Joint pathology_7

 NOTES

OSMOSIS.ORG

NOTES

JOINT PATHOLOGY

▪ Disorders affecting joints

▪ Most commonly caused by trauma

PATHOLOGY & CAUSES

▪ Asymptomatic or pain during rest/

movement

SIGNS & SYMPTOMS

DIAGNOSTIC IMAGING

▪ Radiography

▪ MRI

LAB RESULTS

▪ Synovial fl uid analysis

DIAGNOSIS

▪ Treat symptoms pharmacologically

▪ Surgical procedures

TREATMENT

osms.it/bakers-cyst

BAKER'S CYST

▪ Synovial fl uid accumulates in popliteal

bursa (between medial head of

gastrocnemius, semimembranosus

muscles) → swelling

▪ Adults: popliteal bursa communicates with

synovial sac; underlying knee joint disease

main cause

▫ Knee joint disease → ↑ synovial fl uid

production → synovial fl uid squeezes

through valve-like formation into bursa

→ fl uid unable to fl ow backward →

bursa enlarges → lump-like structure in

the popliteal fossa

▪ Children: noncommunicating cyst; usually

arises as primary process

PATHOLOGY & CAUSES CAUSES

▪ Chronic knee joint trauma

▪ Osteoarthritis

▪ Rheumatoid arthritis

▪ Meniscal tears

COMPLICATIONS

▪ Cyst enlargement

▫ In popliteal space → obstruction of veins

→ lower leg swelling

▫ Extension to calf → swelling, redness,

bruising, positive Homan’s sign (calf

pain during dorsifl exion of the foot) →

similar to deep-vein blood clot

▪ Rupture

GENERALLY, WHAT IS IT?

OSMOSIS.ORG

 Chapter 114 Joint Pathology

659

Figure 114.1 An MRI scan of the knee joint

in the sagittal plane demonstrating a Baker’s

cyst in the popliteal fossa.

▪ May be asymptomatic

▪ Stiffness and pain in the knee → worse

with prolonged standing

SIGNS & SYMPTOMS

DIAGNOSTIC IMAGING

Ultrasound and MRI

▪ Fluid-fi lled cyst; differentiation between

cyst, blood clot

X-ray

▪ Bone, joint pathology associated with cyst

OTHER DIAGNOSTICS

▪ Physical examination

▫ Lump in the back of the knee

DIAGNOSIS

SURGERY

▪ Surgical excision

OTHER INTERVENTIONS

▪ Fluid aspiration, glucocorticoid intraarticular injection → ↓ size and

infl ammation

▪ Treat complications

▫ Leg elevation, resting, analgesics

TREATMENT

osms.it/bursitis

BURSITIS

▪ Infl ammation of bursa (small sac located

between muscles, tendons, bone

structures)

▪ Infl ammation of bursa → ↑ production

of synovial fl uid → enlargement of

bursa → ↑ friction during movement →

symptomatology

▪ Most commonly affected bursas

▫ Subacromial, olecranon, trochanteric,

prepatellar, infrapatellar

PATHOLOGY & CAUSES CAUSES

▪ Autoimmune disorders

▫ Rheumatoid arthritis, ankylosing

spondylitis, scleroderma, systemic lupus

erythematosus → chronic course

▪ Overuse/trauma, gout, bacterial infections

(septic bursitis) → acute course

660 OSMOSIS.ORG

Figure 114.2 An individual with olecranon

bursitis.

Figure 114.3 An MRI scan of the elbow

demonstrating a high signal fl uid collection

in the olecranon bursa in an individual with

olecranon bursitis.

