Posterior malleolar fractures of the ankle

Abstract

Despite an increasing awareness of injuries to PM in ankle fracture-dislocations, there are still many open questions. The mere presence of a posterior fragment leads to significantly poorer outcomes. Adequate diagnosis, classification and treatment require preoperative CT examination, preferably with 3D reconstructions. The indication for surgical treatment is made individually on the basis of comprehensive assessment of the three-dimensional outline of the PM fracture and all associated injuries to the ankle including syndesmotic instability. Anatomic fixation of the avulsed posterior tibiofibular ligament will contribute to syndesmotic stability and restore the integrity of the incisura tibiae thus facilitating anatomic reduction of the distal fibula. A necessary prerequisite is mastering of posterolateral and posteromedial approaches and the technique of direct reduction and internal fixation. Further clinical studies with higher numbers of patients treated by similar methods and evaluation of pre- and postoperative CT scans will be necessary to determine reliable prognostic factors associated with certain types of PM fractures and associated injuries to the ankle.

Full text

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DOI 10.1007/s00068-015-0560-6
Eur J Trauma Emerg Surg (2015) 41:587–600
REVIEW ARTICLE
Posterior malleolar fractures of the ankle
J. Bartonícˇek
1,2
· S. Rammelt
3
· M. Tucˇek
1
· O. Nanˇka
2
Received: 29 April 2015 / Accepted: 31 July 2015 / Published online: 8 August 2015
© Springer-Verlag Berlin Heidelberg 2015
Keywords Ankle fractures · Trimalleolar fractures ·
Posterior malleolus · Classification of posterior malleolar
fractures
Introduction
A fracture of the posterior rim of the distal tibia occurs in
about 46 % of type Weber B or C ankle fracture-disloca-
tions [38]. These fractures are often referred to as posterior
malleolar fractures and have been the subject of continu-
ing interest for a long time as one of the most controver-
sial issues of the treatment of ankle injuries [7–9, 14, 17,
20–24, 26–33, 35–37, 39, 41, 42, 50, 51, 53, 61–65, 68–70,
72, 74–80]. Despite a number of available studies, no con-
sensus has been reached, yet, as to how to classify and treat
these injuries. The aim of this article is to review the cur-
rent concepts in this field.
History
The first to describe a fracture of the posterior rim of the
distal tibia in an ankle fracture-dislocation was probably
Henry Earle [18] in 1828. In the German literature, this
fragment is commonly referred to as “Volkmannsches
Dreieck” (Volkmann’s triangle) [6, 19, 30, 32, 43, 49, 54–
56, 64, 65, 71]. However, Volkmann, in 1875, presented an
avulsion of the anterolateral part of the distal tibia in the
sagittal plane [73]. One of the first to use the term “Volk-
mannsches Dreieck” was Karl Ludloff [49] in 1926 and
later Fritz Felsenreich [19] in 1931.
The fragment of the posterior rim of the tibia was dealt
with in great detail, including radiology, by Étienne Destot
Abstract Despite an increasing awareness of injuries to
PM in ankle fracture-dislocations, there are still many open
questions. The mere presence of a posterior fragment leads
to significantly poorer outcomes. Adequate diagnosis, clas-
sification and treatment require preoperative CT examina-
tion, preferably with 3D reconstructions. The indication
for surgical treatment is made individually on the basis of
comprehensive assessment of the three-dimensional out-
line of the PM fracture and all associated injuries to the
ankle including syndesmotic instability. Anatomic fixation
of the avulsed posterior tibiofibular ligament will contrib-
ute to syndesmotic stability and restore the integrity of the
incisura tibiae thus facilitating anatomic reduction of the
distal fibula. A necessary prerequisite is mastering of pos-
terolateral and posteromedial approaches and the technique
of direct reduction and internal fixation. Further clinical
studies with higher numbers of patients treated by similar
methods and evaluation of pre- and postoperative CT scans
will be necessary to determine reliable prognostic factors
associated with certain types of PM fractures and associ-
ated injuries to the ankle.
* J. Bartonícˇek
bartonicek.jan@seznam.cz
S. Rammelt
stefan.rammelt@uniklinikum-dresden.de
1
Department of Orthopaedics, First Faculty of Medicine,
Charles University and Central Military Hospital Prague, U
Vojenské nemocnice 1200, 169 02 Prague 6, Czech Republic
2
Department of Anatomy, First Faculty of Medicine, Charles
University Prague, U nemocnice 3, 120 00 Prague 2, Czech
Republic
3
University Center of Orthopaedics and Traumatology,
University Hospital Carl Gustav Carus Dresden, Dresden,
Germany

