Clinical

1. ORTHOPEDIC ASPECTS OF
METABOLIC BONE DISEASE
Presented by EKKASIT SRITHAMMASIT, MD.
Leon Lenchik , MD et al
Department of Radiology, The Bowman Gray School of Medicine, Wake Forest University (LL), Winston-Salem, North Carolina
Orthopedic Clinics of North America - Volume 29, Issue 1 (January 1998)

2. Metabolic bone disease (MBD)
• Encompasses a diverse group of disorders
associated with altered calcium and
phosphorus homeostasis.
• To orthopedic surgeons; MBD is often silent
until the patient presents with fracture.
Introduction

3. Table of content
 Osteoporosis.
 Osteomalacia and rickets.
 Hyperparathyroidism.
 Hypoparathyroidism.
 Hyperthyroidism.
 Hypothyroidism.
 Renal osteodystrophy.
 Paget's disease.

4. OSTEOPOROSIS

5. OSTEOPOROSIS
• Most common metabolic bone disease.
• One of the most prevalent conditions
associated with aging.

6. OSTEOPOROSIS
Definition : reduced bone mass of normal composition.

7. OSTEOPOROSIS
• Clinical definition: requires the presence
of a nontraumatic fracture.
• Histologic definition: requires normally
mineralized bone to be present in
reduced quantity.

8. OSTEOPOROSIS

9. Diagnosis Osteoporosis
Bone densitometry; gold standard
1. Detection osteoporosis before fractures.
2. Determination disease severity.
3. Estimation risk of fracture.
– Serial BMD measurements enable determination
of rate of bone loss or gain and thereby help in
monitoring therapy.
Plain film; loss of 30% to 50% of bone is required
before it is detected on conventional
radiographs.

11. Ostoporosis Classification
• Primary osteoporosis. (idiopathic) : more common
– Type 1 (postmenopausal)
– Type 2 (age-related or senile)
• Secondary osteoporosis.
– Metabolic (acromegaly, hypercorticism, hyperthyroidism,
hyperparathyroidism, hypogonadism, pregnancy, diabetes
mellitus)
– Congenital (osteogenesis imperfecta, Ehlers-Danlos syndrome,
homocystinuria, mastocytosis, ochronosis, Gaucher's disease)
– Nutritional (alcoholism, malnutrition, calcium deficiency, scurvy)
– Drug-related (steroids, heparin).

12. Radiological finding (1)
• The m/c radiologic finding is generalized
osteopenia.
– Cortical thinning and accentuation of
weightbearing trabeculae.
– The bone surfaces are well defined, with
sharp margins.

13. Radiological finding (2)
• Fractures - vertebral deformities, which
are also common, include biconcave
end plates (fish vertebrae) and anterior
wedging.

14. Lateral radiograph of the lumbar spine in a 55-year-old woman with postmenopausal osteoporosis shows generalized osteopenia,
compression fractures, and biconcave vertebral endplates ("fish vertebra"). Notice thin, well-defined vertebral cortices ( arrows).

16. Radiological finding (3)
• Patients with osteoporosis secondary to
excess steroids.
– Generalized osteopenia.
– Fractures with exuberant callus
– Steroid-related complications;
• Intravertebral vacuum (nitrogen gas);
• Avascular necrosis.
• Osteomyelitis.

17. Differential considerations for
diffuse osteopenia
1. Osteomalacia.
– indistinct trabeculae and poorly defined interfaces
between cortical and trabecular bone.
– Presence of Looser's zones.
2. Hyperparathyroidism.
– bone resorption at characteristic sites.
3. Multiple myeloma.
– MR imaging may show areas of marrow
replacement.

18. Regional or localized
osteoporosis
1. Immobilization and disuse
2. Reflex sympathetic dystrophy syndrome
(RSDS)
3. Transient regional osteoporosis
– Transient osteoporosis of the hip.
– Regional migratory osteoporosis.
4. Inflammatory arthritis.
5. Tumors
6. Infection.

