Management of orthopaedic conditions Flashcards
What are osteogenic cells? What do they do?
Bone stem cells
What are osteoblasts? What do they do?
Bone forming cells
Secrete osteoid
Catalyse mineralisation of osteoid
What are osteocytes? What do they do?
Mature bone cells
Formed when an osteoblast gets embeded in its secretions
Sense mechanical strain to direct osteoblast and osteoclast activity
What are osteoclasts? What do they do? From where are they derived?
Bone breaking cells
Dissolve and resorb cells by phagocytosis
Derived from bone marrow
What is the fundamental unit of compact bone?
Osteon
How does having few spaces between osteons in compact bone contribute to function?
Provides protection, support and resists stresses produced by weight of movement
Describe the structure of osteons
concentric ‘Lamellae’ around a central ‘Haversian Canal’
‘Haversian Canal’ – contain blood vessels, nerves and lymphatics.
What are lacunae and what radiates from lacunae?
Lacunae – small spaces containing osteocytes
Tiny Canaliculi radiate from lacunae filled with extracellular fluid.
What are Volkmann’s canals?
Transverse perforating canals
Structure of long bones (layers)
Mechanisms of bone fracture
Pahtological causes of bone fracture
Classification of fracture patterns
Describe this radiograph
Mid/distal third tibia
Simple
Transverse
15%lateral translation- you describe translation based off distal fragment
Minimal angulation (distal part anteriorly tilted 10degrees)
Describe this fracture
Mid/distal third tibia/fibula
Immature skeleton- growth plate still open
Multifragmentary
Oblique (butterfly)
Valgus angulation (20 degrees)
Anterior?? tilt (20 degrees)
Minimal translation
Why are children’s bones more elastic than an adults and what can this lead to?
Increased density of haversian canals
Therefore you can get:
Plastic deformity
bends before breaks
Buckle fracture
Greenstick
– like the tree
One cortex fractures but does not break the other side
Fracture reduction classification
Holding a fracture: classification
Fixation classification
What is done in rehabilitation and what are the principles of rehabilitation?
Physiotherapy
Urgent fracture complications
Local visceral injury
Vascular injury
Nerve injury
Compartment syndrome
Haemarthrosis
Infection
Gas gangrene
Less urgent fracture complications
Fracture blisters
Plaster sores
Pressure sores
Nerve entrapment
Myositis ossificans
Algodystrophy
Joint stiffness
Tendon lesions
Ligament injury
Late fracture complications
Delayed union
Mal union
Non union
Avascular necrosis
Muscle contracture
Osteoarthritis
Joint instability
What do we mean when we say that the femoral head has a retrograde blood supply?
blood supply comes up through capsule, not down through heart
Describe the risk to blood supply and of AVN in the case of extracapsular, intracapsular undisplaced and intracapsular displaced fractures
Extracapsular: minimal risk to blood supply and AVN
Intracapsular: if undisplaced: less risk to blood supply
If displaced: 25-30% risk AVN
How would we define fitness/ mobility in >65 when deciding whether to do total hip replacement or hemiarthroplasty in NoF fractures?
Fit and mobile:
Walks >mile day
Independent
Minimal comorbidities
Less fit:
Lower mobility
Multiple comorbities
How do we classify joints?
Describe the mobility and give examples for each type
Fibrous (immoveable): sutures, syndesmosis, interosseous membrane
Cartilaginous (semi-moveable): Synchondroses (e.g. sine), symphyses (e.g. pubic)
Synovial (freely moveable): ball and socket, plane, pivot, hinge, saddle, condyloid
Give examples for each type of synovial joint
How are synovial joints stabilized?
What is cartilage composed of and what is its blood supply?
Cartilage is composed of:
1) specialized cells (chondrocytes)
2) extracellular matrix: water, collagen and proteoglycans
(mainly aggrecan)
Cartilage is avascular – it has no blood supply
What is aggrecan?
a proteoglycan that possesses many chondroitin sulfate and keratin sulfate chains
-characterized by its ability to interact with hyaluronan (HA) to form large proteoglycan aggregates
Two major divisions of arthritis?
Radiographic changes in Rheumatoid Arthritis vs. osteoarthritis
What does joint space narrowing indicate and how does it differ between osteoarthritis and rheumatoid arthritis
Joint space narrowing indicates articular cartilage loss. This can occur in osteoarthritis (primary abnormality) and in Rheumatoid Arthritis (secondary damage due to synovitis)
What are osteophytes at
a)DIP joints
b) PIP joints known as
a) Heberden’s nodes
b) Bouchard’s nodes
Early radiographic sign of rheumatoid arthritis? What other types of inflammatory arthritis can this indicate?
Juxta-articular osteopenia is common early radiographic sign in inflammatory arthritis of any cause
Where do bony erosions initially occur in rheumatoid arthritis?
Erosions occur initially at the margins of the joint where the synovium is in direct contact with bone (the ‘bare’ area)
WHO definition of osteoarthritis?
chronic disease characterized by the deterioration of cartilage in joints which results in bones rubbing together and creating stiffness, pain, and impaired movement.
OA is a degenerative disease of what type of cartilage?
Chondral cartilage
What occurs in late stage OA?
Inflammation occurs late in disease cf. rheumatoid
Inflammatory mediators include proteinases, e.g., matrix metalloproteinases (MMPs) and aggrecanases, and inflammatory cytokines, including interleukin (IL)-1β and tumor necrosis factor α (TNFα), which enhance the synthesis of proteinases and other catabolic factors to degrade the articular cartilage membrane
OA risk factors
What are the key history points for suspected OA?
Pain (exertional/rest/night)
Disability: walking distance/stairs/giving way
Deformity
Previous history: trauma/infection
Treatments given (physio/injections/operations)
Other joints affected
What is this deformity?
Valgus
Likely reason for this scar?
ACL reconstruction surgery
What special tests can be used to look for ACL injury?
Anterior drawer test
Lachmanns (pictured)
Radiographic changes seen in OA?
Joint space narrowing
Subchondral sclerosis
Subchondral cysts
Osteophytes
OA management
Which type of operation is this?
Total knee replacement
What type of operation is this?
Ankle fusion
Give examples for bone infection
Bone: osteomyelitis
Joint: septic arthritis
How can osteomyelitis be classified
Acute or chronic
Primary or secondary
Give examples for bone infection
Bone: osteomyelitis
Joint: septic arthritis
Signs of osteomyelitis
Pain/swelling/discharge
Systemic signs:
Fevers, sweats wt loss
Signs of septic arthritis
Pain
Joint swelling/stiffness
Fevers, sweats, wt loss
Bone infection investigations
Radiology:
Plain films
MRI scans: bony architecture/collections
CT if MRI not available
Bone scans: multifocal disease
Labelled White cell scans
Bloods:
CRP (acute marker)
ESR slower response
WCC
TB culture/PCR
Treatment of osteomyelitis
Antibiotics: iv weeks
Surgical drainage: especially collections/sequestrum
Chronic: antibiotic suppression/dressings
??amputation
Treatment of septic arthritis
Surgery: joint washout and drainage (repeated if required)
Iv antibiotics (days/weeks)
Immobilise joint in acute phase
Physiotherapy once over acute phase
Shoulder conditions by age
Hip conditions by age
Knee conditions by age
