MSK Pathology

1) Nociceptors at fracture ends
2) Haemorrhage and oedema
3) Muscle spasm

1) Extent- complete v incomplete
2) Soft tissue damage - open v closed
3) Alignment - stable v unstable
4) Comminuted (fragmented)

Caused by underlying disease - hyperparathyroidism, osteoporosis, malignancy, other metabolic bone diseases

1) haematoma formation, fibrin deposition
2) Inflammation: death of osteocytes and release of cytokines attracting osteoblasts and mesenchymal stem cells (fibroblast and osteoblast progenetors), PMN's, lymphocytes and macrophages
4) proliferation of fibroblasts producing cartilagenous callus
5) proliferation of osteoblasts calcifying callus into soft bone
6) remodelling by osteoclasts and osteoblasts producing hard bone with greater thickness than original bone

1) young age
2) immobilisation
3) maximising bone-bone contact
4) vascular supply
5) nutrition (A and D)
6) hormones - thyroxine, GH, calcitonin
7) exercise

Age eg. complete femoral fracture (infant 4 weeks, teen 14 weeks, > 60 18-20 weeks)
2) osteomyolitis (infection)
3) Avascular necrosis caused by thrombosis
4) metabolic diseases

congenital - osteogenesis imperfecta
inflammatory - osteomyolitis
metabolic - osteoporosis
neoplastic - osteosarcoma and mets

Days 1-3 haematoma (fibrin clot)
3-7 inflammation: PMN's, lypmphocytes, macrophages
7-21 soft callus (osteoid)
3-6 weeks hard callus
6 weeks to 3 months - remodelling gives 80% strength

1) lack of immobilisation
2) infection
3) pathology (cancer)
4) misalignment

1) poor nutritional status
2) metabolic: osteoporosis, diabetes, smoking
3) old age
4) immune status (steroids, chemo)

1) physical examination of lump (size, character, growth rate, attachment, skin changes, node involvement, systemic symptoms)
2) Imaging
3) Fine needle aspirate

1) Infections: Mastitis (ductal), Adenitis (glandular)
2) Neoplasms: fibroadenoma, cystosarcoma phyllodes, intraductal pappiloma, Complex sclerosing lesion (radial scar - looks malignant but benign)
3) Fibrocystic disease (multiple cysts)
4) Mucocoele-like lesion

Nottingham: closeness to tissue of origin (number of tubules, nuclear pleomorphism, no of mitotic figures)

1) size
2) extent (involvement of skin, chest wall, musculature, nodal involvement, metastases)

1) Grading (Nottingham 1-9)
2) Staging
3) Receptor status (oestrogen, progesterone, HER-2)

1) Osteoid osteoma: nidus of osteoid and woven bone. Proximal femur & tibia
2) Osteochondroma: outgrowths of growth plates

1) Osteosarcoma (20%), osteoblasts, affects metaphyses (knee, hip, shoulder), affects <20YO males (1.6:1) and Pagets
2) Chondrosarcoma: Middle age men, never in distal extremities (shoulder, pelvis, rib)
3) Giant cell, multinucleated osteoclasts, young adults, epiphyses
4) Ewings: < 20YO, small blue round cell tumour containing glycogen forming soft tissue in bone, systemic symptoms
5) metastatic lesions:BLT with a kosher pickle (breast, lung, thyroid, kidney, prostate)

AS, psoriatic arthritis, Reiter's syndrome (reactive arthritis), colitic arthritis (IBD) - all are seronegative for RF

1) Aching pain in adult 20-40 originating in sacroiliac, infrascapular, buttocks and progressing along spine
2) Nocturnal pain, morning stiffness, not relieved by rest, relieved by activity

1) smoking (respiratory insufficiency more likely when thoracic vertebra become fused)
2) low socioeconomic status
3) early age onset
4) Coexistant psoriasis and IBD (causes treatment resistance to TNF blockade)

1) symmetrical
2) wrist, MCP, proximal interphalangeal joints
3) knee, elbow, ankle, spine

1) ?EBC
2) HLA-DRB1 accounts for 20-50% risk
3) Anti-CCP - aggressive disease

1) Morning stiffness for at least one hour for > six weeks
2) Swelling of three or more joints for 6 weeks+
3) Swelling of wrist, metacarpophalangeal, or proximal interphalangeal joints for 6 weeks+
4) Symmetric joint swelling
5) Hand x-ray showing erosions or bony decalcification
6) Rheumatoid nodules
7) RF or anti-CCP antibodies
8) Elevated ESR and CRP

1) Hyperplasia of synoviocytes, oedema and neovascularisation of the synovium
2) Infiltration of lymphocytes, macrophages and mast cells
3) Formation of pannus: fingerlike projections of synovial membrane into the bone causing osteoclast degradation

Core of fibrin necrosis surrounded by epitheloid macrophages and giant cells

1) Acute necrotising vasculitis
2) Pulmonary fibrosis, Caplan's syndrome
3) Pericarditis, MI
4) Renal amyloidosis

Decreased osteoblast activity

Menopause
Smoking
Diet
Lack of exercise

1) Lack of oestrogen prevents inhibition of production of IL1 and IL6, TNF an consequently RANKL secretion by osteoblasts
2) Lack of oestrogen decreases secretion of inhibitory OPG by osteoblasts
3) Increased osteoclast activity relative to osteoblasts

1) Hyperthyroidism
2) Hyperparathyroidism
3) Cushings, corticosteroids
4) GI malabsorption (coeliac, IBD)

1) No production of calcitriol
2) Tubular disease results in lack of reabsorption of phosphate leading to phosphate depletion