19. Radiologic findings in regional
osteoporosis (1)
• RSDS : mediated by the sympathetic
nervous system and is characterized by
– aggressive osteoporosis,
– soft tissue swelling.
 The cause is usually traumatic, but the
disease may also be idiopathic.

20. AP radiograph of the hand in a patient with reflex sympathetic dystrophy syndrome shows soft-tissue swelling and periarticular osteopenia.

22. RICKETS AND
OSTEOMALACIA

23. Rickets and osteomalacia
• Rickets and osteomalacia are similar
histologically.
• Abnormality in vitamin D metabolism.
• Incomplete mineralization of normal
osteoid tissue.
Rickets
Occurs in children
Affects immature bone
Osteomalacia
Occurs in adult
Affects mature bone

24. Rickets and osteomalacia
Maintain calcium and phosphate homeostasis.

25. Clinical findings of
Rickets and Osteomalacia
Rickets: stunted skeletal growth.
• Apathetic, Irritable, Hypokinetic.
• Frontal bossing, softening of the skull,
dental caries, rachitic rosary, kyphosis,
joint enlargement, or bowing of long
bones.
• Fractures and slipped capital femoral
epiphyses.
Depend in part on the etiology and severity of the disorder, as well as the
age of the patient at presentation

27. Clinical findings of
Rickets and Osteomalacia
Osteomalacia: more subtle.
• Fatigue, malaise, or bone pain.
• Proximal muscle weakness and
abnormal gait may be present.
Depend in part on the etiology and severity of the disorder, as well as the
age of the patient at presentation

28. Radiologic findings of
Osteomalacia
• The M/C radiologic sign is generalized
osteopenia.
• Coarsened and indistinct bony trabeculae.
• Poorly defined interfaces between cortical
and trabecular bone.
• Looser's zone, or pseudofracture. (more
specific but less common)
• End plate deformities and fractures of
vertebral bodies, bowing and fractures of long
bones, and basilar invagination of skull.
The radiologic findings of osteomalacia are often nonspecific, difficult to
confirm the diagnosis with imaging studies

29. Radiologic findings of
Osteomalacia
Looser's zone.
• Linear areas of undermineralized
osteoid that occur in a bilateral and
symmetric distribution.
• Characteristic sites; inner margins of
femoral neck, proximal ulna, axillary
margin of the scapula, pubic rami, and
ribs.
• DDx; Paget's disease or fibrous
dysplasia.

30. AP radiograph of the hip in a 50-year-old man with osteomalacia shows coarsened trabecular pattern with indistinct trabeculae.

31. AP radiograph of the hip in a patient with osteomalacia shows multiple Looser zones ( arrows) in the superior pubic ramus.

33. Osteomalacia. AP radiograph of the pelvis showing osteopenia with bilateral femoral neck pseudofractures (arrows).

34. Radiologic findings of
Rickets
• The M/C radiologic sign is generalized
osteopenia.
• Increased lucency, widening, elongation,
irregularity, and cupping of the metaphyses.
– Earliest; Slight axial widening of the physis
– Next; Increased lucency of the zone of provisional
calcification.
– More advance; The physis widens and its contour
becomes irregular.
• Occasionally, in patients with rickets caused
by chronic renal disease, increased sclerosis
may be seen.

35. Radiologic findings of
Rickets
• The regions of highest yield on
radiologic evaluation of rickets are those
that are undergoing rapid growth.
– Costochondral junctions of middle ribs
(rachitic rosary)
– Distal femur
– Both ends of the tibia
– Distal radius and ulna
– Proximal humerus.

36. Radiologic findings of
Rickets
• The complication of rickets.
– Skeletal deformities.
– In neonates; posterior flattening and squaring of
the skull, or craniotabes, may be seen.
– In early childhood; bowing deformities of arms and
legs are common.
– Older children: scoliosis, vertebral end plate
deformities, basilar invagination of the skull may be
seen.
– Advance disease: Slipped capital femoral
epiphysis.