588 J. Bartoníček et al.
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[16] who as the first used the term “malléole postérieure”
(posterior malleolus) in his book of 1911.
In 1915, Frederick Jay Cotton [12] believed that he dis-
covered a “new type” of ankle fracture, with which he was
later eponymised. It was a bimalleolar fracture in combina-
tion with a fracture of the posterior rim of the distal tibia.
However, the first to describe this type of fracture was Rob-
ert Adams [1] in 1836. Later, in 1932, Melvin Henderson
[34] introduced the term “trimalleolar fracture” to specify
this type of injury.
In 1922, Lounsbury and Metz [48] presumably reported
on the first internal fixation of the posterior rim of the tibia
from a posteromedial approach with a bone peg. In 1925,
Leveuf [46] described reduction of the avulsed posterior
malleolus from the posterior Delbet transachillary approach
and posterior-to-anterior screw fixation, with a simultane-
ous screw fixation of the distal fibula.
In 1940, Nelson and Jensen [57] classified fractures of
the posterior rim of the distal tibia as classical, affecting
more than one-third of the articular surface, and minimal,
involving less than one-third. They recommended screw
fixation from a posteromedial approach for classical frag-
ment thus introduced the “one-third rule” used by many
surgeons until today [33].
Anatomy
The distal tibia ending in a horizontal articular surface,
commonly referred to as the tibial pilon, serves to trans-
mit compression forces [5, 7]. The term “pilon” was intro-
duced by the French radiologist Destot and is commonly
believed to refer to a pharmacist’s pestle, but the French
term synonymously depicts a wooden leg [15]. The medial
malleolus is not part of the pilon, it controls movement and
position of the talus without being directly involved in load
transfer. The posterior articular rim of the distal tibia called
the posterior malleolus (PM) projects more distally than
its anterior counterpart). Therefore, the articular surface of
the pilon appears concave in the sagittal plane as shown by
the lateral radiograph of the ankle. The articular cartilage is
1–2 mm thick.
The posterior view shows that the lateral half of PM is
formed by a marked bony prominence, the posterior tuber-
cle of tibia. At the same time, this tubercle forms the poste-
rior part of the notch for the distal fibula (incisura fibularis
tibiae). The medial part of PM is separated from the pos-
terior colliculus of the medial malleolus by the malleolar
groove for the posterior tibial tendon.
The posterior surface of the distal tibia serves as the ori-
gin of the strong and compact posterior tibiofibular liga-
ment. It has a trapezoid shape with its superior, obliquely
oriented fibers originating from the posterior tubercle. Its
inferior, more horizontally oriented fibers originate from
the rim of the articular surface of the distal tibia, medial
to the superior fibers. The superior and inferior borders
of the ligament converge towards the fibula, where at the
circumference of the lateral malleolar fossa they form two
branches inserting at its edge [4, 5] (Fig. 1).
The variable intermalleolar ligament, which is a rein-
forced strip of the joint capsule, inserts into the angle
included by the medial part of PM and the posterior col-
liculus of the medial malleolus.
Biomechanics
Given the above-mentioned anatomical facts, the PM
should significantly contribute to stability and load trans-
fer at the ankle. It appears logical that avulsion of PM with
part of the articular surface of the distal tibia would affect
load transfer in the tibiotalar joint as well as stability of the
tibiofibular syndesmosis. The results of the few available
biomechanical studies are, however, not in line with these
biomechanical assumptions.
In a cadaver experiment, Harper et al. [28] found out
that resection of up to 50 % of the posterior articular sur-
face of the distal tibia had no effect on ankle stability. Simi-
lar observations were also made by other authors [62]. In
another experiment on cadaver specimens, Hartford et al.
[29] revealed that reduction of the articular surface by 25,
Fig. 1 Anatomy of posterior malleolus. Right ankle—posterior
aspect. 1 Posterior tubercle of distal tibia, 2 malleolar groove, 3 pos-
terior talofibular ligament, 4 distal fibula, 5 calcaneofibular ligament,
6 deltoid ligament, 7 posterior tibiofibular ligament

