Osteitis deformans, also known as Paget's disease of bone, is a chronic bone disorder characterized by increased and irregular bone remodeling. It results in thickened and misshapen bones with weakened structural integrity. The cause is unknown but may be related to viral infection or genetic factors. It typically affects people over 50 years of age and involves bones of the pelvis, femur, spine and skull. Symptoms range from bone pain, deformities, fractures to neurological complications. Diagnosis is confirmed by x-ray findings and elevated bone turnover markers. Treatment focuses on reducing bone turnover with bisphosphonates or calcitonin to relieve symptoms and prevent complications like fractures.

1. Dr (Major) Parthasarathy S
Junior Resident,MS Orthopaedics
Stanley Medical College,Chennai
Ref: Chapman’s orthopaedic surgery 3rd
edn
Apley’s system of orthopaedics and
fractures 9th
edn
Davidson’s textbook of medicine
Harshmohan textbook of pathology

3.  Osteitis deformans
 Disturbance in rate of bone turn over
 Initiated by early increase in bone
resorption(osteoclasts)
 Excessive & pathologic bone
formation(osteoblast)
 Result
 Distorted bone
 Thick cortex
 Coarse rabeculations
 Immature woven appearance

4. Can affect any bone
Commonly affects
Pelvis & tibia (commonest)
Femur
Spine 75%
 Lumbar common
 Cervical rare
Cranium
Monostotic or polyostotic
Symtomatic or asymptomatic

5.  Unknown
 Familial clustering
 14%-30% + family history
 Autosomal dominant
 Some HLA correlation
 ? Viral etiology –Rebel et al 1980
 Inclusion bodies resembling nuclear
capsule(osteoclast)
 Resembles paramyxo/measles virus

6.  D/D
 Familial expansile osteolysis
 Expansile skeletal hyperphosphatasia
 Idiopathic hyperphosphatasia
 Early onset PDB

7.  3:2 sex ratio M:F
 >50 yrs
 3-4% >45yrs / 8% >80yrs prevalence in USA
 Common in Europe(north> south)/North
America/Australia/Newzealand
 Uncommon in Asians

8.  Starts at one end & progresses leaving a trail
of altered architecture
 Tends to start at muscle insertion points on
bone
 Marked increase in osteoclast & osteoblast
activity

9. Burned out pattern

13.  Steal syndrome –blood diverted from vital
organs to skeletal circulation
 Cerebral impairement
 Spinal cord ischaemia

14.  Asymptomatic 10-20%
 Bone pain
 Rest
 Motion
 Warmth of bone/skin over bone
 Back pain
 Spinal stenosis
 Compression #
 Paraplegia -secondary GCT
 Skull size increased
 Hearing loss(otosclerosis)

16.  Long bones bend
 Tibia –Ant
 Femur – Antlateral
 Kyphosis
 Becomes shorter
 Ape like
 Arms hanging infront
 Cranial nerve/spinal cord/nerve root
compression
 Pathological #
 Cardiac failure-high output

19.  Pathological #
 10% patients
 most common complication
 Femur tibia forearm
 Nonunion common
 Femoral neck/subtrochanteric #
 75-90% non-union rate
 With these exceptions # heals by abundant callus
 Secondary sarcoma # 5-20%
 Short/oblique/transverse
 Delayed/non-union-common in burned out phase

20.  2-4% in symptomatic
 0.1% overall
 Humerus –common site for malignant change
 Benign tumor
 GCT
 Sensitive to steroid therapy
 Malignant
 Osteogenic sarcoma(poor prognosis)
 Fibrosarcoma
 chondrosarcoma

23.  Signs
 More painful/tender/swollen
 New pain
 New site
 New Lytic area in sclerotic bone

25.  OA-atrophic
 Nerve compression
 High output cardiac failure
 Hypercalcemia

26.  Lab
 Serum Ca normal
 Serum phosphorous normal
 Hypercalcemia(immobilised patients)
 Serum ALP increased(osteoblast)
 90% cases
 May be normal-single bone
 24 hour urinary hydroxyproline & N
Telopeptide(osteoclast)
 Serum Pyridinoline increased

27.  X rays
 Transverse lucencies/pseudofractures
On the convex surface of weight bearing bone
 Focal bone resorption
 Disorded trabecular pattern
 Expanded bone
 Cortex thick
 Flame shaped/blade of grass osteolytic wedge
 sclerosis
 Pathological #

29.  Skull
 Circumscribed patch of osteoporosis in skull
 Osteoporosis circumscripta
 Cotton wool appearance
 Mixed
 Diploic widening
 Tam o'Shanter sign
 frontal bone enlargement, with the appearance of the
skull falling over the facial bones, like a Tam o'
Shanter hat

33.  Spine
 Picture frame sign
 Ivory vertebra
 Squaring on lateral view
 Vertical trabecular thickening

36.  A banana fracture
 Complete
 horizontally oriented pathological fracture
 seen in deformed bones affected
 incremental fractures
 A type of insufficiency fracture.

38.  Gallium bone scan
 Extent
 Tumor differentiation

39.  Biopsy
 Definitive
 Rarely indicated
 only when malignant transformation is suspected

40.  Asymptomatic
 Who do not have disease in weight bearing bone
 Periodic monitoring
 Symptomatic
 Pain
 Neurologic deficit
 Surgery
 Cardiac failure
 Severe polyostotic
 ALP/bone marker elevated twice normal with
disease in weight bearing bone

41.  Biphosphonates
 Preferred
 Inhibit bone resorption
 Bind to hydroxyapatite crystals
 prolonged remission
 Ca & Vit D given along(Osteomalacia)

42.  Calcitonin
 Decrease number & activity of osteoclast
 Daily dose till pain controlled & ALP reduced &
stabilised
 Maintenance once/twice weekly
 Injection/nasal spray
 Dry nares 2%

45.  Mithramycin
 Extremely cytotoxic
 Strong inhibitor of
 Osteoblast
 Osteoclast
 Recommended only in Paget’s paraplegia
 15mg/kg/day for 10days
 Osteotomy to treat deformity

46.  Fracture
 NOF
 Prosthetic replacement
 Subtrochateric femur
 Intramedullary system
 Corrective osteotomy
 Most pathological long bone #
 Intramedullary system
 Even after union protective bracing for 3-6
months
 Because remodelling is slow

48.  Severe disabling arthritis
 THR
 Significant varus deformity
 Bowing
 Acetabular protrusion
 Increased blood loss
 Distorted medullary cavity
 Sclerosis
 Heterotrophic ossification