37. A, AP radiograph of the knee in a 2-year-old girl with rickets shows generalized osteopenia and widening of the metaphyses of the proximal tibia and fibula. B, AP radiograph
of the wrist in another child with rickets shows generalized osteopenia, as well as widening and irregularity of the metaphyses of the distal radius and ulna.

38. Rickets in a young child with growth plate widening and irregularity in the wrist (A) and knees (B). Note the small epiphyses in the knees.

39. Rachitic rosary. (A) and lateral (B) radiographs of the chest showing prominence of the costochondral junctions (arrows).

40. Vitamin D-resistant rickets in a 1-year-old child. (A) AP radiograph of the knees showing irregularity and widening of the growth plates. The epiphyses are
small and irregular as well. (B) Three years after high-dose vitamin D therapy, the knees appear normal. There is residual femoral bowing.

41. HYPERPARATHYROIDISM

42. HYPERPARATHYROIDISM
• Primary
– Parathyroid adenoma
• Secondary
– chronic renal insufficiency.
Hyperparathyroidism may result in either bone
resorption or bone formation, bone resorption
usually dominates.

44. Radiologic findings of
HYPERPARATHYROIDISM
• The M/C radiologic abnormality is generalized
osteopenia.
• Bone resorption, bone sclerosis, brown tumors,
chondrocalcinosis, soft tissue calcification, and
vascular calcification.
• Brown tumors appear as well-defined lytic lesions.
– After resection of parathyroid adenomas, the lesions may
become sclerotic and may mimic blastic metastasis.
• Bone resorption, the most characteristic finding, is
usually classified as
– subchondral, trabecular, endosteal, intracortical,
subperiosteal, subligamentous, and subtendinous.

46. Radiologic findings of
HYPERPARATHYROIDISM
• Subperiosteal resorption - M/C
– Usually occurs in the hands and feet.
– M/C affected site: radial aspects of the middle phalanges.
– Acro-osteolysis or phalangeal tufts resoption may also be
present.
• Trabecular resorption
– Often seen in the diploic space of the skull, where it has a
characteristic salt and pepper appearance.
• Subchondral resorption
– May be seen in the sacroiliac joints, sternoclavicular joints,
acromioclavicular joints, symphysis pubis, and discovertebral
junction .

47. AP radiograph of the hand in a 66-year-old woman with primary hyperparathyroidism owing to parathyroid adenoma shows subperiosteal bone
resorption ( arrows) along the radial aspect of 2nd, 3rd, and 4th middle phalanges.

49. AP radiograph of the knee in a child with hyperparathyroidism shows subperiosteal bone resorption ( arrow) along the proximal medial tibia.

50. Lateral radiograph of the skull in a 23-year-old man with secondary hyperparathyroidism shows trabecular resorption of the diploic space ("salt and pepper" appearance).

52. Dental radiograph in another child with hyperparathyroidism shows resorption ( arrow) of the lamina dura of the mandible.

53. Radiologic findings of
HYPERPARATHYROIDISM
Secondary
• Bony sclerosis; focal
or generalized.
• Rugger-jersey
appearance of
spine.
• Soft tissue and
vascular
calcification.
•
•
Primary
Chondrocalcinosis
usually seen in the
menisci of the
knee, the
triangular
fibrocartilage of
the wrist, and the
pubic symphysis

54. AP radiograph of the wrist in an 83-year-old woman with primary hyperparathyroidism shows
chondrocalcinosis ( arrow) of the triangular fibrocartilage.

56. Secondary HPT. Radiograph of the pelvis and hips showing diffuse osteosclerosis.

57. A, AP radiograph of the spine in a patient with secondary hyperparathyroidism shows generalized bone sclerosis, small kidneys, and left renal calculi. B, Lateral radiograph
of the lumbar spine in another patient with secondary hyperparathyroidism shows horizontal, bandlike ("rugger jersey") sclerosis of the vertebral bodies (
arrows).

