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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