Physeal Fractures of the Distal Tibia and Fibula (Salter

Transcription

TRAUMA SUPPLEMENT
Physeal Fractures of the Distal Tibia and Fibula
(Salter-Harris Type I, II, III, and IV Fractures)
David A. Podeszwa, MD* and Scott J. Mubarak, MDw
Abstract: Physeal fractures of the distal tibia and fibula are
common and can be seen at any age, although most are seen in
the adolescent. An understanding of the unique anatomy of the
skeletally immature ankle in relation to the mechanism of injury
will help one understand the injury patterns seen in this population. A thorough clinical exam is critical to the diagnosis and
treatment of these injuries and the avoidance of potentially
catastrophic complications. Nondisplaced physeal fractures of
the distal tibia and fibula can be safely treated nonoperatively.
Displaced fractures should undergo a gentle reduction with
appropriate anesthesia while multiple reduction attempts should
be avoided. Gapping of the physis >3 mm after reduction
should raise the suspicion of entrapped periosteum that will
increase the risk of premature physeal closure. Open reduction of displaced Salter-Harris type III and IV fractures is critical to maintain joint congruity and minimize the risk of physeal
arrest.
Key Words: physeal fractures, pediatric ankle fractures, physeal
arrest, Tilleaux fractures, triplane fractures
(J Pediatr Orthop 2012;32:S62–S68)
P
hyseal fractures about the ankle are the second most
common physeal fracture, with only the distal radius
being more common. Physeal fractures of the distal tibia
and fibula are more common in boys than in girls and
occur most frequently between 10 and 15 years of age.1
The unique anatomy of the skeletally immature ankle
(strong ligamentous attachments distal to the physis and
the horizontal orientation of the physis) make the ankle
susceptible to injuries that require operative intervention.
Thus, as a result of the injury and/or the intervention,
distal tibia and fibula physeal fractures are more likely to
have a subsequent premature physeal arrest as compared
with distal radius fractures.
From the *Department of Orthopaedic Surgery, Children’s Medical
Center Dallas and Texas Scottish Rite Hospital for Children, Dallas,
TX; and wRady’s Children’s Hospital, San Diego, CA.
None of the authors received financial support for this study.
The authors declare no conflict of interest.
Reprint: David A. Podeszwa, MD, Department of Orthopaedic Surgery,
Children’s Medical Center Dallas, 1935 Medical District Dr., E2300
Dallas, TX 75235. E-mail: [email protected].
Copyright r 2012 by Lippincott Williams & Wilkins
S62 | www.pedorthopaedics.com
CLINICAL EVALUATION
Ankle fractures typically are the result of a twisting
injury. The patient will typically complain of immediate
pain that is significantly worse with attempted weight
bearing and persists when nonweight bearing. Noting the
position of the foot and the deforming force at the time of
injury will help you to interpret the radiographic findings
and apply the classification scheme of Dias and Tachdjian.2
The physical exam of the injured ankle should include a thorough visual inspection and palpation around
the entire ankle. Identifying lacerations or evidence of an
open wound is paramount. If there is a delay in presentation from the time of injury, fracture blisters may be
present and may alter the treatment plan. Localized areas
of ecchymosis and swelling may be a clue to the injury.
Palpation of the distal tibia and fibula physes is critical as
Salter-Harris type I fractures may not be radiographically
evident and diagnosis will be purely on the basis of
physical exam. In the face of a distal fibula fracture with
no radiographic evidence of a medial malleolar fracture,
palpation of the medial soft tissues is the key to diagnosing ligamentous injury that may result in an unstable
ankle mortise.
Vascular exam should include palpation of the
dorsalis pedis and tibial arteries. If excessive swelling
impedes palpation of the pulses, Doppler exam of the
arteries should be performed. If a triphasic wave form is
not heard, vascular compromise should be considered.
Documenting normal capillary refill (< 2 s) is helpful but
may not rule out vascular compromise, as collateral circulation may allow the foot to remain viable in the face of
vascular injury. This combined with careful sensory and
motor exam of the nerves of the foot (superficial and deep
peroneal, tibial and sural) is necessary for early diagnosis
of neurovascular deficits.