59. AP radiograph of the hand in a 50-year-old man with renal osteodystrophy shows acro-osteolysis ( short arrows), subperiosteal bone
resorption ( long arrows), and vascular calcifications.

60. Secondary HPT. Radiograph of the hand showing resorption of the first to third tufts with soft tissue calcification (1). There is articular
calcification (2), and subperiosteal and subligamentous resorption (3).

61. The differential diagnosis of
HYPERPARATHYROIDISM
• Focal subperiosteal resorption involving a single bone
– Neoplasms or osteomyelitis.
• Bone sclerosis in patients with secondary
hyperparathyroidism.
– Metastatic disease, radiation-induced bone disease,
hypoparathyroidism, myelofibrosis, mastocytosis, sickle-cell
disease, and Paget's disease.
• Chondrocalcinosis
– Pyrophosphate arthropathy (CPPD) or hemochromatosis.
• Brown tumors
– includes other focal lytic lesions, such as giant cell tumor
and fibrous dysplasia.

62. HYPOPARATHYROIDISM

63. • The M/C cause is excision of or trauma
to the parathyroid glands.
– may not be recognized for years after
surgery.
HYPOPARATHYROIDISM

64. Clinical presentation:
• Neuromuscular
dysfunction.
• Short stature.
• Delay or failure of tooth
eruption.
• Gastrointestinal
complaints.
HYPOPARATHYROIDISM

65. Radiologic findings are varied.
• Bony sclerosis. = M/C finding
– Focal or generalized
• Subcutaneous calcification.
• Calvarial thickening
• Basal ganglia calcification
• Hypoplastic dentition
• Premature physeal fusion
• Spinal ossification.
• Occasionally : Osteoporosis, Enthesopathy,
Dense metaphyseal bands.
Radiologic findings of
HYPOPARATHYROIDISM

66. Lateral radiograph of the skull in a 5-year-old girl with pseudohypoparathyroidism shows thickening ( arrows) of the calvarium.

67. • Widespread bony sclerosis.
– Blastic metastasis, myelofibrosis, renal
osteodystrophy, sickle-cell disease, and fluorosis.
• Dense metaphyseal.
– Leukemia therapy, heavy-metal poisoning, or
hypothyroidism.
• Calcifications of the basal ganglia
– Toxoplasmosis or cytomegalovirus infections, after
radiation therapy, and after carbon monoxide
exposure.
• Subcutaneous calcifications.
– Collagen-vascular diseases, hypervitaminosis D,
and renal osteodystrophy.
differential diagnosis of
HYPOPARATHYROIDISM

68. • Inherited disorder
• End-organ resistance to parathyroid
hormone.
• X-linked dominant trait
• More common in women.
• Shares many features with
hypoparathyroidism.
Pseudohypoparathyroidism

69. Similar to those of hypoparathyroidism
• Bony sclerosis, Soft tissue calcification, Dense
metaphyseal bands, Calvarial thickening and Basal
ganglia calcification.
In addition
• Short metacarpals, metatarsals, and phalanges;
diaphyseal exostoses; and cone-shaped epiphyses.
• Typically, the first, fourth, and fifth rays are shortened.
• Growth deformities
– Bowing of long bones.
Radiologic findings of
Pseudohypoparathyroidism

70. Pseudohypoparathyroidism. (A,B) AP radiographs of the hands showing shortening of the fourth and fifth
metacarpals.

71. AP radiograph of the hand in another child with pseudohypoparathyroidism shows short 3rd, 4th, and 5th
metacarpals.

72. • Incomplete genetic manifestation of
PHP.
• End-organ resistance to parathyroid
hormone.
• Share most of their clinical and
radiologic features of
pseudohypoparathyroidism.
Pseudopseudohypoparathyroidism

73. HYPERTHYROIDISM

74. HYPERTHYROIDISM
• Children; causes accelerated skeletal
maturation and advanced bone age.
• Adults; causes generalized
osteoporosis leading to vertebral
fractures and kyphosis.

