Knee injuries present frequently in virtually all age groups
within a pediatric practice. The age and mechanism of injury are
guidelines to a correct diagnosis. A swollen, painful knee in an
infant should raise the suspicion of child abuse or infection. In
the young child, significant ligament or meniscal injuries are rare,
but epiphyseal separations and fractures are more frequent. In the
adolescent, internal injuries to menisci and ligaments are common
and most often result from sports activities, with or without contact.
Patellar dislocations are also more common in adolescents.
The examiner should note bruising, swelling about the knee, the
presence or absence of an effusion, and the ability to walk or bear
weight. Most significant injuries are accompanied by an effusion
or hemarthrosis, and the swollen knee is difficult to examine due
to pain and limited motion. After the initial swelling has resolved,
specific findings of an internal derangement can be elicited. The
torn anterior cruciate is indicated by a positive anterior drawer
sign in which the tibia can be anteriorly subluxated with the knee
flexed.1 Meniscal tears often produce a clicking
or grinding when the knee is fully flexed and extended with medial
or lateral stress. Medial collateral and lateral collateral ligament
injuries allow the joint to open either medially or laterally with
stress in a 20° flexed position.
Radiographs should be evaluated and will show swelling only in
the case of meniscal or ligamentous injury. Widening of the distal femoral
growth plate suggests a separation injury of the growth plate (Salter
1). Elevation of the tibial spine indicates an injury in which the anterior
cruciate pulls a fragment of bone up from the tibial articular surface.
Initial treatment usually consists of splinting with compression
using a prefabricated knee immobilizer and ACE bandage.2 Aspiration
of the knee is not necessary. Reevaluation at 2 weeks allows for
a better physical exam for significant injury. Minor injuries will
usually be recovering by then, and significant injuries will show
persistent physical findings. A magnetic resonance imaging (MRI)
examination will help to define internal injuries that will require
A discoid meniscus is an abnormally shaped lateral meniscus found
in children of all ages (Fig. 214-1).3,4 It
may slip in and out of the joint causing the patient to feel something
pop over the lateral aspect of the knee joint. This may be somewhat
painful. The examiner can feel something pop along the lateral joint
line as the knee is flexed and extended. Over time, this may become
more painful and the “popping” may begin to limit
Diagram of partial resection of a discoid meniscus highlighting
the line of incision. Note that the posterior and anterior attachments
of the meniscus are left intact.
(Herring JA, editor. Tachjian’s Pediatric
Orthopaedics. Philadelphia: Saunders; 2008, p. ...