uncommon, ipsilateral tibial shaft fractures²³ and a Maisonneuve fracture² associated with a triplane ankle fracture have been described.

Etiology

Triplane fracture is the result of several factors that exist simultaneously, including the following:

• A partially open distal lateral tibial growth plate, which creates a plane of weakness when a shearing force is applied. This condition is found most commonly during adolescence.
• External rotation (eversion) of the foot on the tibia (horizontal plane influence), which creates stress along the open distal lateral tibial growth plate, and is the essential force that initiates a triplane fracture.
• Exact fracture lines that are propagated further through the coronal and sagittal planes as a result of the foot being in plantar flexion (most common) and the varying forces of axial loading.

Pathophysiology

Triplane fracture of the distal tibia rarely occurs outside of adolescence. This is directly related to the pattern of distal tibial growth plate closure as skeletal maturity is attained (see Images 1-2).

Following medial closure, the lateral tibial growth plate closes progressively from the posteromedial area to the anterolateral area. The anteromedial tibial growth plate is the last area to close; therefore, it is more prone to injury than any other area of the tibial growth plate.

The entire process of distal tibial growth plate closure (physiologic epiphysiodesis) usually spans a period of 18 months. This process generally occurs when the individual is aged 12-15 years (mean age is 13.5 y), with complete closure occurring earlier in girls than in boys.

Regardless of the age of the patient, it is important to remember that variation (age range is 10-18 y) exists around the mean age of expected closure of the tibial growth plate. Any time the lateral distal tibial growth plate is open (unfused), the patient is susceptible to a triplane fracture.

In a 3-part triplane fracture, 3 fracture lines again are present in each of the 3 anatomic planes; however, the fracture line in the coronal plane is complete in its course through the epiphysis, as well as through the posterior metaphysis. The 3 fracture fragments produced are (1) a rectangular fragment of the anterolateral portion of the epiphysis, (2) the remainder of the epiphysis with an attached posterior spike of the distal tibial metaphysis, and (3) the tibial shaft with the anteromedial epiphysis (see Image 4).

The 4-part triplane fracture is similar to the 3-part fracture, with the exception that the fourth fragment consists of the medial malleolus. This is a result of the extension of the fracture forces projecting more medially in the horizontal plane.

Shin et al classified a subtyped of triplane fractures where the fracture extended into the medial malleolus. Using 3D-CT evaluation, they delineated the intramalleolar fracture patterns and demonstrated 3 distinct types of intramalleolar triplane fractures: (1) intra-articular and within the weight-bearing zone; (2) intra-articular and outside the weight-bearing zone; and (3) extra-articular.²⁴

A quadriplane fracture (ie, a typical triplane fracture plus a metaphyseal fragment) has been described. A combination of external rotation and vertical compression has been proposed as the mechanism of injury.²⁵

Kleiger and Mankin described an elevation or hump in the growth plate, about 1 cm from its medial edge, in 40% of adolescents between the ages of 12 and 20 years. They suggested that the medial hump might prevent displacement of the medial part of the epiphysis by a rotational force.²⁶ This was corroborated by Clement and Worlock, who suggested that the medial hump may stabilize the anteromedial part of the epiphysis in the same way as fusion of the medial part of the plate in older children.²⁷

Dias and Giegerich suggested that 2 grades of injury can result from a lateral or external rotation force applied to the distal tibia during the period of growth plate fusion. In a grade I injury, the anterior tibiofibular ligament avulses the anterolateral corner of the distal tibial epiphysis (the juvenile Tillaux fracture). The Tillaux fracture fragment in adults is virtually identical to the anterolateral epiphyseal fragment in a triplane fracture. If there is further lateral or external rotation, the remainder of the distal tibial epiphysis separates through the growth plate, taking with it an attached posteromedial metaphyseal fragment and producing a grade II 3-part triplane fracture.²⁸

Presentation

History

An accurate account recreating the action that led to the injury assists the practitioner in predicting the area of injury. In a triplane fracture of the ankle, nearly all cases involve an external rotation of the foot on the tibia, creating stress along the distal lateral open tibial growth plate. Other contributing forces that propagate the fracture lines are axial loading in combination with the foot being in plantar flexion (most common) and supination, abduction, or pronation.

Patients are more likely to be adolescent males with right-sided ankle injuries.

Inquire about other areas of injury or pain. The pain of a triplane fracture is sufficient to distract attention from other areas, even when a significant injury is present.

Document other chronic medical conditions (eg, prior injury or surgery; orthopedic hardware in the area of injury; diabetes; peripheral vascular disease; metabolic bone disease).

Determine current and recent medication use, including corticosteroids.

Physical

Patients with a triplane fracture of the ankle present with the following:

• Pain
• Swelling
• Possible ecchymosis
• Possible ankle deformity
• Inability to bear weight on the injured ankle

Observe all areas for evidence of open injury, including lacerations and abrasions. Ask the patient to demonstrate any ankle and toe motion that can be performed voluntarily without assistance.

