Circular External Fixator
While proper anteroposterior and lateral radiographs centered on the knee
are important (Figs. 1-A and
1-B), a preoperative computed tomography scan is essential to
evaluate the details of the fracture configuration, to identify the main
fragments, and to help to plan wire placement
(Fig. 2). The patient is
positioned supine on either a fracture table or a long radiolucent table under
general anesthesia (Fig. 3).
The limb is prepared and is draped free appropriately with a tourniquet
applied. While the tourniquet may not be used, it can be a useful adjunct in
certain situations. Bolsters are placed about the limb to allow 360°
visualization. Longitudinal traction is applied to the fracture with use of
either manual means, a fracture table, or a femoral distractor
(Fig. 4). The choice of
traction depends on the complexity and chronicity of the fracture and the
preference of the surgeon. Image intensification is used to assess fracture
alignment. Fracture fragments are reduced into position with use of gentle,
closed pressure or percutaneously inserted periosteal elevators or reduction
forceps (Figs. 5-A and 5-B).
Percutaneous lag screws are inserted to stabilize the articular fragments
(Fig. 6). An anteromedial or
anterolateral mini-arthrotomy is made to repair tibial spine fractures with
use of gentle manipulation with periosteal elevators or reduction clamps; the
fractures are fixed with use of percutaneous screws or sutures tied over a
metaphyseal screw distally. With the articular surface reduced, the circular
external fixator frame is applied next to secure the metaphysis to the
diaphysis of the tibia.
The frame is assembled with use of three or four rings, depending on the
proximity of the fracture to the joint. Rings are sized to the limb to provide
roughly two fingerbreadths of clearance circumferentially
(Fig. 7). The leg tends to
"sag" posteriorly against the frame, and therefore sterile towels
or sponges are used to maintain this clearance posteriorly throughout the
procedure. Fine wires are then placed across the proximal part of the tibia,
parallel to the joint surface. The first is placed from lateral to medial
through the fibular head (Fig.
8). As the proximal tibiofibular joint communicates with the knee
joint in approximately 10% of individuals, the insertion of this wire
theoretically can lead to septic arthritis of the knee if the area around the
wire becomes infected. However, especially in cases of proximal fractures, the
added stability of the proximal fragment attributed to this wire usually
justifies its use. If the area around the wire becomes infected, the wire must
be removed and/or replaced promptly. Care is taken to place the wires at least
1 cm from the joint surface to avoid intra-articular penetration unless this
is absolutely necessary, so that the wires are not intraarticular during their
course. The wires are first tightened on the insertion end with use of a
cannulated bolt and nut and then are tensioned to 90 lb with use of the
tensioner on the opposite end. The opposite cannulated nut and bolt are then
tightened with the tensioner in place. Once tightened, the tensioner is
removed. The olive end of the wire is used to compress and maneuver displaced
fragments of the metaphysis. In this setting, the insertion end of the wire
remains untightened while the wire is gently drawn to the opposite side of the
frame with use of the tensioner. Then the olive end of the wire is tightened
with a cannulated bolt and nut, and the tensioner is removed, reset, and used
to tension the insertion end of the wire
(Fig. 9). The opposite
cannulated bolt and nut are then tightened, and the tensioner is removed. This
procedure is repeated with several wires (usually four), alternating from
lateral to medial and medial to lateral, to provide stability to the proximal
segment. Image intensification is used to assess the articular reduction and
the alignment of the tibia. Fixation of the shaft to the distal rings can then
be performed with transfixion wires or percutaneous threaded half-pins,
depending on local factors, the associated injuries, and the preference of the
surgeon (Fig. 10). In general,
half-pins are used with the distal rings once alignment of the fracture has
been achieved. Half-pin cubes are fixed to the rings with nuts. The
drill-guide is positioned, and the skin is cut and spread with a hemostat,
after which the guide is placed against the diaphysis and a 4.0-mm drill is
passed across both cortices. A 5.0-mm threaded half-pin is then inserted and
fixed to the cube with use of two set screws. This is repeated over the two
distal rings, for a total of four half-pins. Image intensification is used to
assess the position of the half-pins to ensure placement across both cortices
and to evaluate the overall alignment of the tibia. With this complete, the
fine wires are cut and are bent over the rings. The pin sites and surgical
wounds are then closed and dressed. Radiographs are made to confirm reduction
of the intra-articular fracture, alignment with the remainder of the tibia,
and proper placement of the screws and wires
(Figs. 11-A, 11-B, and
11-C).
