What is the benefit of doing an x-ray early on in osteomyelitis?
Rules out fracture and malignancy
Which cells produce osteoid?
Osteoblasts
What stimulates PTH release?
Low Ca2+
Which bone cells does PTH act on directly to increase calcium?
Osteoblasts
What are the 3 organs that PTH acts on to increase calcium levels?
Bone, kidney and GIT
What type of collagen is in hyaline cartilage?
Type 2
Where are the 3 places that elastic cartilage is present?
Ear, epiglottis and thyroid cartilage
What are osteocalcin and alkaline phosphatase both markers of?
Osteoblast activity
What are the little tubes that provide nutrients to osteocytes?
Canaliculae
What is a displaced fracture?
Edges of fracture are not apposed
What causes a stress fracture?
Repeated low force injury to a normal bone
What are the 4 stages of fracture healing?
Inflammatory Reparative - Soft callus Reparative - Hard callus Remodelling
What are the 2 major processes during the remodelling phase of fracture healing?
Osteoblasts and osteoclasts repopulate the bone Woven bone is remodelled to give lamellar bone
Over what time frame does the hard callus phase of fracture healing occur?
Weeks to months
Over what time frame does the remodelling phase of fracture healing occur?
Months to years
What kind of fracture is most susceptible to infection?
Compound fracture
What is the definition of osteoporosis?
Bone mass >2.5 SDs below the mean for healthy young women
What is the definition of osteopaenia?
Bone mass 1-2.5 SDs below the mean for healthy young women
What is the main concern with long term bisphosphonate treatment?
Oesophageal cancer
What are the 2 main risks of long term oestrogen therapy for bone health?
Cardiovascular disease and breast cancer
Is sarcopenia inevitable?
Yes
What effect does VitD have in the gut?
Increases absorption of Ca and PO4 (phosphate)
What are the 2 major processes during the hard callus phase of fracture healing?
Osteoblasts synthesise osteoid Osteoid becomes mineralised
What class of hormone is VitD?
Steroid
At what age does muscle mass start to deteriorate?
50 years old
What is the most common form of calcium phosphate in bone?
Hydroxyapatite
What is the difference between the actions of PTH and VitD3 in the distal nephron?
PTH causes phosphate excretion, whereas VitD3 promotes phosphate reabsorption
What word means progressive loss of skeletal muscle mass with aging?
Sarcopenia
What is the motor uni?
An alpha motor neurone and all muscle fibres it supplies
Which protein is abnormal in Becker muscular dystrophy?
Dystrophin
What are osteocalcin and osteonectin?
Calcium binding proteins in the ECM of bone
Which bone cells produce collagen for cartilage?
Chondrocytes
What is the second common pathogen in osteomyelitis?
Strep pyogenes / Group A strep
Which pathogen is more common for osteomyelitis after a sneaker penetration injury?
Pseudomonas aeruginosa
What protein is a marker of muscle damage?
Creatine kinase
What causes progressive stiffening of muscle fibres with age?
Loss of elastin
Which gene can be knocked out in mice to cause massive muscles?
Myostatin
Define sarcopenia
Progressive loss of skeletal muscle mass and strength or performance with aging
In which 2 structures is fibrocartilage found?
Menisci and intervertebral discs
What percentage of muscle mass must be lost before there is the risk of mortality?
40%
How does denosumab treat osteoporosis?
It is a human monoclonal antibody that binds RANKL and iblocks RANK activity => reduces osteoclast activity
What type of collagen is in fibrocartilage?
Type 1
What is a compound fracture?
Open fracture, ie bone exposed to external world
What are the 2 major processes during the inflammatory phase of fracture healing?
Haematoma and granulation tissue
What are the 2 layers of the periosteum?
Inner cellular layer with osteoprogenitor cells Outer fibrous layer
Which bone cells are multinucleate?
Osteoclasts
In what direction do osteoclasts dig their holes in bone?
Along the stress axis of the bone
What are osteons aka?
Haversian systems
What is at the end of a bone? (-physis)
Epiphysis
What are the main types of muscle atrophy?
Disuse atrophy
Denervation atrophy
Cachexia
What is a comminuted fracture?
Fracture with more than 2 bits of bone
What percentage of cases of osteomyelitis occur in children <5 years old?
50%
Over what time frame does the soft callus phase of fracture healing occur?
Days to weeks
What is osteomyelitis better known as?
Bone infection
What is the proper way to say ‘bone infection’?
Osteomyelitis
Which bones are most commonly involved in osteomyelitis?
Long bones: femur, tibia, humerus
What is a pathological fracture?
Fracture where underlying bone pathology has made it more vulnerable to fracture
How do tendons and ligaments attach to bone?
Sharpey’s fibres
What is raloxifene?
Selective oestrogen receptor modulator
What are bisphosphonates used to treat?
Osteoporosis
In which 3 locations is red bone marrow found in adults?
Skull, scapula and pelvis
Which protein is abnormal in Duchenne muscular dystrophy?
Dystrophin
What is the scaffolding for bone that is laid down by osteoblasts?
Osteoid
What do we call infection of a joint?
Septic arthritis
What percentage of the body’s calcium is in bone?
99%
What effect does oestrogen have on bone?
Maintains bone density by promoting osteoclast apoptosis and increasing life span of osteoblasts and osteocytes
Which cells resorb bone?
Osteoclasts
How is most calcium lost from the body?
Urine
What is the main complication with a compound fracture?
Infection
Which cells are osteoblasts modified from?
Fibroblasts
What is a greenstick fracture?
Only one side of cortical bone is broken
How do bisphosphonates work?
They are an analogue of pyrophosphate thus taken up into bone matrix Taken up by osteoclasts, causing apoptosis
What do osteoclasts secrete?
