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- "Loss of corticomedullary differentiation"
- "Concentric joint space narrowing"
- "Coxa Vara", Bowed femur"
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- Fibrous dysplasia [younger]
- ground glass trabeculae,
- Paget will be high ALP, LDH (bone turn over), urine
- Chondrosarcoma
- Lymphoma [younger]
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- Increased osteoclastic activity with compensatory increase in disorganized osteoblastic bone formation [Accelerated but disorganized]
- Bone is poor quality, very vascular, thickened and bent
- in contrast with osteopetrosis (failure of osteoclast)
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- AD inheritance (40%) but most are spontaneos
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- Ubiquitin Binding Protein Sequestosome-1 5q35-QTER
- (Ubiquitin Specific Protease-6 in ABC)
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- Unknown, may be linked to virus infection (paromyxovirus, Respiratory syncytial virus RSV)
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- Polyostotic 83%, Monostotic 17%
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- ABCD, PPP, M
- A = Arthritis
- B = blood flow complications - high cardiac output failure
- C = Cranial nerve compressions [Osteopetrosis also], Spinal stenosis
- D = deformities - bowing
- PPP = Pain, Pathological Fractures, Pseudoarthrosis
- M = malignant change 1% [osteosarcoma for paget]
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- LAB -
- Lytic - profound resorption of bone
- Active/ Mixed phase - combination of osteoclastic and osteoblastic activity
- Burnout/ sclerotic phase- dense, sclerotic bone
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- Long bones – coarse, thickened trabeculae, loss of corticomedullary differentiation, bowing, stress fractures, large joint arthritis
- Hip – Protrusio, coxa vara (due to mechanical overload in weak bone)
- Skull – cotton wool appearance
- Spine - Picture frame vertebrae - sclerosis of end plates and periphery
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- Bone scan look for polyostotic involvement
- Blood tests - ALP raised (Osteoblastic activity), LDH raised (Osteoclastic activity), serum acid phosphatase , calcium panel (hypercalcemia)
- Urinary markers - N Telopeptide, Hydroxyproline, Deoxypyridinoline
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- Secondary osteosarcoma in 1%
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- This is a Complex Primary
- Pre-op - 5 things to be concerned
- Check disease control - ALP, LDH, Serum tartrate resistant phosphatase levels, Urine test
- Aim to do in Burn out phase (lytic/ active phase will have bleeding ++ and risk of loosening)
- Endocrine review for Hypercalcemia
- Cardio review - High cardiac output failure
- Templating - for deformity planning for osteotomies (rarely needed)
- Standby large prosthesis inventory (protrusio, require large cup), stemmed implants
- Implant choice - aware of concerns with cement interdigitation, some reccomend cementless. However, systematic reviews found no difference but there was a paucity of data. I will use a hybrid fixation which I am familiar with.
- If for deformity correction with osteotomy ➔ cementless stems
- Stand by equipment - sharp burrs to cut sclerotic bone
- II for deformity correction and fixation
- Blood loss - Cross match, cell saver, autologous blood donation, TXA
- 6. ?Need TRO secondary osteosarcoma - biopsy
- Intraop
- Approach - extensile to manage complications, soft tissue contractures may need releases
- Femoral prep - Rasps may be difficult to use in sclerotic bone. Use high speed burr. (need sharp equipment)
- Reduce blood loss - Meticulous hemostasis during approach, hypotensive anaesthesia, [TKR] Tourniquet to reduce blood loss
- Address deformities
- Bowing - osteotomies with long stem implants bypassing by 2 cortical diameters
- Post op
- Risk of HO up to 50%
- HO prophylaxis - Indomethacin 75mg OM x 6/52 OR Radiotherapy pre op 7gray 72 hours before op
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- New onset of pain ➔ need biopsy TRO malignancy
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- "generally accepted that patient's with paget's disease have normal fracture healing capacity to progress through the process at normal speed"