Trauma about the Knee, Tibia, and Foot

In this injury unique to children, the extreme distal or
proximal pole of the patella, together with a significant sleeve of
articular cartilage, periosteum, and retinaculum, is pulled off the
remaining main body of the patella (Fig. 9-1). The easiest pitfall in this fracture is to miss it at initial presentation (Fig. 9-2)
as there may only be a hint of ossified bone on initial radiographs.
The clinical picture at presentation usually includes a palpable defect
at the affected patella pole and an inability to fully extend the knee.

Any significant displacement should be fixed operatively
as there may be a significant articular cartilage avulsion not
appreciated on plain radiographs. If displacement is questionable,
flexion/extension lateral films should be made in superior and inferior
sleeve avulsion fractures to assess intrinsic soft-tissue stability.
Widening of the fracture gap with lateral radiographs in flexion
usually indicates a need for surgical stabilization.¹
During operative repair, retinacular repair is performed. If necessary,
sutures securing the patella tendon or quadriceps tendon may be passed
through drill holes through the patella for fixation. A nonoperative or
inadequate operative repair may progress to further displacement during
healing or rehabilitation (Fig. 9-3). A patella
sleeve fracture should not be confused with Sinding-Johansen-Larsen
disease, which is a chronic overuse injury that may be thought of as an
Osgood-Schlatter disease of the other side of the patella tendon.

At surgery the fragment is often found to be mobile, and
edges comprised of cartilage or fibrous tissue can be delineated by
probing with a Keith needle or scalpel blade. Excision of the fragment
and reattachment of the overlying quadriceps tendon to the patella is
usually curative, as reported by Bourne and Bianco.²

The first pitfall in these fractures is missing the
diagnosis. In the mature skeleton, ligaments usually fail before bone
when a bending stress is applied across the knee joint, thus following
a severe valgus stress across the knee a medial collateral ligament
(MCL) injury may occur (Fig. 9-4). As the
collateral ligaments originate on the epiphysis, in an immature
skeleton the physis will fail in tension and the knee will fall into
valgus though a Salter I or II fracture (Fig. 9-5).
A Salter I fracture may be nondisplaced and not radiographically
obvious. If suspicious of a Type I distal femoral undisplaced fracture,
the width of the physis is often greater than the contralateral physis
on radiograph. Clinically, there should be tenderness about the physis,
which is near the superior pole of the patella on either side of the
knee, and the knee may be unstable to valgus or varus stress. A stress
view radiograph or MRI can confirm the diagnosis; however, the need for
either test has been questioned as the initial treatment for both an
MCL injury and a nondisplaced distal femoral Salter I fracture is
immobilization. Repeat radiographic and clinical examination at 10 to14
days should help clarify the diagnosis.³
It is important to make a diagnosis at some point, because Salter
fractures about the knee require followup for evaluation of possible
growth plate injury.

The most common sequelae of distal femoral physeal
injuries is growth disturbance: either total arrest, which leads to
shortening, or partial arrest leading to angular deformity. Angular
deformity following distal femoral physeal injury is reported in 18% to
51% of recent series.⁴, ⁵, ⁶, ⁷
Growth injuries usually occur at the time of injury, and not a result
of mismanagement. Stay out of trouble (and depositions) by informing
parents before a growth disturbance that
the chances are nearly 50% for this problem occurring in their child,
and that surgery, including stopping the growth of the “normal” side,
may be needed in the future. While these injuries cannot be prevented,
one thing we can do is to follow children
with physeal injuries about the knee closely for at least one year. A
growth disturbance that is identified early may be treated with either
a contralateral epiphysiodesis (near the end of growth) or a
Langenskiöld procedure. An angular deformity recognized late may
require an osteotomy. An MRI with sequences chosen to highlight
cartilage can aid in the early diagnosis of a physeal bar formation.
One mechanism of injury that lies in wait to trap an unsuspecting
orthopaedic surgeon is an unrecognized physeal injury in association
with nonphyseal fractures in the femur or tibia. Hresko, et al.⁸
reported on seven children who had a physeal arrest about the knee in
association with nonphyseal fractures in the lower extremity.