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Posterior malleolar fractures of the ankle
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33 and 50 % resulted in a progressive reduction of the tibi-
otalar contact area by 4, 13 and 22 %, respectively. Simi-
lar results were published by Macko et al. [50]. Fitzpatrick
et al. [21] simulated PM fractures in a cadaver model and
found out that a fragment carrying 50 % of the articular
surface got displaced anteriorly in the region of maximum
load, if there was a 2-mm step-off or gap. Interestingly,
anatomic restoration of joint congruity did not lead to com-
plete normalization of the pressure distribution. On the
other hand, Vrahas et al. [74], on the basis of their cadav-
eric study, came to the conclusion that removal of the PM
did not lead to significant changes in tibiotalar peak contact
stresses. Papachristou et al. [61] demonstrated that with a
normal range of motion, the posterior quarter of the articu-
lar surface of the distal tibia bears almost no load. Gardner
et al. [23] found that in pronation-external rotation stage 4
fractures on cadaveric specimens stability of the tibiofibu-
lar syndesmosis was restored better by fixation of the pos-
terior fragment than by standard stabilization of the tibi-
ofibular syndesmosis with a suprasyndesmal screw. All in
all, the available biomechanical studies do not provide clear
guidelines for clinical management of PM fractures proba-
bly because they cannot fully reflect the conditions in vivo.
Diagnosis
The basic radiographic examination of the injured ankle
includes true anteroposterior, mortise (ap with 15° inter-
nal rotation), and lateral views (Fig. 2). In fracture-dislo-
cations, small PM fragments are sometimes detected on
postreduction radiographs. While PM fractures are obvious
in the lateral radiograph, in the ap projection they may be
detected indirectly by the so-called flake fragment sign or
spur sign: a double contour of the medial malleolus if the
PM fracture involves the medial malleolus [35]). An atypi-
cal (vertical) course of the typically horizontal or slightly
oblique medial malleolus fracture in type Danis–Weber B
and C fractures may also be indicative of a PM fracture.
There is consensus that the true size and geometry of the
fragment, specifically its medial propagation, and interca-
lary fragments may be diagnosed only by CT scanning [9,
11, 20, 51, 64, 65, 79]. CT scans taken in the transverse
and sagittal planes should be combined with 3D CT recon-
struction in order to get an accurate anatomical picture [9].
Highly instructive in this respect is a 3D view of the distal
aspect from below with subtraction of the talus. This view
allows to digitally measure the size of the articular surface
of the avulsed PM. MRI may yield additional information
about syndesmotic ligaments, tendons and osteochondral
lesions, although it is used only exceptionally [24].
Classification
The first attempts at classification of fractures of the pos-
terior rim of the distal tibia appeared soon after the discov-
ery of X-rays [13]. In 1913, Grondahl [25] divided these
fractures into three groups, namely into “proper fractures
of posterior lip, fractures of posterolateral corner of dis-
tal tibia, and fractures consisting of cortical avulsion from
the dorsal surface of the tibia”. In the same year, Soulig-
oux [67] also distinguished between three types of injuries
to the posterior rim. The first group included avulsion of
the “posterior tubercle” only, with the rest of the posterior
rim left intact. The second group comprised avulsion of
the entire posterior rim (lip), in the form of “a thin bone
lamella”. The third group included an avulsion of the entire
posterior rim, namely as a “conical fragment on a wider
base carrying a piece of articular surface of varying size”.
Fig. 2 Radiology of the ankle.
a Anteroposterior view, see
double contour of the medial
malleolus (flake fragment sign
or spur sign); b mortise view;
c—lateral view

