•A
group of conditions in which there is compression, fragmentation or
separation of a small segment of articular cartilage and bone. The affected
area show the features of ischemic necrosis include death of bone cells in
the osteoarticular fragment and reactive vascularity and osteogenesis in
the surrounding bone.
•The disorder occur mainly in adolescence and young adult during phase of
physical activity and initiated by trauma or repetitive stress. Some children
are unusually predisposed to bone ischemia because of an underlying
vascular coagulopaty.
•Pathology:
•Impact
injury may cause bleeding or edema in the subarticular bone result
in capillary compression or thrombosis and localized ischemia.
•Osteo articular fracture cause severance of local blood supply and
separation of a necrotic osteo chodral fragment.
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Traction injury similarly damage the blood supply to an apophysis.
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Crushing osteo chondritis:
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Occur in late adolescence but adult also affected.
Characterized by spontaneous necrosis of ossific nucleus in a long bone
epiphysis or one of the cuboidal bone of the wrist or foot.
Local anatomical feature as metatarsal bone longer than usual or disproportion
in length of radius and ulna result in undue compression stress being applied to
bone.
Pathological changes : bone death, fragmentation or distortion of the necrotic
segment and reactive new bone formation around the ischemic trabiculea.
Clinical feature: pain and limitation of joint movement, tenderness is sharply
localized to the affected bone.
X- ray: show increase density and in later stages there is distortion and collapse
of necrotic segment.
Common example: Freiberg disease of the metatarsal, Kohler disease of the
navicular, Kienbock disease of the carpal lunate and Panner disease of
capitulum, Scheuermann disease of the vertebral end plate.
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Splitting osteo chondritis:
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Small segment of articular cartilage and subjacent bone separate “dissect” as a
vascular fragment.
Typically occur in young adult usually men.
Affect particular site: the lateral surface of the medial femoral condyl in in the
knee, the antero medial corner of the talus in the ankle, the superomedial part
of the head of the femur in the hip joint, the humeral capitulum, and first
metatarsal head.
The cause: repeated minor trauma result in osteo chondral fracture of the
convex surface and fragment lose it’s blood supply.
Clinical feature: the knee is most commonly affected and patient present with
intermittent pain, swelling and joint effusion, if the affected fragment become
completely detached it may cause locking of the joint or the giving way.
X-ray: in tangential projection, the dissecting fragment is defined by radiolucent
line of demarcation, when separate the resulting crater is obvious.
MRI: show early changes before x-ray as decrease signal intensity in the area
around the affected osteo chondral segment.
Radionuclide scan by Tc-HDP show marked increase activity in the same area.
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Treatment: early; load reduction and restriction of activity in children this cause
complete healing while in adult the future coarse is doubtful.
later; partially detached fragment pinned back in position after
roughening of the base, while completely detached fragment; pinned back if
large and preserved, or else completely removed.
Pulling osteochondritis: traction apophysitis
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Result from tensile stress of physeal junction cause localized pain and increase
radiographic density in the unfused apophysis.
Seen at tibial tuberosity “Osgood Schlatter disease” and the calcaneal apophysis
“Sever disease” both subject to unusual traction force from powerful tendon
which insert in to the apophysis.
Kienbock disease:
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Relative shortening of the ulna “ negative ulnar variance “ predispose to chronic
stress over load of the lunate between the distal edge of the radius and the
carpus cause ischemic necrosis “ traumatic softening of the lunate” .
Pathology:
Stage I: ischemia without necked eye or radiographic abnormality.
Stage II: trabicular necrosis with reactive new bone formation and increase
radiographic density but little or no distortion of shape.
Stage III: collapse of bone.
Stage IV: disruption of radio carpal congruence and secondary OA.
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Clinical feature: patient young adult complain of pain and stiffness, tenderness is
localized over the lunate & grip strength is diminished, in later stages wrist
movement is limited & painful.
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X-ray: in stage I; show no abnormality but radio scintigraphy reveal increase
activity & MRI most reliable in detecting early changes. In stage II; x-ray show
mottled or diffuse density of bone, in stage III; the bone lock squashed &
irregular & in stage IV; there are OA changes in the wrist.
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Treatment: A) non operative; splinting of the wrist for 6-12 weeks relief pain &
possibly reduce mechanical stress.
B) operative; 1- if pain persist, 2- bone begin to flatten; while the wrist architecture is
only minimally disturbed up to stage III the aim is to reduce carpal stress by
shortening of the radius or lengthening of the ulna.
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If the bone become collapsed ;1- lunate replacement by prosthesis.
2- inter carpal fusion.
3- excision of the proximal raw of carpus.
C) If pain & restriction of movement become sever radio carpal arethrodesis give
stable pain free wrist.
Osgood Schlatter disease: apophysitis of tibial tubercle
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Traction injury of the apophysis in to which part of the patellar tendon is
inserted cause painful swelling of the tibial tubercle occur commonly in
adolescence. There is no history of injury & some time the condition is bilateral.
A young adolescent complain of pain after activity & of tender lump, it’s
situation over the tibial tuberosity is diagnostic some time active extension of
the knee against resistance is painful.
X-ray: reveal fragmentation of the apophysis.
Treatment: spontaneous recovery is usual but take time & it is wise to restrict
activity as cycling & soccer. If symptoms persist even after wearing back splint
there may be separate ossicle in the tendon which need removal.