The
Tibia
Fractures of the tibial shaft can occur after repetitive loading (stress
fractures) or following a single major traumatic event. The tibia is a
subcutaneous bone on its anteromedial margin and so any significant displacement
of the fracture is likely to result in an open injury. This skin over the tibia
is also a notoriously poor healer, and therefore the open fracture of the tibia
is an especially challenging problem for the trauma surgeon.
Mechanism
of injury
The mechanism of injury is particularly important with respect to the
energy involved, likely contamination of the wound and subsequent problems with
healing.
Stress
fractures
Stress fractures are particularly common in the tibia, particularly in
runners. The patient initially complains of pain during exercise, then pain
during and after exercise, and finally pain at all times. On examination there
may he little to find except for the fact that the tibia may be tender to
percussion. Initially the X-ray may be normal but after some weeks a faint haze
of callous may form locally over the site of the invisible fracture. This X-ray,
if combined with a history of continuous pain, is also characteristic for
osteosarcoma. Careful imaging with MRI or CT scan should be able to distinguish
these two diagnoses.
Management of stress fractures. This condition can prove very difficult to manage. It may occur at a crucial phase in an athlete’s training programme and at some stage, preferably sooner rather than later, it is going to become clear that training for the next few months, or indeed that season, is over. This can be very difficult for an athlete to accept, but until it is the condition is unlikely to settle. One problem may be the boredom that sets in if the significant proportion of the day, which was previously devoted to sport, is now to be spent resting. The alternative is to devise forms of exercise which are as strenuous and as time-consuming as the original activity, but which do not stress the tibia. For runners the nearest sport is cycling, a more remote possibility swimming. As the fracture is incomplete, it should not require any extra protection.
Low-energy
direct blow fractures to the tibia
The tibia may be broken by a direct blow such as a bumper injury to a
pedestrian. Despite the low-energy nature of the injury the skin and soft
tissues may be damaged over the fracture, so the fracture may be technically
open. If the fracture is a simple transverse fracture or a small butterfly
fragment the fracture may be stable to axial compression. In
Internal
fixation can be performed using either a plate or an intramedullary nail. A
plate cannot be fixed on the anteromedial border of the tibia because it is
subcutaneous. If there is any soft tissue defect then a careful plan will need
to be made with the plastic surgeons to ensure that cover of the fracture and
plate can be obtained. This may mean rotating a musculocutaneous flap. A plate
cannot be applied if cover cannot be obtained. Some surgeons apply bone graft to
all tibial shaft fractures which are plated because of their reputation for poor
healing.
The
tibia is well suited to intramedullary nailing (Fig.
23.37), especially using
the newer type of unreamed nail. Fixation can be obtained without unduly
disturbing the fracture. Proximal and distal locking provides control of axial
Operative
technique for unreamed intramedullary nailing
The patient is placed supine on a fracture operating table and the tibia
set either vertically with the femur horizontal or horizontally with the femur
vertical with the tibia above the rest of the table. Either way, the opposite
leg must be put in a different position so that the image intensifier can get a
clear AP and lateral view of the whole length of the tibia. The knee must be
bent up to the right angle to obtain access to the front of the tibia. A
Steinmann pin may be inserted into the calcaneum to provide the traction needed
to hold the tibia straight. If the tibia is allowed to hang vertical then the
weight of the tibia will provide that traction, but access from the image
intensifier may be more difficult. A small incision is made over the medial
margin of the patella tendon and the entry area on the extra-articular superior
surface of the tibia is identified by pushing back the fat pad with a periosteal
elevator. An entry hole is made into the tibia in the midline 2 cm back from the
anterior margin. A guide pin is inserted and a check made on the image
intensifier that the pin is indeed central and can be induced to pass down the
tibia, not out of the posterior cortex. This is only possible if the knee is
flexed at least 90 degree so that the roll back of the knee joint moves the femoral condyles and
patella back out of the way. It also relies on the entry point being made well
enough forward to allow the pin to pass vertically down the tibia without
impinging initially on the anterior cortex and further down on the posterior
cortex.
Leaving
the guide pin in place a circular cutter should be introduced over this pin to
open up a entry hole in the top of the tibia. A guidewire should then be
introduced and passed beyond the fracture down to the sclerotic remains of the
growth plate immediately above the ankle joint. Its length should be measured
and an unreamed nail mounted on its introducer, checking that the proximal screw
guides are on the medial side and that the nail’s curve is concave anteriorly.
The nail should be gently driven down, taking great care that initially it does
not penetrate the posterior cortex. When it reaches the fracture site the nail
should be driven slowly across the fracture site under direct image intensifier
control until the tip is lust above the ankle joint. The image intensifier
should then be centred over the distal holes making sure that the image of each
hole is round and not oval, and is exactly in the centre of the image
intensifier screen. Through a small skin incision the drill should then be
passed through the bone and through the locking hole. The length of screw needed
is measured with a depth gauge, and the two distal screws are introduced from
the medial side. The traction should then be removed and the nail at the
proximal end hammered back a little to draw the two fragments together, as they
may be slightly distracted when the nail is driven down. The jig is used to put
locking screws in the proximal end after once again checking that rotation is
correct.
A
final check is made using the image intensifier to ensure that all screws are
passing through the nail and engaged on both cortices (Fig.
