2. Q31
2
This is a picture of a screw from
the small fragment. Answer the
following questions?
What is a screw?
A mechanical device that
converts rotary force (torque)
into translational motion
providing mechanical advantage
converting rotational forces into
linear motion
Changes angular forces to linear
motion to transmit power or
develop larger forces
3. What are the different parts of a
screw?
Four
parts
Head
Shaft
thread
tip
bending strength is proportionate to
inner (minor) diameter
pullout strength is proportionate to
outer (major) diameter
maximized by
• large outer diameter difference
• fine pitch
pedicle screw pullout most affected by
quality of bone (degree of osteoporosis)
4. Head
is a means of applying a twist
force to core & thread
act as a stop
Can be different design
pitch - Distance travelled by one
360 turn of spiral
Core diameter/root
diameter
thread diameter/outer
diameter
Tips
Five types
A. Non self-tapping
B. Corkscrew
C. Trocar
D. Self-drilling
E. Self-tapping
5. What are the different types of screw
and their differences?
Cortical or cancellous
self-tapping or non self-tapping
solid or cannulated
fully threaded or partially threaded
Conventional or locking
Anatomical screw malleolar ,pedicle ,herbert
etc.
Cannulated screw
has a central hollow core used
at metaphyseal or epiphyseal
fractures -femur neck
-femoral condyle ,
- tibia plateau fracture
6.
7. Locking screw
used in
internal
fixators with
the locking
plate
may be self-
drilling- self-
cutting
Headless screw for
intrarticular fixation
Herbert(headless)screw
Acutrak screw
Bio absorbable screws
Malleolar screw
No tapping
Lag screw design
8. What is working length?
Working distance (length)
the length of bone traversed by the
screw
conventional plate and screw
Load bearing
plate working distance the length
between the 2 screws closest to the
fracture on each end of the
fracture
decreasing the working distance
increases the stiffness of the
fixation construct
bending rigidity proportional
to thickness to the 3rd power
9. Describe working length IMN?
Working length (B)-Length of a nail spanning
the fracture site from its distal portion of
fixation in the proximal fragment to proximal
point of fixation in the distal fragment
Bending stiffness of nail
Inversely proportional to the square of its
working length
R power of 4 for diameter of nail for solid nail
and 3rd power of for slot
Torsional stiffness
Inversely proportional to its working length
proportional to the radius to the 4th power of
nail
Increase by reaming and decrease with
slotting of nail
Shorter the working length stronger the
fixation
Total nail length (A) –total anatomical length
10. Q32
a 6 years old child presented to
you with difficulty of standing
from sitting position as it was
shown by picture and video
below
11. Describe the pathology?
Caused by mutations of the dystrophin gene
located on chromosome Xp21
Deletions
Around 72% of patients
Partial gene duplications
6 – 10% of patients
Point mutations
In the coding sequence or the splicing sites
12. Dystrophin is located on the cytoplasmic face of
the plasma membrane of muscle fibers,
functioning as a component of a large, tightly
associated glycoprotein complex .
Provides mechanical reinforcement to the
sarcolemma and stabilizes the glycoprotein
complex, shielding it from degradation.
In its absence, the glycoprotein complex is
digested by proteases.
Loss of these membrane proteins may initiate the
degeneration of muscle fibers, resulting in muscle
weakness
13. Muscle cell membrane damage related to the loss
of dystrophin may permit the pathologic entry of
extracellular calcium into muscle fibers.
The excess cytosolic calcium can activate
calpains, which promote muscle proteolysis
16. Similar traits to Duchenne's Distinguishing traits from Duchenne's
Becker's • calf pseudohypertrophy
• markedly elevated CPK
• x-linked transmission
• Becker's has slower progression of
weakness with diagnosis made later (~8 yrs)
• prone to cardiomyopathy
Spinal muscular
atrophy
• proximal weakness • onset of weakness is earlier in childhood
• absent deep tendon reflexes and
fasciculations
• CPK levels are normal
• pseudohypertrophy is absent
Emery-Dreifuss
dystrophy
• similar clinical picture • no calf pseudohypertrophy
• CPK levels near normal
• elbow and ankle contractures develop early
Limb girdle
dystrophy
• progressive motor weakness • no calf pseudohypertrophy
• CPK levels are only mildly elevated
Guillain-Barre
syndrome
• acute onset of weakness • absent deep tendon reflexes
• CPK levels are normal
17. What is Gower sign?
To get up from a sitting or supine
position, the child must first
become prone on the elbows and
knees. Next, the knees and elbows
are extended to raise the body.
Then, the hands and feet are
gradually brought together to move
the body's center of gravity over
the legs. At this point, the child may
release one hand at a time and
support it on the knee as he or she
crawls up their legs to achieve an
upright position
Avoid any object around the child
18. Others
Meryon sign -elicited by lifting the child with one arm
encircling the child’s chest
Weakness of the shoulder girdle musculature
Most children contract the muscles around the
shoulder to increase shoulder stability and facilitate
lifting.
In children with muscular dystrophy, however, the
arms abduct because of lack of adductor muscle
tone and severe shoulder girdle muscle weakness
until the child eventually slides through the examiner’s
arms unless the chest is tightly encircled.
Later in the disease process
Thomas test shows hip flexion contracture
Ober test shows an abduction contracture of the hip
19. How do you investigate this patient?
• Labs
• markedly elevated CPK levels (10-
200x normal)
• CPK leaks across defective cell
membrane
• Muscle biopsy
• will show connective tissue
infiltration and foci of necrosis
• will show absent dystrophin with
staining
• DNA testing
• shows absent dystrophin protein
• EMG
• myopathic
• decreased amplitude, short duration,
polyphasic motor
20. What are the medical and surgical
treatment options?