590 J. Bartoníček et al.
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In 1922, Ashhurst and Bromer [3] classified the avulsed
posterior fragment in terms of its size as “small, medium
and large”. In 1940, Nelson and Jensen [57] divided frac-
ture of the posterior rim into classic fractures involving
more than one-third of the articular surface and minimal
fractures involving less than one-third. In the classic type
the authors recommended screw fixation from the postero-
medial approach.
The AO classification of 1987 [56] distinguishes
between three types of PM fractures:
1. extra-articular fracture,
2. small fragment of the articular surface,
3. large fragment of the articular surface.
In 1989, Urs Heim [31] further specified the AO classi-
fication on the basis of analysis of 154 cases and presented
five types of PM fractures, of which two extra-articular and
three intra-articular:
(a) extra-articular avulsion of the posterior tubercle of tibia
with the origin of the posterior tibiofibular ligament,
(b) longitudinal narrow fragment of the posterior rim
avulsed together with the insertion of the articular cap-
sule,
(c) large intra-articular fragment of the posterior rim,
(d) small intra-articular fragment of the posterior rim,
(e) small intra-articular fragment with impression of the
adjacent articular surface of the tibia.
With the advent of CT scanning it became possible to
assess the exact shape and size of the posterior malleolar
fragment, involvement of the fibular notch, and the medial
malleolus. The first CT-based classification was developed
by Haraguchi et al. [26] in 2006, on the basis of examina-
tion of 57 patients with ankle fractures:
Type I posterolateral oblique type as the most common
variant (67 %). The fracture involves a triangular frag-
ment separated from the posterolateral part of the distal
tibia.
Type II medial extension type (19 %) affects the poste-
rior part of the medial malleolus and may be formed by
one or two fragments.
Type III small-shell type (14 %) involves small frag-
ments of the PM cortex.
The authors, however, used only transverse sections,
without 2D or 3D CT reconstructions that would show the
exact shape of the PM fragment.
Bartonícˇek and Rammelt [9] in 2015 analyzed 141 con-
secutive individuals with an ankle fracture or fracture-dis-
location of types Weber B or Weber C and evidence of a
PM fragment in standard radiographs. All patients under-
went CT scanning in transverse, sagittal and frontal planes.
3D CT reconstruction was performed in 91 patients. The
fractures of PM were classified into four basic types with
constant pathoanatomic features with special reference to
involvement of the fibular notch (Fig. 3):
Type 1 extraincisural fragment with an intact fibular
notch (8 %),
Type 2 intraincisural posterolateral fragment involving
1/4–1/3 of the fibular notch (52 %),
Type 3 intraincisural posteromedial two-part fragment
involving the posterior part of the fibular notch later-
ally, and the posterior colliculus of the medial malleolus
medially, typical of this type is the flake fragment sign
(28 %),
Type 4 large posterolateral triangular fragment carrying
the posterior half of the fibular notch (9 %).
In contrast to the Müller/AO [56] and Heim [31] classifi-
cations, the authors did not observe any extra-articular PM
fragments. Analysis of sagittal CT scans revealed that all
fragments, including the extraincisural ones, carried part of
the articular surface of the distal tibia. The number of cases
with subluxation, or dislocation, of the talus, the cross-
sectional area of the fragment, the height of the fragment,
and the extent of involvement of the fibular notch increased
throughout the classification groups. This indicated that the
proposed types indeed represent a scale of increasing injury
severity. Irregular, osteoporotic PM fractures that could not
be classified into one of the above groups were collectively
termed type 5.
The question how to distinguish between a fracture of
the posterior rim in ankle fracture-dislocations and pos-
terior fractures of the tibial pilon caused by compressive
forces has not been satisfactorily resolved, yet. It is difficult
to explain the mechanism of these injuries solely on the
basis of the Lauge-Hansen classification [44]. PM fractures
most likely result from a combination of tensile, compres-
sion and shear forces. Smaller fragments, similar to those
of Bartonícˇek´s and Rammelt´s types 1 and 2 are most
likely produced by ligamentous and capsular avulsions in
rotational injuries while larger and multifragmentary frac-
tures similar to types 3 and 4 are predominately caused
by compression forces, as these fragments usually carry a
large part of the articular surface. Therefore, trimaleollar
ankle fractures with types 3 and 4 PM fragments cannot be
classified as pure fracture-dislocations, as they represent a
transition to partial fractures of the tibial pilon.
In anatomical terms, distinguishing between ankle
fractures with PM fragments and pilon fractures is a mat-
ter of convention. Haraguchi et al. [26] in their study
even included PM fractures that carried the entire medial

