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Femoral Neck Fractures
主讲教师 : 欧阳宏伟 / 蔡友治
浙江大学医学院
High energy injury
Low energy injury
• An 81-year-old • Female• complaining of hip
pain and inability to walk after a simple fall.
Case 1
A 47-year-old female with a history of schizophrenia and alcoholism complaining of hip pain and inability to walk after a fall. The affected leg appeared slightly shorter than the contralateral leg, and any attempted movement was painful.
Case 2
Case 3 82-year-old
female
complaining of hip pain after an unwitnessed fall.
Case report
• A girl fall from a high tree
• Result: simultaneous bilateral fractures of the femoral neck
• process: initially they fall on edge of the roof or on branch of tree fracturing one neck of femur before falling to the ground to fracture the other.
How happened?
Anatomy
Physeal closure age 16 Neck-shaft angle 130° ± 7° Anteversion 10° ± 7° Calcar Femorale
– Posteromedial– dense plate of bone
Anatomy
anteversion
Anatomy
calcar femorale
Anatomy
Blood Supply
Intracapsular are at risk of non union and avascular necrosis due to interruption of the blood supply to the femoral head
– Via cruicate (med and lat circumflex) and intramedullary.
Muscular balances
Muscular balances
Muscular balances
Muscular balances
Muscular balances in hip
What’s the mechanism?
Bone Load and Response
•Stress– force per unit area
•Strain– deformation
• amount of deformation divided by original length
Types of Forces
TensileCompressiveBendingShearTorsion
Compressive Loading(pushing, compressing forces)
Stress, or pressure (): force per unit areaHow much force does it take to cause an effect?
That depends on how much area the force is spread over.
Localize Force with Pisiform Contact
(Greater stress because contact area is smaller)
The concept of strain also applies to compressive loads
LL
If the original length (L) was 300 mm and
the new length was was 291 mm then
= L / L = (new length – original length) / original length
= (291 mm – 300 mm) / 300 mm = -9 / 300
= -0.03, or -3%
Strain by itself tells you nothing about stress
Compressive load compression fracture
Compression Fracture of C5 Bilateral Compression of Femoral Necks
Stress-Strain Relationship
Strain (deformation)
Str
ess
(loa
d)El
astic
Reg
ion
Elastic Limit
Plastic Region
GenericGeneric
Stress-Strain Relationship
Strain (deformation)
Str
ess
(loa
d)E
last
ic R
egio
n FractureThreshold
Plastic Region
BoneBone
Relative Bone StrengthS
tres
s to
Fra
ctu
re
Load Type
Com
pres
sion
Ten
sion
She
arFractures: with excessive loads, bone tends to fracture on the side loaded in tension.
Bone Response to Stress
Wolff's law (1892)– tissue adapts to level of imposed stress
• increased stress– hypertrophy (increase strength)
• decreased stress– atrophy (decrease strength)
– Shape reflects function• Genetics, Body weight, physical activity,
diet, lifestyle (see note clippings)
Protecting our Bones in Sport
The pattern ofTrbecular bone in the greater trochanter neck of the femur head of the femur reflects femur’s roles:muscle attachment flexibility weight transfer support
Atrophy in Bone
Weight & strength decreaseWeight & strength decrease– Calcium content diminishesCalcium content diminishes
• Reduced BMDReduced BMD– Trabecular integrity is lostTrabecular integrity is lost
Bone stimulating factors
Rate of loadingMagnitudeFrequency
BMD and walking
Quartiles based on miles walked/week
Krall et al, 1994, Walking is related to bone density and rates of bone loss. AJSM, 96:20-26
Biomechanics
One mechanism for reducing the resultant load on the femoral head is the use of a walking stick in the opposite hand.
