Radiological Evidence of Degenerative Joint
Disease (DJD)
Classification
- Primary osteoarthritis - most common in the older age group as
the result of wear and tear on articular cartilage over time.
- Secondary osteoarthritis - results from a previous process
that damaged cartilage such as trauma, or inflammatory arthritis.
The most commonly involved joints in primary osteoarthritis
are:
- Distal interphalangeal joints
- First carpometacarpal joint
- Weight bearing joints: spine, hips, knees
Imaging of degenerative joint disease
1. Diagnosis by plain films includes identification of:
- Asymmetric joint space narrowing
- Osteophytes-bony spurs
- Degenerative cysts
- Sclerosis of subchondral bone
2. CT or MRI are also useful on certain occasions
3. OA of the Hip
This is an image of DJD or OA of the hip
which should be differentiated from Rheumatoid Arthritis (RA).
Note the joint space is almost completely obliterated. There
is still a hint of joint space medially but the superior portion
is completely destroyed. The supralateral aspects are going
to be affected most because the weight is transfered through
the roof of the acetabulum. Note the sclerosis and oseophyte
formation (arrow).
4. OA of the Fingers
This is an image of DJD or OA of the finger joints. Note the
narrowing of the joint spaces and the increased density around the
joints due to the subchondral sclerosis (black arrows). There are
also a few osteophytes (white arrow).
5. OA of the Knee
These are plain film images of a right knee with narrowing of the
medial compartment and a widening of the lateral compartment. There
are also a number of osteophytes and a large subchondral cyst where
the bones have been rubbing on each other.
6. OA of the Spine
The left image is OA of the spine with resulting scoliosis. Note the
asymmetric disk space as well as the large osteophytes which develop
in attempt to bear some of the weight of the body (arrow). The right
image is a photo of a gross spine from another patient with OA of
the spine. Note the the large bulky osteophytes and subchondral
sclerosis of the abnormal disk as compared to the normal disk above
(arrow).
Inflammatory Arthritis
An inflammatory process with the target organ being the synovial
membrane leading to pannus formation (inflammatory exudate in the
lining of the synovial cells).
Rheumatoid Arthritis
Imaging in RA
1. Diagnosis usually made by plain film confirmation of:
- Osteopenia - a demineralization of the bone - is the result of
increased blood flow, due to inflammation, which washes out the
calcium.
- Early on in the inflammatory process,only the periarticular
portion of the bones are affected.
- Over time, the inflammatory pain causes disuse of affected
joints leading to generalized osteopenia of whole bones.
- Uniform joint space narrowing - a feature which helps
differentiate RA from OA.
- Marginal erosions at bare areas where synovium lies on bone
- Subluxation due to ligamentous or capsular laxity
7. RA of the Hands
If one metacarpal phalangeal joint (MCP) is involved with rheumatoid
arthritis, then typically all of the joints are involved. In this
image we see that every MCP joint is affected. The DIP (distal
interphalangeal) joints are relatively spared. This patient has also
developed ligamentous abnormalities due to RA. A radial deviation of
the carpus and ulnar deviation of the digits give the hands a
characteristic zig-zag pattern.
8. RA of the Hips
This is an image of advanced RA in the hips. At first glance, the
plain film resembles OA but note the joints are narrowed
symetrically unlike OA. There exists, however, some subchondral
sclerosis due to intervening secondary OA. The hips look like they
will migrate right into the middle of the pelvis this is called
protrusio acetabulae.
9. RA Cervical Spine
9b.. MRI is technique of choice when cord compression is suspected
(C1-C2)
The vertebral bodies appear white due to the large amount of fat
located in the marrow. Notice that the gap between C1 and C2 is too
wide. There is a synovial joint that sits between the odontoid
process and anterior arch of C1 which can be affected by RA. As the
pannus erodes the bone, it will also degenerate the alar check
ligaments which stablize C1. If the ligaments are weakened then C1
can impinge upon the spinal cord (arrow). Injury to the cord
occasionally occurs in surgery when the head is tilted back to
insert the endotracheal tube. This is why anesthesia will
occasionally have orthopedics check for C1-C2 laxity in surgical
patients with RA. The patient is asked to flex and extend their neck
and if they display a large degree of motion , then a CT scan is
generated to check the vertebrae
Ankylosing Spondylitis
10. Ankylosing Spondylitis
AP radiograph of the pelvis shows classic changes of ankylosing spondylitis. Note that the sacroiliac
joints are obliterated bilaterally with osseous fusion. In
addition, there is joint space narrowing of both hips, concentric
in nature, which is similar to rheumatoid arthritis in the
distribution of joint destruction. However, note that there
is extensive sclerosis of both the femur and the acetabulum
as while as large collar osteophytes. This differs significantly
from rheumatoid arthritis. Inflammatory sclerotic changes
of the large bones are common in patients with ankylosing
spondylitis
10b. Progression of Sacroiliitis in Ankylosing Spondylitis
  
