Pediatrics: Musculoskeletal Flashcards
What should you do if you are unsure whether there is a pediatric fracture or not?
Get a repeat radiograph in 7-10 days (when there should be a periosteal reaction if its fractured)
Physical bar
An “early” bone bridge across a growth plate suggesting premature growth arrest
Note: These can occur secondary to infection or trauma.
Physical bar (suggesting premature growth arrest)
Note: These can occur due to infection or trauma.
Salter-Harris Classification of pediatric bone fractures (SALTR mnemonic)
- Type 1 (S: slipped)
- Type 2 (A: above/away from joint)
- Type 3 (L: lower/epiphyseal; also “3 = E” for epiphyseal)
- Type 4 (T: through the physis)
- Type 5 (R: ruined, compression of the growth plate with poor prognosis)
Type 1 Salter-Harris fracture
“S”ALTR: “S”lipped epiphysis (a complete physical fracture +/- displacement)
Type 2 Salter-Harris fracture
S”A”LTR: “A”bove/away from the joint (involves the metaphysis)
Type 3 Salter-Harris fracture
SA”L”TR: “L”ower/epiphyseal involvement; also “3 = E” (involves the epiphysis)
Type 4 Salter-Harris fracture
SAL”T”R: “T”rough the physis (fracture goes right through the physics, involving both the metaphysis and epiphysis)
Type 5 Salter-Harris fracture
SALT”R”: “R”uined, bad prognosis (compression of the growth plate due to axial loading injury)
What is the most common Salter-Harris fracture
Type 2 (sAltr: Above/Away from the joint, involving the metaphysis)
What type of fracture?
Type 1 Salter-Harris
What type of fracture?
Type 2 Salter-Harris
What type of fracture?
Type 3 Salter-Harris
What type of fracture?
Type 4 Salter-Harris
What type of fracture?
Type 5 Salter-Harris
Which type of Salter-Harris fracture is associated with a bony bridge across the physis?
Type 5 (compression of the growth plate)
Note: These have a bad prognosis with a high rate of growth arrest.
What is a Salter-Harris fracture?
Fractures that extend through the growth plate
2 y/o with an oblique fracture of the tibia involving the midshaft posterior cortex…
Think toddlers fracture (tibial fracture secondary to new stresses after learning to walk)
Classic locations for stress fractures in children
- Posterior tibial midshaft (Toddler’s fracture after learning to walk)
- Calcaneus (often after resuming normal activity following an injury that required a cast)
Pediatric elbow radiograph demonstrates “posterior sail sign”…
Elevated posterior fat pad should make you think occult fracture (most often supracondylar)
Note: You can see a sliver of anterior fat pad normally, but you should never be able to see the posterior fat pad.
What are the most likely occult fractures if you see a posterior fat pad on a pediatric elbow radiograph?
- Supracondylar fracture (60%)
- Lateral condyle fracture (20%)
- Medial epicondyle fracture (10%)
Radiocapitellar line
A line drawn along the center of the radius and through the capitellum
Note: This should pass through the middle third of the capitellum on every view (regardless of position), otherwise think radial dislocation.
Anterior humeral line
On lateral elbow radiograph, a line drawn along the anterior cortex of the humerus and through the caputellum
Note: This should pass through the middle third of the capitellum on the lateral view, otherwise think supracondylar fracture.
What is the order of ossification for the elbow ossification centers?
CRITOE:
- Capitellum
- Radius
- Internal/medial epicondyle
- Trochlea
- Olecranon
- External/lateral epicondyle
What is the age at which the elbow ossification centers ossify?
Odd years starting at 1 (approximation):
- Cap (1)
- Rad (3)
- Int/med epi (5)
- Tro (7)
- Ole (9)
- Ext/lat epi (11)
How can you know whether a lateral humeral condyle fracture is unstable?
If the fracture line passes through the capitello-trochear groove to involve the trochlea-ulna articulation (best seen on an internal rotation oblique view), it is unstable
If you see a lateral humeral condyle fracture, what additional view must you order?
Internal rotation oblique view (to look for displacement, which needs surgery)
Complications of ulnar nerve injury at the elbow
- Lost sensation in the pinky and 1/2 of ring fingers
- Denervation of flexer carpi ulnaris or flexor digitorum profundus
Which elbow ossification centers often has a fragmented appearance because it can have multiple ossification centers?
