Paediatric Orthopaedics

Question 1

What is Perthe’s disease? Who does it most commonly affect?

Answer 1

Disruption of the blood flow to the femoral head - leads to avascular necrosis

Boys aged 4-8

Question 2

What is the long-term affect of Perthe’s disease?

Answer 2

Over time, re-vascularisation of the femoral head leads to early hip osteoarthritis

Question 3

How does Perthe’s disease present?

Answer 3

Gradual onset of…

Pain in the hip/groin

Limping

Restricted hip movement

Question 4

How is Perthe’s disease diagnosed?

Answer 4

XR may be normal but can show sclerosis and fragmentation
May also show widening of joint space and decreased femoral head size (flattening of femoral head)

If XR is normal can do an MRI

Question 5

How is Perthe’s disease managed?

Answer 5

If less than 50% of the femoral head is affected - conservative management (analgesia)

If more than 50% affected - plaster cast (mobilisation)

If less than 6 years: observation
Older: surgical management with moderate results

May need surgical management

Question 6

What is developmental hip dysplasia?

Answer 6

Structural abnormality of the hips

Caused by abnormal development of fetal bones during pregnancy

Tendency for dislocation

Question 7

What are risk factors for developmental hip dysplasia?

Answer 7

1st degree family history

Breech presentation from 36 weeks

Breech presentation at birth

Multiple pregnancy

Question 8

What 2 special tests can be used to diagnose developmental hip dysplasia?

Answer 8

Ortolani test

Barlow test

Question 9

How is developmental hip dysplasia managed?

Answer 9

<6 months = Pavlik harness (holds infants hips in flexed position): The aim is to hold the femoral head in the correct position to allow the hip socket (acetabulum) to develop a normal shape. This harness keeps the baby’s hips flexed and abducted
-harness is removed when their hips are more stable, usually after 6 – 8 weeks.

> 6 months = surgery
- After surgery is performed, an hip spica cast is used to immobilise the hip for a prolonged period.

Question 10

What is Rickets?

Answer 10

Defective bone mineralisation caused by a deficiency of vitamin D or calcium, leading to soft/deformed bones due to secondary hyperparathyroidism

Question 11

What are risk factors for Rickets?

Answer 11

Dark skin

Colder climate

Spend a lot of time indoors

Question 12

What are symptoms of Rickets?

Answer 12

Lethargy

Bone pain

Bone deformity

Poor growth

may be symptoms of high serum calcium - stones

Question 13

What bone deformities are seen in Rickets?

Answer 13

Bowing of legs

Knock knees

Rachitic rosary

Question 14

What blood tests should be conducted in suspected Rickets?

Answer 14

Serum 25-hydroxyvitamin D

Low calcium

Low phosphate

Increased ALP

Increased PTH

Question 15

How is Rickets managed?

Answer 15

Vitamin D supplementation

Question 16

What is Achondroplasia? What is the hereditary pattern?

Answer 16

Most common cause of dwarfism

Autosomal dominant

Question 17

What are features of Achondroplasia?

Answer 17

Short limbs + short digits

Normal trunk length

Large head

Flattened mid-face + nasal bridge

Foramen magnum stenosis

Question 18

What is osteogenesis imperfecta? How does it present?

Answer 18

A genetic condition causing brittle bones which are prone to fracture

Recurrent inappropriate fractures

Blue/grey sclera

Hypermobility

Deafness

Dental imperfections

Question 19

What is slipped upper femoral epiphysis? How does it present?

Answer 19

When the head of femur slips along the growth plate

More common in obese children

May be some trauma that triggered onset of symptoms

Pain is disproportionate to severity of trauma

Restricted range of movement - Loss of internal rotation

Painful limp

Question 20

How is slipped capital femoral epiphysis diagnosed?

Answer 20

AP and lateral Xrays

Question 21

How is slipped capital femoral epiphysis managed?

Answer 21

Internal fixation with a single cannulated screw

Question 22

What is transient synovitis? How does it present?

Answer 22

Acue hip pain following a recent viral infection

Limp/inability to weight bear
Groin/hip pain
Low grade fever

Self-limiting

Question 23

When might you consider septic arthritis over transient synovitis?