An AP radiograph of the pelvis from 1975 shows that the sacroiliac
joints are normal radiographically. A subsequent radiograph in 1981
shows that there is irregularity of the sacroiliac joints, more so
on the iliac side of the joint. This is due to the fact that the
cartilage thickness of the ilium is less than that of the sacrum and
hence bone erosions appear first on the iliac side. A follow-up
radiograph in 1982 demonstrates that both the sacral and iliac sides
of both sacroiliac joints show conspicuous erosion and sclerosis.
The findings are characteristic of the symmetric seronegative
spondylarthropathies, including ankylosing spondylitis and arthritis
associated with inflammatory bowel disease.
11. Ankylosing Spondylitis of the Spine
 
AP and lateral views of the lumbosacral spine show classic changes
of ankylosing spondylitis. Note bilateral symmetric sacroiliac
erosive changes with sclerosis. Characteristically, delicate
vertical syndesmophytes bridge multiple vertebra causing a "bamboo
spine". On the lateral view, annular calcification is noted causing
the appearance of squared vertebral bodies
Crystal Arthritis
12. Calcium Pyrophosphate Deposition Disease
 
Calcium pyrophosphate deposition disease, also known as
pseudogout, is a very common entity. Radiographically, the presence
of chrondocalcinosis is typical of this entity. Common locations for
chrondocalcinosis include the knee, symphysis pubis, and triangular
fibrocartilage at the wrist. Chrondrocalcinosis in the setting of
CPPD is commonly associated with calcification of fibrocartilage.
The AP radiograph of both knees shows chrondrocalcinosis of the
menisci. The lateral view of the left knee (Erin, this is flipped
vertically) shows calcification within the menisci. The lateral view
of the right knee (Erin, flipped horizontally) also shows
calcification of the menisci. Incidentally, also noted in this
patient is Paget's disease of the right tibia, consisting of
enlargement of the proximal tibia, thickening of the cortex as well
as a lucent advancing front (arrow).
13. Gout
Dorsoplantar views of both feet show an asymmetric arthritis
involving the great toes predominantly as well as other joints. This
arthritis is characterized by well marginated erosions, a large area
of soft tissue swelling related to tophus, with relative
preservation of the joint space given the amount of periarticular
erosion present. The findings are typical of gout, which spares the
joint space itself until late in the disease. The erosions with
their overhanging edges have been called "Mickey Mouse ears" or
"cookie cutter" type erosions.
Neuropathic Arthropathy
14. Charcot Arthropathy
 
Charcot arthropathy, also known as neuropathic arthropathy, is most
commonly caused in the United States by diabetes. It commonly
affects the foot, and especially the midfoot region.
Radiographically, Charcot arthropathy is characterized by
fragmentation, sclerosis, swelling, and destruction of the affected
joints. It is difficult radiographically to separate from infection
and osteomyelitis, which are also common in diabetics
Charcot's arthropathy can affect both people with Type 1 or Type
2 diabetes. In the majority of cases only one foot is affected,
however both feet can be affected over a period of years. Diabetes
is usually long standing and diabetic neuropathy is always present
and quite severe.
Typically, the foot suddenly becomes very swollen and warm to touch
. The patient can recall no history of trauma or only a very minor
episode (eg. twisted the ankle a few weeks ago). The first clue to
the diagnosis is the disproportionate lack of pain. The second clue
is the slowness of recovery. (i.e the swelling does not go away).
X-ray at this stage may be normal or show a minor fracture but may
already show quite gross bone destruction.
At presentation, it is important to exclude other pathologies such
as gout, infective arthritis or osteomyelitis. The first two are
excluded by clinical examination, joint fluid examination and blood
tests. Distinction of osteomyelitis from Acute Charcot's Arthropathy
is always a difficulty. A practical rule of the thumb is that if
there has not been a break in the skin it is likely to be Charcot's
arthropathy
|
