MSK Flashcards
List three features seen in tendinopathy.
- degeneration, disorganisation of collagen fibres
- increased cellularity
- little inflammation
List some risk factors of tendinopathy.
age, chronic disease, DM, RA, adverse biomechanics, repetitive exercise, quinolone antibiotics
Describe the pathology of tendinopathy. (4 points)
- deranged collagen fibres/degeneration with a scarcity of inflammatory cells
- increased vascularity around tendon
- failed healing response to micro tears
- inflammatory mediators released IL-1, NO, PG’s - cause apoptosis, pain and provoke degeneration through release of MMPs
Lateral epicondylitis is commonly known as?
tennis elbow
What is another name for medial epicondylitis?
golfers elbow
What are the clinical features of tendinopathy?
pain, swelling, thickening, tenderness, provocative tests
List some non-operative treatment options for tendinopathy.
NSAIDS, physiotherapy, GTN patches, extra corporeal shockwave therapy - common ones
Discuss how physiotherapy is beneficial in tendinopathy.
eccentric loading - contraction of the musculotendinous unit whilst it elongates - beneficial in 80%
Discuss the operative treatment options for tendinopathy.
- debridement
- excision
- tendon transfers
What is compartment syndrome?
elevated interstitial pressure within a closed fascial compartment resulting in microvascular compromise
What are the common sites of compartment syndrome?
leg, forearm, thigh
What causes compartment syndrome?
- increased internal pressure e.g. bleeding, swelling, iatrogenic infiltration
- increased external compression e.g. casts/bandages, full thickness burns
Describe the pathophysiology of compartment syndrome.
continuous cycle of increased pressure, increased venous pressure, reduced blood flow, ischaemia, muscle swelling, increased permeability
Over time, what are the effects of ischaemia in compartment syndrome?
irreversible nerve and muscle damage
ischaemia
List some clinical features of compartment syndrome.
- pain - out of proportion to that expected from the injury
- pain on passive stretching of the compartment
- pallor
- parasthesia
- paralysis
- pulselessness
How might you use compartment pressure measurement in the diagnosis of compartment syndrome?
A pressure higher than 30 mmHg of the diastolic pressure in conscious or unconscious person is associated with compartment syndrome
How might you treat compartment syndrome?
- open any constricting dressings/bandages
- reassess
- surgical release
- later wound closure
- skin grafting/plastic surgery input
What is the commonest form of primary bone tumour?
myeloma
Where do secondary tumours in bone usually arise?
bronchus, breast, prostate, kidney, thyroid
Name two childhood secondary bone tumour origins.
neuroblastoma, rhabdomysosarcoma
What are the effects of metastases on bone?
- often asymptomatic
- bone pain
- bone destruction
- long bones - pathological fracture
- hypercalcaemia
- spinal metastatic effects
List some effects of spinal metastases.
- vertebral collapse
- spinal cord compression
- nerve root compression
- back pain
What is the best imaging technique for metastatic bone disease?
PET CT
What is the mechanism of destruction in bone tumours?
- osteoclasts, not tumour cells
- stimulated by cytokines from tumour cells
- inhibited by bisphosphonates
Where do sclerotic metastases of bone originate from?
- prostatic carcinoma
- breast carcinoma
- carcinoid tumour
Renal and thyroid carcinomas typically lead to which type of bone metastases?
solitary
Monoclonal proliferation of which type of cell leads to myeloma?
plasma cells
Discuss the impact of renal impairment caused by myeloma.
- precipitated light chains in renal tubules - Bence Jones protein in urine
- hypercalcaemia
- amyloidosis
Discuss the impact of marrow replacement caused by myeloma
- pancytopenia
- anaemia
- leukopenia: infections
- thrombocytopenia: haemorrhage
Name 3 benign primary bone tumours.
- osteoid osteoma
- chondroma
- giant cell tumour
Name 3 malignant primary bone tumours.
- osteosarcoma
- chondrosarcoma
- Ewing’s tumour
List four clinical features of osteoid osteoma.
- M:F 2:1
- any bone, especially long bones
- pain - worse at night, relieved by aspirin
- sympathetic synovitis - juxta-articular tumours
What is an osteoid osteoma?
a small, benign osteoblastic proliferation
What is an osteosarcoma?
a malignant tumour whose cells form osteoid or bone
What are the two commonest sites of osteosarcoma?
metaphysis of long bones e.g. around knee
early lung metastases
Define Paget’s disease.
- disorder of excessive bone turnover
- increased osteoclasis, increased bone formation, structurally weak bone
- disorganised bone architecture
Where is Paget’s disease common?
vertebrae, pelvis, skull, femur
List some clinical features of Paget’s disease.
