Locomotor Flashcards
What is comorbidity?
comorbidity is the presence of one or more additional conditions often co-occuring with a primary condition
What are the 3 parts of long bone?
metaphysics (head of the bone), epiphysis (growth plate) and diaphysis
What are chondrocytes?
They are the only cells found in healthy cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans.
exclusively responsible for synthesis/breakdown of ECM components. Can synthesis. the full range of ECM proteins and can synthesis cartilage-specific ECM components such as collagen type II.
What happens in growth plates?
Areas of cartilage where growth takes place. Chondrocytes undergo dramatic growth and then die, leaving behind the basis of bone.
What are harris lines?
Also known as growth arrest lines- regions of increases bone density.
represents the position of the growth plate at time it was slowed down- possibly due to injury or malnutrition or possibly due to growth spurts
What is a recent technique used to fix leg length discrepancy in young aged patients?
The ‘8th plate’ is used, a high quality steel implant applied to leg growing too fast- letting the other catch up.
What is osteoporosis and what is the most common type?
Porous bones that are fragile to low impact trauma.
Most common type of OP is vertebral compression fractures
Symptoms of this are back pain and kyphosis (curvature of the spine)
What are the 3 types of connective tissue?
Connective tissue proper- loose and dense
Fluid connective tissues- blood and lymth
Supporting connective tissue- cartilage and bpne
What are the 3 types of cartilage?
hyaline cartilage, fibro-cartilage and elastic cartilage.
What is cartilage ECM made of?
Made of fibres, eg collagen, complex interstitial fluid and filling material known as proteoglycans.
What are the resident cells in cartilage, connective tissue and tendons?
chondrocytes in cartilage
fibroblasts in most CT
tenocytes (fibroblast-like) in tendons.
What are the basic functions of osteoclasts, osteoblasts and osteocytes?
OSTEOBLASTS= build new bone
OSTEOCLASTS= remove old bone
OSTEOCYTES= maintains bone matrix/ assists bone repair
How are the chrondrocytes arranged in collagen type 1 and type 2?
Type 1- rope like structure
Type 2- basket weave
What are fibroblasts and fibrocytes?
Two types of the same cell- fibroblasts are active, fibrocytes less active
They are connective tissue cells characterised by abundant rough endoplasmic reticulum and resposible for synthesis of fibrous matrix proteins particularly collagens.
Tissue damage stimulates fibrocytes to become fibroblasts
What are proteoglycans?
also called ground substance, unstructured material composed of negatively charged glycosaminoglycans which attract cations and swell and resist compressive forces.
What does the ‘modes of failure’ graphs look like for failure rate, wear and tare and random.
What occurs in red and yellow bone marrow?
Red bone marrow is where the production of blood cells takes place, a process known as haematopoiesis.
Yellow bone marrow contains adipose tissue, and the triglycerides stored in the adipocytes of this tissue can be released to serve as a source of energy for other tissues of the body.
What are the functions of bone?
Metabolism, producing RBC, structural, protective, facilitating respiration, storing of adipose tissue, and there are highly specialised bones, such as the bones in the middle ear as well.
Why and how have humans adapted to bipedalism?
- Freed the upper limb for other functions
- Enlarged hip and knee joints to cope with increased forces
- The foot has evolved to support entire body weight on one leg and so has lost its fine motor functions. Also have a highly stable tripod structure.
What are the phases of walking gate?
Heel strike is also known as initial contact
Gait cycle refers to the movement of one leg (two steps)
What is the structure of collagen?
3 polypeptide chains are wound together in a right-handed superhelix
there are H-bonds between chains
What is elastin?
Another ECM protein, which forms elastic fibres in lungs, arteries, skin and tendons.
What are glycosaminoglycans and proteoglycans?
These are major components of the extracellular matrix
GAGs are negatively-charged
Proteoglycans are formed of glycosaminoglycans (GAGs) covalently attached to the core proteins
Proteoglycans act as molecular sponges as they are associated with cations and water
What is cartilage made of?