Check for posterior tibial and dorsalis pedis pulses, and compare these with the pulses on the uninjured side. Note that up to 15% of the population has a congenital absence of the dorsalis pedis artery. Check for adequate distal capillary artery refill—that is, 2 seconds or less.

Check for distal sensation and evidence of compartment syndrome tingling, decreased sensation, swelling, pale skin, diminished pulses, and severe pain with passive movement of the toes.

Examine the knee, the leg, and the foot for tenderness, ecchymosis, and swelling. Radiographs of the knee, the leg, and the foot are needed if there are positive findings. Pay careful attention to the fibula, which must also be palpated and inspected along its entire length. Fibular fractures are commonly associated with triplane fractures. A fibular fracture likely to be missed upon initial evaluation is the Maisonneuve fracture of the proximal fibula, as reported by Healy.²³

Inspect and palpate other areas at high risk for fracture, such as the calcaneus and the proximal fifth metatarsal. Cup the calcaneus as if it were a tennis ball, and gently compress it. If pain is elicited, be highly suspicious of a calcaneal fracture.

Indications

Surgical fixation of a triplane fracture should be undertaken if the residual fracture gap is 2 mm or greater after attempted closed reduction and casting. A successful closed reduction can be predicted in displacements greater than 3 mm secondary to energy of the injury, soft-tissue interposition at the fracture site, and swelling.^16,29

Relevant Anatomy

The distal tibial physis contributes 50% of tibial growth and approximately 4-6 mm (0.25 in) of longitudinal growth per year.^30,31

Triplane fracture of the ankle involves the bony structures and their associated ligamentous supports as follows (see Image 2):
 

• The tibia is the main weightbearing bone of the lower leg.
• Tibial metaphysis consists of the distal quarter of the tibia, excluding the tibial growth plate and epiphysis.
• The distal tibial physis, also called the growth plate, is located between the tibial metaphysis and the epiphysis.
• The distal tibial epiphysis is bordered proximally by the physeal growth plate and distally by its articulation with the articular surface of the talar dome.
• The fibula is situated laterally along the length of the tibia in the lower leg, giving stability to the lateral ankle joint and serving in a non–weightbearing role.

The ankle joint bears more weight per unit surface area than any other joint in the body. The ankle joint is formed by the fibula (laterally), the tibia (superiorly and medially), and the dome of the talus (inferiorly). The joint is saddle shaped. The dome of the talus becomes wider anteriorly, such that when the foot is in dorsiflexion, the talus is situated more snugly in the tibiofibular saddle than when the foot is plantar flexed. Thus, plantar flexion (a position contributing to the triplane fracture) is a less stable position of the ankle than is dorsiflexion.

The only pure motions of the ankle joint are dorsiflexion and plantar flexion. Inversion and eversion of the ankle joint take place at the subtalar joint formed by the opposition of the talus and the inferiorly situated calcaneus. The talus always moves in the same direction as the calcaneus in normal gait.

Ankle injuries typically follow forces that are directed perpendicularly (inversion or eversion) to the normal motion of the ankle. That motion is perpendicular to the motions of dorsiflexion and plantar flexion that occur in the sagittal plane.

Ligamentous support of the ankle is extensive. Ligaments situated laterally consist of anterior and posterior talofibular and tibiofibular ligaments. The strong deltoid ligament is located medially and is the only ligament of the ankle containing elastic fibers.

The tibia and fibula are joined by the anterior and posterior talofibular ligaments distally and the interosseous membrane more proximally.

Knowledge of the anatomic planes of the body is essential to understanding the lines, planes, and fragments produced in a triplane fracture. In the anatomic position (ie, with the person standing, palms forward), these 2-dimensional planes are as follows:

• The horizontal plane passes horizontally through the body, dividing it into upper and lower segments.
• The coronal plane passes through the body from one shoulder to the other, dividing it into front and back segments.
• The sagittal plane passes through the body from front to back, dividing it into right and left segments.

Motions of the ankle and foot are described by a number of interchangeable terms, including the following:

• Eversion - External rotation
• Inversion - Internal rotation
• Dorsiflexion - Extension
• Plantar flexion - Flexion
• Abduction - Lateral deviation of the foot on a longitudinal axis through the tibia
• Adduction - Medial deviation of the foot on a longitudinal axis through the tibia
• Supination - Adduction and inversion
• Pronation - Abduction and eversion

Neurovascular structures in the area of the ankle and foot include the following:

• Medially, both the posterior tibial artery and tibial nerve pass deep to the flexor retinaculum spanning between the distal tibia and the calcaneus.
• Arterial pulses of the foot and ankle should be checked in any injury to the region and are readily palpable over the posterior tibial artery area medially and the dorsalis pedis artery on the dorsum of the foot between the bases of first and second metatarsals.

Contraindications

An absolute contraindication is the presence of infective lesions and cellulitis. In the presence of significant swelling and blisters, adequate wound closure may not be achieved; therefore, surgery is delayed until the swelling resolves, and measures to reduce the swelling, such as limb elevation and cryocompressive therapy, are initiated immediately.

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