- bone pain
- bowing of long bones
- pathological fracture
- osteoarthritis
- deafness
- spinal cord compression
- high cardiac output
- Paget’s sarcoma - lytic
- age > 40
- M > F
Name 3 cartilaginous tumours.
- enchondroma
- osteocartilaginous exostosis
- chondrosarcoma
What is an enchondroma?
lobulated mass of cartilage within medulla
Where does enchondroma affect? And what are the symptomatic features?
hands - swelling, pathological fracture
feet
long bones - often asymptomatic
What is an osteocartilaginous exostosis?
benign outgrowth of cartilage with endochondral ossification, probably derived from growth plate (metaphysis of long bones)
When is osteocartilaginous exostosis common?
adolescence
Is chondrosarcoma primary or secondary?
Both
primary - de novo
secondary - pre-existing enchondroma or exostosis
What sites are chondrosarcomas usually found?
axial skeleton, pelvis, ribs, shoulder girdle, proximal femur and humerus
What is a chondrosarcoma?
a cancer composed of cells derived from transformed cells that produce cartilage
What is Ewing’s sarcoma?
a malignant small, round, blue cell tumour. It is a rare disease in which cancer cells are found in the bone or in soft tissue
At what age does Ewing’s sarcoma peak?
5-15 years
Where does Ewing’s sarcoma affect?
long bones (diaphysis or metaphysis) flat bones of limb girdles
Name 3 common sites for Ewing’s sarcoma to metastases to.
lung, bone marrow, bone
What are the three basic steps in indirect fracture healing?
inflammation
repair
remodeling
Define indirect fracture healing.
formation of bone via a process of differential tissue formation until skeletal continuity is restored
Give more detail about the inflammatory process in indirect fracture healing.
- fracture haematoma forms from broken vessels
- 6-8 hours after injury
- swelling and inflammation to dead bone cells
Describe fibrocartilage callus formation in fracture healing.
- lasts about 3 weeks
- new capillaries organise fracture haematoma into granulation tissue - ‘procallus’
- fibroblasts and osteogenic cells invade procallus
- make collagen fibres which connect ends together
- chondrocytes begin to produce fibrocartilage
Describe bony callus formation in fracture healing.
- after 3 weeks and lasts about 3-4 months
- osteoblasts make woven bone
Discuss bone remodeling in relation to indirect fracture healing.
- osteoclats remodel woven bone into compact bone and trabecular bone
- often no trace of fracture line on X-rays
Define direct fracture healing.
‘direct formation of bone via osteoclastic absorption and osteoblastic formation, without the process of callus formation, to restore skeletal continuity’
- unique ‘artificial’ surgical situation
- relies upon compression of bone ends
- cutting cones cross fracture site
Briefly describe the blood supply of bone.
- endosteal - inner 2/3rds
- periosteal - outer 1/3rds
Which fractures are prone to problems with union or necrosis because of problems with blood supply?
- proximal pole of scaphoid fractures
- talar neck fractures
- intracapsular hip fractures
- surgical neck of humerus fractures
List some patient factors which inhibit fracture healing.
increasing age, diabetes, anaemia, malnutrition, peripheral vascular disease, hypothyroidism, smoking, alcohol
Name some medications which inhibit fracture healing.
NSAIDs, steroids, bisphosphonates
Describe how NSAIDs inhibit fracture healing.
- reduce local vascularity at fracture site
- additional reduction in healing effect independent of blood flow
- specifically COX-2 inhibitors
Describe how bisphosphonates inhibit fracture healing.
- inhibit osteoclastic activity
- delay fracture healing as a result
List potential fractures of the femoral neck.
- subcapital
- transcervical
- intertrochanteric
- subtrochanteric
- fracture of greater trochanter
- fracture of less trochanter
What is the hallmark sign of degenerative bone disease?
bone production
What is the hallmark sign of inflammatory joint disease?
periarticular erosions
What is the hallmark of depositional bone disease?
periarticular soft tissue masses
On X-ray how can you tell the difference between an active and old bone erosion?
active = ill-defined old = well-defined
What are the X-ray features of primary degenerative arthritis?
- narrowed joint space
- osteophytes
- subchondral sclerosis/cysts
Where is excessive wear and tear most common?
hips and knees
List the common causes of secondary degenerative arthritis.
trauma, infection, avascular necrosis, calcium pyrophosphate dihydrate deposition (CPDD) disease, RA, haemophilia
What causes CPDD disease?
idiopathic or associated with hyperparathyroidism and haemochromatosis
What impact does CPDD have on articular cartilage? And which bones does it most commonly affect?
calcification
- triangular fibrocartilage of wrist
- knee, hip, shoulder
- symphysis pubis
Describe the clinical features of CPDD.