▪ Joint pain; stiffness of joints; surrounding

skin red

▪ Acute bursitis

▫ Tenderness, pain during activation of

muscles adjacent to infl amed bursa

▪ Chronic bursitis

▫ Swelling with minimal pain

SIGNS & SYMPTOMS

DIAGNOSTIC IMAGING

Ultrasound

▪ Differentiation from Baker’s cyst

LAB RESULTS

▪ Aspiration and analysis of synovial fl uid

▫ Infection: ↑ polymorphonuclear

leukocytes, proteins, ↓ glucose

▫ Gout: ↑ monosodium urate crystals

DIAGNOSIS

MEDICATION

▪ Non-steroidal infl ammatory drugs (NSAIDs)

▪ Injection of steroids, local anesthetics

▪ Septic bursitis

▫ Antibiotics

SURGERY

▪ Surgical excision

▫ Chronic or recurrent bursitis

OTHER INTERVENTIONS

▪ Resting, elevation

TREATMENT

OSMOSIS.ORG

 Chapter 114 Joint Pathology

661

Figure 114.4 Heberden’s node on the distal

interphalangeal joint of the right index fi nger

in an individual with osteoarthritis.

osms.it/osteoarthritis

OSTEOARTHRITIS

▪ Progressive loss of articular cartilage,

underlying bone of synovial joints

▪ Articular cartilage damage → chondrocytes

replace type II collagen with type I, ↓

proteoglycans → eventual exhaustion,

apoptosis of chondrocytes → ↓ elasticity,

↑ cartilage breakdown → clefts in articular

surface (fi brillations), “joint mice” in synovial

space with infl ammation of synovium →

bone exposition → rubbing other bone →

eburnation (polished ivory look)

▪ Due to damage/infl ammation, new bone

formation on edges of bone with outward

growth → osteophyte (enlargement of the

joint with a knob-like look)

▫ Bouchard nodes: proximal

interphalangeal fi nger joints affected

▫ Heberden nodes: distal interphalangeal

fi nger joints affected

▪ Most commonly affected joints

▫ Lower spine, hip, knee, foot and hand

joints

CLASSIFICATION

▪ Primary

▫ Usually idiopathic

▪ Secondary

▫ Caused by some other condition

(e.g. diabetes, alkaptonuria,

hemochromatosis, chronic joint injury)

RISK FACTORS

▪ Aging

▫ Cartilage thinning with ↓ hydratation

→ protein accumulation, collagen

crosslinking → cartilage is more

breakable; ↑ calcifi cation of meniscus,

cartilage

▪ Infl ammation → ↑ proinfl ammatory

cytokines

▫ IL1, IL6, TNF → ↑catabolism/↓

PATHOLOGY & CAUSES

▪ Sharp pain/burning sensation worsened by

prolonged activity

▪ Limited range of motion

▪ Morning stiffness > one hour

▪ No swelling

SIGNS & SYMPTOMS

anabolism of cartilage

▪ Obesity

▫ Excessive load, metabolic disorders

affect joints

▪ Genetic disorders

▫ Mutations in cartilage building collagens

(types II, IX and XI)

▪ Biological sex

▫ Biologically female more prone

▪ Previous joint injuries

▪ Infection

▪ Neurologic disorders

COMPLICATIONS

▪ Cystic degeneration of subchondral bone

▪ Surrounding ligaments, neuromuscular

abnormalities

662 OSMOSIS.ORG

Figure 114.5 An X-ray image of the pelvis

demonstrating osteoarthritis of the right hip

joint. The femoral head is malformed, there

is marked loss of joint space and there are

numerous subchondral bone cysts.

DIAGNOSTIC IMAGING

Radiography

▪ Loss of joint space

▪ Subchondral bone sclerosis

MRI

▪ Loss of joint space

▪ Subchondral bone sclerosis

▪ Osteophytes

▪ Visualisation of articular cartilage,

surrounding soft tissues

CT scan

▪ Displacement of foot, ankle, patellofemoral

joint

Bone scan

▪ Detect abnormalities

LAB RESULTS

▪ Arthrocentesis

DIAGNOSIS

MEDICATIONS

▪ Pain management

▫ Acetaminophen, tramadol, topical and

oral non-steroidal anti-infl ammatory

drugs (NSAIDs)