75. HYPERTHYROIDISM
• The M/C causes of hyperthyroidism in
adults are toxic diffuse goiter and toxic
nodular goiter.
• Excessive production of thyroid
hormone by the thyroid gland results in
bone resorption is dominant.

76. HYPERTHYROIDISM
• Patients may experience
– Weakness.
– Fatigue
– Nervousness
– Weight loss
– Palpitations
– Diarrhea
– Hypersensitivity to heat.

77. Radiologic findings in
HYPERTHYROIDISM
Pt with radiologic abnormalities typically have had
the disease for at least 5 years, more
common in men

78. Radiologic findings in
HYPERTHYROIDISM
Skeletal findings
• Generalized osteopenia: M/C Finding
• Thyroid acropachy (0.5% to 1%) .
• Kyphosis and insufficiency fractures are
occasionally seen.

79. Radiologic findings in
HYPERTHYROIDISM
Thyroid acropachy
• A dense, solid periosteal reaction with a
feathery contour
– Asymmetric distribution
– Radial margin of metacarpals and
phalanges.
– Occasionally, long bones are also involved.
• Soft tissue swelling
– Hands, feet, and pretibial region of the leg.

80. AP radiographs of the hand in a 46-year-old man with thyroid acropachy who presented with hand swelling and hypothyroidism 2 years after a
thyroidectomy. Note the dense, solid periosteal reaction with feathery contour ( arrows) along the shafts of 2nd, 3rd, and 4th proximal and middle
phalanges.

81. Thyroid acropachy. (A,B) Radiographs of the hands showing diaphyseal periostitis (arrows) and
generalized swelling. (C) Radiograph in a different patient showing marked soft tissue promin
ence.

82. Differential for
HYPERTHYROIDISM
• Thyroid acropachy
Periosteal reaction involving multiple bones
– Hypertrophic osteoarthropathy:
• long bones.
• Feathery contour is absent.
– Pachydermoperiostosis:
• Long bones.
• Periosteal reaction extends to the metaphyses
and epiphysis.

83. A, AP radiograph of the leg in a child with hypertrophic osteoarthropathy shows thin periosteal reaction ( arrowheads) along the diaphyses of the tibia and fibula. The hands
were not involved. B, Frontal radiograph of both forearms in a patient with pachydermoperiostosis shows dense periosteal reaction involving the diaphyses
and metaphyses of both radii and ulnae.

84. HYPOTHYROIDISM

85. HYPOTHYROIDISM
Manifests
• Delayed physeal closure and bone age.
• In infants: cretinism
• In children: mental retardation, obesity,
developmental delay, growth retardation, lethargy,
and constipation.
• In adults: dry coarse skin and hair, fatigue, lethargy,
paresthesias, constipation, and bradycardia.
Causes of hypothyroidism
• Surgery, tumors, iodine deficiency, medications, and
pituitary disorders.

86. The radiologic findings in
HYPOTHYROIDISM
Depend on the patient's age at presentation.
• In infants:
– Absence epiphysis : distal femoral and
proximal tibial.
– In the skull, wormian bones and prolonged
separation of sutures.

87. The radiologic findings in
HYPOTHYROIDISM
• Depend on the patient's age at presentation.
• In children:
– Fragmented, irregular epiphysis. Referred to as
epiphyseal dysgenesis, the appearance may
simulate that of Legg-Calve-Perthes disease.
– Slipped capital femoral epiphysis.
– In the spine, anteriorly wedged bullet vertebrae.
– Dentition and pneumatization of the sinuses may
be delayed.
– Occasionally, dense metaphyseal bands are seen.

88. A, Radiograph of the knee in a 2-year-old boy with delayed bone maturity owing to hypothyroidism shows nonossification of the epiphysis of the distal femur and proximal
tibia. Both epiphyses should be ossified by 1 month of age. B, AP radiograph of the left hip in another child with hypothyroidism shows a fragmented, irregular (
arrow) proximal femoral epiphysis. This appearance may mimic Legg-Calve-Perthes disease.