HCl and proteases
What effect does PTH have on [Ca2+] in plasma?
Increases it
How long do most lower limb fractures take to heal?
12-16 weeks
What can be done to attenuate sarcopenia?
Strength training
Decreases in which 3 hormones are thought to be related to sarcopenia?
Growth hormone, IGF-1 and testosterone
What do osteoblasts turn into when they are less active?
Osteocytes
What is the name of the process by which long bones grow in length?
Endochondral ossification
What effect does PTH have on plasma [phosphate]?
Decreases
What is another name for cortical bone?
Compact bone
Which cells build bone?
Osteoblasts
Which two conditions are especially common in travellers to Asia?
Dengue fever and typhoid fever
Which cells are responsible for ongoing maintenance of cartilage?
Chondrocytes
What is calcitriol?
VitD3
How long do most upper limb fractures take to heal?
6-8 weeks
What is a complete fracture?
A bone is broken all the way through
What is the most common pathogen in osteomyelitis?
Staph aureus
How does PTH increase VitD levels?
PTH activates the kidney enzyme to hydroxylate/activate VitD3
What are 4 synonyms for the inner bit of a bone?
Medullary; cancellous; trabecular; spongy
Which NSAID should not be given for gout?
Aspirin
What does PTH cause osteoblasts to do?
Release OPG and RANK ligand to activate osteoclasts
What is Gower’s sign?
Muscle weakness causes difficulty getting of floor, so Pt uses accessory muscles such as arms to help themselves get up
What is a sarcolemma?
Cell membrane of skeletal muscle
Where do osteoprogenitor cells usually reside?
Periosteum or endosteum
What type of muscle is more susceptible to sarcopenia?
Fast fatiguable
What is the goal of management of a fracture?
Unite the ends of the fractured bone
Over what time frame does the inflammatory phase of fracture healing occur?
Days
What is the antibiotic of choice for osteomyelitis?
Flucloxacillin
What are the 2 major processes during the soft callus phase of fracture healing?
Progenitor cells turn into chondrocytes Chondrocytes form cartilage
What is the role of dystrohpin?
It i links actin in the cytoskeleton to laminin via glycoproteins
What is at the middle of a bone? (-physis)
Diaphysis
What type of cell is in hyaline cartilage?
Chondrocyte
Name 4 things found inside a Haversian canal
Capillary, nerve, supportive connective tissue and lymphatic
For joint pathology, what will be the consequence of fibrillation and sloughing of articular cartilage?
Loss of joint space
For joint pathology, what will be the consequence of calcification of periarticular cartilage and synovium?
Osteophytes
For joint pathology, what will be the consequence of synovial fluid entering bone?
Subchondral cysts
For joint pathology, what will be the consequence of thickening of subchondral bone and trabeculae?
Subchondral sclerosis
What are the 4 main components of hyaline cartilage?
Type 2 collagen
Glycoaminoglycans
Chondrocytes
Water
What type of blood vessels are present in hyaline cartilage?
None
What type of nerves are present in hyaline cartilage?
None
How is hyaline cartilage nurished?
Perfusion by compression and decompression of the cartilage
What is added to plasma filtrate in the formation of synovial fluid?
Hyaluronic acid
What are the two types of cell in synovium?
Type A cells (macrophage-like)
Type B cells (fibroblast-like)
Give a 4 word definition of the pathophysiology of osteoarthritis
Chronic degeneration of cartilage
Which disease is characterized by degeneration of cartilage that results in structural and functional failure of synovial joints?
Osteoarthritis
How would you explain osteoarthritis to a lay person in 5 words?
Wear and tear of joints
At what time of day is pain from osteoarthritis worse?
At the end of the day
Pain at the end of the day suggests what type of arthritis?
Osteoarthritis
Which joints tend to be most affected by osteoarthritis?
Weight-bearing joints
At what time of day does pain from rheumatoid arthritis tend to be worst?
In the morning
Morning stiffness of joints suggests what type of arthritis?
Rheumatoid arthritis
Which disease is characterised by autoimmune inflammatory joint disease with systemic involvement?
Rheumatoid arthritis
What is podagra?
Gout in the great toe
What do we call gout in the big toe?
Podagra
Define gout
Very painful
acute inflammation
due to accumulation of uric acid crystals
in a joint
In which part of bone would you find osteons?
Cortical bone
What are 3 signs of osteoarthritis?
Reduced ROM
Crepitus
Osteophytes
What are 3 microscopic pathological features of rheumatoid arthritis?
Mononuclear infiltrate
Synovial hyerplasia forming pannus
Germinal centres
List 3 signs of rheumatoid arthritis
Inflamed joints
Rheumatoid nodules
Destruction and deformity of joints
Which joints of the hand are often spared in rheumatoid arthritis?
Distal interphalangeal joint
What diagnosis should you consider when someone presents with swollen joints, nodules and deformed joints?
Rheumatoid arthritis
What is the prevalence of rheumatoid arthritis?
1% of the population
List 3 x-ray features of rheumatoid arthritis
Juxta-articular osteopaenia
Subchondral erosions
Uniform joint space loss
What percentage of rheumatoid arthritis is genetic?
50%
List 3 risk factors for rheumatoid arthritis
Female gender
Age 25-55
Smoking
Accumulation of what causes gout?
Uric acid crystals
What are tophi?
Uric acid crystal depositions in soft tissues other than joints
What is the cardinal sign of gout?
Acutely inflamed, intensely painful joint
What type of inflammation is caused by tophi?
Granulomatous inflammation
What is the gold standard diagnostic test for gout?
Joint or tophus aspiration during an acute attack