▪ Intra-articular injections

▫ Corticosteroids

▫ Sodium hyaluronate

SURGERY

▪ Osteotomy

▫ Individuals < 60 years with

malalignment of hip, knee joint

▪ Arthroplasty

▪ Stem-cell therapy

OTHER INTERVENTIONS

▪ Exercise

▪ Weight loss

▪ Physical therapy

▪ Electromagnetic fi eld stimulation for

individuals with knee osteoarthritis

TREATMENT

OSMOSIS.ORG

 Chapter 114 Joint Pathology

663

Figure 114.6 An X-ray image of the pelvis

demonstrating a slipped capital femoral

epiphysis on the left side.

osms.it/slipped-capital-femoral-epiphysis

SLIPPED CAPITAL FEMORAL

EPIPHYSIS

▪ Anterior displacement of femoral head

metaphysis, with epiphysis remaining in hip

acetabulum

▪ Caused by growth plate (physis) fracture

▪ Example of type I Salter–Harris fracture

usually affecting one hip

▪ Hypertrophy of growth plate → abnormal

endochondral ossifi cation, cartilage

maturation → growth plate weakness →

if too much force generated across growth

plate → slippage

CLASSIFICATION

▪ Based on disease course

▫ Acute: > three weeks

▫ Chronic: < three weeks

▫ Acute on chronic: chronic with acute

exacerbations

▪ Based on lesion stability

▫ Stable: walking possible with/without

crutches

▫ Unstable: walking impossible, even with

crutches

▪ Displacement of the femoral head from

neck; seen on radiography

▫ Type I: slippage < 33%

▫ Type II: 33–50%

▫ Type III: > 50%

RISK FACTORS

▪ Obesity

▪ ↓ thyroid, growth hormone

▪ Osteodystrophy

▪ Down syndrome

▪ Demographics

▫ Adolescent black males of African

descent most commonly affected

PATHOLOGY & CAUSES

▪ Hip, groin, knee pain

▪ Duck-like gait

▪ Hip in external rotation, fl exion

SIGNS & SYMPTOMS

COMPLICATIONS

▪ Osteoarthritis

▪ Metaphysis slippage → ↓ blood fl ow →

avascular necrosis

▪ Secondary SCFP affecting other hip; usually

within a year of fi rst SCFP

▪ Unstable displacement: ↑ complication rate

664 OSMOSIS.ORG

DIAGNOSTIC IMAGING

X-ray

▪ Anteroposterior X-ray

▫ Melting ice cream cone appearance

visible through line of Klein (virtual line

parallel to femoral neck’s upper edge)

▪ Frog-leg X-ray

▫ Straight line through center of femoral

neck anterior to epiphysis (rather than

central)

MRI, CT scan

▪ Accurate measurements of displacement

degree

DIAGNOSIS

SURGERY

▪ Fixation with a cannulated screw

▪ Preventive fi xation of the other hip

▫ Children with SCFP before the age of 10

▫ Persons with endocrinopathies

▪ Osteotomy

TREATMENT

osms.it/transient-synovitis

TRANSIENT SYNOVITIS

▪ Infl ammation of hip joint synovial

membrane

▪ Cause relatively unknown, but may be

preceded by upper respiratory tract

infection

▪ Most commonly seen in male children 3–10

years

▪ Most commonly limited to one side

PATHOLOGY & CAUSES

▪ May be asymptomatic

▪ Tenderness/pain during passive movement

▪ One-sided pain in the hip, groin, thigh, knee

▪ Antalgic limping

SIGNS & SYMPTOMS

▪ Diagnosis of exclusion

DIAGNOSIS

DIAGNOSTIC IMAGING

Ultrasound

▪ Fluids in joint capsule

LAB RESULTS

▪ Slightly ↑ white blood cell count

▪ ↑ Erythrocyte sedimentation rate

▪ ↑ C-reactive protein

▪ Needle aspiration

▫ Differentiation between transient

synovitis and septic arthritis

OTHER DIAGNOSTICS

▪ Limited abduction and internal rotation

MEDICATIONS

▪ NSAIDs

OTHER INTERVENTIO