Compartment syndrome of the leg or foot, although
uncommon, can be associated with physeal fractures of
the distal tibia and fibula. A high index of suspicion must
be maintained in the face of severe swelling, pain out of
proportion to the injury, and marked increased pain with
passive range of motion of the toes. The extensor retinaculum syndrome has been described in patients with
physeal fractures of the distal tibia.3 Anterior displacement of the distal tibia causes compression of the extensor
tendons and anterior neurovascular structures under the
superior extensor retinaculum (Fig. 1). These patients
present similarly to those with a classic compartment
J Pediatr Orthop
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Volume 32, Number 1 Supplement, June 2012
J Pediatr Orthop
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FIGURE 1. A, Anteroposterior and lateral ankle radiographs of a 9–year-old boy who sustained a Salter-Harris II distal tibia fracture
while skateboarding. B, Postoperative lateral radiograph after closed reduction and percutaneous pinning. Within 24 hours
postoperatively, he developed significant ankle pain, first web space numbness, and weakness with great-toe extension. Note
anterior physeal gapping. C, Intraoperative photo demonstrating the swollen, contused musculature trapped between the
anterior tibia and extensor retinaculum (solid arrow). D, After release of the extensor retinaculum, a large, entrapped flap of
periosteum was removed from the physis. E, Final postoperative radiograph demonstrating reduction of anterior gapping.
syndrome: severe pain and swelling of the ankle, hypoesthesia or anesthesia of the web space of the great toe,
weakness of the extensor hallucis longus and extensor
digitorum communis, and pain with pain passive range of
motion of the toes, particularly the great toe. Similar to
the release of the compartments of the leg or foot for a
compartment syndrome of the leg or foot, prompt release
extensor retinaculum is the definitive treatment.3
RADIOGRAPHIC EVALUATION
Initial radiographic examination should include
anteroposterior, lateral, and mortise views of the ankle.
The mortise should be carefully evaluated for symmetry
throughout the entire joint space. An external rotation
stress radiograph, helpful to rule out ankle joint instability, will demonstrate joint space asymmetry if there
is ligamentous instability. A computed tomography (CT)
scan of the ankle is indicated to confirm and delineate the
intra-articular displacement of an epiphyseal fracture.
The CT scan will frequently demonstrate additional
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2012 Lippincott Williams & Wilkins
fracture lines, comminution, and fracture step-off or
gapping previously unrecognized on the plain radiographs. The CT scan has been shown to be more sensitive
than plain radiographs in detecting distal tibial epiphyseal
fractures with >2 mm of displacement and is considered
to be the preferred imaging modality of the distal tibial
epiphyseal fractures.4
Accessory centers of ossification may be present at
the medial malleolus in up to 20% of cases as compared
with only about 1% at the distal fibula. Comparison radiographs of the contralateral ankle along with the clinical exam may be beneficial to identify true pathology
versus normal variants.
SALTER-HARRIS TYPE I AND II DISTAL
FIBULA FRACTURES
Salter-Harris type I and II distal fibula fractures are
the most common pediatric ankle fractures and are most
common between 10 and 12 years of age.5 Skeletally immature patients generally do not get isolated ankle
www.pedorthopaedics.com |
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Podeszwa and Mubarak
sprains. The ligaments around the ankle are far stronger
that the physis when placed under tension, resulting in
physeal failure before ligament rupture. These physeal
injuries are most commonly a supination-inversion injury
and will typically present with swelling and ecchymosis
around the lateral ankle. Always check for ecchymosis
medially and pain with palpation of the medial ligaments,
which may indicate a more severe injury pattern that may
result in an unstable ankle mortise and the need for fixation of the fibula.
A nondisplaced Salter-Harris type I injury may not
be evident on radiographs and thus will be a clinical diagnosis based on lateral swelling and tenderness directly
over the distal fibular physis. A thorough and systematic
review of the radiographs is critical as displaced SalterHarris type I and II fractures are frequently associated
with Salter-Harris type III and IV distal tibia fractures.
Nondisplaced distal fibular physeal fractures can
safely be treated in a walking cast or boot for 4 weeks
with activity modifications for 6 weeks total. Once the
cast is removed, a self-guided range of motion and
strengthening program is instituted until symmetric calf
strength has returned. Displaced fractures requiring reduction should be treated in a non–weight-bearing short
leg cast for 4 to 6 weeks followed by a self-guided range of
motion and strengthening program.
SALTER-HARRIS TYPE I DISTAL TIBIA
FRACTURES
Salter-Harris type I distal tibia fractures account for
about 15% of all pediatric distal tibiofibular fractures and
can occur with any mechanism of injury as described by
Dias and Tachdjian.2,5 There is an associated fibula
fracture in approximately 25% of cases, and the fibula
fracture may offer a clue to the mechanism of injury.