We prefer this method for the treatment of fractures that are associated
with compartment syndrome as it eliminates the problem of exposed fixation
devices in open fasciotomy wounds. On the other hand, although transfixion pin
placement can be planned to facilitate eventual wound closure, the use of
local rotational flaps such as the gastrocnemius can be compromised by the use
of the circular frame.
Open Reduction and Internal Fixation
Formal open reduction and internal fixation of bicondylar tibial plateau
fractures (Fig. 12) may need
to be delayed until the anterior soft-tissue structures are healthy and
viable. Positioning is similar to that for the circular fixator technique. The
patient is placed supine under general anesthesia. A fracture table or long
radiolucent operating table is used to facilitate visualization. The limb is
prepared and draped free with a tourniquet applied proximally and bolstered
appropriately; we have found that an adjustable triangular frame is useful in
this situation. In general, widely separate posteromedial and anterolateral
incisions are made to minimize the soft-tissue dissection
(Fig. 13) and yet allow access
to the major fracture lines and fragments that are often difficult to address
from an anterior approach. Anterior fractures (as from a hyperextension type
of injury) with mainly anterior comminution can be treated through a single
anterior incision. The main goal is to avoid extensive soft-tissue dissection
that devascularizes bone fragments or creates precarious soft-tissue flaps
leading to wound breakdown. The incisions should be only as long as necessary
to visualize and reduce the fracture. While concerns regarding possible later
conversion to total knee arthroplasty are valid, the conversion rate is
surprisingly low and the surgical approach should not compromise exposure of
the fracture site. An arthrotomy is created to visualize the joint. This is
usually performed just proximal to the articular surface of the plateau and
below the meniscus by sectioning the coronary ligament. The articular surface
is visualized and reduced by elevating any depressed fracture fragments
(Figs. 14-A and 14-B).
Kirschner wires are used to hold the reduction while lag screws are placed
across the fragments. The articular reduction is assessed directly through the
arthrotomy as well as with image intensification. The cruciate ligaments can
be visualized by extending the arthrotomy anteriorly or by performing a formal
anterolateral arthrotomy in a vertical plane. The overall alignment of the
tibia should be assessed in the anteroposterior and lateral planes. When the
alignment is satisfactory, the metaphysis is fixed to the diaphysis with
medial and lateral plates and screws. This fixation follows conventional
plating techniques with an emphasis on minimizing soft-tissue dissection. The
lateral plateau is fixed to the diaphysis with use of a precontoured 3.5 or
4.5-mm proximal tibial periarticular plate, depending on the size of the
patient and the size of the fracture fragments. Image intensification is used
to ensure appropriate placement in the anteroposterior and lateral planes.
Bicortical screws are placed from lateral to medial in the metaphysis and
diaphysis. The medial plateau is fixed to the diaphysis with use of a
hand-contoured 3.5 or 4.5-mm low-contact dynamic compression buttress plate.
Bicortical screws are placed across the metaphysis and diaphysis. At least
four cortices are required in both the metaphysis and the diaphysis
(Figs. 15-A and 15-B). Large
osseous defects created by the elevation of depressed articular fragments can
be filled with a number of compounds, including autogenous bone graft or any
one of a number of newer bone substitutes. Tibial spine or cruciate ligament
injuries are repaired through the arthrotomy with use of screw fixation or
sutures woven through the ligament and tied over a well-fixed screw in the
tibial metaphysis. Meniscal injuries are repaired to the capsule with use of
interrupted nonabsorbable sutures. Image intensification is used for a final
check in the anteroposterior and lateral planes. The wounds are irrigated with
sterile saline solution and are closed in layers after the tourniquet has been
deflated and hemostasis has been obtained. Postoperatively, the limb is placed
in a long-leg plaster splint. Early range of motion is instituted on the basis
of the stability of the fracture.