- sudden onset of pain/fever
- tender, swollen, red joint
- may mimic septic arthritis
Which organisms commonly cause infectious arthritis?
staph, strep, TB
Which joints does infectious arthritis commonly affect?
- fingers from bites
- feet in diabetes
- hips in total hip replacements
Describe the clinical features of a infectious arthritis joint.
- soft tissue swelling
- destruction of cartilage/bone
- rapid loss of joint space
- +/- periosteal reaction
- osteoporosis
- later subluxation, OA, fusion
What are the radiographic findings in discitis?
- normal 1-3 weeks
- end-plate erosion
- disc space narrowing
- bone destruction
- paravertebral mass
- late - sclerosis
- ankylosis
What is the newest classification for RA?
presence of bilateral wrist, MCP or PIP joint enhancement on MRI and leads to a more accurate diagnosis of early RA
Describe a RA joint.
- soft tissue swelling
- synovitis
- effusion
- erosions and cysts
- joint space narrowing
- secondary degenerative changes
- bone marrow oedema
How do sero-negative inflammatory arthropathies differ from RA?
- negative rheumatoid factor
- normal bone density
- periostitis
- ankylosis (fusion)
- asymmetrical pattern
What gene is positive in sero-negative inflammatory arthropathies?
HLA-B27
List 4 causes of sero-negative inflammatory arthropathy.
Psoriatic arthritis
Ankylosing spondylitis
Inflammatory bowel disease
Reactive arthritis
Discuss the clinical features of psoriatic arthritis.
- usually skin and nail changes
- DIP joints of hands > feet
- pencil in cup deformity
- resorption of distal phalanges
- M=F, young adults
What is the other name for reactive arthritis?
Reiter’s syndrome
Discuss the clinical features of reactive arthritis including extra-articular manifestations.
- M > F
- 20-40 yrs
- asymmetrical oligoarthritis
- lower limb and sacroiliac joint
- dactylitis, enthesitis, bursitis
- circinate balanitis
- keratoderma blennorrhagicum
- mouth ulcers
What organisms cause reactive arthritis?
chlamydia, salmonella, shigella
What illnesses go in hand with reactive arthritis to form a triad?
- urethritis
- conjuncitivitis
Who does ankylosing spondylitis commonly affect?
- M:F 3:1
- 20-40 yrs
- HLA B27 +ve
Describe the clinical features of AS?
- low back pain
- stiffness
- bilateral sacro-illiitis
- squaring of vertebral bodies
- peripheral large joint arthritis
What is gout?
sodium urate crystal induced synovial inflammation
Who does gout usually affect?
elderly males, hereditary, young age suspect renal disease or myeloproliferative disorder
What are the radiographic features seen in gout?
- para-articular erosions
- sharply marginated with sclerotic rims
- overhanging edges
- no joint space narrowing till late
- little or no osteoporosis
- soft tissue swelling
- tophi not usually calcified
What is osteonecrosis?
avascular necrosis - refers to bone infarction near a joint
Where is osteonecrosis most common?
hip and shoulder
What are the consequences of osteonecrosis?
- pain from infarction
- death of subchondral bone can lead to collapse of the joint surface and end stage arthritis
Describe how osteonecrosis present with particular focus on femoral head.
- often asymptomatic and found on imaging
- pain - either from infarction or arthritis
- groin pain that worsens with weight-bearing and motion
- rest pain 2/3
- night pain 1/3
Osteonecrosis accounts for what percent of total hip replacement?
10
What is the peak age of prevalence for avascular necrosis?
40-50
What is the prevalence of osteonecrosis in sickle cell anaemia?
10
Discuss the pathophysiology of osteonecrosis.
- decreased intraosseous blood flow
- ischaemia
- bone necrosis
What can cause decreased blood flow in osteonecrosis? (4 points)
- Blood vessel disruption e.g. trauma
- Intraluminal obliteration e.g. fat microemboli and thrombosis
- Increased marrow pressure e.g. adipocyte hypertrophy and bone oedema
- Cytotoxicity
List factors which lead to poor outcome of osteonecrosis.
- extensive
- heavy loads
What happens to cause the necrotic cancellous bone to collapse?
- osteoclasts resorb the necrotic trabeculae while remaining ones serve as scaffolding for deposition of new bone
- ‘creeping substitution’ may not be fast enough
What is the crescent sign seen in osteonecrosis?
subchondral radiolucency which precedes subchondral collapse
Discuss what is seen in imaging in late stages of AVN.
- loss of sphericity and collapse of femoral head
- joint space narrowing
- bone remodelling