In terms of treatment, one should strive for anatomic
reduction of these fractures. Series have reported rates of 43% to 70%
of distal femoral fractures treated without internal fixation have
displaced.⁹,¹⁰
Unless a fracture is truly nondisplaced and stable, stay out of trouble
by providing internal fixation. To avoid further injury to the physis,
reduction should be 90% traction and 10% manipulation, preferably in
the operating room with maximal relaxation. Salter I fractures may be
stabilized by smooth K-wires. Wires should not cross at the fracture,
but one should attempt to have the K-wires maximally separated at the
fracture line. Clinical experience and animal studies have demonstrated
that crossing the physis with smooth K-wires of the size commonly used
should not cause a growth disturbance.¹¹
Anteriorly displaced Salter I fractures deserve special mention.
Previous texts have recommended closed reduction and casting with the
knee in a flexed position; however, this treatment may lead to knee
stiffness, and makes evaluation of frontal plane alignment quite
difficult. Stay out of trouble by pinning these fractures and providing
immobilization in near full extension. Of course, the knee should not
be immobilized in extension until the fracture has been reduced, as
vascular occlusion or peroneal nerve injury may result.

A potential pitfall using intraarticular K-wires is the
possibility of a superficial pin tract infection progressing to a
septic knee joint. Early fracture healing usually allows these pins to
be pulled at 3 to 4 weeks, which helps prevent this complication.
Continued protected immobilization is still indicated until clinical
healing. In thin children, pins may be brought out of the skin proximal
to the fracture site, and thus not be intraarticular. Salter II
fractures may often be closed reduced and fixed with cannulated screws
in compression across the metaphyseal fragment.

Associated ligament injuries may occur at time of
injury; they should be evaluated following fracture fixation and again
following fracture healing. Knee stiffness can be expected in about 25%
of patients,¹² so the surgeon should
warn parents ahead of time, as well as consider early physical therapy.
Fortunately, while peroneal nerve and popliteal artery injuries may
occur with distal femoral physeal fractures, they are not common.

This injury is mentioned only to avoid the pitfall of
trying to treat a displaced fracture with casting without fixation. The
gastrocnemius muscle attaches to the distal femur, thus pulling the
distal femur into flexion. This tempts the surgeon to cast reduce and
cast this fracture in knee flexion. However, if the knee is casted in
flexion, exact alignment of varus/valgus positioning is nearly
impossible to verify. Unfortunately, once the knee is extended after
fracture healing, the full extent of varus or valgus malalignment
becomes apparent. Avoid this complication by providing fixation, often
with K-wires, flexible intramedullary nails, or an external fixator for
displaced distal femoral metaphyseal fractures.

Tibial tubercle fractures occur almost exclusively in
boys, usually during jumping sports such as basketball. This fracture
occurs along the apophysis deep to the tibial tubercle, and should not
be confused with Osgood-Schlatter disease (Table 9-1).

This fracture tends to occur in adolescents near
completion of physical maturity, so growth disturbance is usually not a
problem in these older kids. The fracture may extend into the joint, in
which case anatomic reduction is needed, and associated intraarticular
injuries such as meniscus or ligamentous injuries should be searched
for. Beware that some active knee extension may still be present
through retinacular fibers, so active knee extension does not rule out
a tibial tubercle fracture.

Tibial tubercle fractures may involve extensive
soft-tissue avulsion requiring repair as well. Sleeve avulsion
fractures of the tibial tuberosity extending over the anterior
metaphyseal area of the tibia have been recently described.¹⁵
These injuries are similar to patellar sleeve fractures in that initial
radiographs may show no more than small subchondral fragments of bone.
Davidson and Letts¹⁵ report that
fixation of the Type V sleeve avulsion fracture is challenging because
of a lack of a large bony fragment. They recommend fixation with
small-diameter screws and heavy nonabsorbable sutures between the
intact periosteum or bone and the large avulsed segment of periosteum.

The most common complication following fracture healing
is prominent hardware requiring removal. The use of multiple smaller
screws (4.5 mm instead of 7.3 mm) may help minimize this complication.

The most serious complication of this fracture is compartment syndrome.¹⁶,¹⁷
Because this fracture is associated with relatively low-energy trauma,
compartment syndrome may not be on the radar screen of the unsuspecting
surgeon. Compartment syndrome occurs presumably because of tearing of
anterior tibial recurrent vessels, which fan out at the tubercle but
retract into the anterior compartment when torn (Fig. 9-8). Close monitoring is necessary for patients treated

nonoperatively; careful inspection, possibly with prophylactic anterior
fasciotomy, is recommended for patients treated operatively.