80% water; the remainder is collagen (~2/3) and glycosaminoglycans (~1/3). GAG aggregates are maintained within a mesh of collagen fibrils. This confers elasticity and low friction in joints.
What is common in creation of collagen genes?
Because of the complexity of collagen genes, splicing errors are common.
There are many types of post-translational modification. Errors in these processes (caused by
mutations in genes encoding collagen itself or encoding processing enzymes) result in the failure of collagen secretion by fibroblasts.
What is hyaline cartilage?
Hyaline cartilage (e.g. articular cartilage) is found on articulating surfaces of moveable joints - adapted to withstand mainly compressive forces (i.e. load-bearing) although surface can withstand tensile (i.e. stretching) forces.
Contains chondrocytes
What is synovial fluid?
Primary source of nuticion and removal of waste for cartilage cells
Produced by synoviocytes of the synovial membrane
What is fibro-cartilage?
Fibro-cartilage (e.g. intervertebral disc, meniscus) adapted to withstand mainly tensile but also compressive forces.
Supports bone to bone contact
Collagen fibres thick and have clear parallel orientation.
Mainly fibroblasts but also some chondrocytes
What is elastic cartilage?
Contains elastin- highly and reversible deformable.
Similar to hyaline- chondrocytes synthesise some collagen but mainly elastin
Why are you taller after you have slept?
When cartilage is static, fluid builds up
How is cartilage able to withstand load?
- No blood vessels or nerves (fragile)
- No epithelium at the cartilage surface- this is delicate so would be damaged on movement
- Low cell density (1-10%)
- There is a complex ECM (fibre-reinforced gel) which is highly resiliant and adapted to compressive and tensile forces.
What are osteogenic cells?
Precursor cells that differentiate into various different lines of cells (includes adipocytes, myocytes, chondrocytes and osteoblasts) depending on the mechanical environment they exist in.
Also known as osteoprogenitor cells
They can be present within the bone marrow, the endosteum and the cellular layer of the periosteum.
What is the endosteum and periosteum?
The periosteum is a membranous tissue that covers the surfaces of bones
Endosteum lines the inner surface of the medullary cavity of all long bones.
What effects osteoprogenitor cell’s fate?
Their fate is determined by environment- when there is minimal movement in the environment, become osteoblasts. If there is more movement in the local tissues, they become chondrocytes.
What are osteoblasts?
Single nucleus cells. Functions- form bone by producing non-mineralised matrix.
When synthesised by PTH (parathormone) they produce type 1 collagen and enzymes which initiate the calcification of the matrix by laying down deposits of calcium phosphate
Also regulates osteoclasts by producing RANK-ligand which bonds to RANK nd stimulates osteoclast precursors to become active osteoclasts, thus stimulating bone resorption
What are the 4 main types of tissue?
Epithelia, neural, muscular and connective.
What is connective tissue?
Makes up roughly half of body weight, consists of widely seperated cells situated in a ECM.
Main components are cells- both resident and immigrant
ECM- cotains proteins eg collagen, ground substance eg proteoglycans and GAGs
there is also intersitial fluid
What immigrant cells are present in connective tissue?
Macrophages- specialised cells involved in the detection, phagocytosis and destruction of bacteria
Lymphocytes-a type of white blood cell, produce antibodies
Neutrophils- a type of white blood cell
What are the two types of resident cells in connective tissue? And what is their function?
Fibroblasts and chondrocytes
Active secretion and synthesis of ECM components, some degradadive enzymes
Fibroblasts synthesis and secrete collagen, elastin, fibrillin and PGs
Chondrocytes are collegen and PGs
What are the 4 main proteins of the ECM?
(A) collagen- rope like- determines tensile properties
(B) elastin- determines elasticity
(C) Fibrillin- forms microfibrils that act as scaffold for elastin
(D) fibronectin- attachment point for anchoring of cells
What are the two causes of Osteoporosis?
- Primary-* due to the effects of aging, post-menopausal and decreased renal function
- Secondary-* associated with other causes such as diabetes, Vit C deficiency ect
What occurs in osteoarthritis?