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Posterior malleolar fractures of the ankle
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malleolus. Switaj et al. [69] and Klammer et al. [41] termed
the medial extension type of a fracture of the posterior rim
(Haraguchi´s type II, Bartonícˇek´s and Rammelt´s type 3)
a “posterior pilon fracture”. Weber [77] considers this type
as a part of trimalleolar fractures of the ankle. In order to
distinguish between trimalleolar fractures and fractures of
the tibial pilon, Bartonícˇek and Rammelt [9] set the line
connecting the center of the fibular notch and the intercol-
licular groove as the conventional criterion. If the posterior
fragment carries the anterior colliculus of the medial malle-
olus or more than 50 % of the fibular notch, the injury is
classified as a partial fracture of the tibial pilon.
Treatment
Historically, the first indication for internal fixation of
the PM resulted from ankle instability [46, 48, 49]. Later,
attention was paid to the importance of joint congruity and
restoration of the articular surface of the tibial pilon [54,
55, 76]. Only recently, emphasis has been put on stability
of the tibiofibular mortise and reduction of the distal fibula
into the fibular notch [23, 64].
For a long time the decisive factor for indication to sur-
gery was the size of the articular surface carried by the
PM fragment and its displacement [30, 55, 57, 75]. The
Fig. 3 Classification of fractures of posterior malleolus after
Bartonícˇek and Rammelt (Reprinted from Bartonícˇek J, Rammelt
S, Kostlivý K, Vaneˇcˇek V, Klika D, Trešl I: Anatomy and classifica-
tion of the posterior tibial fragment in ankle fractures. Arch Orthop
Trauma Surg 2015;135:506–516). a Type 1 extraincisural fragment;
b Type 2 posterolateral fragment; c Type 3 two-part fragment with
involvement of medial malleolus; d Type 4 large triangular postero-
lateral fragment

592 J. Bartoníček et al.
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critical size was considered to be one-quarter to one-third
of the articular surface on the lateral radiograph and frag-
ment displacement of more than 2 mm [55, 57, 71]. How-
ever, because of the oblique or irregular fracture lines it is
impossible to determine the exact size of the fragment and
articular surface involvement [20].
For a balanced indication to operative treatment the
following parameters that can be achieved by anatomi-
cal reduction and fixation of the posterior rim have to be
considered:
–– restoring the original size and congruence of the articu-
lar surface of the tibial pilon and thus posterior stability
of the ankle,
–– restoring the stabilizing role of the posterior tibiofibular
ligament and thus stability of the ankle mortise,
–– restoring integrity of the fibular notch which facilitates
reduction of the distal fibula, particularly in high fibular
fractures of Weber type C including Maisonneuve frac-
tures.
The operative approach will also be determined by the
accompanying injuries to the ankle [9, 68], primarily the
type of injuries to medial structures (fracture of medial
malleolus, rupture of the deltoid ligament or combined
osteo-ligamentous lesions) [59, 60] and the type of fibu-
lar fracture (mainly a low versus a high Weber C fibular
fracture).
The CT classification of PM fractures published by
Bartonícˇek and Rammelt [9] may be used as a guide for
decision making:
–– Type 1 (extraincisural) non-operative treatment.
–– Type 2 (posterolateral) indication to surgery depends on
the fragment size, the presence of an impacted intercal-
cary fragment, and the type of fibular fracture (Fig. 4).
If associated with a high fibular fracture, reduction even
of a relatively small fragment, may significantly con-
tribute to anatomical reduction of the distal fibula into
the fibular notch.
–– Type 3 (two-part) surgery is indicated with increasing
size of the articular surface, involvement of the fibular
notch, and tibiotalar instability. Reduction and internal
fixation of displaced fragments primarily restores joint
congruity and stability. In addition, this type of injury
almost always involves also the posterior colliculus of
medial malleolus potentially leading to impingement of
the tibialis posterior tendon.
–– Type 4 (large triangular) open reduction and internal fix-
ation is always indicated due to the size of the avulsed
articular surface and ankle instability.
Operative methods and fixation technique
Open reduction and internal fixation of the posterior tibial
rim may be performed by both direct and indirect tech-
niques [30, 63, 65]:
–– indirect reduction and screw fixation from the anterior
approach,
–– transfibular reduction and screw fixation from the ante-
rior or posterior approach,
Fig. 4 Variability of Type 2.
a Small fragment; b typical
fragment; c large fragment with
medial extension

