OSTEOARTHRITIS

435 medicine teamwork

[ Important | Notes | Extra | Editing file ]

lecture objectives:
⇨ Not given -_-

Done By: Rawan Aldhuwayhi

Shamma Alsohaily
Revised By: Luluh Alzeghayer
References:
Slides+Davidson+Kumar+Master The board
 Basic Review of The Normal Joint
Joint Anatomy:
Joints classification
Functional structural
Synarthroses Amphiarthroses Diarthroses fibrous cartilaginous synovial
(immovable) (slightly moveable) (freely moveable)
e.g.: Skull e.g.: symphysis pubis, vertebral e.g.:shoulder e.g.: Skull e.g.:symphysis pubis e.g.: knee, elbow, shoulder

The normal articular surface of synovial joints Synovial joint anatomy

✓ articular cartilage (chondrocytes) surrounded by extracellular synovial joint consists of:
matrix includes: proteoglycans and collagen.
✓ The cartilage facilitates joint function and protects the underlying Subchondral
subchondral bone by distributing large loads, maintaining low bone
contact stresses, and reducing friction at the joint. Synovial
Fluid..
✓ Hyaline cartilage forms the articular surface and is AVASCULAR.
✓ It relies on diffusion from synovial fluid for its nutrition. Synovial membrane

Superficial zone Superficial zone is a

Middle zonemmmm Critical zone very imp to
maintain the integrity
Deep zone…
of the cartilage bc it
contains cartilage stem
cells , Cartilage stem Two bones articulating in this area of long bone
precursor cells which And now what you are see is where they are articulate
found in superficial there is structure which called cartilage and it is
zone and if there any
surrounded by a cavity which is filled with synovial fluid
injury it will go repair it.
If deficiency or loss which come from synovial membrane that lined the
degeneration joint capsule
Enthesis: Structure where must be muscle tendon attach to a bone
Synovial Fluid
Its synthesis:
→ Synovial fluid is formed by (synoviocytes).
→ Synovial cells also manufacture hyaluronic acid (HA, also known as hyaluronate):a glycosaminoglycan that is the
major noncellular component of synovial fluid.
Its Functions:
✓ Synovial fluid supplies nutrients to the avascular articular cartilage; it also
✓ provides the viscosity needed to absorb shock from slow movements
✓ provides elasticity required to absorb shock from rapid movements

Joint Physiology:
Cartilage homeostasis
How can the cartilage maintain its integrity?
balancing between syntheses and degradation
Cartilage matrix is constantly turning over and in health there is a
perfect balance between synthesis and degradation.
Degradation of cartilage matrix is carried out by aggrecanases(a
proteolytic enzymes) and matrix metalloproteinases, responsible for the
breakdown of proteins and proteoglycans, and by glycosidases,
responsible for the breakdown of GAGs.
In inflammatory arthritis:
Pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumour
necrosis factor (TNF), stimulate production of aggrecanase and
metalloproteinases, which contribute to cartilage degradation in
inflammatory arthritis.
 Osteoarthritis(OA)
:
General Characteristic of OA:
What is it:
- Heterogeneous group of conditions resulting in common histopathologic and radiologic changes or at
clinical level involving Entire joint organ,including:
o the articular cartilage
o the subchondral bone and
o the synovium.
- It characterized by progressive destruction and loss of articular cartilage with an accompanying
periarticular bone response.

Epidemiology:
- Internationally, osteoarthritis is the most common articular disease. Estimates of its frequency vary
across different populations.
- The prevalence of OA increases with age, and most people over 60 years will have some radiological
evidence of osteoarthritis although only a proportion of these have symptoms(Does not have necessary to
be clinical evidence).
- the prevalence of osteoarthritis is higher among women than among men.
- Interethnic differences in the prevalence of osteoarthritis have been noted (e.g.: white people have chance
to get knee OA than black..).

Involved Joints:
- most commonly involved joints:
o the distal interphalangeal joints (DIPJs) and first carpometacarpal joint of the hands
o first metatarsophalangeal joint(MTP) of the foot
o the weight-bearing joints (vertebrae, hips and knees).
- rarely affected joints: Elbows, wrists and ankles.
MCP is usually spared in OA while DIP can be affected those helping u to rule out RA

Aetiology:

▪ Obesity
▪ Heredity: Familial tendency to develop nodal and
generalized OA
▪ Gender: Polyarticular OA is more common in women; a
higher prevalence after the menopause suggests a role for
sex hormones
▪ Hypermobility: Increased range of joint motion and
reduced stability lead to OA
▪ Osteoporosis: There is a reduced risk of OA
▪ Diseases: See Table 11.12
▪ Trauma: A fracture through any joint. Meniscal and
cruciate ligament tears‫ قطع الرباط الصيلب‬cause OA of the
(calcium pyrophosphate
knee deposition in the cartilage)

