Ross A. Benthien, MD, MPH*wz
Summary: The large posterior malleolus fragment seen in many
unstable trimalleolar ankle fractures can be safely and effectively
approached through the posterolateral approach to the ankle. This
approach allows for thorough debridement of the fracture and ankle
joint and anatomic reduction of the posterior malleolus with secure
plate fixation on the posterior tibia. This approach also allows for
reduction and posterior fixation of the related fibula fracture and in
combination with reduction of the posterior malleolus, may reduce and
secure the distal tibiofibular syndesmosis without the need for transosseous
fixation of the syndesmosis. With prone positioning, fixation
of a related medial malleolus fracture and intraoperative imaging is
Key Words: posterior malleolus—posterolateral approach—trimalleolar
(Tech Orthop 2014;29: 8–12)
Displaced trimalleolar ankle fractures often represent a
complex injury that results in malalignment of the tibiotalar
joint, disruption of the weight-bearing portion of the tibial
plafond, and possible disruption of the distal tibiofibular syndesmosis.
Not surprisingly these injuries have poorer outcomes
than more straightforward ankle fractures and the source of this
increased disability is very likely multifactorial.1 Although the
tendency toward worse outcomes may be the result of factors
such as higher-energy injuries or osteopenia, the lack of a
comprehensive approach to address all components of these
injuries may also play a significant role.
The posterior malleolus historically has been treated as an
afterthought in the surgical management of ankle fractures, and
no consensus currently exists on when fixation should be
pursued.2 Anatomic reduction and rigid fixation of medial and
lateral malleolus fractures have routinely been the key components
of surgical strategy, with posterior malleolus fractures
comprising up to 25% of the anterior-posterior dimension of
the distal tibia often left untreated. Some reports have supported
this “benign neglect” of the posterior malleolus based
upon clinical observation, despite the fact that biomechanical
evaluations have clearly shown that tibiotalar joint contact area
decreases along with the size of the posterior fracture fragment.
3–5 Others have demonstrated in biomechanical studies
that the posterior malleolus is not a primary restraint to posterior
subluxation of the talus but they did not assess the
impact on joint contact area. None of these investigations
assessed joint contact pressures or syndesmotic alignment.6,7
All but the smallest fractures of the posterior malleolus
represent intra-articular fractures of the ankle, a major weightbearing
joint of the lower extremity. These fractures can be
highly variable, involving the medial malleolus in up to 20% of
cases and computed tomography scans can be helpful in
defining the fracture anatomy.8 In addition, the posterior
malleolus acts as the origin of the posterior ankle joint capsule
and attachment of the posterior-inferior tibiofibular ligament
(PITFL), a key stabilizer of the distal tibiofibular syndesmosis.
Open reduction and rigid internal fixation of the posterior
malleolus fracture fragment holds the promise of restoring
tibiotalar contact area, facilitating anatomic alignment of the
syndesmosis and prevention of posterior capsular contracture
and the resultant loss of ankle dorsiflexion.
Recent clinical and biomechanical studies have demonstrated
that the standard method of syndesmotic fixation, with
clamp reduction and transosseous syndesmotic screws, may
lead to subluxation of the fibula or overcompression of the
syndesmosis, and this raises the possibility of degenerative
changes and persistent postinjury impairment.9–11 Gardner
et al12 demonstrated by magnetic resonance imaging an intact
PITFL in all 15 patients with pronation-external rotation type
ankle fractures and in a related biomechanical model of this
injury type, showed that repair of the posterior malleolus
fracture resulted in greater stiffness of the syndesmosis than
traditional screw fixation. Direct fixation of the posterior
malleolus holds the promise of reducing the need for syndesmotic
fixation, the potential for malreduction, and subsequent
surgery for syndesmotic screw removal.