Nondisplaced fractures can be safely treated in a
short leg, non–weight-bearing cast for 4 to 6 weeks followed by a self-guided range of motion and strengthening
program. Displaced fractures should be gently reduced by
reversing the mechanism of injury and applying a long leg
cast for 4 weeks followed by walking boot for 2 to 4 weeks
while instituting a range of motion and strengthening
program. If open reduction is necessary or an acceptable
alignment cannot be maintained after closed reduction,
smooth wire cross pinning of the distal tibia should be
considered.
Although the exact amount of acceptable residual
fracture displacement is not universally agreed upon,
Barmada et al6 have demonstrated that 3 mm of residual
physeal gapping (in a patient with Z2 y of growth remaining) following a reduction of a Salter-Harris type I
or type II distal tibia fracture may be the result of entrapped periosteum. In their series, 60% of patients with a
residual gap of Z3 mm went on to a premature physeal
closure. All of the 5 patients who had residual gapping
and who underwent open reduction of the distal tibia had
entrapped periosteum blocking the reduction.6
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SALTER-HARRIS TYPE II DISTAL TIBIA
FRACTURES
This is the most common distal tibial physeal injury,
accounting for up to 40% of all pediatric ankle fractures
with the average age of the patient being 12.5 years.5 A
fibular shaft fracture is associated with 20% of these injuries. The most common mechanisms are supinationexternal rotation and supination-plantar flexion, but any
of the 4 mechanisms described by Dias and Tachdjian2
can cause this injury. The location of the metaphyseal
fragment may be helpful in determining the mechanism of
injury that will dictate the reduction technique (ie, a
posterior metaphyseal fragment indicates a supinationplantar flexion injury).
Nondisplaced fractures can be safely treated in a
long leg cast for 3 to 4 weeks and then changed to a short
leg walking cast or walking boot for an additional 2 to 3
weeks. Displaced fractures should undergo a gentle closed
reduction with long leg casting for 4 weeks followed by a
short leg walking cast or walking boot for 2 to 3 weeks. It
cannot be stressed enough that understanding the mechanism of injury is one of the keys to a successful closed
reduction. In addition, complete relaxation of the patient
during the reduction is paramount to a successful outcome. The choice of conscious sedation in the emergency
department or general anesthesia in the operating room
should be based on the surgeon’s judgment, taking into
account the patient’s age, type of fracture, and severity of
injury.7 Multiple attempts at closed reduction should be
avoided so as to reduce the risk of premature growth
arrest. Failure of a closed reduction should be followed
by open reduction. As seen with the Salter-Harris type I
fractures, a residual physeal gap of Z3 mm in a patient
with Z2 years of growth after a closed reduction may
indicate entrapped periosteum and increase the risk of a
premature physeal closure.6 Open reduction is indicated
for these fractures. Similarly, retrograde smooth wire
cross pinning of the distal tibia should be considered in
those patients undergoing open reduction.
SALTER-HARRIS TYPE III/IV DISTAL TIBIA
FRACTURES (INCLUDING TILLAUX, TRIPLANE,
AND MEDIAL MALLEOLUS FRACTURES)
Salter-Harris type III fractures account for about
20% of all distal tibia fractures, whereas Salter-Harris type
IV (medial malleolus) fractures only account for approximately 1% distal tibia fractures. Twenty-five percent of
Salter-Harris type III fractures are associated with fibular
fracture and occur at an average age of 11 to 12 years.5
Salter-Harris type III fractures are the result of a
supination-inversion injury. The inversion force causes a
lateral ligament stress frequently resulting in an avulsion
fracture of the fibula while the talus is driven into the
medial distal tibia. The fracture line is medial to midline
of epiphysis as compared with Tillaux or triplane fracture
where the fracture line is at the midline or lateral to it.
Similarly, a Salter-Harris type IV (medial malleolus)
fracture is also the result of a supination-inversion injury
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resulting in the talus being driven into the medial distal
tibia creating a fracture line that traverses the articular
surface, epiphysis, and metaphysis.
Nondisplaced fractures can be treated in a long leg,
non–weight-bearing cast for 4 weeks, followed by a boot
for 4 weeks. The initial 2 weeks of boot wear is nonweight
bearing, but the patient is allowed to remove the boot to
begin ankle range of motion exercises. Weekly evaluation
for the first 2 or 3 weeks is encouraged to confirm that the
fracture does not displace.
