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
Slide 2
DEFINITIONS
• Insufficiency fracture: bone fails with normal
weight-bearing
• Fragility fracture: result of a fall from a
standing height or less
Slide 3
CONTENTS
• Osteoporotic cortical bone
 Biomechanical properties
 Choice of implants
 Surgical technique
• Trabecular bone
 Biomechanical properties
 Choice of implants
 Surgical technique
Slide 4
CONTENTS
• Osteoporotic cortical bone
 Biomechanical properties
 Choice of implants
 Surgical technique
Slide 5
BONE MASS CHANGES
DURING LIFE
• Peak bone mass is reached at age 25
• Heredity
• Medications
• Diet, tobacco, and alcohol
• Race / weight
Slide 6
CONTENTS
• Osteoporotic cortical bone
 Biomechanical properties
 Choice of implants
 Surgical technique
Slide 7
LOCKED-PLATE PRINCIPLE
Slide 8
PULLOUT OF REGULAR SCREWS
by bending load
Slide 9
SHEARING CONVENTIONAL PLATE
OR SCREW DOWN
Slide 10
RESISTANCE AGAINST BENDING LOAD
Slide 11
RESISTANCE AGAINST BENDING
LOAD IN LOCKED PLATE
Plate-screw connection
is solid
Screw-bone interface
Fails as a unit
Slide 12
CONTENTS
• Osteoporotic cortical bone
 Biomechanical properties
 Choice of implants
 Surgical technique
Slide 13
UNI- VS. BICORTICAL SCREW FIXATION
female
Slide 14
FAILURE WITH UNICORTICAL SCREWS
Thin cortices: choose screw diameter
as large as possible
Slide 15
5 days later
10 months
postop.
Slide 16
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
Slide 17
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
Slide 18
BRIDGING WITH LOCKED IMPLANT
Slide 19
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
Slide 23
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
Slide 28
CONTENTS
• Trabecular bone
 Biomechanical properties
 Choice of implants
 Surgical technique
Slide 29
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
Slide 35
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
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
Slide 37
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
Slide 39
THANK YOU FOR YOUR TIME!
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