Progressive destruction of articular cartilage- fibrillation (splitting) or the cartilage occurs. Hydration increases and PG decreases. This pushes collagen fibres away from each other and the cartilage breaks down. This exposes the sub-chondral bone and the resulting friction can be painful.
What occurs in rheumatoid arthritis?
Inflammation of synovial fluid- instead of it being smooth it is covered
What are a few perinatal modes of failure?
Spinal scoliosis
congenital deficiences- disorders that result from failure of formation of a bony part of the body
Developmental deformity of the hip
Growth disorders- endocrine or genetically or nuticionally caused
Trauma to physis can cause abnormality
What are some examples of trauma modes of failure?
Ligament and tissue injury
Fractures
What are some examples of elderly modes of failure?
What is different about running gate from walking gait?
There is a float phase
Increased movement at all joints in the leg
Increased stride length and shorter cycle time
What is bone made of?
20% collagen, 70% inorganic salts and 10% water.
Major mineral is hydroxyapatite, but other ions also present in the crystal lattice
What does immobilisation of cartilage cause?
Thinning, however this is REVERSIBLE
What are the 4 principle components of articular cartilage?
Collagen
Proteoglycans (have GAGs attached to them)
Interstitial fluid (also known as ground substance)
Chondrocytes (only living cell)
What percentage of total possible swelling does cartilage swell to?
20% - as restricted by collagens
What happens first before OA?
Damage to the basketweave streucture of collagen causes increased cartilage concentration - swe
What is the treatment for OA?
Education, weight loss advice, exercise,v
What are the 4 main cells in bone?
What are osteocytes?
Maintain the bone and cellular matrix, regulating the concentration of calcium and phosphorus in bone.
Regulation of bone controlled by mechanical or systemic signals such as hormones.
They increase OC formation of RANKL. Inhibits osteoblast concentration by producing sclerostin. If sclerostin is inhibited by PTH, there is increased bone formation.
What is mechanotransduction?
When tissue is placed under compressive load, fluid is squeezed out and flows to an area of lower compression. Osteocytes sense this movement- known as mechanotransduction
What are osteoclasts?
Multinucleated giant cells
Function is to reabsorb bone by dissolving the hydroxyapatite and then disgesting organic matrix
What is Howship’s lacunae?
When reabsorption of bone forms a small pit.
What are the different areas of bone?
Epiphysis- end of bone, covered in articular cartilage and contains the physis. Made of spongey/cancellous bone
Diaphysis- middle of bone, made out of cortical bone surrounding central canal of bone marrow
Metaphysis- where bone changes from diaphysis to epiphysis, made of cortical bone surrounding loose trabecular bone
Where and what are the functions of periosteum?
Covers outer region of diaphysis, functions are to provide blood supply, provide fibroblasts and progeniutor cells that can develop into osteoblasts and chondroblasts.
Where and what is the endosteum?
Lines inside of meduallry cavity, which is primarily involved in bone remodelling and turnover
What is the physis?
Growth plate, specialised zone of cartilage that is responsible for long growth.
Endochondral ossification occurs here
What is a description of cortical bone?
What is a description of cancellous (trabecular) bone?
A loose network of struts, making it more elastic.
What is lamellar and woven bone?
What is the composition of bone?
What are the two ways bone forms in an embryo?
Intramembranous ossification- develop directly from sheets of undifferentiated mesenchymal cells (adult stem cells). These cells form clusters and begin to differentiate into different specialised cells.
Endochondral ossification, bone is layered down on an existing cartilage scaffold. Chondrocytes calcify matrix around them, resulting in their death (no nutrients reaching them). The cartilage around them disintigrates, allowing blood vessels to invade space they have left. This is the primary ossification centre. The same thing occurs in the secondary ossificastion centre- at the head of the bone.
What are the different zones of the physis?
What is happening at the resting zone of the physis?
There is sparsely packed cells. The epiphyseal arteries supply the blood.
Cells are not producing matrix or changing in size.
What is happening in the proliferative zone in the physis?
