OSTEOCHONDRITIS JUVENILIS
OSTEOMALACIA
O
immobilized in a plaster
cast
to allow
reattachment. Loose bone or cartilage
fragments in the knee are removed dur-
ing
arthroscopy.
Disruption
to
the
smoothness of the joint surface increas-
es the risk of
osteoarthritis
.
osteochondritis juvenilis Inflamma-
tion of an
epiphysis
(growing end of
bone) in children and adolescents, caus-
ing pain, tenderness, and restricted
movement if the epiphysis forms part of
a joint. The inflammation leads to soft-
ening of the bone, which may result in
deformity. The condition may be due to
disruption of the bone's blood supply.
There are several types:
Perthes' disease;
Scheuermann's disease, which affects
several adjoining vertebrae; and other
types that affect certain bones in the
foot and wrist.
The affected bone may be immobi-
lized in an orthopaedic
brace
or plaster
cast
. In Perthes' disease, surgery may be
required to prevent more deformity. The
bone usually regenerates within 3 years
and rehardens, but deformity may be
permanent and increases the risk of
osteoarthritis
in later life.
osteochondroma A noncancerous
bone
tumour, which is formed from a stalk
of bone capped with cartilage, and
appears as a hard round swelling near a
joint. An osteochondroma develops in
late childhood and early adolescence,
usually from the side of a long bone
near the knee or shoulder. The tumour
causes problems only if it interferes
with movement of tendons or the sur-
rounding joint, in which case it may be
removed surgically. Large osteochondro-
mas can interfere with skeletal growth,
causing deformity.
osteochondrosis See
osteochondritis
juvenilis.
osteodystrophy Any generalized bone
defect due to
metabolic disorders
. Types
of osteodystrophy include
rickets
;
osteo-
malacia
;
osteoporosis
due to Cushing's
syndrome or excessive intake of
cortico-
steroid drugs
; and bone cysts and bone
mass reduction associated with chronic
kidney failure
or
hyperparathyroidism
. In
adults, an osteodystrophy is usually
reversible if the underlying cause is
treated before bone deformity occurs.
osteogenesis imperfecta A
congenital
condition characterized by abnormally
brittle
bones
that are unusually suscep-
tible to
fractures
. The condition is caused
by an inherited defect in the
connective
tissue
that forms the basic material of
bone. Severely affected infants are born
with multiple fractures and a soft skull
and do not usually survive. Others have
many fractures during infancy and child-
hood, often as a result of normal
handling and activities, and it may be
difficult to distinguish the condition from
child abuse
. A common sign of the con-
dition is that the whites of the eyes are
abnormally thin, making them appear
blue. Sufferers may also be deaf due to
otosclerosis
. Very mild cases may not be
detected until adolescence or later.
There is no specific treatment. Frac-
tures are immobilized and usually heal
quickly, but they may cause shortening
and deformity of the limbs, resulting in
abnormal, stunted growth. Skull frac-
tures may cause brain damage or death.
Parents may have
genetic counselling
to
estimate the risk in future children.
Severe cases can be diagnosed prena-
tally by
ultrasound scanning
.
osteogenic sarcoma see
osteosarcoma.
osteoid osteoma A
bone
disorder in
which a tiny abnormal area of bone, usu-
ally in a long bone, causes deep pain,
which is typically worse at night. The
condition is cured by removing the area
of bone. (See also
osteoma.)
osteoma A hard, noncancerous, usually
small tumour that may occur on any
bone.
Surgical removal may be neces-
sary if an osteoma causes symptoms by
pressing on surrounding structures.
osteomalacia Softening, weakening, and
demineralization of
bones
in adults due
to
vitamin D
deficiency. Osteomalacia is
rare in developed countries; it most
commonly affects housebound, elderly,
and dark-skinned people who live in
countries that have less sunlight than
their country of origin.
Healthy bone production requires cal-
cium and phosphorus, which cannot be
absorbed from the diet without suffi-
cient vitamin D (found in certain foods
and manufactured by the skin in sun-
light). Causes of osteomalacia include a
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