John H Wilber, Friedrich Baumgaertel
Plate fixation of fractures is a form of stabilization with the potential
for both load bearing and load sharing properties. Functional treatment of the
limb for preservation of muscle strength, coordination, and joint mobility
depends on the stability provided by the plate-bone construction. Fracture
consolidation is to be expected if the mechanics of fixation and the biology of
the fracture are compatible and mutually beneficial.
- Biological bridge plating uses the plate as an extramedullary splint
fixed to the two main fragments. The complex fracture zone is virtually left
untouched; however, it is bridged by the plate. Length, alignment, and rotation
are restored, but anatomical reduction of each fragment is not
This concept combines the relative stability provided by the plate with the
preservation of natural fracture biology to achieve rapid callus formation and
- Bridge plating techniques are applicable to all long-bone fractures with
complex fragmentation and where intramedullary nailing or conventional plate
fixation is not suitable.
a Complex fracture of tibia and fibula (42-C2). There is severe
softtissue injury. Proximal extension of the fracture and polytrauma (ISS = 48)
precludes intramedullary nailing.
b Emergency fixation with a unilateral external fixator.
c Percutaneous bridge plating 3 weeks post injury after the soft
tissues had settled. Percutaneous lag screws have been used to reduce some of
the severely displaced fracture fragments. The external fixator was retained to
provide additional medial support.
d Clinical aspect 8 weeks after the accident.
e Fracture union with callus formation at 29 weeks.
With “classical” direct fracture reduction and plate fixation with absolute
stability, the viability of soft tissues and bone fragments may be jeopardized.
This risk exists to a lesser degree in simple fractures (with less soft-tissue
injury) and thus has less consequence on fracture healing. It is the goal of
fracture surgery to maintain vascularity at the fracture site. This calls for
the use of bridging techniques in fracture patterns with significant
Simple type A diaphyseal fractures can be successfully treated with
intramedullary nailing, a technique of relative stability, or by anatomic
reduction and compression plate fixation, providing absolute stability.
- Experience has shown that bridge plating, providing relative stability,
has a high risk of nonunion or plate failure in simple type A diaphyseal
This is because the strain at the fracture site is above the strain
tolerance of the granulation tissue within the fracture site and so normal
fracture healing will not take place. In complex type C diaphyseal fractures
with numerous intermediate fragments, the bridging plate allows micromovement
between the different fragments, while tissue strain is within the strain
tolerance of granulation tissue, allowing normal callus formation . If a
complex, multifragmentary fracture is splinted in a cast, there will be some
movement between fragments. However, the system as a whole will tolerate a
significant amount of deformation, since it is distributed along the whole
distance of the fracture zone. Thus, strain will be low and this allows tissue
differentiation to progress. Callus formation between intermediate fragments
can occur rapidly, even in the presence of considerable fragment displacement.
This is the basis of Perren’s strain theory. The prerequisites for successful
bone healing in this situation are optimal preservation of fragment vascularity
and a favorable mechanical and cellular environment for the production of
- Bone fragments, once they have been stripped of their softtissue
attachments (periosteum, muscles, etc), will not be incorporated into the early
callus, since they will first need to be revascularized.
Perren's strain theory
a Motion at the fracture results in deformation producing strain in
the granulation tissue at the fracture site.
b A perfectly reduced simple fracture (small gap) stabilized under
compression (absolute stability and low strain) heals without external callus
c A simple fracture (small gap) fixed with a bridging plate
(relative stability) is exposed to movement (high strain). Fracture healing is
delayed or will not occur at all.
d In a complex fracture (large gap) fixed with a bridging plate
(relative stability) the strain will be low in spite of movement, and fracture
healing will occur with callus formation (indirect bone healing). Fracture
union with callus formation at 29 weeks.
a Shotgun injury. Grade IIIc open, complex radial shaft fracture
with radial artery disruption and compartment syndrome.
b Arterial repair and fasciotomy were performed. The bridging plate
on the radial shaft has corrected length, axis, and rotation with anatomical
reduction of both radio-ulnar joints to maintain forearm function. Additional
lag screws were used for indirect reduction.
c Indirect bone healing with callus formation 3 months after
(With permission by Christoph Sommer.)
In diaphyseal type C fractures, the endosteal blood supply of fragments is,
as a rule, interrupted. Preservation of bone vitality relies on periosteal
vascularity, which also contributes to fracture healing. In the absence of
mechanical continuity between the two main fragments, maintenance of stability
entirely lies with the bridging plate. Wide exposure with periosteal stripping
to allow precise fragment reduction and fixation by interfragmentary
compression and plating further compromises the vascularity and must be
avoided, as it increases the risk of bone-healing complications in type C
fractures [2-8]. Mechanistic thinking and technique, together with
misapplication and misinterpretation of the principles of interfragmentary
compression, are probably responsible for the majority of failures and
Simple metaphyseal fractures (type A) that require fixation are best treated
with techniques of absolute stability that provide anatomic reduction and
compression with screws and plates. In general, the same principle should be
applied to simple metaphyseal fractures with simple articular fractures (C1).