Most commonly, the posterior malleolus is addressed
after fixation of the medial and lateral injuries and often with
the patient positioned supine. Although alignment of the posterior
malleolus is routinely improved with reduction of the
fibula, because of the intact PITFL, in many cases gaps and
step-off of the joint surface often persists, likely because of the
result of interposed fracture debris or imperfect reduction of
the fibula. An alternative approach to the treatment of trimalleolar
ankle fractures is anatomic reduction of the posterior
malleolus as the first step in repair of the unstable ankle, which
arguably addresses the most important intra-articular portion of
the fracture and through attachments of the PITFL, also helps
to reestablish the length and rotation of the distal fibula.
The use of the posterolateral approach for displaced ankle
fractures has been well described in the literature, and although
the results have been comparable to those of operative ankle
fractures in general, the number of patients has been limited, as
have the follow-up and outcomes.13–16
Surgery is routinely performed on an ambulatory basis, in
the prone position, under tourniquet control, with general
From the *Orthopedic Associates of Hartford; wBone and Joint Institute
at Hartford Hospital; and zDepartment of Orthopaedic Surgery, University
of Connecticut School of Medicine, Hartford, CT.
The authors declare that they have nothing to disclose.
Address correspondence and reprint requests to Ross A. Benthien, MD,
MPH, 85 Seymour Street, Suite 607, Hartford, CT 06106.
Copyright r 2014 by Lippincott Williams & Wilkins
INVITED REVIEW ARTICLE
8 | www.techortho.com Techniques in Orthopaedics$ _ Volume 29, Number 1, 2014
anesthesia and popliteal and saphenous nerve blocks. Prone
positioning provides a number of advantages including: easy
access to all fracture components with minimal manipulation
of the limb, the decreased need for surgical assistants, ease of
soft-tissue retraction, and improved surgeon comfort. In addition,
prone positioning with a bump under the leg facilitates
reduction of the posteriorly displaced fibula and posterior
malleolus fracture fragments through gravity and direct
downward pressure on the posterior malleolus during reduction.
If medial fixation is required it can be helpful to place a
bump under the contralateral hip to allow for better visualization,
and flexing the knee intraoperatively can also be
helpful by elevating the medial malleolus above the table and
the nonoperative limb. Both prone and lateral decubitus positioning
have been advocated for the posterolateral approach to
Minifluoroscopy is utilized during surgery and with
experience, posteroanterior, mortise, and lateral views can
easily be obtained. Placing the ankle on a bump during surgery
allows for easier lateral imaging by raising the operative leg
above the contralateral limb. Stress radiographs are routinely
obtained to check for stability of the tibiotalar joint and the
A longitudinal incision is made midway between the posterior
border of the fibula and the lateral border of the Achilles
tendon (Fig. 1A). The incision is carried no more distal than the
tip of the fibula and the sural nerve is rarely visualized, although
care should be taken to prevent nerve injury as anatomy can
be variable. The fascia overlying both the peroneal and flexor
hallucis longus muscle bellies is divided separately and allows
for muscle mobilization.
The flexor hallucis longus in retracted medially with a
Homan retractor placed over the medial border of the tibia.
The periosteum of the posterior malleolus is elevated to allow
for mobilization of the posterior malleolus. Care must be taken
to leave the attachments of the PITFL on the fibula and posterior
malleolus undisturbed. With a smooth lamina spreader,
even in osteopenic bone, the malleolus is distracted and the
articular surface of the talus is visualized (Fig. 1B). Fracture
debris is often removed from the joint with a pituitary rongeur
and the tibial joint surface can be reduced if local impaction
has occurred. The posterior malleolus is then reduced and
secured with K-wires and then rigidly fixed, typically with a
combination of partially threaded cannulated screws and a one
third tubular buttress plate (Fig. 1C).
