Musculokeletal Flashcards
What proportion of the population don’t have musculoskeletal symptoms?
42%
What are the leading causes of sickness absence from work?
Back, neck and upper limb pain
Name 5 bone diseases
Osteoporosis Osteomalacia/rickets Bone malignancy Paget's disease Osteomyelitis
Name 5 joint disorders
Osteoarthritis Inflammatory arthritis Crystal arthritis Septic arthritis Haemarthosis
Name 5 disorders of muscle
Polymyalgia rheumatica Polymyositis Dermatomyositis Pyomyositis (abscesses) Neurological issues
Name 4 connective tissue disorders
SLE
Systemic sclerosis
Sjogren’s syndrome
Vasculitis
What gait to people with severe OA have?
Antalgic gait
Weight bears on unaffected side
Decreased swing phase on unaffected side
What are the 4 changes seen on xray in OA?
Joint space narrowing
Sclerosis
Subchondral cysts
Osteophytes
Features of OA
Morning stiffness50yrs
Bony enlargements/tenderness
Symmetrical, polyarticular
Pathophysiology of OA
Ligament damage
-> instability/malalignment
-> increased load and microtrauma
-> remodelling of adjacent bone (osteophytes)
2º synovial inflammation and crystal deposition
Risk factors for OA
FH
Obesity
Ligament rupture/fracture through joint/malalignment
Occupation
Assessment in OA
Effects on activities of daily living (family duties, hobbies, sleep, occupation) Pain medication, waking at night? Self help strategies Beliefs/expectations/mood
Management of OA
Physio, exercise, weight loss Local heat and cold Supports, braces, insoles Paracetamol and topical NSAIDs Capsaicin, oral NSAIDs, opioids Intra-articular joint injections TENS (transcutaneous electrical nerve stimulation) Joint arthroplasty
What is DEXA?
Dual energy xray absorptometry
What is normal with a DEXA scan?
T score of more than -1
What DEXA reading counts as osteoporosis?
Less than -2.5
Who should have a DEXA scan? (Give 8 indications)
Prior low trauma fracture Height loss & kyphosis on examination Vertebral deformity on spine xray Steroid users FH of fracture Early menopause Heavy smokers/excess alcohol/malabsorption FRAX score
What is FRAX?
Osteoporosis fracture predicting system Age, DOB, sex, weight, height Previous fracture? Parental hip fracture? Current smoker? Glucocorticoids? RA? 2º osteoporosis? Alcohol>3units per day Femoral neck BMD
What does a FRAX score of 10% in a 80 yr old mean?
10 year probability of major osteoporotic fracture is 10%
Not within treatment level (Needs to be >30% in over 80yr olds)
Why is HRT not recommended for osteoporosis anymore?
Increases risk of CHD, stroke, breast cancer and VTE
What is recommended for treatment of osteoporosis?
Raloxifene Bisphosphonates Synthetic parathyroid Dietary calcium, Vit D Weight bearing exercise Smoking cessation Alcohol restriction
What are the revision rates for arthroplasty?
5% at 7rs
15% at 7yrs is metal on metal
How do you engineer tissue?
Bone stem cells + inductive agents + conductive scaffold/forces
Where can you derive stem cells for bone grafts?
Embryonic Induced pluripotent Adult derived skeletal stem cells Trabecular bone periosteum Placental/umbilical cord blood Foetal derived
What can bone stem cells form?
Cartilage, bone and fat
Dependent on growth factors (BMPs, VEGF)
Positives and negatives of allogenic bone grafts
Off the shelf
Risk ratio life threatening situations
Reduced manufacturing costs
Process favoured
Positives and negatives of autologous bone grafts
No infectious disease risk Patient specific therapy High manufacturing costs Custom variability Disease/previous therapy issues
How has CAD CAM aided bone grafts?
3D printed hydroxyapatite scaffolds
Bone stem cells can proliferate
= bone formation
3D printed titanium constructs for hip revisions and osteointegration tailored to individual’s bone
What are osteoblasts derived from?
Mesenchymal stem cells
What are the most abundant cells in bone? Function?
Osteocytes
Can perceive changes in mechanical forces and transmit signals to other cells
Central in bone remodelling
What are osteoclasts derived from?
Macrophage lineage
RANKL receptors lead to differentiation
Osteoprotegrin-> stay as precursor
Can osteoclasts work solo?
No, they need low pH for solubilisation of minerals and need factors from osteoblasts
How does the matrix of bone versus cartilage differ?
Bone is heavily mineralised and mainly type 1 collagen
Cartilage is usually non organic and is formed of type II collagen and proteoglycans
3 types of bone development
Intramembranous, endochondral, appositional
Where does intramembranous ossification occur?
Flat bones (skull, clavicle)
Where does endochondral bone formation occur?
In fetus
Hyaline cartilage model of bones -> bone
1º ossification centre in diaphysis & cartilage anlage
Death of chondrocytes in centre-> infiltration of marrow and blood vessels
2º ossification centre at birth
Name the zone in a growth plate
Reserve zone Proliferation zone Transition zone Hypertrophic zone Calcification
What causes growth of bones?
Proliferation of chondrocytes
Synthesis of cartilage matrix
Chondrocyte hypertrophy
What happens with decreased weight bearing activity?
Decreased strain sensed by osteocytes
Osteoprogenitors differentiate into osteoclasts
-> bone resorption
How often is the adult skeleton completely remodelled?
Every 10yrs
Why is bone remodelling useful?
Allows adaption to mechanical loading
Enables fracture healing
Prevents bone fatigue by constantly renewing matrix
Why do you prescribe differently for children?
Decreased body weight Different body composition Decreased surface area Nutritional status Organ maturation
