treating musculoskeletal conditions

Question 1

What is osteogenic cell?

Answer 1

Bone stem cell

Question 2

What is osteoblast?

Answer 2

Bone forming cell, secretes osteoid, catalyses mineralisation of osteoid

Question 3

What is osteocyte?

Answer 3

Mature bone cell formed when osteoid becomes embedded in its secretions (osteoid).
Sense mechanical strain to direct osteoblast/clast activity

Question 4

What are osteoclasts?

Answer 4

Bone breaking cells, dissolve & resorb bone by phagocytosis, derived from bone marrow

Question 5

How is compact bone organised?

Answer 5

Has osteons - repeated structural units with concentric lamellae around a central haversian canal (contains blood vessels, nerves & lymphatics). 
Has lacunae (small spaces containing osteocytes tiny canaliculi radiate from lacunae filled with ECM). 
Has volkman's canals (transverse perforating canals). Provides protection, support & resists stresses of weight

Question 6

What is the structure of long bones?

Answer 6

• periosteum (connective tissue covering outside of bone),
• compact bone (hard outer shell of bone), cancellous bone (inner porous less dense part of bone).
• Has medullary cavity containing yellow bone marrow.
• Nutrient artery.
• Articular cartilage on surface of bone at joint.
• Top part of bone is epiphysis, physis underneath (growth plate), metaphysis below, diaphysis.

Question 7

What are pathological fractures?

Answer 7

Normal stresses on abnormal bone (local or general) eg. Osteoporosis (loss of bone density), malignancy (primary, bone mets), vitamin D deficiency (osteomalacia, rickets), osteomyelitis, osteogenesis imperfects, pagets

Question 8

What are stress fractures?

Answer 8

Abnormal stresses on normal bone

Question 9

What investigations are used for fractures?

Answer 9

X-ray, MRI (soft tissue + bone), CT scan, bone scans (widespread disease - cancer/infection)

Question 10

What are some general fracture complications?

Answer 10

Fat embolus (within hours), DVT (days/weeks), PE, infection/sepsis (especially if come through skin or have metal inside), prolonged immobility (UTI, chest infection, sores)

Question 11

What are some urgent local complications of fractures?

Answer 11

Local visceral injury, vascular injury, nerve injury, compartment syndrome (pressure within compartment increases restricting blood flow to area), haemarthrosis, infection, gas gangrene

Question 12

What are some less urgent local complications of fractures?

Answer 12

Fracture blisters, plaster sores, pressure sores, nerve entrapment, myositis ossificans, ligament injury, tendon lesions, joint stiffness, algodystrophy

Question 13

What are late local complications of fractures?

Answer 13

Delayed union (heals late), malunion (heals in wrong position), non-union (doesn’t heal at all), avascular necrosis, muscle contracture, joint instability, osteoarthritis

Question 14

What types of joints do we have ?

Answer 14

1. fibrous (sutures, syndesmosis, interosseous membrane),
2. cartilaginous (synchrondoses eg spine, symphyses eg. Pubic),
3. synovial (plane, hinge, condyloid, ball & socket, pivot, saddle)

Question 15

How are synovial joints stabilised?

Answer 15

Ligaments, muscles/tendons, bone surface congruity

Question 16

What is pathophysiology of OA?

Answer 16

• Chronic disease with deterioration of cartilage in joints so bones rub together creating stiffness, pain, limited ROM.
• Disease of chondral cartilage, inflammation occurs late, inflammatory mediators include proteinases (aggrecanases, matrix metalloproteinases) + inflammatory cytokines (IL-1β, TNFa which enhance synthesis of proteinases & catabolic factors to degrade articular cartilage membrane)

Question 17

What are risk factors for OA?

Answer 17

Age, obesity, mechanical constrains (professions, intense sport), heredity, female/menopause, osteonecrosis, leg bone malalignment, oestrogen def, metabolic syndrome, advanced hip osteoarthritis due to RA or spondyloarthritis, injury (cruciate ligament rupture, menisectomy), metabolic diseases (chondro-calcinosis, genetic haemochromatosis), infectious disease with bone, RA sequlae

Question 18

How do you assess injury?

Answer 18

Look, feel, move, special tests

Question 19

How is OA managed?

Answer 19

1. conservative - analgesics, physio, walking aids, avoid intense activity, injections (steroids, viscosupplementation).
2. operative - replacement (knee/hip), realign (knee/big toe), excise (toe), fuse (big toe), synovectomy (RA), denervate (wrist)

Question 20

What is osteomyelitis?

Answer 20

Inflammation of bone because of infection somewhere else (secondary) or in bone itself (primary) - pain/swelling/discharge + fevers/sweats

Question 21

Presentation of septic arthritis?

Answer 21

Pain, joint swelling/stiffness, fevers, sweats, weight loss

Question 22

What investigations for osteomyelitis/septic arthritis?

Answer 22

1. radiology: plain films, MRI scan (bony architecture/collections),
   CT if MRI not available, bone scans (multifocal disease), labeled white cell scans.
2. bloods: CRP (acute marker), ESR (slower response), WCC, TB culture/PCR

Question 23

What is treatment for osteomyelitis?

Answer 23

Antibiotics (Iv weeks), surgical drainage (esp collection/sequestrum), chronic (abx suppresion/dressing), possibly even amputate

Question 24

Treatment for septic arthritis?

Answer 24

Surgical joint washout and drainage (repeat if needed), IV abx (days/weeks), immobilise joint in acute phase, physio after acute phase