Children's orthopedics Flashcards
What are the 2 types of bones in our body?
- Flat bones
- Long bones
What process of bone development is used to form long bones and flat bones?
Flat bones= Intramembranous
Mesenchymal cells»bone
Long bones= Endochondral
Mesenchymal»cartilage»bone
Which bone development process is more clinically relevant?
Endochondral- based on ossification centres
Describe the process of Intramembranous ossification
- Condensation of mesenchymal cells which differentiate into osteoblasts – Ossification centre forms (start building bone without any cartilage model)
- Secreted osteoid traps osteoblasts which become osteocytes
- Trabecular matrix and periosteum form
- Compact bone develops superficial to cancellous bone. Crowded blood vessels condense into red bone marrow
Describe the process of endochondral ossification?
- Mesenchymal cells first differentiate into chondrocytes, that build a hyaline cartilage model, which will then turn into bone
- The centre/ diaphysis of this cartilage model is the primary ossification centre and blood vessels (nutrient artery) enter it, which bring in nutrients, osteoblast cells (to build bone) and osteoclast cells (to reabsorb bone)
- The osteoblasts start to replace the chondrocytes and they replace the cartilage with bone
- As the bone grows thicker and sturdier, osteoclasts start to reabsorb bone in the middle of the bone, making it more prous- bone marrow formation and elongation of diaphysis and epipheyseal plate formation (as you continue to get bone deposition by osteoblasts)
- Secondary ossification forms at epiphysis, and spongy bone is formed, cartilage only remains at the articular cartilage and epiphyseal plate
What is the primary ossification centre?
Sites of pre-natal bone growth through endochondral ossification from the central part of the bone
What is the secondary ossification centre?
Occurs post-natal after the primary ossification centre and long bones often have several (the physis)
In what 2 ways can bones grow?
- Interstital growth (elongation)
- Appositional growth (getting wider)
Describe the process of bone lengthening
“Interstitial growth”
1. At epiphyseal side- hyaline cartilage gets activated and chondrocytes in cartilage proliferate and mature to produce hyaline cartilage matrix, as more cartilage is produced the bones lengthen
2. At diaphyseal side- as cartilage calcifies and it gets older, chondrocytes die off, osetoblasts move into cartilage and start to ossify it (turn it into bone)
3. Articular cartilage covering tips of the bone also expands by secreting more matrix to cover the expanding bone
4. By the end of adolescence, the growth plate is completely ossified and at that point a person can’t grow taller
Describe the process of bone widening
“Appositional growth”
- Happens by osteoblasts laying down new circumferential lamellae in periosteum, so the bone grows outwards. At the same time osteoclasts in medullary cavity reabsorb bone so bone doesn’t get too heavy
What are the key differences in the bone of children vs adults?
Children:
- Presence of physis (growth plate) and epiphysis
- Less lamella
- Immature bone- less dense with greater porosity. (blood vessels to carry nutrients)
- Thick periosteum (soft tissue layer that surrounds bone- provides remodelling potential, harder for kids to break; stays intact for them even if bone is broken
What is the clinical significance of the ossification centres?
We need to know at what age different ossifications form- to determine what children have damaged secondary centres from injuries
Compare the elasticity in children’s bones with adults
Children’s bone can bend – more elastic than adult
Increased density of haversian canals
What type of “bone bending” fractures can occur in children?
- Plastic deformity – bends before breaks
- Buckle fracture – Torus like the column:
* One side of a bone bends, raising a little buckle, without breaking the other side of the bone
* usually happens when the bone is compressed (pressed together with force) - Greenstick – like the tree: One cortex fractures but does not break the other side
How are bends/ these fractures treated?
- Treated like a normal fracture- still displaced (some bends can be left with no intervention- straightens on it’s own)
- Chance of remodeling depends on the age of the child
What is the significance of the physis in bone growth?
- Growth occurs at varying rates at varying sites (some physis of different bones more active than others (fracrure where there is more growth + remodelling- much more worried about injuries)
- Growth stops as the physis closes (different physis close at different times
- Gradual Physeal closure, Puberty, Menarche, Parental height: Complete at (Girls 15-16 and Boys 18-19)
- Physeal injuries are catgorised by Salter-Harris
- Physeal injuries can lead to growth arrest (can occur on one side of a physis= bending deformity)
- Growth arrest can lead to deformity
What is the speed of healing and remodeling of bone?