89. The radiologic findings in
HYPOTHYROIDISM
• Depend on the patient's age at presentation.
• In adults :
– Usually mild.
– Generalized osteoporosis is M/C.
– Occasionally, soft tissue edema, dystrophic
calcification, ligamentous laxity, and carpal
tunnel syndrome are present.
– Coxa vara may develop.

90. ACROMEGALY

91. ACROMEGALY
• Results from excessive growth hormone after physeal
closure.
• Third or fourth decade of life.
• Usually caused by a pituitary adenoma.

92. ACROMEGALY
Clinical findings;
•
• Coarse facial features
• Thick skin
• Poor dental occlusion
• Thick calvarium
• Deepening of voice
• Lantern jaw
• Prominent tongue
• Broad hands
• Organomegaly (kidneys, liver, pancreas, spleen thyroid, heart).
• Arthropathy mostly involves large joints.
• Compressive neuropathy, such as carpal tunnel syndrome or
spinal cord compression, may result from soft tissue and bony
hypertrophy.
Fatigue and lethargy are also quite common.

93. Radiographic findings of
ACROMEGALY
Bony and soft tissue overgrowth
• Soft tissue thickening is classically seen in the heel
pads and digits .
• Bony enlargement is most notable in the skull,
vertebra, phalnageal tufts.
• Calvarial thickening, prominent supraorbital ridges.
Joint
• In the early stages of the disease, joint-space
widening is seen.
• In later stages, as the thickened cartilage, and
radiologic signs of joint-space narrowing, subchondral
sclerosis, subchondral cysts, and osteophytes
become apparent.

94. Radiographic findings of
ACROMEGALY
• Additional radiologic findings
– enlargement of costochondral junctions
– enlargement of the sella turcica and paranasal sinuses
– intervertebral disk widening
– posterior vertebral scalloping
– Spade like phalangeal tufts.
– degenerative enthesopathy
– periarticular calcification
– osteoporosis.
• The most common musculoskeletal complications of
acromegaly are premature osteoarthritis and
degenerative disk disease.

95. A, Lateral radiograph of the foot in a patient with acromegaly shows soft-tissue thickening of the heel pad. B, Lateral radiograph of the skull in another patient with
acromegaly shows enlarged prognathic mandible and enlarged sella turcica ( arrow).

96. AP radiograph of the hand in a patient with arthropathy of acromegaly shows joint-space narrowing and osteophytes involving the 3rd and 4th interphalangeal
joints.

97. AP radiograph of the distal phalanx in a 36-year-old man with acromegaly shows spade-like phalangeal tuft with soft-tissue overgrowth.

98. The radiologic differential diagnosis in
ACROMEGALY
• In advanced disease, the combination
of soft tissue and bony findings allows
accurate diagnosis.
• Earlier in the disease course, isolated
radiologic findings allow some
differential considerations.

99. The radiologic differential diagnosis in
ACROMEGALY
• Pachydermoperiostosis
– Enlarged sinuses, prominent supraorbital
ridges, and thickened phalanges.
– Sella turcica is normal, no joint-space
widening. does not occur.
• Long-term phenytoin therapy- Heel pad
thickening

100. RENAL
OSTEODYSTROPHY

101. RENAL OSTEODYSTROPHY
• Bone disease in patients with chronic renal
insufficiency.
• It combines features of rickets, osteomalacia,
secondary hyperparathyroidism, and osteoporosis.
• Aluminum toxicity is an additional component that
may be seen in patients undergoing dialysis.
• In children with chronic renal failure, the findings of
rickets dominate, whereas in adults the findings of
secondary hyperparathyroidism are more prominent.

102. Radiologic findings in
RENAL OSTEODYSTROPHY
Combination of the findings of rickets,
osteomalacia, secondary
hyperparathyroidism, and osteoporosis
• Periosteal neostosis (lucency between
the periosteum and subjacent bone)
may be present.
– It is usually seen in asymmetric distribution
in the metatarsals, femur, and pubic rami.

