FRACTURE FIXATION IN OSTEOPOROTIC BONE Stephen Kates, MD Hansj?rg Wyss

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FRACTURE FIXATION IN OSTEOPOROTIC BONEStephen
Kates, MDHansj?rg Wyss  Professor of Orthopaedic
SurgeryDepartment of Orthopedics and
RehabilitationAssociate Director, Center for
Musculoskeletal ResearchUniversity of Rochester
Medical CenterMichael BlauthNorbert SuhmJorg
Goldhahn
AGS
THE AMERICAN GERIATRICS SOCIETY Geriatrics Health
Professionals. Leading change. Improving care for
older adults.
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LEARNING OUTCOMES

• Understand the factors influencing fixation in
  cortical and trabecular bone affected with
  osteoporosis
• What implant characteristics help with fixation?
• What aspects of surgical fixation are important?
• Understand basic metabolic bone work-up

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Definitions

• Insufficiency fracture bone fails with normal
  weight-bearing
• Fragility fracture result of a fall from a
  standing height or less

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CONTENTS

• Osteoporotic cortical bone
• Biomechanical properties
• Choice of implants
• Surgical technique
• Trabecular bone
• Biomechanical properties
• Choice of implants
• Surgical technique

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CONTENTS

• Osteoporotic cortical bone
• Biomechanical properties
• Choice of implants
• Surgical technique

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BONE MASS CHANGESDURING LIFE

• Peak bone mass is reached at age 25
• Heredity
• Medications
• Diet, tobacco, and alcohol
• Race / weight

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CONTENTS

• Osteoporotic cortical bone
• Biomechanical properties
• Choice of implants
• Surgical technique

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LOCKED-PLATE PRINCIPLE
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PULLOUT OF REGULAR SCREWS
by bending load
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SHEARING CONVENTIONAL PLATE OR SCREW DOWN
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RESISTANCE AGAINST BENDING LOAD
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Resistance against bending load in locked plate
Plate-screw connection is solid Screw-bone
interface Fails as a unit
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CONTENTS

• Osteoporotic cortical bone
• Biomechanical properties
• Choice of implants
• Surgical technique

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UNI- VS. BICORTICAL SCREW FIXATION
female
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FAILURE WITH UNICORTICAL SCREWS
Thin cortices choose screw diameter as large as
possible
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10 months postop.
5 days later
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BIOMECHANICS NORMAL BONE
Load (N)
36
600
18
6
500
4.5 mm Cortex, bicortical
5.0 mm Locking, bicortical
4.0 mm Locking, bicortical
4.0 mm Locking, unicortical
400
300
200
100
0
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BIOMECHANICS OSTEOPENIC BONE
Load (N)
600
91
82
500
400
17
300
4.5 mm Cortex, bicortical
5.0 mm Locking, bicortical
4.0 mm Locking, bicortical
4.0 mm Locking, unicortical
200
100
0
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BRIDGING WITH LOCKED IMPLANT
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CONCEPTS OF PLATE FIXATION IN OSTEOPOROTIC BONE

• ? compression technique
• Bridge plating useful
• Neutralization plates useful
• Long plate for bone protection

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CONTENTS

• Trabecular bone
• Biomechanical properties
• Choice of implants
• Surgical technique

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OSTEOPOROSIS
Normal bone
Osteoporosis

• In osteoporotic metaphyseal bone
• Fewer trabeculae for screws to engage
• Loss of critical bony interconnections
• Thinner internal support

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SIGNS YOUR PATIENT HASPOOR-QUALITY BONE

• Poor dentition teeth are formed similarly to
  bone
• Multiple vertebral compression fractures
• Previous hip, radius, or tibial plateau fracture
• End-stage renal disease
• On steroid therapy
• Anticonvulsant use

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OSTEOPOROTIC TRABECULAR BONECLINICAL
CONSEQUENCES

• Cut out
• Loss of screw fixation
• Spontaneous fractures

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CONTENTS

• Trabecular bone
• Biomechanical properties
• Choice of implants
• Surgical technique

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Flat surface, increased area
Lag screw
Helical blade
Less loss of bone with helical blade (right)
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CHOICE OF IMPLANTONE FIXED ANGLE VS. MANY
Elderly woman who fell down one step
One fixed angle with blade plate
Multiple fixed angles, longer implant
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VARUS COLLAPSE DUE TO LACK OF MEDIAL BUTTRESS
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CONTENTS

• Trabecular bone
• Biomechanical properties
• Choice of implants
• Surgical technique

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INTRA-OP IMPACTION
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Augmentation to Improve Screw Fixation Enlarges
the bone implant surface area
NOT FDA APPROVED!
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Augmentation in practice
Slide 32
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If bone is very poor, consider prosthetic
replacement
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DONT FORGET THE SOFT TISSUES
The wound must heal also Skin is also 98 years old
Slide 34
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Basic Osteoporosis Work-up Metabolic

• 25-OH vitamin D level
• Intact PTH level
• Calcium
• Phosphate
• TSH
• Albumin level

Slide 35
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Radiologic Work-up OF OSTEOPOROSIS DEXA Scan

• DEXA is gold standard
• T score is comparison to normal young bone
• Z score is comparison to peers
• Treat with fragility fracture and osteoporosis,
  osteopenia

Slide 36
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Vitamin D Repletion

• Vitamin D2 50,000 units PO
• Level 0?10 ng/dL 3 times / week
• Level 11?20 ng/dL 2 times/week
• Level 21?32 ng/dL 1 time/week
• For 6?12 weeks, then recheck level
• Maintain with vitamin D3 1200 IU/day

Slide 37
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TreatmentsAfter Vitamin D repletion

• For viable patients
• Bisphosphonates
• Selective estrogen receptor modulators (SERMs)
• Parathyroid hormone
• Dont forget the bone itself treat the
  osteoporosis or refer

Slide 38
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TAKE-HOME MESSAGES

• Age bone quality affect cortical and trabecular
  bone in different ways
• Absolute stability often not possible
• Principles of fixation
• Angular stability
• Fracture reduction
• Long bridging plates
• Enlarged surface area of implant / bone
• Augmentation
• Prosthetic replacement

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THANK YOU FOR YOUR TIME!
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