Infection of bone,joint and soft tissue 化脓性骨髓炎(purulent osteomyelitis) 金黄色葡萄球菌(staphylococcus aureus) Infection pathway 血行感染(haematogenous spread) 直接延伸(direct extend) 开放性骨折(open fracture)

Acute Purulent Osteomyelitis clinical symptom： pathology：metaphysis－cortex of bone－subperiosteum abscess －medullary cavity of bone－sequestrum(死骨）－plerosis(修复)

Acute Purulent Osteomyelitis X-ray film： Soft tissue Muscle interspace clouding Subcutaneous fat clouding bone Destruction of bone Sequestrum(死骨) Parallel periosteal proliferation(平行骨膜反应）

Acute Purulent Osteomyelitis CT：It is better than X-ray plain film.

Acute Purulent Osteomyelitis MRI：It is better than X-ray and CT. It can make early diagnosis, low signal in T1WI and high signal in T2WI. The wall of the abscess should be enhancement after injection of Gd-DTPA.

急性化脓性骨髓炎 Acute Purulent Osteomyelitis

双侧胫骨骨髓炎 Both tibiae acute purulent osteomyelitis

胫骨中下段感染

Chronic Purulent Osteomyelitis X-ray：bone hyperplasia or sclerosis, diaphysis asper(粗糙)，medullary cavity of bone narrow, destruction of bone, sequestrum CT：similar to X-ray MRI：hyperostosis osteosclerosis(骨质增生硬化),sequestrum and periosteal proliferation are low signal. MRI can show abscess cavity and fistula cannulas(瘘管) high signal.

Chronic Purulent Osteomyelitis(慢性骨髓炎)

慢性硬化性骨髓炎 （Garre Osteomyelitis ） Periosteal proliferation(骨膜增生)，cortex thickening， osteosclerosis， medullary cavity constriction or emphraxis(闭塞), no destruction and sequestrum

慢性局限性骨髓炎 （Brodie abscess of bone） Low toxicity(低毒性)pyogenic infection Metaphysis(干骺端) Light symptom Round destruction surrounded by osteosclerosis

Brodie abscess of bone 慢性局限性骨髓炎

Pyogenic Arthritis X-ray：articular capsule swelling, joint subluxation or dislocation，bone destruction(首先见于持重面），joint space constriction，even bone stiff(强直) CT：similar to X-ray film MRI：MRI can display synovitis, hydrarthrosis, destruction of articular cartilage. It is better than X-ray and CT.

化脓性关节炎 Pyogenic Arthritis

Tuberculosis of Bone X-ray film TB of Long bone: epiphysis and metaphysis osteoporosis and destruction, sediment sequestrum(泥沙样死骨) TB of Diaphysis：metacarpal bone(掌骨), metatarsal bone(跖骨)destruction, “tambour” (骨“气鼓”征) TB of Spine：collapse of vertebra，intervertebral space constriction, vertabral body confluence(融合)，cold abscess, calcification

Tuberculosis of Bone CT： MRI： TB of bone：destruction of bone, sediment sequestrum, soft tissue swelling TB of spine: bone destruction, sequestrum, cold abscess MRI： TB of spine

TB of spine 脊柱结核

Tuberculosis of Joint X-ray film CT similar to X-ray film Soft tissue swelling，joint space constriction，articular bone destruction(首先见于非持重面） Synovium TB of joint CT similar to X-ray film MRI hydrarthrosis, synovium swelling, articular cartilage and bone destruction, cold abscess

关节结核(TB of joint)

infection of soft tissue CT：hyperemia, edema, abscess MRI：it is best for making early diagnosis in infection of soft tissue

膝前皮下软组织脓肿

Arthritis

Definition Disease that affects bones on both sides of the joint space and Narrows the space in between them

Classification Hallmarks Hallmark Hypertrophic Bone production Sclerosis Infectious Hallmark Destruction of articular cortex Erosive Erosions

Hypertrophic Arthritis Degenerative arthritis Primary Secondary Charcot arthropathy

1º Degenerative Arthritis Intrinsic degeneration of articular cartilage Excessive wear and tear Most commonly hips and knees Less commonly shoulders and elbows

1º DJD of knees affects medial, weight-bearing surface 1º DJD of hips affects superior, weight-bearing surface

1º Degenerative Arthritis Hands Not due to mechanical stress F:M 10:1 Most often involves DIP joints Sclerosis Marginal osteophyte formation 1st MCP joint of thumb

1º DJD of Hands

2º Degenerative Arthritis Another process destroys articular cartilage Degenerative changes supervene How to recognize Atypical locations (CPPD and knee) Atypical appearance (Marked DJD of 1 hip) Atypical age (DJD in 20 year-old)

2º Degenerative Arthritis Causes Trauma Infection Avascular necrosis CPPD RA Hemophilia

2º Degenerative Arthritis More Causes Hemochromatosis Acromegaly Ochronosis Wilson's Disease Bottom line: Any arthritis can end as DJD

2º DJD of right ankle following fracture

Calcium Pyrophosphate Deposition Disease (CPPD) May be idiopathic or associated with Hyperparathyroidism, hemochromatosis Symmetric involvement: knees (most common), wrists, MCPs Sudden onset of pain and fever Clinically Tender, swollen, red, LOM

CPPD Findings Calcification of articular cartilage Knee, hip, shoulder Triangular fibrocartilage of ulna Symphysis Large subchondral cysts Preferential involvement of femero-patellar compartment

Chondrocalcinosis

Hypertrophic Arthritis Classification Degenerative arthritis Primary Secondary Charcot arthropathy

Charcot’s Arthropathy General Disturbance in sensation leads to multiple microfractures Pain sensation intact from muscles and soft tissue Causes Shoulders – syrinx, spinal tumor Hips – tertiary syphilis, diabetes Feet – diabetes