23.38). A check is
also made of the distal circulation. Postoperatively, sensation should be
checked and the patient put under observation to ensure that circulation to the
foot is maintained and that a compartment syndrome is not developing. The
operation and immediate postoperative
Management
of the severely crushed tibia
In the high-energy injury to the tibia or where there are has been
severe crushing, the fracture may be highly unstable, contaminated and
surrounded by damaged soft tissues which cannot cover the fractures (Fig.
23.39). The patient will need resuscitating and a check made for other injuries.
The neurovascular status of the foot distal to the fracture will also need to
be checked. Where possible, Polaroid photographs should be taken and then the
fracture site wrapped in sterile saline swabs. The management of this fracture
is going to be by a team approach but the continuous re-exposure of the fracture
for each member of the team to inspect should be avoided as this will increase
the overall risk of infection. The first decision which will need to be made is
whether the limb is salvageable at all or whether an early amputation will
Complications
of tibial fracture and their management
Loss
of circulation to the foot
This is the most important complication and treatment must be started
immediately. If the limb is angulated it should be put straight immediately in
case the cause is merely kinking vessels to the foot. If this does not produce
an immediate improvement in circulation and the patient is young enough for a
repair of the vessels distal to the trifurcation to be a possiblity, then
arrangements need to be made immediately for surgery with an arteriogram on the
table. In some units a temporary stent is inserted to start reperfusion of the
foot before stabilisation of the fracture is attempted. In other units the
fracture is first stabilised. Otherwise there is a risk of disrupting the
vascular repair when stabilising the fracture. However, stabilising the fracture
significantly prolongs the warm ischaemic time of the foot so if it is decided
to stabilise the fracture first then this must be
Neurological
damage to the lower limb
If the soft-tissue damage around the fracture is so extensive that the
nerves cannot be repaired then primary amputation should be considered. An
insensate limb is unlikely to be of any use to the patient. If the nerves are
damaged in continuity, then some recovery can be expected and salvage of the
limb should be attempted. In closed injuries it is likely that damaged nerve is
in continuity and reasonable recovery can be expected provided that the blood
supply to the foot is restored as quickly as possible.
Infection
Infection of closed tibial fractures should be rare but of open tibial
fractures is common. All fractures with a puncture wound over them, however
small, should be treated as open fractures with contamination. They are all
treated in the same way. The skin edges of the wound should be excised and the
wound extended so that a clear view of all damaged tissue can be obtained. Any
dead and necrotic tissue should be removed and the wound should be washed out
with several litres of saline. The wound should be left open and re-inspected at
24 hours. Again, any necrotic or contaminated tissues should be excised and the
wound washed out. This process should be repeated until the wound is clean. When
this occur delayed primary close can be performed. Throughout this time high
levels of intravenous broad-spectrum antibiotics should be used aimed at
covering Staphylococcus, Streptococcus and Clostridium. If
infection develops when internal fixation is in place then the surgeon is caught
on the horns of a dilemma. Stabilisation of the fracture is needed to bring
infection under control but foreign material may be acting as a focus for the
infection. If a nail is in place then exchange nailing may need to be performed
under intravenous antibiotic cover. If a plate has been used then this too may
need to be replaced and all infected tissue excised and the wound washed out. An
alternative is to change fixation to an external fixator while removing all
internal metal ware.
Compartment
syndrome
A compartment syndrome may develop at any time in the first 48 hours
after the accident or after surgery. The patient usually complains of severe
unremitting pain with some numbness in the foot. The foot may be cold but there
may still be pulses even though a compartment syndrome is developing. Passive Dorsiflexion
of the toes produces severe pain in the leg. There are no reliable
investigations for compartment syndrome and if the condition is suspected then
the suspicion should be acted on.
Operation
note for fasciotomies
The Mubarek fasciotomy is probably the most reliable form as it ensures
that all four compartments are decompressed. An anterolateral incision allows
the anterior and perineal compartment to be entered through one incision. Care
is taken not to damage any nerves running in the fascia. The fascia is divided,
first with a sharp knife and then with a pair of scissors, under direct vision.
If a compartment syndrome is present the
Nonunion
Atrophic nonunion of the tibia is not uncommon. The blood supply to the
mid shaft of the tibia is not good and the soft-tissue cover is also minimal.
High-energy trauma may strip the periosteum off the tibia and infection may
further compromise healing ability. If after 8—12 weeks the tibia is showing
no radiological signs of union then delayed union is occurring and may go on to
nonunion. If a plate or nail has been used there is a risk that the metalwork
will fatigue before the fracture unites. Bone grafting can be used to stimulate
callus formation. If an intramedullary nail is already in place then exchange
nailing may need to be considered to stabilise the fracture with a new nail
which has not yet started to fatigue. Hypertrophic nonunion usually develops if
there is too much movement at the fracture site. This is unlikely to occur if
internal fixation or an external fixator is used but might occur if a plaster is
used to hold the fracture.
Treatment.
The fracture site should be opened and the cleft of the fracture cleaned of all
fibrous tissue. Consideration should then be given to inserting a reamed nail or
putting on a carefully moulded plate to compress the fracture ends and stabilise
them. Bone graft should then be put around the fracture site. The patient should
only be mobilised under careful supervision of a physiotherapist.