Cells stack themselves in columns. they multiply many times as well. They begin to produce cartilaginous ECM (similar structure to bone without calcium)
What happens in the hypertrophic zone of the physis?
First sub-zone is maturation wher cells differentiate and mature, increasing in size. This size increases continues in the zone of degeneration, where chondrocytes have increased 5-fold. They are too big to survive and undergo programmed cell death in the zone of provisonal calciofication.
What happens in the metaphyseal bone area of the physis?
After the chondrocytes have died, blood vessels infiltrate the calcified matrix and lay down woven bone. Then over many months, bone is remodelled to lameller bone.
Where is calcium stored?
99% in bone, 1% in blood;
35-50% bound to protein
5-10% in complexes with acids or phosphates
50-60% is in ionised form- measurable
Where are some locations of activity of calcium?
Bone as hydroxyapatite
Parathyroid gland controls calcium blood levels- a fall in blood calcium ions is detected by the PTH receptors and PTH synethsis is increased
Thyroid gland also has receptors for calcium and releases calcitriol- inhibits OC activity
What role does Vit D have in calcium metabolism?
Once Vit D reaches active form after reactions, it stimulates Obs to release RANKL and stimulates Ocs. Also increases absoprption in the GI tract
How does oesteogen influence calcium metabolism?
It inhibits the release of RANKL from osteoblasts. This reduces osteoclast activity and hence bone resorption decreases.
What are the 4 stages of bone remodelling?
Quiescence, resorption, reversal and formation
Q= period of inactivity
How is bone mineralisation regulated?
Locally- OB dervided proteins and inorganic pyrophoisphate
Systemically- Vit D, endocrine regulators, PTH
What are the definitions of the following:
What are the types of complete fracture?
Why do you have to radiograph a specific area of a bone?
Too large area will cause beam divergence, where rays spread out and image can become distorted
What is primary healing of a fracture?
Healing without callous- healing cone. Requires surgery where bone ends cannot move
OC resorb the bone, OB deposit the bone and osteocytes which are OBs which have been trapped in the bone matrix.
There is a blood vessel at the centre, brings the progenitor (stem) cells in from the circulation.
Finished product- osteon. Produces the Haversian system- for this reason, primary healing is also known as haversian remodelling.
What is secondary healing of a fracture?
Needs to be relatively stable. Repaired by endochondral ossification and involves the classical stages of inflammation, repair and remodelling.
What are the phases of secondary healing?
- Inflammatory phase, a hematoma forms and provides a source of Hematopoetic cells capable of secreting growth factors. osteoprogenitor cells begin to infiltrate the fracture and differentiate into osteoblasts and fibroblasts
- Repair phase, the osteoprogenitor cells differentiate into chondroblasts which begin to make cartilage- this forms soft callus
- Repair phase 2, the soft cartilage is replaced by bone via endochondral ossification
- remodelling phase, Continues until the woven bone that’s rapidly produced to stabilise the fracture is remodelled into mature lamellar bone
What are the 4 R’s of fracture care?
Resuscitate (prevent life threatening injuries), reduce (the bone fragments into a normal position), restrict (hold it in place) and rehabilitate (allow normal function).
How can you tell if a fracture is stable or not?
What is the indirect reduction method of healing a fracture?
bend the bone back into place by moving or squeezing the body part
What are bow legs and how are treated?
when legs are at an unusual angle when looking at a child straight forward. Now treated with guided growth- by an eight plate
What are the usual causes of abormal gait?
pain, mechanical problem or neuromuscular problem.
What is the most common cause of an abnormal gait?
Most common cause is an irritable hip- transient synovitis is non-specific and is short term inflammatory synovitis of the hip which goes away its self. This can be caused after a viral infection.
What is wolf’s law?
bone remodels based on the mechanical stress that is placed upon it. Bone is deposited on the compression side and absorbed on the tension side.
What are the types of Salter-Harris fractures (around the physis)?
Straight, Above, Lower, Through and Ruined
Why are there 3 peaks in the rate of death after trauma?