▪ Congenital joint dysplasia: Alters joint biomechanics and

leads to OA. Mild acetabular dysplasia is common and
leads to earlier onset of hip OA
▪ Joint congruity: Congenital dislocation of the hip or a
slipped femoral epiphysis causes early-onset OA
▪ Occupation: Miners develop OA of the hip, knee and
shoulder, cotton workers OA of the hand, and farmers OA
of the hip
▪ Sport: Repetitive use and injury in some sports causes a
high incidence of lower-limb OA.
Pathology and pathogenesis:
Pathogenesis :
inflammation 1 Inflammation occurs as cytokines and metalloproteinases* are released into the joint
* Metalloproteinases, e.g. stromelysin and collagenase, secreted by chondrocytes degrade collagen and proteoglycans.
Cartilage 2 lead to breakdown of the cartilage matrix most imp thing to remember is there’s degradation of Extracellular matrix
changes (the level of proteoglycans eventually drops very low, the cartilage softens and lose elasticity and
compromising joint surface integrity)
3 Flaking and fibrillations (vertical clefts) develop along on the surface of an osteoarthritic joint.
o Over time, the loss of cartilage results in loss of joint space
Bony 4 The exposed subchondral bone responds with vascular invasion and increased cellularity,
Changes becoming thickened and dense (a process known as eburnation(sclerosis)) at areas of pressure
5 Attempts at repair produce cartilaginous growths at the margins of the joint which later become
calcified (osteophytes).
6 subchondral bone undergo cystic degeneration.
o Osteoarthritic cysts are also termed as: subchondral cysts, pseudocysts, geodes, or
Egger cysts if it involved the acetabulum(hip)
o Osteoarthritic cysts may range from 2 to 20 mm in diameter

Inflammation Cartilage changes Bony Changes

→ →

What is the different between the inflammation in RA and OA?

• RA: there is initial inflammation which is going to cause inflammatory response and damage.
• In OA: secondary inflammation occurring to whatever damage e.g. genetic or environmental
which lead to inflammation and different mediatory mediator

Clinical features:
Presenting Symptoms
- The main presenting symptoms are joint pain and functional restriction:
o in a patient over the age of 45, but more often over 60 years.
o Joint pain made worse by movement and relieved by rest
- Stiffness occurs after rest (‘gelling’) and in contrast to inflammatory arthritis there is only transient (Less
than 30 minutes) morning stiffness.
On Examination
periarticular limited joint muscle wasting of Crepitus (grating) is a common finding Synovitis
tenderness movement surrounding muscle and it is Palpable, sometimes audible when bending the mild or absent
joint, coarse crepitus due to rough articular surfaces.

deformity and bony enlargement of the joints:

Heberden’s nodes Bouchard’s varus deformity Valgus
are bony nodes are resulting from deformity
swellings bony marked medial tibio- Less
at the DIPJs swellings at femoral osteoarthritis commonly
(bone twist is toward the (bone twist is
the IPJs center of the body) away from the
center of the
body)
Subtypes of Primary OA:
Three Suptypes:
Primary generalized OA Erosive osteoarthritis Chondromalacia Patellae(Knee OA)
- common form of OA - This is rare. is a condition where the cartilage on the
- This is usually seen in combination with - The DIPs and PIPs are inflamed, undersurface of the patella deteriorates
nodal OA(Generalized nodal osteoarthritis) and equally affected and the and softens.
- Its onset is often sudden and severe. functional outcome is poor. Degeneration of the cartilage underneath
- There is a female preponderance and a - MCP is spared the patella and this is more seen in the
strong familial tendency. - Radiologically, there is marked runner and younger people
- The other joints affected are the knees, first osteolysis.
MTP,hip, and intervertebral (spondylosis). - Destructive phases are followed
by phases of remodelling.

