osteoporosis

1. Osteoporosis

2. Definition
 Porous bone – holes become bigger, bone
becomes fragile and easier to break
 Progressive systemic skeletal disease,
characterized by low bone mass and micro-
architectural deterioration of bone tissue with
consequent increase in bone fragility and
susceptibility to fracture
 Different from osteomalacia – deficient
mineralization, normal matrix
 Porosis – deficient matrix and normal
mineralization

3.  Porosis – decrease in bony density with
increase in porosity.
 Insufficiency fracture – bone fails with normal
weight bearing, (due to physiological stresses)
 Fragility fracture – fall from standing height or
less
 Primary osteoporosis
 Postmenopausal
 50-70, Colle's # and vertebral compression
more common, high turnover
 Senile – >70, hip fractures more common,
low turnover

4.  Secondary
 Nutritional disorders
 Endocrine: Cushing's, hyperthyroid,
hyperparathyroidism
 Drugs: steroids, anticonvulsants, heparin,
GnRH analogues, immunosuppresants
 Multiple myeloma, Paget's, CTD, Ehler
Danlos, Osteogenesis Imperfecta

5. Pathology
 Normally, young patients have more blastic
activity
 Plateaus for the majority of life (blastic =
clastic)
 Older – more osteoclastic activity
 Overactive remodelling – deeper resorption
cavities
 Continuous remodelling of microfractures
 Patients with history of one fragility fracture
are upto 10 times more likely to have future
fractures

6. WHO
 Bone mineral density = T score < -2.5 SD
 Guidelines to screen
 Women > 65, males >70
 Young postmenopausal (post hysterectomy)
or with risk factors like long term
corticosteroid
 Post menopausal with history of fracture
 Diagnosis
 FRAX (fracture risk assessment)
 Risk factors + BMD
 Age, sex, height, weight, family history,
previous fracture, steroid, tobacco, alcohol,

7.  10 year fracture risk – hip, and other.
 Screening
 Ca, Vit D3, PTH, S. Creat
 Can also screen for ddx
 Infection – ESR, CRP
 Secondaries
 Multiple myeloma - SPEP

8. X-ray
 Empty bone appearance – resorption of
trabeculae
 Ground glass appearance
 Fish mouth appearance
 Spine, end plate weakening and intra discal
expansion

10. Singh and Maini Index

11. CT
 True density
 QCT (quantitative measurement of mineral
content)

12.  DEXA – dual energy Xray absorptiometry
 2 xray beams – difference is calculated to
eliminate the amount of radiation absorbed
by the soft tissue
 BMD – bone mineral content (g) / area
(cm^2)
 Bone density indicates bone strength (60-
80%)
 Early predictor of fracture risk
 Permits diagnosis even before first fracture
 Mean and standard deviation
 T score – is considered for a young healthy
person of same gender
 Z score – gender + age group

13.  Commonly measured in spine and hips (L2,
L3, L4 vertebrae are good as they don't have
other bones nearby)
 T Scores:
 Normal = 0 to -1
 Osteopenia = -1 to -2.5
 Osteoporosis = -2.5 or less

15. Treatment
 Risk factors – tobacco, alcohol
 Nutrition + supplement
 Ca – 1200 mg
 Vit D – 1500 IU
 Mg, Si, Vit K, boron
 Exercise
 Strength
 BMD increase
 Prevent fall
 Post fracture rehab

16. Medical Management
 T < -2.5 without risk factors, or < -1 with
history of fracture or other risk factors
 Fracture risk of 3% hip and 20% other.
 Goal
 Lower fracture risk
 Safe, affordable, well tolerable

17.  Anti resorptive
 HRT – estrogen/progestin
 SERM – tamoxifen (10 mg), raloxifen (60
mg/day)
 Bisphosphate
 Calcitonin (nasal spray – 200 IU)
 Denosumab – RANKL monoclonal antibody
 60 mg/6 month, upto 10 years. Nephro safe
 Bone forming
 Teriparitide
 New trabeculae formation
 Osteoblast lifespan
 More bone formation occurs
 Daily 20 ug sub-cut “pulse” doses are anabolic

18. Bisphosphonates
 Inhibit osteoclastic activity, thereby allowing for
more mineralization
 Non nitrogenous (tilduronate, clodronate,
etidronate) – interferes with ATP in osteoclast,
leading to apoptosis
 Nitrogenous (pami, neri, olpad, alendronate,
ibandronate, risedronate, zolendronate)
 Disrupts enzyme Farnesyl diphosphate
synthase, which disrupts the protein
synthesis in cell membrane and cytoskeleton
 Complication – gastritis, AVN mandible
 Patient should be able to sit for at least 30 min

19.  Dose
 Alendronate – 70 mg per week, upto 4 years
 Risedronate – 35 mg per week
 Zolendronic acid – 5 mg per year
 Outcome
 BMD improvement
 Bone turnover markers
 Formation
 bone specific Alk Phos
 Osteocalcin
 Propeptide of Type 1 Collagen
 Resorption
 N telopeptide of Type 1 collagen
 C telopeptide
 Urine and free deoxypyridinoline
 Tartrate resistant acid phos (Trap5b)

20. Atypical fracture
 3-5 years of treatment
 Remodelling less, therefore microfractures and
stress fractures healing impaired, poor quality
 Atypical femur fracture (subtrochanteric)
 Stress fracture of tensile surface due to
repeated wt bearing
 On X-ray – thick cortex, transverse or short
oblique, locally dense cortex, thigh pain
before the fracture occurs, bisphophonate
line
 Fracture – lateral to medial, non
comminuted, minimal trauma, delayed
healing
 NOT NOF, IT, periprosthetic, Mets, Fibrous

23. Surgery
 Reduction - gentle, stable
 Locking plates preferred, avoid rigid fixation
 Nailing > plating
 Hip – cemented arthroplasty

24. Spine
 Osteoporotic vertebral compression fractures
 Transitional +/- radicular pain
 Management
 Fresh #
 Late presentation with neurodeficit
 Deformity
 Evaluation
 Sitting vs supine Xrays
 CT/MRI/DEXA
 Blood work

25.  Kummel's sign
 Collapse and cleavage within the body with a
fluid cleft – doubtful union

26. Management
 Minimal bed rest, prefer bracing + mobilization
 Medical management
 Surgical Modalities:
 Cement Augmentation
 Subacute (6 weeks) vertebral #
 Vertebroplasty
 Kyphoplasty if there is kyphosis
 Fenestrated screws
 Posterior decompression with fixation
 Neurodeficit and instability, with cord
compression

27.  Anterior – not preferred
 Hartshill – very old bone where screws won't
hold even with cement
 Neurodeficit with kyphosis – PSO
 Deformity correction
 Mesh + graft can be used
 Challenges – reduce the failure rate
 Pedicle screws
 Hydroxyappetite coated
 Cement augmented
 Bicortical
 Laminar hooks, sublaminar wiring