103. The differential diagnosis of
RENAL OSTEODYSTROPHY
• Periosteal neostosis
– hypertrophic osteoarthropathy,
osteomyelitis, or neoplasm.
• Soft tissue calcification
– Collagen-vascular diseases, idiopathic
tumoral calcinosis, hydroxyapatite crystal
deposition disease, and hypervitaminosis
D.

104. RENAL OSTEODYSTROPHY
• The most common complications in
patients with renal osteodystrophy are
insufficiency fractures.
• In patients who have had renal
transplantation, osteonecrosis,
insufficiency fractures, tendinitis, and
tendon ruptures are common.

105. Frog-lateral radiograph of the hip in a patient with osteonecrosis of the femoral head shows a characteristic
subchondral lucency ( arrow) and collapse of the femoral head.

106. PAGET'S DISEASE

107. PAGET'S DISEASE
• A common disorder of unknown etiology
that is characterized by excessive and
abnormal remodeling of bone.
• Men > women
• Age > 40 years.
• Polyostotic > monostotic.

108. PAGET'S DISEASE
• Asymptomatic.
• Bone pain, progressive bony enlargement,
bowing of long bones, or fractures at
presentation.
• Deafness
– from cranial-nerve compression at the skull base
or from middle-ear ossicle involvement.
• The spinal cord compressed
– basilar invagination of the skull or enlargement of
the vertebrae.

109. Radiologic findings of
PAGET'S DISEASE
• Epiphyseal involvement with sharply demarcated lysis
that advances down the diaphyses is quite specific.
• Three sequential stages may be seen:
1. Lytic; most common in skull and long bones.
2. Mixed
3. Sclerotic; typically involves the axial skeleton.
• The hallmarks of advanced Paget's disease are bone
enlargement and increased bone sclerosis.
• Cortical and trabecular thickening and distortion are
also frequently present.

110. Radiologic findings of
PAGET'S DISEASE
• Spine
– M/C in lumbar region: picture-frame vertebra, ivory vertebra,
or compression fractures.
• Skull
– Lytic phase, or osteoporosis circumscripta, usually begins in
the frontal or occipital bones.
– More advanced disease in the skull manifests a cotton wool
appearance of mixed sclerosis and lysis.
• Pelvis
– The earliest finding = thickening of the iliopectineal line.
– Occasionally, patchy areas of lucency and sclerosis.
– Protrusion deformity of the acetabula is a well-recognized
complication of advanced disease of the pelvis.

111. Radiologic findings of
PAGET'S DISEASE
• Long bones
–
– Lysis of subarticular bone is seen initially.
– A wedge of lucency down the diaphyses:
flame-shaped or blade-of-grass.
In the tibia, the lytic phase occasionally
begins in the diaphysis.
– Advanced disease of the long bones is
characterized by coarsened trabecula,
bony sclerosis, bony enlargement, and
deformity.

118. A, Frontal radiograph of the pelvis in a patient with advanced Paget's disease shows bony enlargement, bone sclerosis, and trabecular disorganization involving the right femur,
right hemipelvis, and sacrum. B, Frontal radiograph of humerus in another patient with advanced Paget's disease shows bony enlargement, cortical and trabecular
thickening, and trabecular disorganization.

119. Frontal radiograph of the femur in a patient with advanced Paget's disease shows bowing deformity of the femur along with bony enlargement, bone sclerosis,
cortical thickening, and trabecular disorganization.

120. Complications of
PAGET'S DISEASE
• Basilar invagination
• Spinal stenosis
• Premature osteoarthritis
• Insufficiency fractures
• Osteomyelitis
• Neoplasms: osteosarcomas.
• Sarcomatous degeneration: common in
patients with widespread disease

121. Frontal radiograph of the pelvis in a patient with widespread Paget's disease shows enlargement and cortical thickening of the pelvis. Additionally, there is an expansile
lytic lesion ( arrows) in the ischium, representing malignant degeneration of Paget's disease into fibrosarcoma.