593
Posterior malleolar fractures of the ankle
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–– direct reduction and fixation from a posterolateral
approach,
–– direct reduction and fixation from a posteromedial
approach.
The individual choice of treatment depends on the type
of PM fracture, i.e., its particular geometry, size and dis-
placement, but also on the other injuries to the ankle,
i.e., the type of fibular fracture (Danis–Weber B or low C
types versus high C “Maisonneuve” type) and the type of
injuries to the medial structures (bicollicular fracture of
medial malleolus, rupture of deltoid ligament or combined
lesion—fracture of the anterior colliculus and rupture of
the tibiotalar part of the deltoid ligament).
In PM fractures of types 2 and 4 (Bartonícˇek and Ram-
melt classification), the posterolateral approach is indicated
for direct reduction as it allows a simultaneous treatment
of the fracture of the posterior rim and the fibular fracture.
In some cases of type 3 PM fractures the posteromedial
approach is adequate to treat simultaneously both parts of
the posterior rim and the fracture of the medial malleolus.
In other cases, it is necessary to treat the posterolateral part
of PM from the posterolateral and the posteromedial part of
PM from the medial approach.
Indirect reduction and anterior‑to‑posterior fixation
This approach has been widely popularized in classical
textbooks and reviews [30, 31, 55, 75]. Typically, after
internal fixation of the medial and lateral malleolus, the
posterior fragment is reduced by dorsiflexion of the ankle,
percutaneously by a K-wire, sharp elevator, or bone for-
ceps and temporarily fixed by a K-wire. Definitive fixa-
tion is usually performed by two lag cancellous compres-
sion screws or, where appropriate, by cannulated screws.
This approach is most suitable for single, large fragments
(Bartonícˇek and Rammelt type 4) without intercalary frag-
ments. In the authors’ preference, reduction of the posterior
tibial fragment is performed first, because hardware in the
medial and lateral malleolus will overlap with the line of
the tibial plafond thus rendering the control of joint reduc-
tion difficult, if not impossible [63, 65]. The smaller the
fragments are, the more difficult it is to obtain solid fixation
and compression. If the threads of a standard screw exceed
the joint line it is necessary to cut the screw thread short
[31, 58]. However, these short threads will not provide ade-
quate fixation in many cases.
Transfibular reduction according to B.G. Weber
In long, oblique Weber Type B fractures of the fibula, the
fracture line can be opened by external rotating the dis-
tal fragment and displacing it distally, e.g., with a gently
introduced laminar spreader [65, 75]. This will visually
expose the fibular notch as far as the posterior rim. Sub-
sequently, the posterior rim may be reduced under visual
control with a pointed reduction clamp introduced anter-
oposteriorly, fixed temporarily by a K-wire and finally by
anterior-to-lateral screw fixation. A modification of this
technique has been recently described by Kim et al. [40]
who used posterior-to-anterior screw fixation. However,
with the transfibular technique adequate vision on the tibial
plafond may be hard to obtain and the technique is not fre-
quently used.
Direct reduction and fixation from the posterolateral
approach
This approach allows to treat simultaneously fractures
of the posterior rim of tibia and distal fibula from single
incision (Figs. 5, 6). It is indicated mainly in types 2 and
4 [9]. It is especially useful with PM fragments of a rela-
tively small diameter and in the presence of intercalary
fragments that cannot be reduced indirectly [30, 65]. The
patient is placed in a prone or semiprone position. The
incision runs longitudinally along the posterior rim of the
distal fibula until the apex of the lateral malleolus, where
it turns slightly anteriorly. Alternatively, the incision is
placed halfway between the distal fibula and the Achilles
tendon as a classical posterolateral (Gallie) approach. It is
essential to identify and spare the sural nerve in the sub-
cutaneous tissue. The peroneal fascia is dissected in the
same interval and the peroneal tendons are retracted ante-
riorly. Subsequently, a longitudinal incision through the
deep fascia of the flexor hallucis longus muscle (FHL) is
made. The FHL tendon is held away far medially thus pro-
tecting the deep posterior neurovascular bundle and allow-
ing an almost complete overview over the posterior tibial
rim. The posterolateral fragment is gently mobilized while
keeping the posterior tibiofibular ligament intact. After
cleaning of the fracture surfaces, the fracture is reduced
and temporarily fixed by K-wires. Intercalary fragments
of sufficient size and cartilage quality are reduced towards
the tibial plafond and fixed with K-wires or resorbable
pins, comminuted osteochondral fragments not amenable
to fixation are resected. Reduction is controlled visually at
the distal tibial metaphysis and joint reconstruction with
a lateral image intensifier view (Fig. 7). Definite internal
fixation may be performed using 3.5 mm lag screws with
a washer or a buttress plate, preferably T-shaped, from the
small fragment set (Figs. 8, 9). A buttress plate may pre-
vent secondary displacement of the fragment, particularly
in osteoporotic bone. During screw insertion, the concave
shape of the articular surface of the distal tibia in the lat-
eral view must be respected in order to avoid penetration
of screws through the joint or perforation of the fibular