This fracture is associated with lots of trouble.

In contrast to the distal femoral physis, the proximal
tibial physis has intrinsic anatomic stability from the proximal
fibula, an overhanging tibial tubercle, and the MCL extending beyond
the physis to insert into the upper metaphysis. Because of this
protection, separation of the proximal tibial epiphysis is relatively
rare and requires significant force.

The most serious injury associated with proximal tibia
physeal fracture is vascular compromise. The popliteal artery is
tethered by its major branches to the posterior surface of the proximal
tibial epiphysis, with the anterior tibial artery passing forward just
proximal to the interosseous membrane. A hyperextension injury that
results in posterior displacement of the upper end of the metaphysis
may stretch and tear the bound popliteal artery (Fig. 9-9). It is important to remember that even a fracture that appears minimally displaced at presentation

in an emergency department may have had significantly more displacement
at the time of injury, particularly in motor vehicle accidents (Fig. 9-10).

These fractures may be difficult to appreciate on plain
radiographs, and are associated with patellar dislocations. Despite the
fact that these fractures involve articular cartilage, they do not
always require surgery if they are in non-weight-bearing areas and
stuck in synovium out of the way of weight-bearing surfaces.

It has been proposed that a fracture of the proximal
tibial metaphysis without a fibula fracture may develop a valgus
deformity over 50% of the time.¹⁹
Maximum valgus occurs about one year following injury. A 15-year
followup of seven patients with this fracture demonstrated a mean of 8
degrees of improvement of the proximal tibia valgus from the point of
maximal deformity. Less well known is that every patient had a limb
length discrepancy (mean = 9 mm) at time of last followup.¹⁹

It is common sense to try to cast these fractures in no
valgus, and even a little varus if possible. It is unclear, and
probably unlikely, that anatomic operative reduction will prevent
future valgus.²⁰ Stay out of trouble
by expecting varus remodeling to be sufficient in most patients, and
wait at least 2 to 3 years following injury before considering
intervention in most cases. Valgus deformity has been shown to recur
following early osteotomies.²¹
However, if malalignment does not remodel over time, joint degeneration
of the lateral compartment requiring an osteotomy has been reported.¹⁹
For those rare cases in which intervention for the valgus deformity is
necessary, we recommend consideration of staple hemi-epiphysiodesis in
children with growth remaining.

The majority of tibial shaft fractures in children heal
well with casting, though loss of reduction is common in unstable
fractures. Fractures may be manipulated up to 2 to 3 weeks when the
callus is “sticky,” with good results.

One third of fractures of the tibial shaft, with the
fibula intact, tend to drift into varus and/or posterior angulation
over the first three weeks and deserve close monitoring during this
time.²² The initial cast should
attempt to mold maximum valgus; especially in lower third fractures,
consider casting the foot in equinus to prevent posterior angulation.
Residual or recurrent varus and posterior angulation of ≤10 degrees has
been shown to correct spontaneously with growth and remodeling.²² We would observe for remodeling a fracture with even more deformity prior to recommending open realignment or osteotomy.

These fractures tend to be the result of higher-energy
injuries than tibia fractures alone. While many may be managed by
casting alone, unstable fractures may require fixation. Unlike adults,
stabilization with K-wires alone is frequently sufficient for many
fractures, including open fractures. Wires may be left out of the skin
and removed in about 4 weeks in clinic after early callus formation.

Initial experience with flexible intramedullary nails in
tibia fractures are quite encouraging and applicable for most fracture
patterns, except truly length-unstable fractures. For open fractures,
intramedullary nails avoid the soft-tissue tethering of external
fixation and keep the plastic surgeons happy by maximizing their access
to the wound. In some cases, only one intramedullary nail may be used (Fig. 9-12). Flexible nails may by left out of the skin and removed in clinic after callus formation. External fixation, (a.k.a.

nonunion generators) may be indicated in length-unstable fractures and those near joints.

An oblique, nondisplaced fracture of the tibia, with the
fibula intact, often results from a young child falling while running.
The big pitfall here is missing the fracture (Fig. 9-13).
At times, in addition to standard AP and lateral views, oblique views
may be needed to see a nondisplaced spiral fracture of the tibia. If
the surgeon is convinced there is localized pain in the tibia (which
may be difficult in a toddler), and the child is not walking, many
recommend treatment for a

presumed
toddler’s fracture. However, always beware of the possibility of
infection, and counsel the family that if the symptoms are worsening
despite casting, return for reevaluation soon.