Osteomalacia - defective mineralisation due to absence of vitamin D due to:
diet, lack of sunlight, kidney or liver disease

Endochondral
Intramembranous (clavicles, skull)

At either end (primary growth plates) and at the greater and lesser trochanters (secondary)

Resting zone
Proliferative zone
Hypertrophic zone
Calcification zone

Olllier's - multiple enchondromas
Mafucci's syndrome - multiple enchondromas with haemangioma

True leg length: ASIS to medial malleolus
Epiph plate damage: trauma, infection, avascular necrosis
Dislocated hip (DDH developmental hip dysplasia)
Bone dysplasia: Fibrous dysplasia, Ollier's/Mafucci's

Apparrent LLD is measured by the apparrent leg length ie from naval to medial malleolus. If real leg lengths are same, then problem is scoliosis rotating the pelvis

HLA class 2: HLA-DRB1 - inflammation of synovium, thickening, pannus, erosion
Symmetric, inflammatory, polyarthritis affecting the MCP w ulnar deviation, DIP, radial ulnar carpal deviation, Boutonniere, Swan neck
Rheumatoid nodules, lung fibrosis, membranous glomerulonephropathy, Sjogren's

3 months, age <45 with arthritis, enthesis, dactylitis plus HLAB27 or uveitis or sacrolilitis (MRI).
AS: loss of lumbar lordosis, restricted movement, joint fusion, Romanus lesions (fatty changes at vertebral corners), bone marrow oedema

1) Paed bone water content is high and mineral content is low, hence bone is softer relative to ligaments
2) Physis is cartilaginous and easily damaged

Salter-Harris 2 because the metaphysis because of:
1) Decreased cortical bone thickness
2) Increased porosity
3) Increased bone turnover

Forearm - fracture of metaphysis, commonly a buckle but also SH2
Arm - supracondylar fracture of the humerus due to hyperextension of the elbow(Gartland Classification based on amount of displacement)

Gunstock deformity (cubitus varus) caused by a supracondylar fracture of the humerus in children

1) Supracondylar
2) Lateral condyle (capitulum) fracture
3) Fracture of the medial epicondyle

Radial head displacement (Salter-Harris 1) or displacement and fracture of the radius (SH 2)

Monteggia fracture of the proximal ulna causing dislocation of the radial head. On X-ray the radial shaft doesn't bisect the capitulum

1) Hx: does Hx from parent fit with clinical findings
2) Multiple injuries
3) Previous admissions, old injuries (callused fracture sites)
4) Paternal attitude and background
5) If suspicious - must report to DOCS

1) tibial tuberosity
2) calcaneal
3) medial epicondyle
4) inferior patellar pole

Ligament:
Grade 1: partial tear, ecchymosis and swelling. Immobilisation only
Grade 2: partial significant tear, joint laxity, immobilise and refer
Grade 3: complete tear, unstable joint, surgical repair

1) Shock due to haemorrhage
2) Crush syndrome (myoglobinurea)
3) Fat embolism (lipidurea, PE)
4) Infection
5) Nerve injury (distal weakness, parasthaesia, numbness)
6) Vascular injury (major artery - haemorrhage -> shock, compartment syndrome

1) Scaphoid as radial artery supply is interupted
2) Head of femur if NOF is fractured

1) Malunion resulting in joint disturbance
2) Growth arrest if Salter Harris 3-5 (ie epiphysis moves and damages growth plate)

1) Paeds and adolescents
2) Metaphyseal: proximal tibia and humerus, distal femur
3) Histology: malignant osteoblasts forming pleomorphic cells, mitoses, lots of osteoid
4) Clinical: night pain, pathological fractures, stage III metastasises to lungs

1) Deformity: Osgood Schlatter's, callus, fracture maluniom
2) Benign Neoplasm: osteoid osteoma, osteochondroma, osteoblastoma
3) Malignant Neoplasm: osteosarcoma, chondrosarcoma, Ewing's disease (sarcoma)

1) Mechanical: ligaments, tendons, muscles, meniscus, Osgood Schlatter, fractures, soft tissue, bursae, osteoarthritis
2) Inflamatory: RA, osteomyolytis, synovitis
3) Neoplasms: primary and mets
4) Neurological: referred from back and hip
5) Vascular: ischaemia

1) Irregular margin
2) Invasion of cortex and tissue
3) Periosteal reaction

1) Loss of proteoglycan, weakening of collagen network and increased water content of joint cartilage
2) Formation of osteophytes, eburnation
3) Damage to articular surface allows sinovial fluid to form subchondral cysts
4) Heberden and Bouchard nodules form on phalangeal joints

1) Lymphocytic infiltration: lung fibrosis, Sjogren syndrome, pleural effusion, pericarditis, myocarditis, valvular disease
2) Kidneys: nephrotic syndrome due to membranous nephritis and membranoproliferative glomerulonephritis, analgesic nephropathy, vasculitis

High titres of:
1) RA
2) Anti cyclic citrullinated antibodies
3) CRP

TNF-alpha, receptors are blocked by Enteracept, Infliximab

Methotrexate: dihydrofolate reductase inhibitor

1) seronegative
2) Affect entheses
3) Cause joint ankylosis

Reiter's syndrome is associated with reactive arthritis following an STI of non-gonnococcal urethritis: arthritis (typically lower limb, assymetrical) and conjunctivitis

1) osteomyolitis
2) soft tissue abcess
3) haematogenous
4) penetrating injury/iatrogenic

1) Court order
2) Part of research
3) Minors
4) Statutory decision maker
5) Overwhelming public interest
6) Notifiable conditions