594 J. Bartoníček et al.
1 3
Fig. 5 Anatomy of posterolateral approach. a Posterolateral aspect of
the ankle; b peroneal tendons were displaced anterolaterally; c deep
layer of the ankle, situation after removing of the Achilles tendon and
peroneal tendons; d posterior aspect of the ankle joint. 1 Flexor hal-
lucis longus, 2 peroneal tendons, 3 fibula, 4 posterior tubercle of the
distal tibia, 5 Achilles tendon, 6 intermalleolar ligament
Fig. 6 Posterolateral approach.
a Skin incision; b dissection of
peroneal tendons; c dissection
of fibular fragments; d dissec-
tion of fascia of flexor hallucis
longus, e retraction of flexor
hallucis longus medially; f dis-
section of posterior tubercle. 1
peroneal tendons, 2 distal fibula,
3 fascia of flexor hallucis lon-
gus, 4 flexor hallucis longus, 5
posterior tubercle of distal tibia

595
Posterior malleolar fractures of the ankle
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Fig. 7 Internal fixation of
posterior malleolus. a Reduc-
tion and temporally fixation by
K-wires; b definitive fixation
by lag screws and buttress
T-shaped plate
Fig. 8 Type 3 posterior fragment. a, b Transverse CT scans; c frontal CT scan; d 3D CT of medial aspect; e sagittal CT scan; f 3D CT of poste-
rior aspect; g 3D CT of posterolateral aspect

596 J. Bartoníček et al.
1 3
notch. For maximum stability, the distal screws should be
inserted close to the articular surface and reach the anterior
cortex of the tibia. Internal fixation of the posterior tibial
rim is followed by internal fixation of the fractured distal
fibula. We prefer to place the plate from the lateral aspect.
An additional fracture of the medial malleolus is stabilized
via a slightly curved medial incision with either screws or
tension band wiring [31, 65].
Direct reduction and fixation from the posteromedial
approach
This technique allows simultaneous fixation of the frac-
ture of the posterior tibial rim and the medial malleolus
from single incision [2, 10, 77]. It is especially useful in
Bartonícˇek and Rammelt type 3 PM fractures with a pos-
teromedial fragment involving the medial malleolus [9].
The patient is placed in a supine position. The incision runs
along the posterior rim of the distal tibia as far as the apex
of the medial malleolus, where it turns slightly anteriorly.
The crural fascia is incised, and the tendons of the tibialis
posterior and flexor digitorum longus muscles are mobi-
lized and retracted anteriorly. This will expose the posterior
tibial tubercle. Care is taken not to injure the posteromedial
neurovascular bundle. In the next step, reduction and fixa-
tion of the posterior tibial rim and the medial malleolus is
performed in analogy to the posterolateral fragments.
Authors’ preferred treatment
In our practice, direct reduction and fixation from posterior
is preferred over indirect reduction and anterior-to-poste-
rior fixation as it allows a more accurate and stable fixation
of PM fractures and removal or reduction of impacted or
displaced intercalary interfragments (Fig. 10). Both poste-
rolateral or posteromedial approaches allow good visuali-
zation of the posterior tibial rim and the individual choice
of approaches is made on the basis of the exact fracture
anatomy on CT examination. After anatomic reduction and
stable fixation of the posterior tibial fragment(s) and any
accompanying lateral and medial malleolar fractures, syn-
desmotic stability is tested with an interoperative external
rotation or hook test. In many cases, fixation of the avulsed
posterior tibiofibular ligament together with malleolar frac-
ture fixation will restore syndesmotic stability thus obviat-
ing the need for an additional transsyndesmotic screw [23,
53, 65, 77].
Prognosis and complications
The literature contains a number of contradictory opinions
on the indication and prognosis of operative treatment of
PM fractures in ankle injuries based on analysis of the out-
comes of both operative and non-operative treatment [33,
65]:
Trimalleolar fractures carry a worse prognosis than
bimalleolar fractures, i.e., the mere presence of a small pos-
terior fragment has a negative effect on the clinical outcome
[37, 45, 70, 80]. In their classical study, Nelson and Jensen
[57] found good results in 3 patients with large PM frag-
ments carrying more than one-third of the joint surface that
were fixed surgically and poor results in 5 patients in whom
the large PM fragments have not been fixed. Later, Jaskulka
et al. found that for larger PM fragments, the results of
reduction and internal fixation are better as compared to
non-operative treatment [37]. Several studies did not reveal
different results after non-operative or operative treatments
Fig. 9 Fracture of the ankle from: a, b radiographs before surgery; c, d radiographs after surgery