Trochlea
Common cause of a lateral condyle fracture
Elbow hyperextension due to fall onto outstretched hand
Fall onto elbow tip or elbow hyperflexion injuries are at high risk for…
Ulnar nerve injury
Which elbow ossification center is the last to fuse?
The External/medial epicondyle ossification center
Note: This doesn’t fuse until ~11 years; don’t mistake a normal ossification center for a medial epicondyle fracture.
Are elbow joint effusions common with a medial epicondyle avulsion fracture?
No, the medial epicondyle is an extra-articular structure
Complications of medial epicondyle avulsion fracture
Dislocation of avulsed bone fragments into the joint (look for loose bodies between the humerus and olecranon)
Note: This can happen even if there is no joint dislocation, but is more common if there is a joint dislocation (always look for avulsion fragments on the post-reduction films).
What should you look for if there is a pediatric elbow dislocation?
The medial epicondyle ossification center (is it in the normal location or dislocated)
You see a trochlear ossification center, but not the medial epicondyle ossification center…
What you think is a trochlear ossification center is probably actually a displaced bone fragment
Note: You should never see the Trochlea before seeing the Internal/medial epicondyle (“the importance of IT in CRITOE”).
Little League Elbow
Medial epicondyle avulsion
Nursemaids elbow
Subluxation of the radial head into the annular ligament
Note: This can happen if the Childs arm is pulled on forcefully.
Next step: you see an ulnar shaft fracture on a forearm radiograph
Get a dedicated elbow radiographs (to look for radial head dislocation)
Note: This would be the Monteggia fracture-dislocation pattern commonly seen in children (rare in adults).
Monteggia fracture-dislocation
Ulnar shaft fracture with dislocation of the radial head
Which avulsion fracture? What muscle attaches?
Iliac crest avulsion fracture (abdominal muscles)
Which avulsion fracture? What muscle attaches?
ASIS (anterior superior iliac spine) avulsion fracture (sartorius muscle)
Which avulsion fracture? What muscle attaches?
AIIS (anterior inferior iliac spine) avulsion fracture (rectus femoris muscle)
Which avulsion fracture? What muscle attaches?
Greater trochanter avulsion fracture (gluteus medius/minimus muscles)
Which avulsion fracture? What muscle attaches?
Lesser trochanter avulsion fracture (iliopsoas muscle)
Which avulsion fracture? What muscle attaches?
Ischial tuberosity avulsion fracture (hamstring muscles)
Which avulsion fracture? What muscle attaches?
Symphysis avulsion fracture (adductor group muscles)
13 y/o boy with sudden onset pain after jumping
Patellar sleeve avulsion fracture
How can you differentiate a patellar sleeve avulsion fracture from Sinding-Larsen-Johansson?
Timing
Patellar sleeve avulsions fractures are an acute injury
Sinding-Larsen-Johansson is a chronic fatigue injury
Sinding-Larsen-Johansson
A chronic traction injury at the insertion site of the patellar tendon on the patella seen in active adolescents
Osgood-Schlatter
Chronic injury to the patellar tendon at its insertion site on the tibial tuberosity
Note: It is bilateral 25% of the time.
Risk factors for Sinding-Larsen-Johansson
Cerebral palsy
“celery stalk” appearance of bone (linear sclerotic streaks at the metaphyses) in a neonate…
Congenital Rubella
Note: Can also be seen in congenital syphilis(though not until 6-8 weeks of life), CMV, and also osteopathia striata.
Congenital syphilis
Note: This is the “wimberger sign” of osseous destruction of the medial portion of the proximal tibial metaphysis.
Caffey disease
A self liminting disorder of soft tissue swelling, periostea reaction, and irritability seen within the first 6 months of life
Classic imaging appearance of Caffey disease
Very hot mandible on bone scan
Note: The clavicle and ulna are other classic sites.
Neonatal chest radiograph demonstrating sternotomy wires and a periostea reaction in the bilateral humeri…
Think prostaglandin therapy
Note: The sternal wires make you think congenital heart disease and prostaglandin therapy is often used to keep a patent ductus arteriosus open).
What is the major childhood malignancy that occurs in newborns and metastasizes to the bone?
Neuroblastoma
Physiologic periostitis of the infant
Physiologic bone growth can result in a periostea reaction usually around 3 months of age that resolves by 6 months
Where do you most commonly see physiologic periostitis due to bone growth?