CRITICAL CONCEPTSINDICATIONS: While indications vary depending on the age, health
status, and functional demands of the patient, operative treatment for
displaced intra-articular bicondylar tibial plateau fractures is generally
appropriate for patients with the following findings.Intra-articular displacement of =2 mmMetaphyseal-diaphyseal translation of >1 cmAngular deformity of >10° in the coronal (varus-valgus) or sagittal
planeOpen fractureAssociated compartment syndromeAssociated ligament injury requiring repairAssociated fractures of the ipsilateral tibia or fibulaCONTRAINDICATIONS:Contraindications to the operative fixation of bicondylar tibial plateau
fractures include the following.Undisplaced fractureLack of familiarity with either surgical techniqueA patient who is medically unfit for an anestheticA patient who is unable to comply with the rehabilitation protocol or
benefit from the procedure (for example, because of dementia)Active infection in or around the surgical siteSevere soft-tissue swelling that would jeopardize the healing of
incisionsOpen growth platesPITFALLS:Circular External FixationCare must be taken to ensure adequate reduction of intra-articular
fragments prior to the application of the frame. Once the frame is applied,
access to the proximal fragments is limited.The tibia has a tendency to sag posteriorly during frame application and
must be bolstered posteriorly with towels to prevent frame-leg contact.Fine wires should be placed 1 cm distal to the joint line to avoid
intra-articular placement as pin-track infections are frequent and may result
in septic arthritis if the pins are intracapsular.The overall alignment of the tibia must be assessed radiographically in
both the anteroposterior and lateral planes to ensure the adequacy of the
reduction.If proximal purchase is inadequate despite multiple transfixion wires
and/or if there is substantial ligamentous injury in the knee, spanning the
knee with an extension of the circular frame to the distal part of the femur
should be considered with a hinge placed at the center axis of the knee and
connected to the distal part of the femur with half-pins or transfixion
wires.Open Reduction and Internal FixationThe extensive soft-tissue disruption of the fracture combined with the
secondary soft-tissue injury associated with surgery can result in
complications, including wound dehiscence and infection. Care must be taken
when handling the proximal soft tissues; gentle handling of tissue, minimizing
incision length and flap formation, and meticulous, layered closure are
required. This may mean an extended period of time with the limb in a splint
or in a spanning external fixator before the soft tissues are robust enough
for surgical intervention.Care must be taken to directly assess the articular reduction through a
submeniscal or parapatellar tendon arthrotomy as image intensification alone
can be misleading.Overall alignment of the tibia must be assessed in both the anteroposterior
and lateral planes to ensure the adequacy of reduction.AUTHOR UPDATE:We continue to use both surgical techniques for the fixation of displaced
bicondylar tibial plateau fractures, and we have found the two techniques to
be complementary rather than mutually exclusive. Fractures associated with
severe soft-tissue injury or swelling, predominantly metaphyseal-diaphyseal
comminution and displacement, fracture extension into the tibial shaft, and
less severe intra-articular fracture displacement are ideal for closed or
limited open reduction and circular frame fixation. Fractures associated with
extensive intra-articular displacement and comminution are ideally suited for
formal open reduction and internal fixation with use of a two-incision
technique. The utility of this method has been augmented by the advent of
precontoured plates for the proximal part of the tibia and the use of
minimally invasive techniques for the application of these plates distally
along the shaft.Locking plates are gaining in popularity for the treatment of complex
fractures, particularly those of the proximal part of the tibia. While it is
tempting to minimize soft-tissue dissection in cases of bicondylar tibial
plateau fractures by using a single axially stable locking plate to secure
both condyles, we have not been uniformly satisfied with that technique. We
have observed collapse or settling of the far (usually medial) condyle when a
single (usually lateral) plate is used alone for fixation. At the present
time, we do not routinely recommend solitary lateral plate fixation; this is
especially true for posteromedial fractures with a predominantly coronal
fracture line.
CRITICAL CONCEPTS
INDICATIONS: While indications vary depending on the age, health
status, and functional demands of the patient, operative treatment for
displaced intra-articular bicondylar tibial plateau fractures is generally
appropriate for patients with the following findings.
Intra-articular displacement of =2 mmMetaphyseal-diaphyseal translation of >1 cmAngular deformity of >10° in the coronal (varus-valgus) or sagittal
planeOpen fractureAssociated compartment syndromeAssociated ligament injury requiring repairAssociated fractures of the ipsilateral tibia or fibula
Intra-articular displacement of =2 mm
Metaphyseal-diaphyseal translation of >1 cm
Angular deformity of >10° in the coronal (varus-valgus) or sagittal
plane
Open fracture
Associated compartment syndrome
Associated ligament injury requiring repair
Associated fractures of the ipsilateral tibia or fibula
CONTRAINDICATIONS:
Contraindications to the operative fixation of bicondylar tibial plateau
fractures include the following.
