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There are three types of arthritis(which often can be
distinguished radiologically):
1- Degenerative joint disease
Osteophytes,
Subchondral sclerosis
Uneven loss of articular space
2- Inflammatory arthritis
Unrnarginated erosions
Periarticular osteoporosis is common
Soft tissue swelling
Uniform loss of articular space
3- Metabolic arthritis
Lumpy bumpy soft tissue swelling
Marginated bony erosions with
overhanging edges
Degenerative joint disease (DJD) = osteoarthritis (OA).
80% of population > 50 years have radiological evidence of OA.
types:
--Primary OA
* No underlying local etiological factors
*Abnormally high mechanical forces on normal joint
*Age related
--Secondary OA
Underlying etiological factors:
* trauma, inflammatory arthritis, hemochromatosis,
acromegaly, congenital hipdysplasia, osteonecrosis, loose
bodies
*Normal forces on abnormal joint
Radiographic features
Five hallmarks:
* Narrowing of joint space,
usually asymmetrical
*Subchondral sclerosis
* Subchondral cysts (true cysts
or pseudocysts)
* Osteophytes
* Lack of osteoporosis
* Lower cervical and low lumbar spine are most comonly
affected.
* Osteophytes may encroach on neural foramina (best seen
on oblique views).
*Vacuum phenomenon: gas (N2),is pathognomonic of the
degenerative process.
* OA of the spine occurs in the apophyseal joints .
* Degenerative spondylolisthesis (pseudospondylolithesis)
Lumbar spondylosis. There is distal narrowing and a vacuum
phenomenon is present in the degenerative discs. Marginal osteophytes are
present. Inferiorly the facet joints show features of degeneration and, with the increase
in lordosis, the spinous processes are in contact
Cervical spondylosis
There are three types of inflammatory arthritis
1- Autoimmune arthritis
RA
Scleroderma
Systemic lupus erythematosus (SLE)
Dermatomyositis
2- Seronegative spondylarthropathies
Ankylosing spondylitis
Reiter's syndrome
Psoriasis
Enteropathic arthropathies
3- Erosive OA
Early changes
* Peri articular soft tissue
swelling (edema, synovial
congestion)
*Peri articular osteoporosis in
symmetrical distribution
(hallmark)
* Preferred sites of early
involvement
Hands: 2nd and 3rd MCP joint
Feet: 4th and 5th MTP joint
Late changes
*Erosions (pannus formation,
granulation tissue) first attack joint
portions in which protective cartilage
is absent (i.e., capsular insertion site).
* Erosions of the ulnar styloid and
triquetrum are characteristic.
* Subchondral cysts formation results
from synovial fluid, which is pressed
into bone marrow through destroyed
cartilage.
Subluxations , Carpal instability and •
ulnar deviation .
* Fibrous ankylosis is a late finding.•
Rheumatoid arthritis.
(A) The initial radiograph shows a hint of early trabecular loss around the proximal interphalangeal joint of a finger
with preservation of the joint space and early marginal cortical loss at the
base of the middle phalanx.
(B) The subsequent radiograph shows established erosive change in the area of ill-defined demineralisation in
association with joint space narrowing .
Rheumatoid arthritis. Bilateral changes are fairly symmetrical. Softtissue swelling is demonstrated, especially over the ulnar
styloids. Erosions are demonstrated at the carpus, distal radius
and ulna, with joint space narrowing and collapse of bone.
Metacarpophalangeal erosions are also seen associated with joint
space narrowing. There is a swan-neck deformity of the right
fifth distal interphalangeal joint
Gross rheumatoid arthritis at the
carpus with ulnar deviation,
subluxation and joint narrowing
at the metacarpophalangeal
joints.
Boutonniere deformities are
present at the index and little
fingers.
Seronegative spondyloarthropathy of the axial skeleton and proximal large
joints.
Clinical: males >> females. HLA-B27 in 95%. Insiduous onset of back pain and
stiffness. Onset: 20 years.
Radiographic features
* SI joint is the initial site of involvement:
bilateral, symmetrical
Erosions: early ,Sclerosis: intermediate , ankylosis: late
* Contiguous thoracolumbar involvement
Vertebral body "squaring": early osteitis
* Syndesmophytes
* Bamboo spine: late fusion and Bamboo spine
ligamentous ossification
*ankylosed spine (fracture)
* Enthesopathy is common(("whiskering of tuberosities )
* Arthritis of proximal joints (hip > shoulder) in 50% ,erosions and
osteophytes
Radiographic features
*Flowing osteophytes of at least four
contiguous vertebral bodies
*Preserved disk height
*No sacroiliitis or facet ankylosis
*Calcification of ligaments and tendons
*Associated with hypertrophic DJD
OA with superimposed inflammatory, erosive
changes. Characteristically affects middleaged women.
Radiographic features
* Erosive and productive changes of DIP and
PIP
* Gull-wing pattern: secondary to central
erosions and Marginal proliferation
osteophytes .
Typical involvement of first CMC may help
distinguish erosive OA from rheumatoid
arthritis (RA), psoriatic arthritis, and adult
Still's disease.
* Interphalangeal fusion may occur.