Any fracture with Z2 mm displacement should be
reduced to minimize the risk of premature physeal closure, prevent joint incongruity, and minimize the risk of
subsequent early degenerative arthritis.8 A Salter-Harris
type III (including Tillaux and triplane) fracture is typically approached through a 3 to 4-cm anterior incision
directly over the fracture. The fracture and joint line can
be directly visualized. Reduction can typically be achieved
indirectly with a large periarticular reduction clamp or
directly with a dental pick. Percutaneous transepiphyseal
fixation with 1 or 2 stainless steel cannulated screws can
then be easily performed. Removal of epiphyseal metallic
implants is recommended as the total force transmission,
and peak contact pressures are significantly increased
over baseline with the presence of the epiphyseal screws.9
Alternatively, bioabsorbable transepiphyseal screws have
been shown to be safe and equally effective while negating
the cost and potential risk of removal of the stainless steel
screws10 (Fig. 2).
A displaced Salter-Harris type IV (medial malleolus) fracture can be approached by an anterior or traditional medial malleolar approach. Transepiphyseal
fixation (stainless steel or bioabsorbable screws) is the
preferred fixation. Small or comminuted fractures may
necessitate a tension band construct (Fig. 3), and an unstable vertical shear fracture may necessitate a metaphyseal buttress plate. The tension band and buttress
plate will span the physis and should be removed once
healing of the fracture is confirmed. Postoperatively, the
patient is nonweight bearing for 6 weeks, initially with a
short leg cast for 4 weeks followed by a boot for 2 weeks.
Serial ankle radiographs should be performed every 6
months for a minimum of 2 years to monitor for a distal
tibial growth arrest.
FIGURE 2. A, Twelve-year-old girl twisted her ankle while running through mud. The mortise view of her ankle and computed
tomographic scan demonstrates a displaced Salter-Harris type III fracture (Tillaux fracture). B, Anteroposterior, mortise, and lateral
radiographs of the ankle s/p open reduction with a transphyseal bioabsrobable screw. Fracture is healed in an anatomic position.
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FIGURE 3. A, Nine-year-old girl sustained a comminuted open medial malleolus fracture and fibular shaft fracture. B, Status postORIF with tension band construct performed after appropriate irrigation and debridement. The bony fragments were too small for
screw fixation. The physis was spared by placing only smooth wires across the physis. C, Ten months status after injury. The
symmetric Park-Harris growth arrest line confirms the absence of a physeal bar.
PREMATURE PHYSEAL CLOSURE/GROWTH
ARREST
The incidence of premature physeal closure, partial
or complete, is the most common complication after a
distal tibial physeal injury and varies depending on the
fracture type (Salter-Harris type, I/II 2% to 39.6% and
Salter-Harris type III/IV, 7.7% to 50%).4,8,11–14 The arrest is caused by injury to the germinal layer of the physis,
creating vertical septa that allow open access for marrow
cell, osteoclast, and osteoblast infiltration from the epiphyseal or metaphyseal marrow spaces.15 General risk
factors include high-energy injuries, significant initial
displacement, mechanism of injury, and multiple attempts
at closed reduction.13,14
As mentioned in the discussion of Salter-Harris type
I and II fractures, a residual physeal gap of Z3 mm after
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FIGURE 4. A, 9+5-year-old female s/p pedestrian versus motor vehicle crash sustained a Salter-Harris II distal tibia fracture and
distal fibular shaft fracture. Attempt at closed reduction was performed but residual anterolateral gapping of the physis was
present. B, Status after open reduction and percutaneous pinning. Entrapped periosteum was removed from the fracture physis.
C, Fourteen months after injury, patient has distal tibial physeal arrest and varus deformity of the ankle. D, Radiographs after a
distal tibial opening wedge osteotomy with allograft and distal fibular epiphyseodesis. E, A 5 ½ year follow-up demonstrating
anatomic alignment and remodeling of the distal tibia. Clinically, the patient does not have a leg-length difference.
closed reduction is associated with high rate of premature
physeal closure resulting from entrapped periosteum.6
Gruber et al16 have demonstrated in an animal model that
the histologic process of bar formation secondary to entrapped periosteum is similar to bar formation without
entrapped periosteum. The physeal fracture is through
the hypertrophic zone and spares the germinal zone,
therefore anatomic reduction is not as critical. Recognition of the persistent gapping followed by open reduction and removal of the entrapped periosteum is the
primary method of preventing premature closure in these
types of fractures. Closed cast treatment is a significant
risk factor for the development of a growth arrest in
Salter-Harris type III and IV fractures in younger patients.8 Anatomic reduction of the physis, in particular
the germinal layer, is the critical step in preventing premature closure in these fractures. Salter-Harris type III
fractures in teenagers (Tillaux and triplane fractures) are
much less like to cause a significant growth abnormality
given the relative lack of remaining growth.