597
Posterior malleolar fractures of the ankle
1 3
of PM fractures even with fragments carrying 25 % of the
articular surface [17, 27, 36]. The results of non-anatomical
reduction and internal fixation of PM are inferior than those
obtained by non-operative treatment [24, 30, 77]. Both the
clinical results and the degree of post-traumatic arthritis
are reported to correspond to the size of the avulsed PM
fragment [37, 47]. In a prospective study of 321 patients,
Lindsjø [47] revealed a higher incidence of post-traumatic
arthritis in patients with the avulsed PM involving a consid-
erable part of the articular surface of the tibial plafond than
in those with only a small fragment. Heim et al. [32] on the
basis of a prospective study found a tendency towards dete-
rioration 7 years after the injury in patients with a PM frag-
ment involving more than one-third of the articular surface
despite a perfect reduction and fixation. They attributed
this finding to the primary injury to the articular cartilage
with larger PM fragments. Similarly, other authors found
that the results of PM fracture treatment correlated with the
size of the fragment [17, 24, 53]. Miller et al. [53] came to
the conclusion that with PM reconstruction the distal fibula
is reduced more accurately into the fibular notch. Numer-
ous authors [32, 52, 65, 68] recommend internal fixation of
PM in any case of ankle instability, regardless of its size
because it substantially contributes to syndesmotic stability.
Malunion of PM fragments is a problem addressed only
recently by some authors [66, 76] (Fig. 11). Symptomatic
malunions or nonunions with joint displacement may be
treated by joint-preserving osteotomies if no post-trau-
matic arthritis has developed. Ankle fusion with realign-
ment remains a salvage option in cases of manifestation of
arthritis.
A detailed analysis of these studies reveals several draw-
backs. A number of earlier studies were retrospective,
assessment of fractures was not optimal and treatment of
associated injuries was not standardized. In most of the
recent studies, the fragment of PM was assessed on lateral
radiographs only in terms of its size, without CT exami-
nation and regardless of the anatomical variability. PM
fractures within one cohort were often treated by various
techniques. In case of indirect techniques, reduction of the
Fig. 10 Postoperative CT
control of reduction of fractured
posterior malleolus, type 2. a, c
Sagittal and transverse CT scans
before surgery, b, d sagittal and
transverse CT scans after direct
reduction and direct fixation
from posterolateral approach.
Note the perfect reduction of
distal fibula into fibular notch
after anatomic reduction of
posterior fragment

598 J. Bartoníček et al.
1 3
PM fractures was not assessed visually. Accuracy of PM
reduction and quality of its fixation were postoperatively
assessed on plain radiographs only, without CT follow-up.
Only a few studies evaluated one particular type of PM
fractures [41, 69, 77]. Therefore, based on the available
literature, it is impossible to develop true evidence-based
guidelines for the treatment of PM fractures.
Conclusion
Despite an increasing awareness of injuries to PM in ankle
fracture-dislocations, there are still many open questions.
The mere presence of a posterior fragment leads to signifi-
cantly poorer outcomes. Adequate diagnosis, classification
and treatment require preoperative CT examination, prefer-
ably with 3D reconstructions. The indication for surgical
treatment is made individually on the basis of comprehen-
sive assessment of the three-dimensional outline of the PM
fracture and all associated injuries to the ankle including
syndesmotic instability.
Anatomic fixation of the avulsed posterior tibiofibu-
lar ligament will contribute to syndesmotic stability and
restore the integrity of the incisura tibiae thus facilitating
anatomic reduction of the distal fibula. A necessary pre-
requisite is mastering of posterolateral and posteromedial
approaches and the technique of direct reduction and
internal fixation. Further clinical studies with higher num-
bers of patients treated by similar methods and evaluation
of pre- and postoperative CT scans will be necessary to
determine reliable prognostic factors associated with cer-
tain types of PM fractures and associated injuries to the
ankle.
Compliance with ethical standards
Conflict of interest Jan Bartonícˇek, Stefan Rammelt, Michal Tucˇek
and Ondrˇej Nanˇka declare that they have no conflict of interest.
Compliance with ethics guidelines An approval by an ethics com-
mittee was not applicable.
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