Transcript Fracture Fixation in Osteoporotic Bone

FRACTURE FIXATION IN
OSTEOPOROTIC BONE
Stephen Kates, MD
AGS
Hansjӧrg Wyss Professor of Orthopaedic Surgery
Department of Orthopedics and Rehabilitation
Associate Director, Center for Musculoskeletal
Research
University of Rochester Medical Center
Michael Blauth
Norbert Suhm
Jorg Goldhahn
THE AMERICAN GERIATRICS SOCIETY
Geriatrics Health Professionals.
Leading change. Improving care for older adults.
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 CHANGES
DURING 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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5 days later
10 months
postop.
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Load (N)
BIOMECHANICS: NORMAL BONE
+36%
600
+18%
+6%
500
400
4.5 mm
Cortex,
bicortical
4.0 mm
Locking,
unicortical
4.0 mm
Locking,
bicortical
5.0 mm
Locking,
bicortical
300
200
100
0
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BIOMECHANICS:
OSTEOPENIC BONE
Load (N)
600
+82%
500
400
+91%
+17%
300
200
4.5 mm
Cortex,
bicortical
4.0 mm
Locking,
unicortical
4.0 mm
Locking,
bicortical
5.0 mm
Locking,
bicortical
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
Slide 20
CONTENTS
• Trabecular bone
 Biomechanical properties
 Choice of implants
 Surgical technique
Slide 21
OSTEOPOROSIS
Normal bone
Osteoporosis
In osteoporotic metaphyseal bone:
•Fewer trabeculae for screws to engage
•Loss of critical bony interconnections
•Thinner internal support
Slide 22
SIGNS YOUR PATIENT HAS
POOR-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 BONE:
CLINICAL CONSEQUENCES
• Cut out
• Loss of screw fixation
• Spontaneous fractures
Slide 24
CONTENTS
• Trabecular bone
 Biomechanical properties
 Choice of implants
 Surgical technique
Slide 25
Flat surface,
increased area
Lag screw
Less loss of bone with helical blade (right)
Helical blade
Slide 26
CHOICE OF IMPLANT:
ONE FIXED ANGLE VS. MANY
Elderly woman who fell down one step
One fixed angle with blade plate
Multiple fixed angles, longer implant
Slide 27
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
Slide 30
Augmentation to Improve Screw Fixation
Enlarges the bone implant surface area
NOT FDA APPROVED!
Slide 31
AUGMENTATION IN PRACTICE
32
Slide 32
IF BONE IS VERY POOR, CONSIDER
PROSTHETIC REPLACEMENT
Slide 33
DON’T FORGET THE SOFT TISSUES
The wound must heal also
Skin is also 98 years old
Slide 34
BASIC OSTEOPOROSIS WORK-UP:
METABOLIC
• 25-OH vitamin D level
• Intact PTH level
• Calcium
• Phosphate
• TSH
• Albumin level
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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
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VITAMIN D REPLETION
• Vitamin D2 50,000 units PO
Level 010 ng/dL:
Level 1120 ng/dL:
Level 2132 ng/dL:
3 times / week
2 times/week
1 time/week
• For 612 weeks, then recheck level
• Maintain with vitamin D3 1200 IU/day
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TREATMENTS
AFTER VITAMIN D REPLETION
• For viable patients:
Bisphosphonates
Selective estrogen receptor modulators
(SERMs)
Parathyroid hormone
• Don’t forget the bone itself: treat the
osteoporosis or refer
Slide 38
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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