Treatment of DMD
Medical or non operative vs operative
Non operative
corticosteroid therapy (prednisone 0.75 mg/kg/day) or
deflacortis
5 to 7-year-old child with progressive disease
goals
to maintain ambulatory capacity as long as possible
outcomes
significant positive effect on disease progression
acutely improves strength, slows progressive weakening, prevents scoliosis
formation, and prolongs ambulation
delays deterioration of pulmonary function
side effects
Osteonecrosis , weight gain ,cushingoid appearance , GI symptoms ,
mood lability , headaches short stature cataracts
21. pulmonary care with nightly ventilation
rehabilitation
techniques
physical therapy for range of motion exercises
adaptive equipment
power wheelchairs
KAFO bracing (controversial)
22. operative
Goal -functional ambulation as long as possible
Specific procedure is Based on age of child and
stage of the disease
It is easier to keep patients walking than to
induce them to resume walking after they
have stopped.
23. three approaches for surgical correction of lower
extremity contractures
Ambulatory approach
Before lost ambulation
Rehabilitative approach
After ambulation stop to resume walking
Palliative approach
treats only contractures that interfere with shoe
wear and comfortable positioning in a wheelchair.
24. What are the surgery?
Soft tissue release
indications
ambulatory child with Duchenne's
techniques
hip abduction contractures treated by
release of iliotibial band
Hip flexion contractures treated by
release of sartorius, rectus femoris,
and tensor fascia lata
hamstring releases
Achilles tendon and posterior tibialis
lengthenings
postoperative care
early mobilization and ambulation to
prevent deconditioning
25. Equinovarus Foot
• common foot deformity seen with Duchenne
muscular dystrophy
•Pathoanatomy
• muscle imbalance secondary to muscle
replacement with fibrofatty tissue
•Diagnosis
• made upon clinical exam
•Treatment
• nonoperative
• stretching, physical therapy, and
night time AFO use
• operative
• Tendinoachilles lengthening
with posterior tibialis tendon
transfer, toe flexor tenotomies
Scoliosis
considered a neurogenic
curve OR PROGRESSIVE
occurs in 95% of patients
after becoming wheelchair
dependent
curve progresses
rapidly from age 13 to 14
years
cardiac and pulmonary
function studies
preoperativly
Bracing contraindicated
affect pulm function
Surgery
early PSF with
instrumentation
26. Q33
26
This is ankle x-ray of a 45
years old immediately after
RTA
Describe the X-Ray?
Not proper x ray
Grossly
Lateral x ray of ankle
There is Talar neck
fracture involving the sub
talar joint
27. Other investigation
Proper AP , lateral and morties
view of ankle
Canale view to see talar neck
AP x ray with internal and external
rotation to see lat process
Oblique ankle view
AP, lateral and oblique radiographs
of foot
CT scan
To see fracture clearly including size
displacement and artiular
involvement
Ligament or tendon involvement
MRI-not for acute diagnosis
For AVN
28. Discuss blood supplies to the talar
neck?
Three main extra osseous
vascular sources are
Artery of sinus tarsi…anterior tibial
and peroneal arteries
Artery of tarsal canal …posterior
tibial artery
Deltoid branch ….tarsal canal
supplies blood to medial talar
body
Dorsalis pedis ..head
Multiple capsular artery
contribution of blood to talus
16.9% for peroneal artery
36.2% for anterior tibial artery
47.0% for posterior tibial artery
29.
30. How do you classify talar
fractures?
Different classification
Anatomical
Neck 50%
Body 10% to 25%
Head 5-10%
lateral process
Posterior process
OTA
32. Discuss the treatment options of talar
neck fractures?
Non operative
Limited for neck #
Can be used for head
lateral and posterior
process
Displacement should
be excluded by CT
scan
How?
NWB cast for 6 to 12
wks
Then progressive wt
bearing
33. Operative
Goal
Anatomic reduction
providing stable internal fixation
Congruent ankle and subtalar
,TN joint
Prevent arthritis
Option
body
Cortical screws
Herbert screws
Kirschner wires
threaded wires
Neck
Screws for simple fractures
Mini-fragment plates for
comminuted fractures:
Medial and / or lateral
Arthrodesis
nonconstractable
Ex fix
Compound and
contaminated
Temporary
After talectomy for length
34.
35. Approach
Posteriolateral
protect sural nerve
Only necessary for
placement of posterior
to anterior fixation
Posteromedial
posterior to
posteromedial
neurovascular
structures
Allow med mall
osteotomy
36. Anteriomedial
With or with out medial
malleollar osteotomy
Most commonly used
Protect saphenous NV
Anteriolateral
To see lat talar neck
sinus tarsi
Protect sup peroneal
nerve
Bn p.tertsious and EDL
Combined
AM and minimal lat to
see talonavicular joint
37.
38. List common complications of this
fractures?
Acute complications
skin necrosis
infection.
Skin necrosis
seen only with type III and IV
fractures, and I
minimized by prompt
reduction of talar body.
Infection
Open injuries but can often be
avoided by:
Early irrigation and debridement
Rigid fracture fixation
Delayed wound closure and
Prophylactic antibiotics.
If talar body is completely avascular,
an established osteomyelitis may be
resistant to treatment
Late complications
avascular necrosis
malunion
posttraumatic arthritis