Undisplaced fractureLack of familiarity with either surgical techniqueA patient who is medically unfit for an anestheticA patient who is unable to comply with the rehabilitation protocol or
benefit from the procedure (for example, because of dementia)Active infection in or around the surgical siteSevere soft-tissue swelling that would jeopardize the healing of
incisionsOpen growth plates
Undisplaced fracture
Lack of familiarity with either surgical technique
A patient who is medically unfit for an anesthetic
A patient who is unable to comply with the rehabilitation protocol or
benefit from the procedure (for example, because of dementia)
Active infection in or around the surgical site
Severe soft-tissue swelling that would jeopardize the healing of
incisions
Open growth plates
PITFALLS:
Circular External Fixation
Care must be taken to ensure adequate reduction of intra-articular
fragments prior to the application of the frame. Once the frame is applied,
access to the proximal fragments is limited.The tibia has a tendency to sag posteriorly during frame application and
must be bolstered posteriorly with towels to prevent frame-leg contact.Fine wires should be placed 1 cm distal to the joint line to avoid
intra-articular placement as pin-track infections are frequent and may result
in septic arthritis if the pins are intracapsular.The overall alignment of the tibia must be assessed radiographically in
both the anteroposterior and lateral planes to ensure the adequacy of the
reduction.If proximal purchase is inadequate despite multiple transfixion wires
and/or if there is substantial ligamentous injury in the knee, spanning the
knee with an extension of the circular frame to the distal part of the femur
should be considered with a hinge placed at the center axis of the knee and
connected to the distal part of the femur with half-pins or transfixion
wires.
Care must be taken to ensure adequate reduction of intra-articular
fragments prior to the application of the frame. Once the frame is applied,
access to the proximal fragments is limited.
The tibia has a tendency to sag posteriorly during frame application and
must be bolstered posteriorly with towels to prevent frame-leg contact.
Fine wires should be placed 1 cm distal to the joint line to avoid
intra-articular placement as pin-track infections are frequent and may result
in septic arthritis if the pins are intracapsular.
The overall alignment of the tibia must be assessed radiographically in
both the anteroposterior and lateral planes to ensure the adequacy of the
reduction.
If proximal purchase is inadequate despite multiple transfixion wires
and/or if there is substantial ligamentous injury in the knee, spanning the
knee with an extension of the circular frame to the distal part of the femur
should be considered with a hinge placed at the center axis of the knee and
connected to the distal part of the femur with half-pins or transfixion
wires.
Open Reduction and Internal Fixation
The extensive soft-tissue disruption of the fracture combined with the
secondary soft-tissue injury associated with surgery can result in
complications, including wound dehiscence and infection. Care must be taken
when handling the proximal soft tissues; gentle handling of tissue, minimizing
incision length and flap formation, and meticulous, layered closure are
required. This may mean an extended period of time with the limb in a splint
or in a spanning external fixator before the soft tissues are robust enough
for surgical intervention.Care must be taken to directly assess the articular reduction through a
submeniscal or parapatellar tendon arthrotomy as image intensification alone
can be misleading.Overall alignment of the tibia must be assessed in both the anteroposterior
and lateral planes to ensure the adequacy of reduction.
The extensive soft-tissue disruption of the fracture combined with the
secondary soft-tissue injury associated with surgery can result in
complications, including wound dehiscence and infection. Care must be taken
when handling the proximal soft tissues; gentle handling of tissue, minimizing
incision length and flap formation, and meticulous, layered closure are
required. This may mean an extended period of time with the limb in a splint
or in a spanning external fixator before the soft tissues are robust enough
for surgical intervention.
Care must be taken to directly assess the articular reduction through a
submeniscal or parapatellar tendon arthrotomy as image intensification alone
can be misleading.
Overall alignment of the tibia must be assessed in both the anteroposterior
and lateral planes to ensure the adequacy of reduction.
AUTHOR UPDATE:
We continue to use both surgical techniques for the fixation of displaced
bicondylar tibial plateau fractures, and we have found the two techniques to
be complementary rather than mutually exclusive. Fractures associated with
severe soft-tissue injury or swelling, predominantly metaphyseal-diaphyseal
comminution and displacement, fracture extension into the tibial shaft, and
less severe intra-articular fracture displacement are ideal for closed or
limited open reduction and circular frame fixation. Fractures associated with
extensive intra-articular displacement and comminution are ideally suited for
formal open reduction and internal fixation with use of a two-incision
technique. The utility of this method has been augmented by the advent of
precontoured plates for the proximal part of the tibia and the use of
minimally invasive techniques for the application of these plates distally
along the shaft.
Locking plates are gaining in popularity for the treatment of complex
fractures, particularly those of the proximal part of the tibia. While it is
tempting to minimize soft-tissue dissection in cases of bicondylar tibial
plateau fractures by using a single axially stable locking plate to secure
both condyles, we have not been uniformly satisfied with that technique. We
have observed collapse or settling of the far (usually medial) condyle when a
single (usually lateral) plate is used alone for fixation. At the present
time, we do not routinely recommend solitary lateral plate fixation; this is
especially true for posteromedial fractures with a predominantly coronal
fracture line.