First proximally (e.g. femur) and then distally (e.g. tibia), always involving the diaphyses
Note: This occurs in infants around 3 months of age and resolves by age 6 months.
What characteristics make you think that periostitis in an infant is not just physiologic periostitis due to bone growth?
- Periostitis before 1 month of age
- You see it in the tibia before the femur (physiologic periostitis should progress proximally to distally)
- It does not involve the diaphysis
Think Langerhans cell histiocytosis (AKA eosinophilic granulomatosus)
Note: This is the “hole within a hole” or “beveled edge” sign. Neuroblastoma metastases would also be on the differential.
Think Langerhans cell histiocytosis (AKA eosinophilic granulomatosus)
Note: This is vertebra plana (pancaked vertebral body).
What are the characteristic imaging features of Langerhans cell histiocytosis (AKA eosinophilic granulomatosus)
- Lytic skull lesions with a beveled edge
- Lytic rib lesions with expanded appearance
- Vertebra plana (pancaked vertebral body)
What is the typical age group for pediatric osteomyelitis?
Infants (30% of cases occur before age 2)
Pediatric osteomyelitis often seeds the bone by what method of spread?
Hematogenous
Note: In adults, direct spread from a diabetic ulcer is more common.
Where does osteomyelitis usually begin in infants?
In the metaphyses (which has the largest blood supply because its growing the fastest)
Note: It then spreads to the epiphysis via perforating vessels that traverse the physis in infants.
Why does osteomyelitis affect different parts of the bone at different ages?
Only infants have perforating vessels that connect the metaphysis to the epiphysis (allowing osteomyelitis to spread that way)
In older children, these perforating vessels regress and the avascular growth plate prevents osteomyelitis from spreading to the epiphyses (older children tend to have more of a smoldering infection in the long bone metaphyses)
In adults, the growth plates fuse which again allows osteomyelitis to cross over to infect the epiphysis
What is the most common site of osteomyelitis in older children?
Metaphyses of long bones (75%)
Note: Most commonly the femur.
How long does it take bony changes in osteomyelitis to appear on radiographs?
10 days
Brachydactyly
Short fingers
Polydactyly
Too many fingers
Syndactyly
Two or more fused fingers
Camptodactyly
Contractures of fingers
Clinodactyly
Radially angulated fingers (usually the 5th digit)
Arachnodactyly
Long, spider-like finger
Amelia
Limb is absent
Meromelia
Limb is mostly absent
Acromelic
Hands/feet (distal limbs) are short
Note: Think acromegaly (big hands).
Mesomelic
Forearm or lower leg are short (middle limbs)
Note: Meso in the middle.
Rhizomelic
Femur or humerus (proximal limbs) are short
Micromelic
Entire limbs are short
What is the most common type of skeletal dysplasia?
Achondroplasia
Pathophysiology of achondroplasia
Defect in the fibroblast growth factor receptor
What bones are short in achondroplasia
Short femur and short humerus
Note: It is a rhyzomelic dysplasia.
Risk factor for achondroplasia
Advanced paternal age
Narrowing of the interpedicular distance is seen in which skeletal dysplasia?
Achondroplasia
What is the most common lethal form of deawfism?
Thanatophoric dysplasia
Classic features of thanatophoric dysplasia
- Severe rhizomelic shortening (short humerus/femur)
- Platyspondyly (plate-like vertebral bodies)
- Cloverleaf skull
Note: This is usually lethal in the perinatal period.
Asphyxiating thoracic dystrophy (Jeune)
A skeletal dysplasia that results in a bell shaped throax with short ribs that is often fatal in the perinatal period
What is the best way to differentiate thanatophoric dysplasia from asphyxiating thoracic dystrophy (Jeune)
Look at the vertebral bodies:
Severe skeletal dysplasia with flattened vertebral bodies -> Thanatophoric dysplasia
Severe skeletal dysplasia with normal vertebral bodies -> Asphyxiating thoracic dystrophy
Dwarfism and polydactyly…
Think Ellis-Van Crevald syndrome
Note: Polydactyly also occurs in 15% of pts with Asphyxiating thoracic dystrophy (Jeune).
Looks like achalasia but spares the skull and isn’t present at birth (develops later)…
Pseudoachondroplasia
Dwarfism with osteopetrosis, wide-angled jaw, and acro-osteolysis…
Pyknodysostosis