- 1st due to instant death
- 2nd= people who have initially compensated for trauma, for example increasing heart rate and shutting down peripheral circulation, but have subsequently used up their physiological reserves and perish
- 3rd= patients experience sequelae of trauma, such as infection and multi‐organ failure.
What is the ABCDE of trauma?
A=airway, is there blockage. Treated with suction, basic airway manoeuvres. Must be done with spine control.
B= breathing, check injuries of the chest, observe breathing rate and palpitate injuries. Check for pneumothorax Treated with high flow oxygen needle then a definitive chest drain.
C=circulation and haemorrhage control= need to look out for signs, pale, heart signs, pulse, BP. Establish 2x IV access to allow fluid resuscitation. Control the obvious source of bleeding by external pressure. Look out for massive haemothorax
D= disability, looks for head and neck injuries. GCS total out of 15, AVPU scale can also be used.
E=Exposure and environment control, full examination of patient whilst keeping them warm.
What is a massive haemothorax and shock?
MA= When there is 1500 mls of blood in pleural cavity
Shock= end-organ dysfunction due to inadequate oxygen availability for tissues.
What blood products do you give trauma patients who have lot alot of blood?
Stop the bleeding, then give blood products such as red blood cells: fresh frozen plasma: platelets at a ratio 1:1:1. tranexamic acid can be given- promotes clotting.
What is an open fracture?
Open fractures are fractures that are open to the external environment at some point in the injury. There is an increased risk of infection.
What is the scale used to grade open fractures?
Gustilo-Anderson
Split into 3- I= <1cm wound, II= 1-10cm and III >10CM
How do you treat arterial injury?
Is a surgical emergency
Resuscitate the patient, realign and splintthe leg, contact surgeon who will use a shunt (allows blood to flow from area to another)
What is compartment syndrome?
Increased pressure inside a fixed fascial compartment.
Result in reduced blood supply to tissue.
Treatment is fasciotomy to allow swelling tissues to bulge out
Why do apophyseal injuries occur?
In children and adolescents, the secondary ossification centres haven’t fused to the rest of the bone yet and are instead only connected by cartilage. This means they are a relative weak point in the bone
If a sudden, forcefull contraction of a muscle occurs then its tendon can pull or ‘avulse’ the apophysis from it’s position on the rest of the bone.
What are the 3 types of shoulder dislocation?
- anteriorly (outwards)
- posterior occurs with extreme muscle contractions- humeral head rotates posteriorly
- luxatio erecta, is when the humeral head is levered out with hyperabduction and becomes trapped inferior to the glenoid
What are strains and sprains?
Sprains are injuries to ligaments, like the ligaments of the ankle, and occur during sudden stretching of ligaments past their elastic limit, deforming or tearing them. Strains are injuries to muscle fibres or tendons, which anchor muscles to bones.
How are strains and sprains treated?
All are treated with rest, ice, activity modification and early RoM (range of motion) excercises. Repeated or severe injuries to the ankle ligaments can result in chronic instability that, like shoulder instability, can require stabilisation surgery.
What are meniscal injuries?
tears in the c-shaped structures in the tibia sitting on the condyles
Treatment- conservative, surgery has poor outcome. Management is symptoms control (analgesia) and physio
What ligaments can you tear in your knee?
ACL- typical history of an acute ‘popping’ sound
Posterior cruciate ligament- Same history as ACL tear
Medial collateral ligament- most common ligament to injure in the knee. They may present with medial knee pain and valgus instability with tenderness directly over the MCL or its origin and insertion
Lateral collateral- rarely injured on its own
What are shin splints?
Inflammation of the periosteum at the origins anterior/posterior muscles
Patients will complain of a diffuse pain over the mid‐tibia- worse after doing exercise
It can lead to stress fractures, which occurs in around 5% of untreated cases
What is erythema?
Red swollen area of skin, usually due to inflammation.
What may be the cause of acute monoarthritis?
Septic arthritis- important to treat quickly
Caused when bacteria that circulate in the blood settle into a joint and cause an infection, know as haematogenous spread
Investiagte using blood tests and joint aspiration
Could also be reactive arthritis- when bacterial infection is somehwere else in the body. Treated with analgesics and physio
What is polymyalgia rheumatica?