A physeal arrest can appear as long as 2 years
postoperative; therefore, extended follow-up is important.
If an arrest is suspected, the plain radiographs may show
a bony bar. Asymmetric Park-Harris growth arrest lines
may be visible. Comparison with the contralateral ankle
may also be helpful. CT or magnetic resonance imaging
(MRI) can be used to evaluate the extent of a bony bar,
but all metallic implants should first be removed.
Treatment options are defined by the location and
size of the bar and the amount of growth remaining. Bar
resection can be considered if there is >2 years growth
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remaining and <50% of the width of physis is involved.
If the patient has <2 years growth remaining or >50%
of the width of physis is involved, one should consider
completing the epiphyseodesis with or without contralateral epiphyseodesis. An opening wedge corrective osteotomy (Fig. 4) at the time of epiphyseodesis should be
considered if significant varus deformity is present.7
SUMMARY
! Knowledge of the mechanism of injury combined with
a thorough clinical exam will aid in the interpretation
of the radiographs and instituting a plan of care.
! Significant displacement (> 3 mm) after a closed
reduction attempt for Salter-Harris type II fractures
and any displacement of Salter-Harris type III and IV
fractures (Tillaux, triplane, medial malleolus) >2 mm
is an indication for open reduction to minimize risk of
physeal arrest.
! General risk factors for premature physeal closure
include high-energy injuries, significant initial displacement, mechanism of injury, and multiple attempts at
closed reduction.
REFERENCES
1. Peterson CA, Peterson HA. Analysis of the incidence of injuries to
the epiphyseal growth plate. J Trauma. 1972;12:275–281.
2. Dias LS, Tachdjian MO. Physeal injuries of the ankle in children:
classification. Clin Orthop Relat Res. 1978;136:230–233.
3. Mubarak SJ. Extensor retinaculum syndrome of the ankle
after injury to the distal tibial physis. J Bone Joint Surg Br. 2002;84:
11–14.
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4. Horn BD, Crisci K, Krug M, et al. Radiologic evaluation of juvenile
tillaux fractures of the distal tibia. J Pediatr Orthop. 2001;21:162–164.
5. Spiegel PG, Cooperman DR, Laros GS. Epiphyseal fractures of the
distal ends of the tibia and fibula. A retrospective study of two
hundred and thirty-seven cases in children. J Bone Joint Surg Am.
1978;60:1046–1050.
6. Barmada A, Gaynor T, Mubarak SJ. Premature physeal closure
following distal tibia physeal fractures: a new radiographic
predictor. J Pediatr Orthop. 2003;23:733–739.
7. Herring JA. In: Herring JA, ed. Tachdjian’s Pediatric Orthopaedics,
from the Texas Scottish Rite Hospital for Children. 4th Edition.
Philadelphia: W.B. Saunders; 2008.
8. Kling TF Jr, Bright RW, Hensinger RN. Distal tibial physeal
fractures in children that may require open reduction. J Bone Joint
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9. Charlton M, Costello R, Mooney JF III, et al. Ankle joint
biomechanics following transepiphyseal screw fixation of the
distal tibia. J Pediatr Orthop. 2005;25:635–640.
10. Podeszwa DA, Wilson PL, Holland AR, et al. Comparison of
bioabsorbable versus metallic implant fixation for physeal and
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epiphyseal fractures of the distal tibia. J Pediatr Orthop.
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Cass JR, Peterson HA. Salter-Harris type-IV injuries of the distal
tibial epiphyseal growth plate, with emphasis on those involving the
medial malleolus. J Bone Joint Surg Am. 1983;65:1059–1070.
Langenskiold A. Traumatic premature closure of the distal tibial
epiphyseal plate. Acta Orthop Scand. 1967;38:520–531.
Leary JT, Handling M, Talerico M, et al. Physeal fractures of the
distal tibia: predictive factors of premature physeal closure and
growth arrest. J Pediatr Orthop. 2009;29:356–361.
Rohmiller MT, Gaynor TP, Pawelek J, et al. Salter-Harris I and
II fractures of the distal tibia: does mechanism of injury
relate to premature physeal closure? J Pediatr Orthop. 2006;26:
322–328.
Wattenbarger JM, Gruber HE, Phieffer LS. Physeal fractures, part
I: histologic features of bone, cartilage, and bar formation in a small
animal model. J Pediatr Orthop. 2002;22:703–709.
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Physeal Fractures of the Distal Tibia and Fibula (Salter

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