OSTEOCHONDRITIS
DISSECANS (OCD)
Many activities place repetitive
stress on the legs, more specifically the knees. Knees
are extremely vulnerable to overuse injuries as well
as acute injuries from stresses brought against them.
When a young patient presents with generalized or anterior
knee pain, and there aren't any definitive abnormalities
after examination, OCD should be considered.
Definition
Osteochondritis Dissecans (OCD)
is a condition in which a section of articular cartilage
and its underlying bone slowly separates from the surrounding
bone. This condition is painful and can do significant
damage to the undersurface of the knee. The pain intensifies
when the bone separates because at this time you have
bone floating around the knee, and in and out of the
joint space.
Causes/Symptoms
The usual suspects of OCD are adolescents
to young adults, and men are more likely then women
to have OCD. The affected site is usually the medial
femoral condyle. About half of the time patients present
with some sort of trauma in the recent history. Patients
may present with swelling , locking, or pain to additional
sites. There's usually limitation with movements and
flexibility, also nearly always there is some quadriceps
atrophy.
A good test to reveal OCD is Wilson's
Test, where the knee is flexed to 90 degrees and the
tibia is rotated internally, and then the knee is extended.
Pain can usually be seen at about 70 degrees of flexion
around the medial femoral condyle. Sometimes patients
have deformities of the knee, such as genu valgum (knock-knees),
or genu varum (bow-leg).
Additional Studies
If a patient's findings include
the following: joint swelling, diminished thigh girth,
or a positive Wilson's Test, then additional study
is indicated. Usually radiographic study is the next
in line to try and solve the problem. The specific
x-ray that usually can locate signs of OCD are the
Tunnel View x- rays because they best show the intercondylar
notch, which is the region of most OCD lesions. Other
tests that can be helpful are MRI'S, Arthroscopy's,
and Arthrography's.
Treatment
If the problem is recognized and
diagnosed early then immobilization by cast or soft
knee immobilizer may be the prescribed treatment, along
with 4 to 6 weeks of rest including little or no weight
bearing. The leg can be casted in a way which protects
tibiofemoral contact for protection. Once x-rays show
good position and healing, the doctor will allow more
activity to proceed. The younger the patient and the
shorter the duration of symptoms the more satisfactory
the healing will be. In the older patient, or the more
chronic the lesion, surgery is often the treatment
of choice. If there's a loose bone in the knee surgery
is a definite to get it out of the knee. For the lesion
which is still attached there are a few alternatives
available, such as curettage and drilling, simple drilling,
and pinning in place what's left. Sometimes the surgery
can be done arthroscopically, but regardless of the
surgical method, cast immobilization for up to 8 weeks
will be necessary. If pins are used during the operation,
then a second operation will be later performed to
remove the pins.
Prognosis
Older people tend to have lots
more trouble than young folks with this condition,
but if the lesion is treated early enough then people
do very well. The problem with older folks is that
they sometimes already have degenerative joint changes
before surgery. With younger skeletally mature people
the outcome is often a lot better. The overall prognosis
is generally good to excellent, depending on the size
of the lesion and early detection.
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