An autoimmune syndrome characterised by widespread joint and muscle aches with flu-like symtoms of fatigue, weight loss, fever and poor appetite. Causes joint stiffness.
Is autoimmune attack of the joint synovium causing pain and local inflammation.
Treatment is steriods and NSAIDs as well as physio.
How can you diagnose gout?
The aspirate is examined under a microscope, one of the tests carried out involves shining a polarised light through the sample. This can identify the culprits that cause gout crystals of monosodium urate
What is rheumatoid arthritis?
a chronic systemic autoimmune disease that occurs as a result of a cell mediated immune response that attacks both soft tissue and bone.
Why is RA caused?
An environmental triggers causes a modification of the proteins normally synthesised by host cells We calls this process citrullination as it’s a conversion of one amino acid into another, namely arginine into citrulline.
What is erosive arthritis?
when the joint surfaces become completely eroded and fibrous tissue fills the gap. As the inflammatory process settles, the body is effectively fooled into thinking the two bare ends of bone are a fracture and begins to form bone and remodel across the gap, eventually ending with a bony fusion
What are the symptoms of OA?
Symptoms are pain, worse on use of joint, mild morning stiffness, loss of movement, tenderness, bony swelling (due to remodelling) and occasionally soft tissue swelling. Joint crepitus or creaking is common.
Radiological features are narrowing of joint space, osteophytosis, altered bone contour, bone cysts and sometimes soft tissue swelling.
What are the risk factors for OA?
What are the treatments for OA?
What is metabolic bone disease?
Metabolic bone disease is a term used to refer to a number of different pathologies that are caused by defects in the process of normal bone turnover and result in abnormalities or deformities of bone. We can split these into 2 broad categories which are disorders of bone remodelling and bone mineralisation.
What are some bone remodelling diseases?
Osteoporosis-
Paget’s disease- there is excessive bone resorption, by overactive osteoclasts, and increased but abnormal bone formation. Can be monostotic (one bone) or polyostotic
What are the 3 phases of Paget’s disease?
Lytic phase- intense osteoclastic resorption
The other 2 phases are the sclerotic phase, where there is predominant disorganised osteoblastic formation, and the mixed phase where both resorption and formation occur.
What are the main effects of PTH (parathyroid hormone)?
What causes hypersecretion of PTH?
Hyperparathyroidism is the presence of increased serum parathyroid hormone
The vast majority of primary disease is due to a parathyroid adenoma which produces an abnormally increased volume of PTH.
Secondary disease occurs when chronic hypocalcaemia or hyperphosphataemia, caused by vitamin D deficiency or kidney disease
What effects does hypersecretion of PTH have?
‘Bones, stones, abdominal groans, Thrones and psychic moans’
Bones- referes to gout and osteoporosis
Stones- hypercalcaemia, which leads to more calcium being excreted in urine also so increased urinary calcium absorption. This can cause kidney stones.
Abdominal groans and thrones- constipation, nausea and vomiting due to muscle weakness of smooth bowl muscle
Psychic moans- fatigue, depression, forgetfulness and anxiety
How is vitamin D converted into its active form?
Active form= calcitrol
2 hydroyxlations, first in the liver and then in the kidneys
What is a vertebral wedge compression fracture?
Occur from a low energy fall (eg falling on bottom) or multiple mini stress fractures. Heigh loss is one of first changes to occur- due to increasing kyphosis of the thoracic spine and vertebrae pressing down.
Squashes organs which can lead to constipation and early satiety, which is when a patient feels full from eating less food, leading to weight loss and malnutrition.
What are the types of hip fracture?
Intracapsular fractures will tear the arteries that travel up the femoral neck and therefore interrupt the blood supply to the femoral head. If this happens then the bone will died due to lack of blood supply.
Extracapsular fractures- can divide this further into fractures around the trochanters which we call inter-trochanteric and fractures below the trochanters which we call sub-trochanteric.