The fibula fracture is approached through the same incision
after secure fixation of the posterior malleolus. Simple
fracture patterns are opened and reduced in the typical manner
and then secured with interfragmentary fixation and a neutralization
plate placed either posterior or lateral. A posterior
plate is often applied to the fibula, especially for more proximal
fractures and for comminuted fractures wherein a bridgeplating
technique is being utilized (Fig. 1D). Attention must be
paid to the peroneal tendons, making sure that fixation devices
are not prominent distally and that the retinaculum is intact
distal to the tip of the fibula to prevent peroneal tendon
Medial fixation is based upon the fracture pattern and
may require typical open interfragmentary fixation, percutaneous
cannulated screws, or buttress plates for vertical sheartype
fractures. Medial fractures are approached through a
separate medial longitudinal incision. Purely ligamentous
medial injuries are not routinely repaired. Wounds are closed
in layers and a bulky Jones type dressing is applied in the
prone position with neutral ankle dorsiflexion.
Patients are followed up back in the office at 2 weeks,
radiographs are obtained, a CAM boot is supplied, and active
FIGURE 1. A, Patient is positioned prone and posterolateral incision is marked equidistant between the posterior border of the fibula
and the lateral border of the Achilles tendon. B, Flexor hallucis longus reflected medially with smooth lamina spreader in the posterior
malleolus fracture site. C, Posterior plating of the fibula with the peroneal muscles retracted laterally. D, One third tubular plate on the
posterior tibia securing the malleolus fracture.
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range of motion is initiated. Typically, at 6 weeks from surgery,
weight-bearing radiographs are performed and weightbearing
and formal physical therapy is initiated. In most cases
patients are maintained on aspirin for 4 to 6 weeks for DVT
Closed, unstable trimalleolar ankle fracture was sustained by a
42-year-old, diabetic, motorcycle racer. The fracture was reduced and
splinted at an outside hospital (Figs. 2A, B). The large, comminuted
posterior malleolus fracture was particularly amenable to direct
reduction and posterior plating, and the fibula was also reduced and
secured through the same incision. Intraoperative stress maneuvers
showed the syndesmosis to be stable. A medial buttress plate secured
the vertical shear-type medial malleolus fracture through a medial,
longitudinal incision (Figs. 2C, D). Partial weight-bearing was initiated
at 6 weeks in a CAM walker and full weight-bearing with an ankle
brace was allowed at 9 weeks. Final follow-up was at 7 months with
healed fractures, anatomic alignment, and full range of motion.
Closed, unstable trimalleolar ankle fracture was sustained in a
work-related slip and fall injury by a 38-year-old diabetic patient with
a body mass index of 42. The comminuted posterior malleolus fracture
included an interposed fragment that would have likely prevented
anatomic alignment and the posterolateral approach was chosen as it
allows for more thorough joint debridement and secure fixation of large
fracture fragments (Figs. 3A, B). Intraoperative imaging demonstrated
anatomic alignment of the ankle mortise and a stable syndesmosis.
Weight-bearing was permitted at 5 weeks in a CAM walker with
weaning to an ankle brace with physical therapy. The small medial
malleolus fracture fragment was not directly addressed at the initial
surgery, but persistent pain in this area ultimately resulted in ankle
arthroscopy, fragment excision, and deltoid ligament repair. At 18
months, range of motion was full, no degenerative changes were evident,
and the patient had no work restrictions.
Closed, unstable ankle fracture was observed in a 52-year-old as
a result of a slip and fall on a wet subway platform. The fracture was
reduced and splinted at an outside hospital. Radiographs revealed a
nearly 50% posterior malleolus fracture with local comminution. The
medial injury was deltoid ligament rupture (Figs. 4A, B). The posterior
malleolus was addressed with a cannulated screw and buttress plate
and the comminuted fibula fracture with bridge plating. Intraoperative
imaging confirmed a stable syndesmosis. Weight-bearing was initiated
at 6 weeks in a CAM walker with weaning to an ankle brace with
physical therapy. At 4 months the patient was brace-free with nearly
full range of motion, and radiographs showed anatomic alignment of
the ankle (Figs. 4C, D).