However, this technique is not suitable for complex metaphyseal fractures (A1
and A3) or those associated with articular fractures (C2 and C3). Anatomical
reconstruction and absolute stability of the joint surface is paramount. The
metaphyseal bone, given its good healing qualities, will withstand a higher
degree of iatrogenic damage from manipulation than will the diaphysis. The
critical area is not the metaphysis but its junction with the more compact bone
of the diaphysis. These regions of transition remain under significant bending
loads and show a tendency to delayed or failed fracture healing. In the past,
liberal use of bone grafting was advocated in attempts to restore the biologic
activity that was compromised by the injury and the subsequent treatment.
- Current plating concepts embrace the principle of placing biology before
This development has led to a more flexible and individualistic approach to
internal fixation, based on the “personality” of a fracture. The surgeon
attempting operative stabilization of a complex multifragmentary fracture must
be able to reduce the fracture without further interfering with the blood
supply and, at the same time, apply a fixation device that provides adequate
fixation to maintain length, alignment and rotation, and produce a biological
and mechanical environment that stimulates rapid healing by callus.
Indirect reduction techniques
The femoral distractor is an excellent tool for indirect fracture reduction.
- Biological or bridge plating is usually applied following some form of
The goal of indirect reduction is to manipulate fragments into the correct
position without opening the fracture site, thus minimizing further damage to
the bone blood supply [9-12]. The mechanical principle underlying indirect
reduction is distraction. This principle applies to diaphyseal as well as to
metaphyseal bone. The muscular envelope surrounding the diaphysis of long bones
provides the mechanical environment for indirect reduction, since a controlled
pull on the muscle and periosteal attachments of any single fragment tends to
align it in the desired way. A muscle envelope under distraction exerts
concentric (hydraulic) pressure on the shaft, easing fragments into place. This
also holds true for metaphyseal and epiphyseal bone, although the distraction
required to align fragments is transferred through capsular tissues, ligaments,
tendons, and muscular attachments. This phenomenon, regularly seen as part of
nonoperative fracture management, is described by the term “ligamentotaxis”,
coined by Vidal . Traction applied by a traction table to an entire limb
produces indirect reduction of a fracture. However, the use of an implant or
large distractor to a single bone controls reduction more effectively and
permits subtle adjustments as well. Indirect reduction techniques with
distractor or external fixator and plate can sometimes be combined.
In biological or bridge plating, the surgeon must study the fracture
morphology, carefully plan reduction, and finally choose a plate appropriate to
the anatomical location and the configuration of the fracture.
- The majority of plates can function as a bridging plate.
a Subtrochanteric fracture (32-C1.1).
b Indirect reduction with angled blade plate and bridging of
fracture zone. Large intermediate fragment deliberately left unreduced. No bone
c Indirect healing with callus formation 21 weeks
d Complete reconstitution of cortical continuity and massive stable
callus after implant removal at 2 years.
Wave plate allowing for grafting of lateral defect.
If an angled blade plate is used, one has the option of first placing it
underneath the muscle and then inserting it into the metaphyseal fragment prior
to reduction. Reduction can then be obtained using the plate as a reduction
The common denominator in all bridge plating is the use of a very long plate
as a splint on the outside of a bone, in the same way a nail splints the bone
from within or an external fixator spans the fracture and holds the bone from
the outside. Splinting of complex fractures has been a principle applied by
surgeons for many years, but it has only recently been accepted as a principle
of plate fixation. The wave plate, with its central curved segment, is a
special type of bridging plate and provides three advantages for the treatment
- It reduces interference with the vascular supply of the fracture site by
avoiding bone contact.
- It provides excellent access to the fracture site for application of a bone
- It alters the load to pure tension forces on the plate.
If there is a fracture gap, stress concentration on one screw hole may lead to fatigue failure.
In practice, both ends of a bridging plate are solidly fixed to a main
fragment and the strength of fixation to each main fragment should be balanced.
Long plates (about 3 times the length of the fracture zone) bridging an
extensive zone of fragmentation with only short fixation on either end of the
bone will undergo considerable deformation forces.
- As bending stresses are distributed over a long segment of the plate,
the stress per unit area is correspondingly low, which reduces the risk of
In simple fractures, repetitive bending stresses will be concentrated and
centered on a short segment of a plate with a high risk of failure. If stress
is concentrated on a screw hole, it may break more easily due to fatigue. The
incidence of mechanical failure can be considerably reduced if longer plates
are used despite short zones of comminution, so that stresses are deliberately
distributed over a proportionately longer section of the plate. This is
accomplished by fixing the end of the plate over longer segments, well away
from the fracture, producing an elastic construction [14, 15]. Furthermore, the
bridging concept using plates has been aided by the new principles established
for the internal fixator and the developments in plate design, such as LCP and
LISS. The internal fixator principle is based on the locking head screws
providing angular stability and minimizing the area of contact between plate
and bone, thus interfering less with periosteal blood supply while enhancing
axial stability. The LCP and LISS also display an even distribution of strength
throughout the plate, thereby eliminating stress risers at a screw hole.