Heterogeneous group of entities characterized by
recurrent attacks of arthritis secondary to
deposition of sodium urate crystals in and around
joints.
*90% of patients are male
*Causes due to either Uric acid overproduction, 10%
or underexcretion, 90%.
Radiographic features
*Lower extremity > upper extremity; small joints > large
joints
* First MTP is most common site
* Marginal, peri articular erosions: overhanging edge
* Erosions may have sclerotic borders
* Joint space is preserved
* Soft tissue and bursa deposition
Tophi: juxtaarticular, helix of ear
Bursitis: olecranon, prepatellar
* Erosions and tophi only seen in longstanding disease
* Tophi calcification, 50%
*Chondrocalcinosis
Infectious arthritis usually results from hematogenous spread to synovium and
subsequent spread into the joint.
Direct spread of osteomyelitis into the joint is much less common.
The diagnosis is made by joint aspiration.
Organism , Staphylococcus aureus (most common) ,B-Streptococcus in
infants , Salmonella is seen in sickle cell patients ; however, the most
common infection in sickle cell patients is Staphylococcus.
Radiographic features
Plain film
* Joint effusion
* Juxtaarticular osteoporosis
* Destruction of subchondral bone on both sides of the joint
Primary loss of sensation in a joint leads to arthropathy.
Distribution helps determine etiology.
Causes
Diabetes neuropathy: usually foot
Tertiary syphilis : usually knee
Syringomyelia: usually shoulder
Radiographic features
Common to all types
*Joint instability: subluxation or dislocation
*Prominent joint effusion
--- Hypertrophic type, 20%
Marked fragmentation of articular bone
Much reactive bone
--- Atrophic type, 40°/0
Bone resorption of articular portion
--- Combined type, 40%
Osteonecrosis (avascular necrosis, ischemic necrosis, aseptic
necrosis) may be caused by two mechanisms:
* Interruption of arterial supply
* Intra/extraosseous venous insufficiency.
The pathophysiology of all osteonecrosis is the same:
Ischemia > revascularization >repair > deformity>
osteoarthrosis
Plain films
Findings lag several months behind time of injury.
These findings include areas of radiolucency, fissuring ,
fragmentation , bone collapse and condensation , end
with dense and flat bone with loss of bone contour and
secondary osteoarthritis
MRI
Most sensitive imaging modality: 95%-100% sensitivity
Legg-Calve-Perthes disease : osteochodrosis of the femur head
Usually affects 5-10 years , started as hip pain , if not treated it will ends with
mushroom deformity due to neglected and untreated perthis seen later on
and is liable for early OA chnges .
Perthes' disease. A series of
radiographs showing the stages
of healing. (A) The initial
radiograph shows a flattened,
sclerotic femoral head
The left femoral neck is broadened, the
metaphysis sclerotic
with focal areas of lucency, the growth
plate irregular and the femoral head
flattened and sclerotic. It is uncovered
laterally. The joint space appears
widened
Scheuermann's disease : (adolecent
Kyphosis).
osteochodrosis of the vertebral end plates .
Usually affects 8- 10 years , characterized by
erosion of anterior superior and inferior
vertebral margin resulting in decrease in the
height of anterior part of the vertebra
(vertebral wedging ) ending with kyphosis.
Osgood-Schlatter : 12-16 y,osteochodrosis of
the tibial tuberocle.
Blount's disease: tibial epiphysis
Kohler's : 4-8 y ,osteochodrosis of the
Navicular bone .
Kienbock's: adults , osteochodrosis of the
lunate bone .
Osgood-Schlatter
disease.
Fragmentation of the
tibial tuberosity
Scheuemann's disease
Osteochondritis of
lumbar vertebral bodies
(advanced case).
Adolescent kyphosis
Osteochondritis dissecans :
affects the large articular surface , commomnly medial femural condylee
,talus and trochlea .
Ends by separation of the affected part in to the joint space resulting in
intra-articular loose body .
Osteochondritis dissecans of the medial femoral condyle
Osteochondritis dissecans of the medial
part of the articular
surface
An abnormally lax joint capsule allows the femoral head to fall out
of the acetabulum, leading to deformation.
Predisposing factors for the development of CDH are:
* Abnormal ligamentous laxity (effect of estrogen; fema1e:male = 6:l)
* Acetabular dysplasia .
CDH occurs most commonly (70%) in the left hip. Bilateral
involvement is seen in 5%.
Radiographic features
US (commonly used today) at 1-3 months
* Normal femoral head is covered at least 50% by acetabulum , In
CDH < 50% of femoral head is covered by acetabulum .
Plain film
At 3-6 months :
By doing special veiw (Von Rosen veiw )by abduction of the thigh 45 degree and
internal rotation .
In DDH the lines that drown through the femura will meet in higher level than the
normally should at lumbosacral joint .
6 months and later
* AP veiw ( femural epiphysis are visualized ):
* Superolateral displacement of proximal femur (disturbed shenton’s line )
* Increase in acetabular angle
* Small capital femoral epiphysis
Femoral head is located lateral to Perkin's line •
•
* Other features that are sometimes present
Abnormal sclerosis of the acetabulum
Shallow acetabulum
Formation of a false acetabulurn
Delayed ossification of femoral head