Common mechanisms of this injury include road drag or
lawnmower. The soft tissue and portion of the bone and physis about the
medial malleolus are removed in shear, usually in a high-energy, dirty
setting. Customarily, care efforts are focused on the open injury, and
the consequences of the physeal damage are not apparent until much
later (Fig. 9-17). While it is unproven,
covering the exposed physeal edge in an effort to prevent the formation
of a peripheral bony bar may be worthwhile. We have used bone wax for
this. Warning the family ahead of time, and recognizing and addressing
the growth disturbance early, may improve outcome and minimize surgery.

As above, this often occurs from road drag or lawnmower
injuries. Skin grafts and flaps are often needed, but plastic surgeons
warn us they are at risk of not “taking” due to motion about the ankle.
An external fixator spanning the ankle, with pins in the calcaneus and
metatarsals, allows wound care, promotes soft-tissue healing of graft
or flap, and prevents the development of ankle equinus (Fig. 9-18).

The distal tibial physis closes predominantly in a
medial to lateral direction over about an 18-month period. Fractures
through the partially opened lateral growth plate deserve mention
because they are usually intraarticular, often require operative
reduction, and have potential for being missed or undertreated.

A Tillaux fracture is an avulsion of the anterolateral
corner of the distal tibial epiphysis by the anteroinferior
tibiofibular ligament. These fractures are believed to occur secondary
to external rotation of the ankle, so the maneuver for closed reduction
is internal rotation. A triplane fracture has a more complex geometry,
with the fracture extending into the metaphysis. The fracture may be in
three planes (hence the name): the sagittal plane within the epiphysis
and extending into the joint; the transverse plane along the open
growth plate; and the frontal plane extending proximally into the
metaphysis. The metaphyseal component of the fracture is surprisingly
easy to miss at times, and often best appreciated in the lateral view,
which demonstrates a posterior metaphyseal fragment. The fracture may
be in one piece, or multiple pieces, but do not be distracted by the
exact nature of the fracture pattern—it is of secondary importance.

Stay focused on the most important issue in these
fractures: the joint surface. The amount of displacement, and more
important, the amount of intraarticular stepoff, is notoriously
difficult to assess on plain films, particularly when the child is in
plaster. To stay out of trouble, consider a CT scan for a Tillaux or
triplane fracture with any displacement seen on plain films (Fig. 9-19).
For fractures of questionable displacement, the child may be placed in
a long leg cast with internal rotation of the ankle, prior to the CT to
evaluate the fracture after attempted closed reduction.

As this fragment of bone is intraarticular, operative
treatment has been recommended for fragments with >2 mm
displacement, with series reporting an increased risk of poor results
in fractures healing with >2 mm displacement. We think an important
distinction should be made between joint stepoff and fracture gap. Some
surgeons will accept up to 5 mm of fracture gap in triplane fractures,
and possibly even more in a Tillaux fracture that does not involve a
significant amount of bone in a weight-bearing region. However, no more
than 2 mm of intraarticular stepoff can be accepted, and if present,
closed or open reduction using standard surgical principles is
indicated. Cannulated screws are helpful in these fractures. Often the
posterior metaphyseal fragment can be reduced and fixed through an
anterior incision.

One good thing about transitional fractures is that
there is no significant growth potential left in the growth plate, so
in terms of treatment the growth of the physis can be ignored. This is
one of the few times you can put a screw across an open growth plate
with a clean conscience.

The differentiation of a nondisplaced Salter I fibula
fracture from an ankle sprain in a child with an open physis may be
difficult on physical examination, and initial radiographs in both
conditions may be normal. In a fresh injury, the location of tenderness
usually allows one to make the diagnosis with some confidence. If there
is tenderness (and swelling) anterior to the distal fibula, along the
anterior talofibular ligaments, assume there is a sprain. Fibular
tenderness may be assessed by tapping with your finger on the posterior
half of the distal fibula that is free of the anterior talofibular
ligament. If there is bony tenderness, assume an occult Salter I
fracture. The bottom line, however, is that either injury could be
treated with functional bracing.