The posterolateral approach is most helpful in those trimalleolar
fractures that include a large posterior malleolus
fracture, generally 20% to 50% of the distal tibia, and an
associated fibula fracture. This approach allows for direct
inspection of the injury, direct assessment of reduction quality,
and application of robust fixation constructs.
For the author this approach resulted in few superficial
wound complications and no cases of sural neuropathy or
complex regional pain syndrome was reported. Fixation
hardware on the posterior tibia is deep and to this point
removal has not been necessary. Similarly, fixation hardware
on the posterior fibula is less prominent than typically noted
with lateral placement and to this point has not been a problem.
Others have reported the need for removal of symptomatic
hardware and sural nerve-related pain and neuropathy at rates
similar to other approaches to ankle fractures.13–16
FIGURE 2. A and B, Anteroposterior and lateral radiographs of a pronation-external rotation type ankle fracture with a posterior
malleolus fracture estimated at 50% of the anterior-posterior depth of the distal tibia. Although somewhat obscured by overlying cast
material, the posterior malleolus is comminuted. C and D, At 7 months’ follow-up, the joint surfaces are in anatomic alignment, all
fractures are healed, and degenerative changes are not evident.
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A significant potential advantage of this approach to
unstable trimalleolar ankle fractures is reduction and stabilization
of the syndesmosis through rigid fixation of the posterior
and lateral malleolus. Traditional syndesmotic fixation has
come under increasing scrutiny as a potential source of malreduction
and degenerative changes within the distal tibiofibular
articulation. The PITFL is consistently intact in these
fracture patterns, and anatomic, secure reduction of these
fractures should limit the need for transosseous fixation of the
syndesmosis. It has been the author’s experience that with
stable fracture fixation, syndesmotic fixation has been unnecessary.
It is of course possible to have an unstable syndesmosis
even after rigid fracture fixation and this should
always be evaluated with intraoperative stress maneuvers.
Intraoperative observation generally shows the posterior
periosteum to be intact and with division and elevation, the joint
FIGURE 3. A and B, Initial radiographs showing a trimalleolar ankle fracture with comminution of the fibula, interposed fracture
fragments at the posterior fracture site, and a small medial malleolar avulsion fracture. C and D, Final follow-up radiographs demonstrating
anatomic alignment of the ankle mortise and well-healed fractures. Note that the suture anchor is placed medially after excision
of a symptomatic medial malleolus avulsion fracture.
FIGURE 4. A and B, Initial radiographs showing comminuted posterior malleolus and fibula fractures with posterolateral subluxation of
the talus. C and D, Anatomic reduction is achieved with a cannulated screw and buttress plate on the posterior malleolus and posterior
plating of the fibula has reestablished length and rotation.
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can be visualized in all cases. This allows for thorough joint
debridement and irrigation, which holds the possibility of less
postsurgical cartilage damage and more precise fracture reduction.
Cortical fracture lines and intraoperative imaging allows for
anatomic or near-anatomic reduction of all fractures. Anatomic
alignment and rigid fixation has always been the “gold-standard”
for the operative treatment of intra-articular fractures as this is felt
to reestablish normal joint mechanics and load distribution.
Lindsjo1 showed that up to one third of patients with posterior
malleolus fractures large enough to violate the weight-bearing
portion of the tibial plafond developed posttraumatic arthrosis,
twice the rate seen with small extra-articular fractures. This certainly
suggests that anatomic reduction may decrease the rate of
arthrosis and potentially patient outcomes.
The posterolateral approach toward unstable trimalleolar
may offer a number of potential advantages, including
improved joint debridement, improved reduction of the
weight-bearing portion of the distal tibia, and possibly secure,
anatomic fixation of the syndesmosis, minimizing the need for
more traditional fixation methods. Complications are few,
comparable to those seen in ankle fractures more generally.
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- Forberger J, Sanandal PV, Dietrich M, et al. Posterolateral approach to
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- Franzone JM, Vosseller JT. Posterolateral approach for open reduction
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Benthien Techniques in Orthopaedics$ _ Volume 29, Number 1, 2014
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