- The speed of healing and remodeling potential is dependent on the location and the age of the patient
- Younger child heals more quickly
- Physis at the knee grows more
- Physis at extreme of upper limb grows more
Why is rotation important to note in a fracture?
Fractures in the direction/ plane as the movement of a joint more likely to heal than a fracture from a joint rotated; rotation is v. important to follow
What are the possible patterns of fractures?
- Transverse
- Oblique
- Spiral (spiral fracture is always rotational)
- Comminuted
- Avulsion (bone is pulled off by ligament/ tendon)
What is a transverse fracture?
Transverse fractures occur when your bone is broken perpendicular to its length
What is an oblique fracture?
bone is broken all the way through and at an angle
What is a spiral fracture?
bone is broken with a twisting motion.
What is a comminuted fracture?
The bone is broken into more than two pieces.
What is an avulsion fracture?
occurs when a small chunk of bone attached to a tendon or ligament gets pulled away from the main part of the bone.
What terms are used to describe the anatomy of a fracture?
(where it is on the bone)
- Proximal 1/3 (toward or nearest the trunk or the point of origin)
- Middle 1/3 Diphysis
- Distal 1/3 (away from or farthest from the trunk)
- also mention if the fracture includes growth bed or not
What is the difference between primary vs secondary bone healing?
PRIMARY: (bone heals exactly like what it was before)
- Heals by direct union
- No callus formation
- The preferred healing pathway in intra-articular fracture as minimises risk of post traumatic arthritis
SECONDARY: (callus eventually remodels into cortical bone)
- Bone healing by callus
What types of displacement can occur from a fracture?
- Displaced/ translated
- Angulated
- Shortened (needs to be pulled down)
- Rotated
What is the Salter-Harris criteria?
Classification of physeal injuries (SALT)
- Physeal Separation (separation/ slip v. subtle- hard to see on x-ray early on)
- Fracture traverses physis and exits metaphysis (Above) [fracture that exists above the epiphysis]
- Fracture traverses physis and exits epiphysis (Lower) [fracture that exists through the epiphysis]
- Fracture passes Through epiphysis, physis, metaphysis (goes through both epiphysis & metaphysis)
- Crush injury to physis (not much can be done to treat)
- Risk of growth arrest increases from 1 -5
- Type 2 injuries most common
What is growth arrest?
Growth Arrest= stop in growth (worse for younger patients- not done growing)
- Injuries to the physis can cause growth arrest
- The location and timing is key
- Whole physis – limb length discrepancy
- Partial – angulation as the non affected side keeps growing
What are the 2 forms of treatment when there is growth arrest?
- Limb length correction (either shorten the long side OR lengthen the short side)
- Angular deformity (either stop the growth of the unaffected side OR reform the bone (osteotomy))
What are the steps of management for a fracture?
- Resuscitate
- Reduce
- Restrict
- Rehabilitate
How is a fracture reduced?
(Correct the deformity and displacement and Reduce secondary injury to soft tissue / NV structures)
a) CLOSED:
- Reducing a fracture without making an incision
- Such as traction and manipulation in A&E
b) OPEN:
- Making an incision
- The realignment of the fracture under direct visualisation
How is a fracture restricted?
- Maintain the fracture reduction
- Provides the stability for the fracture to heal
- Children rarely have issues with bone not healing (can have issues with too much healing)
- Children have quicker fracture healing times and remodeling potential
you can have
1. External restriction:
- splints
- Plaster
2. Internal restriction:
- Plate and screws
- Intra-medullary device
How does orthopedic operation differ in children vs adults?
Operation in kids uses different tools; avoid soft tissue trauma; elastic/ thin nails used
- Avoid penetration through the growth plate, end sticking out- nail will be removed after 6 months, not left in permanently
What is important to consider during internal restriction?
Consider the ongoing growth at the physis
Metalwork may need to be removed in the future
How are patients rehabilitated following a fracture?
- Children generally rehabilitate very quickly
- Play is a great rehabilitator
- Stiffness not as major issue as in adults
- Use it, Move it and Strengthen!
What is Developmental Dysplasia of the Hip?
- Group of disorder of the neonatal hip where the head of the femur is unstable or incongruous in relation to the acetabulum. (where the “ball and socket” joint of the hip does not properly form in babies and young children)
- A ‘Packaging Disorder’
- The normal development relies on the concentric reduction and balanced forces through the hip
- Spectrum with dysplasia – subluxation – dislocation
What are the risk factors of Developmental Dysplasia of the Hip?