Gull wing sign

Differential diagnosis:
- Crystalline arthropathies (ie, gout and pseudogout): Examination of synovial fluid using compensated polarized
microscopy will demonstrate crystals
- Inflammatory arthritis (eg, rheumatoid arthritis):OA is differentiated from RA by the pattern of joint involvement
and the absence of the systemic features and marked early morning stiffness that occur in RA.
- Seronegative spondyloarthropathies (eg, psoriatic arthritis and reactive arthritis):affecting the DIPJs may
mimic OA.
- Septic arthritis or postinfectious arthropathy
- Fibromyalgia:The main presenting feature of fibromyalgia is widespread pain, which is often worst in the neck and back
,The pain is characteristically diffuse and unresponsive to analgesics
- Tendonitis

Investigations:
1) The most accurate test(DIAGNOSTIC) is X-rays: are only abnormal in advanced disease and show
narrowing of the joint space (resulting from loss of cartilage), osteophytes, subchondral sclerosis
and cyst formation.x ray won’t show the cartilage
2) MRI demonstrates early cartilage changes. (It is not necessary for most patients with suggestive
symptoms and typical plain X-ray features).MRI looks for tendon ,muscle any soft structure
3) Laboratory tests are normal:Full blood count and ESR are normal. Rheumatoid factor is negative,
but positive low-titre tests may occur incidentally in elderly people.
Radiographic Changes
▶ Notes: MCQ!!! X ray shows
Arthrocentesis(aspiration joint space
of synovial fluid) always narrowing
indicated when an ,osteophytes &
infected or crystal induced subchondral cyst?
arthritis is suspected, Your mind always
particularly a X ray of hip showing changes of osteoarthritis. X ray of knee joint affected by OA, showing should think of OA
monoarthritis Note
the superior joint space narrowing (N),
osteophytes at joint margin (white arrows),
subchondral sclerosis (black arrows) and
subchondral sclerosis (S), marginal osteophytes subchondral cyst (open arrow).
(white arrows) and Egger cysts (C).
Management:
Non 1 Life style modification, physical and rehab therapy I can’t emphasize this enough
pharmacologic - Obese patients should be encouraged to lose weight, particularly if weight-bearing
joints are affected.
- Physical measures are the keystone of OA treatment. Local strengthening and aerobic
exercises improve local muscle strength, improve the mobility of weight-bearing joints
and improve general aerobic fitness
Pharmacotherapy 2 Medication:
- Paracetamol is the initial drug of choice for pain relief,
- NSAIDs are used in patients who do not respond to simple analgesia and should be used
in short courses rather than a continuous basis. NSAIDs can also be given topically.
- Intraarticular corticosteroid injections produce short-term improvement when there is a
painful joint effusion; systemic corticosteroids are not used.
Surgical 3 - Arthroscopy: look at the damages ,if there any problem with the tendon it can repair it.
- Osteotomy: Bone cutting to Correct bone Deformity
- Arthroplasty :Total joint replacement has transformed the management of severe
symptomatic OA
- Fusion and joint Lavage: Joint washing enables ridding the enzymes that are responsible for
damage to the cartilage
- Stem cell therapy? not approved
▶ Notes:
Treatment should focus on the symptoms and disability, not the radiological appearances

MCQs
1)50 y\o male diabetic patient,presents with an acutely 4)80 y\o female came to the hospital with low back pain
painful right knee for 5 days.He denied history of trauma.on after carrying heavy bag. What is the most appropriate
examination his temperature is 37.8 C with a hot swollen investigation you will order at the moment?
right knee.investgations revealed a white cell count of a. MRI
𝟏𝟐. 𝟔 × 𝟏𝟎𝟗 and a knee x ray shows reduced joint b. Bone scan
space.which one of the following qould be the most c. X-ray for fracture
appropriate step? d. Electrolytes levels
a. arthrocentesis
b. Blood culture
c. MRI of the right knee 5)An otherwise healthy middle aged man with no prior
d. Request rheumatoid factor medical history has had increase back pain and right hip
pain for the past 10 years . the pain is worse at the end of
2)A 45 y\o lady complains of gradual development of distal the day . He has bony enlargement of the distal
interphalangeal joins swelling and pain. She denied interphalangeal joints . A radiograph of the spine reveals the
presence of oral ulcers, skin rash and morning stiffness. On presence of prominent osteophytes involving the vertebral
examination the joints involved were 3rd and 4th DIP joints bodies .There is sclerosis and narrowing of the joint space at
bilaterally. What is the most likely diagnosis? the right acetabulum seen on radiograph of the pelvis
a. Gouty arthritis .which of the following pathological process is the most
b. Rheumatoid arthritis likely in the patient ?
c. Osteoarthritis a. gout
d. SLE b. reiter's disease
c. osteoarthritis
3) What is the treatment of choice of osteoarthritis? d. rheumatoid arthritis
a. Colchicine
b. Paracetamol
c. Prednisone
d. Propranolol

Answer key:
1 (A) | 2 (C)| 3(B) | 4 (C) | 5(C)