Charcot’s Arthropathy Findings X-ray findings Fragmentation Soft tissue swelling Destruction of joint Sclerosis Osteophytosis

Charcot’s Knees-Diabetes

Charcot’s Shoulder - Syrinx

Charcot’s Arthropathy of Foot - Diabetes

Classification Hallmarks Hallmark Hypertrophic Bone production Sclerosis Infectious Hallmark Destruction of articular cortex Erosive Erosions

Infectious Arthritis More common in adults Usually from local trauma-surgery or accident Children get osteomyelitis Destruction of articular cartilage & cortex Tends to affect one joint (DDx from gout) Fingers from human bites Feet from diabetes Hips from THRs

Normal articular cortex Normal joint Normal articular cortex

Infectious Arthritis Causes Usually staph - “early” destruction of articular cortex Rapid course (unlike most arthritides) TB spreads via bloodstream from lung More protracted course In children, spine most common; in adults, knee Severe osteoporosis Healing with ankylosis common in both

Septic arthritis of hip with pathologic fracture Acetabular white line R3 Septic arthritis of hip with pathologic fracture Normal hip

Septic arthritis of toe

TB septic arthritis over 1 year

Classification Erosive Arthritis Hypertrophic Hallmarks Bone production Sclerosis Infectious Hallmark Destruction of articular cortex Erosive Erosions

Erosive Arthritis General Synovial proliferation (pannus formation) Inflammation Erosions seen in small joints (hands) better than large (hips) Destroy portion of cortex

Erosive Arthritis Types Rheumatoid arthritis Gout Hemophilia Erosive osteoarthritis Rheumatoid variants Psoriatic arthritis Reiter's Ankylosing spondylitis Inflammatory bowel disease

Erosive Arthritis More Types Connective tissue disease Scleroderma SLE Jaccoud's arthropathy Sarcoidosis Rare Amyloid

Rheumatoid Arthritis General Bilaterally symmetrical Earliest change: STS MCP, PIP, ulnar styloid Radiocarpal jt most commonly narrowed Periarticular demineralization Begins MCP jts of 1st and 2nd fingers Large joints usually no erosions

Rheumatoid Arthritis General Can lead to 2º DJD Marked narrowing of joint space with intact articular cortex, think of RA Little or no sclerosis Especially, hips and knees

RA of Hips – Marked narrowing, little sclerosis

R3 RA Hands

RA usually involves 5th MT-P joint first RA of Foot

Gout General Long latent period between onset of symptoms and bone changes Asymmetric and monoarticular More common in males Most common at 1st MT-P joint Tophi rarely calcify Olecranon bursitis is common

Gout Findings Juxta-articular erosions Sharply marginated with sclerotic rims Overhanging edges (rat-bites) No joint space narrowing until later Little or no osteoporosis Soft tissue swelling Tophi not calcified

R3 Gout

R3 Gout

Erosive Osteoarthritis Post-menopausal females Changes like DJD but with marked inflammation and erosions IP joints of hands and carpal-MCP joint of thumb DDx: Psoriasis (skin changes)

Erosive Osteoarthritis

Erosive Osteoarthritis

Ankylosing Spondylitis HLA-B27 positive B/L SI arthritis Squaring of vertebral bodies Bamboo-spine from continuous syndesmophytes Peripheral large joint erosive arthritis

Ankylosing Spondylitis

Overview Hypertrophic Infectious Primary Secondary Degenerative Arthritis Primary Secondary Charcot Arthropathy Infectious Pyogenic Tuberculous

Overview Erosive RA Gout Hemophilia Erosive osteoarthritis Psoriatic arthritis Reiter’s Syndrome Ankylosing Spondylitis

Chronic Arthritis

Rheumatoid Arthritis RA Multilation disease(致残性疾病) Symmetric chronic polyarthropathy Incidence rate is about 1% Episode(发病) age: 40-70 F/M: 2-3/1 Small joints: hand, wrist, foot PIP，MCP（+）DIP（-）

Rheumatoid Arthritis RA X-ray plain film： Symmetrical fusiform(梭形) soft tissue swelling Joint space: widening----narrowing Bone matrix erosion in border of articular suface Articular suface clouding，subchondral cysts Regional (periarticular) osteoporosis(骨质疏松) Amyotrophy(肌肉萎缩)，joint deformaton，fibrosum stiff，dislocation or subluxation

Rheumatoid Arthritis RA

MRI synovitis early manifestation Soft tissue lesion Bone erosion pannus (血管翳) , granulation tissue(肉芽组织) Soft tissue lesion

Enhancement scan Synovium enhancement 5-10 minuts After Gd-DTPA injection Dynamical enhancement

MRI clinical application Earlier diagnosis Progress evaluation Effect evaluation

Rheumatoid Arthritis RA

Rheumatoid Arthritis

Rheumatoid Arthritis RA

Rheumatoid Arthritis RA 平扫 增强

Bone erosion

Subchondral cysts and bone erosions SE STIR SE C+

Carpal canal(腕管) syndrome

ankylosing spondylitis (强直性脊柱炎) X-ray：sacroiliitis(骶髂关节炎), small arthritis, ligament calcification “bamboo spine” CT and MRI: similar to X-ray appearance

Degenerative Osteoarthropathy X-ray film：irregular joint space narrowing，marginal osteophytes(骨赘),subchondral cysts, joint corpus liberum(游离体) Spine degenerative osteoarthropathy：include disc degeneration, apophyseal joint osteoarthritis, spondylosis(关节强直）

关节软骨消失 关节软骨变薄 关节软骨肿胀

退行性骨关节病

退行性骨关节病

图示：颈椎退行性变