Biomechanics
Biomechanics of Cane
Cane in Contralateral hand decreases JRF
Long moment arm makes so effective
15% BW to cane reduces joint contact forces by 50%
Fracture mechanism
Fracture mechanism
Fracture mechanism
Fracture mechanism
Fracture mechanism
Fracture mechanism
Blood supply insufficiently
Fracture mechanism
Garden Classification
Garden I: incomplete fracture of the femoral neck
Garden II: complete fracture without displacement
Garden III: complete fracture with partial displacement
Garden IV: complete fracture with full displacement
Fracture of femur neck
• Geriatric population – simple fall
• Younger population – high energy injury
Risk Factors Age: >65 years Co-morbid factors: osteoporosis, endocrine disorders
(hyperthyroidism, hypogondaism), GIT disorders interfering with calcium/ Vit D absorption, neurological disorders (Parkinsons, MS)
Gender: F RTA
Risk Factors Nutrition: lack of calcium and Vit
D in diet, eating disorders (anorexia), high caffeine intake
Smoking Alcohol Medication: steroids,
anticonvulsants, diuretics Environmental factors: loose
rugs, dim lighting, cluttered floors
TreatmentOptions
– Non-operative• very limited role• Activity modification• Skeletal traction
– Operative• ORIF• Hemiarthroplasty• Total Hip Replacement
biological therapy
Management
Conservative: analgesia, bed rest, traction–if pt not willing to consent for surgery or if
not expected to survive surgery
Surgical: Manninger et al showed significant reduction in osteonecrosis and segmental collapse if performed within 6 hr–Head sparing: screws, DHS–Head sacrificing: hemi, THR
Young Patients
Non-displaced fractures• At risk for secondary displacement• Urgent ORIF recommended
Displaced fractures• Patients native femoral head best• AVN related to duration and degree of
displacement• Irreversible cell death after 6-12 hours• Emergent ORIF recommended
Elderly PatientsOperative vs. Non-operative
–Displaced fractures • Unacceptable rates of mortality, morbidity, and
poor outcome with non-operative treatment
–Non-displaced fractures • Unpredictable risk of secondary displacement
– AVN rate 2X
–Standard of care is operative for all femoral neck fractures• Non-operative tx may have developing role in
select patients with impacted/ non-displaced fractures
Acceptable Reduction
Lowell’s Alignment theory– outline of femoral head
& neck junction will have convex outline of femoral head meeting concave outline of femoral neck regardless on all views
– Image should produce an S or reverse S
– If image is a C fracture is not reduced
Garden Alignment Index
Treatment choices:
1: Cannulated Hip screws.
2: Dynamic Hip Screw.
3: Cephalo-medullary device.
4: Hemiarthroplasty Hip.
5: Total Hip Replacement.
operations
ORIF
Hemi
THR
Cannulated Screws
Cannulated Screws
Good Bad
Dynamic Hip Screw
Good for fracture with more vertical fracture line
Problem w this is that cannulated screw will prevent fracture impaction non union
Sacrifices large amount of boneAnti-rotation screw often needed
Hemi Vs. THR• Dislocation rates:
– Hemi 2-3% vs. THR 11% (short term)• 2.5% THR recurrent dislocation (Cabanela1999)
• Reoperation:– THR 4% vs. Hemi 6-18%
• DVT / PE / Mortality – No difference
• Pain / Function / Survivorship / Cost-effectiveness• THR better than Hemi (Iorio 2001)
Complications
Failure of Fixation• Inadequate / unstable reduction• Poor bone quality• Poor choice of implant
Treatment–Elderly: Arthroplasty–Young: Repeat ORIF
Valgus-producing osteotomy Arthroplasty
讲者简介
• 蔡友治 03 级浙大临床七年制• 浙大附属第一医院骨科运动医学中心 医生• 专注于运动创伤微创诊治及创新性医疗手段的研发 .• 目前在干细胞及纳米组织工程领域有一定深入研究。• 发表 SCI 及中华医学期刊十几篇,负责国家自然科学基金一项(在研),并
参与多项科研基金。• Email : [email protected]• TEL : 13588270341
运动让生命更健康 医学让运动更美好