- Female 6:1
- First born
- Breech
- FH
- Oligohydramnios
- Native American/Laplanders – swaddling of hip
- Rare in African American/Asian
What examination is used to monitor Developmental Dysplasia of the Hip?
Usually picked up on baby check – screening in UK
- RoM of hip:
* Usually limitation in hip abduction
* Leg length (Galeazzi)
- In those 3 months or older Barlow and Ortalani are non-sensitive
What investigations are used to monitor Developmental Dysplasia of the Hip?
- Ultrasound – birth to 4 months:
- After 4 months X-ray
- If prior to 6 weeks needs to be age adjusted
- Measures the acetabular dysplasia and the position of hip
How is Developmental Dysplasia of the Hip treated?
- Reducible hip and <6 months:
- Pavlik harness 92% effective
Failed Pavlik Harness or 6-18 months:
* Secondary changes- capsule + soft tissue
* MUA + Closed reduction and Spica
What is Clubfoot?
a.k.a Congenital Talipes Equinovarus
- Congenital deformity of the foot where a baby is born with a foot or feet that turn in and under
CAVE deformity due to muscle contracture
Cavus –high arch: tight intrinsic, FHL, FDL
Adductus of foot: Tight tib post and ant
Varus: Tight tendoachillies, tib post, tib ant
Equinous: tight tendoachilles
How is clubfoot treated?
Ponseti Method
Gold standard
- First a series of casts to correct deformity
- Many require operative treatment
Soft tissue releases - Foot orthosis brace
- Some will require further operative intervention to correct final deformity.
What is Achondroplasia?
“short-limbed dwarfism”/ Rhizomelic dwarfism
- The most common skeletal dysplasia
- Autosomal Dominant
- G380 mutation ofFGFR3
- inhibition of chondrocyte proliferation in theproliferative zoneof thephysis
- results in defect in endochondral bone formation
- Humerus shorter than forearm
- Femur shorter than tibia
- Normal trunk
- Adult height of approx. 125cm
- Normal cognitive development
- Significant spinal issues
What is Osteogenesis Imperfecta?
“Brittle bone disease”
- Hereditary – autosomal dominant or recessive
- Decreased Type I Collagen due to:
* Decreased secretion
* Production of abnormal collagen
- Insufficient osteoid production
What effects are caused by Osteogenesis Imperfecta?
- Bones:
- Fragility fractures
- Short stature
- Scoliosis
- Non-orthopaedic manifestations:
- Heart:
- Blue Sclera
- Dentinogenesis imperfecta – brown soft teeth
- Wormian skull
- Hypermetabolism
What is meant by “The Limping Child”?
Limping due to hip pain caused by 4 conditions:
1. Septic Arthritis
2. Transient Synovitis
3. Perthes
4. SUFE
(always think of non-accidental injury with kids- safe guarding issue)
What is Septic arthritis?
painful infection in a joint:
- Septic arthritis in a child is a orthopaedic emergency!
- Can cause irreversible long term problems in the joint:
* Therefore needs surgical washout of the joint to clear the infection
What is Kocher’s classification?
derived to identify factors important in distinguishing septic arthritis and transient synovitis
Kocher’s classification can help score probability
Non weight bearing
ESR >40
WBC >12,000
Temperature >38
(the more features you have, the more likely you are to have SA)
Transient synovitis is a diagnosis once septic arthritis has been excluded
Is a inflamed joint in response to a systemic illness
Supportive treatment with antibiotics is the treatment
What is Perthes disease?
“Idiopathic necrosis of the proximal femoral epiphysis”
- a childhood condition
- occurs when blood supply to the ball part (femoral head) of the hip joint is temporarily interrupted and the bone begins to die.
- Usually in those 4-8 years old
- Male 4:1 Female
- Septic arthritis needs to be excluded first
- Treatment is usually supportive in the first instance
What is SUFE?
“Slipped upper femoral epiphysis”
- The proximal epiphysis slips in relation to the metaphysis
- Usually obese adolescent male:
* 12-13 years old during rapid growth
* Associated with hypothyroidism/hypopituitrism
- Septic arthritis needs to be excluded first
- Treatment is operative fixation with screw to prevent further slip and minimise long term growth problems