Demonstration of “stress concentration” on a strip of plywood.
Demonstration of “stress distribution” on a strip of plywood.
Biological plating provides relative stability, preserves vascularity around
the fracture and allows controlled micromotion, resulting in more rapid and
abundant callus formation, as observed in intramedullary nailing or in
nonoperative fracture treatment. However, the success of this operative
approach greatly depends on how the surgeon handles the soft tissues and on how
well the anatomical characteristics of any given fracture have been taken into
consideration during the planning and execution of surgery.
If required, the muscle envelope over the fracture site may be elevated from
the intermuscular septum by gentle blunt dissection. The periosteum is left
untouched and the perforating vessels are only ligated, if needed. The plate is
pushed through a tunnel between muscle and bone. The exposure can safely be
extended to control plate position and fracture alignment at either end of the
long bridging plates where close contact between bone and plate is necessary.
Using implants with locking head screws (eg, LISS or LCP), long incisions are
avoided by restricting the exposure to where the plate is anchored to bone
- It is most important not to damage the soft-tissue envelope around the
In the tibia, a plate can be introduced subcutaneously on the medial side.
However, care should be taken not to place excessive tension on the delicate
overlying skin . For placement lateral to the tibial crest, somewhat more
dissection with a sharp elevator is necessary. Screws are easily introduced
through stab incisions.
Other areas of application for minimal access plating include the distal
femur and the proximal and distal tibia . These locations have distinct
anatomical characteristics requiring precision not only in positioning, but
also in contouring the plate. New anatomically designed plates, in combination
with locking head screws, have improved the ability to apply these techniques
in complex areas. The surgeon may find it necessary to combine direct open
reduction of the articular components with indirect reduction and submuscular
positioning of the plate for associated metaphyseal or diaphyseal fractures. If
difficulties occur, a conventional approach is advisable, which still allows
careful handling of the soft-tissue cover and minimal exposure of the bone
itself. Even when using biological techniques, the surgeon must always be
mindful of soft-tissue damage caused by the initial trauma. Hohmann retractors
and reduction tools such as Verbrugge forceps should not be used since they
leave large tracks and can cause significant soft-tissue stripping and
crushing. We recommend pointed reduction forceps, ball spikes, picks, and awls
as instruments for bone manipulation, and Langenbeck retractors for the soft
Bridge plating with the LISS-PLT using MIPO.
a-b Complex proximal tibial fracture (41-C3) extending into the
c Intraoperative photograph showing the limited exposure for the
articular reconstruction and the submuscular plate insertion as well as the
small incision for the more distal locking head screws.
d-e Open reconstruction of articular components with independent
lag screws. Bridging of the meta-/diaphyseal fracture zone with 14-hole tibia
LISS fixed with locking head screws to distal main fragment. The large
intermediate butterfly fragment has been reduced by two additional lag screws
in AP direction.
f-g The patient was immediately allowed to freely move the limb and
start partial weight bearing of 15–30 kg after 3 weeks. Follow-up x-rays after
(With permission by Christoph Sommer.)
In grade III open fractures or closed injuries with considerable soft-tissue
contusion, bridge plating is not the first choice for fixing a multifragmentary
fracture in an emergency situation. Here, a bridging external fixator or the
use of intramedullary nailing may be indicated. Bridge plating techniques are
often applied later, when soft-tissue injury has stabilized. The management of
difficult fractures is demanding and requires experience, as well as careful
planning of options and tactical steps. Major pitfalls are the correct axial
and rotational alignment as these can only be judged indirectly.
Closed fracture of the left lower leg (42-B1).
a-b AP and lateral preoperative x-rays. Length and alignment of the
bone are satisfactory. There is minor malrotation.
c-d AP and lateral postoperative x-rays. Using the distractor for
indirect reduction, percutaneous bridge plating of the tibia and intramedullary
splinting of the fibula were carried out. No attempt was made to achieve
anatomical reduction. Intermediate screws are placed in the main fragments
e-f AP and lateral views at 5 months. The fracture has healed by
indirect bone healing. Length and alignment are correct.
g-h AP and lateral views at 1 year. Remodeling is complete.
Numerous clinical studies have demonstrated excellent results when applying
the biological or bridging technique of plating [10, 16, 18, 20–22]. Animal
experiments have been performed to study the effect of biological plating in a
multifragment subtrochanteric fracture model in sheep. This was used to compare
anatomical reduction to various forms of indirect reduction with subsequent
bridge plating . As a result, the group of indirect reduction healed with
greater production of bone mass and higher resistance to breaking. This caused
a decrease in failure rate.
Techniques of indirect reduction in combination with bridge plating
have proven, experimentally and clinically, to optimize healing in complex,
multifragmentary fractures. Direct anatomical reduction and interfragmentary
compression to provide absolute stability should be reserved for simple type A
fractures with minimal soft-tissue injuries that are not considered suitable
for intramedullary nailing. With locking plates , the trend to minimal access
surgery continues, so that submuscular tunnelling and plate introduction will
be facilitated by new reduction tools, instruments for radiographic and
endoscopic viewing and navigated surgery.
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