Answer 23

High grade fever warrants investigation for septic arthritis

Question 24

A 2-year-old boy is taken to his GP with a 1 day history of right-sided limp. His parents report him being otherwise fit and well apart from a recent cold and his nursery deny observing any physical trauma. On examination, he is afebrile and evidently in pain however has a normal range of movement in the right hip. What would be the most appropriate management at this stage?

A. Watch and wait with strict safety-netting

B. Urgent hospital assessment

C. Routine hospital referral

D. Advise that this is a self-limiting condition and provide simple analgesia

E. Provide simple analgesia and request bloods and a hip X-ray

Answer 24

B. Urgent hospital assessment

-Urgent assessment should be arranged for a child < 3 years presenting with an acute limp (higher risk of septic arthritis/child maltreatment)

Question 25

A 6-year-old boy presents with an groin pain. He is known to be disruptive in class. He reports that he is bullied for being short. On examination he has an antalgic gait and pain on internal rotation of the right hip.

A. Musculoskeletal pain
B. Congenital dysplasia of the hip
C. Slipped upper femoral epiphysis
D. Transient synovitis
E. Septic arthritis
F. Perthes disease
G. Tibial fracture

Answer 25

F. Perthes disease

This child is short, has hyperactivity (disruptive behaviour) and is within the age range for Perthes disease. Hyperactivity and short stature are associated with Perthes disease.

Question 26

What blood tests would suggest septic arthritis?

Answer 26

the WCC should ideally be > 12 and the ESR > 40 to suggest septic arthritis.

Question 27

A 16 year old girl has been referred for review by the orthopaedic specialist by her GP with a 3 month history of worsening pain and swelling around her right knee. She is a keen athlete and has recently been preparing for football trials. She believes this may have started following an injury to her knee whilst playing several months ago. Recently the pain has become so bad that she has had to miss training even though she is now taking regular paracetamol. She reports the pain is worse at night. On examination there is a tender mass noted above the right knee and the thigh appears enlarged compared to the left. The patient is also noted to be walking with a limp.

An x-ray of the right knee shows new disorganised bone growth around the distal end of the right femur with a poorly defined border. There is also area of radiolucent lesions and a sunburst appearance of the periosteum is noted.

Given her presentation what is the most likely diagnosis?

A. Lymphoma

B. Ewing’s sarcoma

C. Malignant fibrous histiocytoma

D. Osteosarcoma

E. Chondrosarcoma

Answer 27

D. Osteosarcoma

Osteosarcoma is the most common non-haematological primary malignant neoplasm of bone in children and adolescents. Pain and swelling with a prolonged onset are characteristic. The x-ray findings of new bony growth and a periosteal reaction causing a sunburnt appearance are typical of osteosarcoma

Question 28

what is the criteria for septic arthritis called & 4 parameters?

Answer 28

Kocher’s criteria is used to assess the probability of septic arthritis in children using 4 parameters:
1. Non-weight bearing - 1 point
2. Fever >38.5ºC - 1 point
3. WCC >12 * 109/L - 1 point
4. ESR >40mm/hr

Question 29

A father brings his 15-month-old son in for review. He started walking two months ago. The father has noticed that his son seems to be ‘bow-legged’ when he walks.

Examination of the knees and hips is unremarkable with a full range of movement. Leg length is equal. On standing the intercondylar distance is around 7cm.

What is the most appropriate action?

A. Refer to orthotics for shoe inserts

B. Reassure that it is a normal variant and likely to resolve by the age of 4 years

C. Refer to paediatric orthopaedics

D. Refer to physiotherapy for plantar flexion stretching exercises

E. Request an x-ray of the knees

Answer 29

B. Reassure that it is a normal variant and likely to resolve by the age of 4 years

Bow legs in a child < 3 is a normal variant and usually resolves by the age of 4 years

Question 30

normal lower limb variants in children:

Answer 30

Question 31

A 12-year-old boy presents with hip pain. He reports that it has been ongoing for the last 1 week and he has been unable to participate in sports. He recently has been absent from school due to feeling unwell with fever and fatigue but this has resolved.

On examination, there is pain on palpation of the right hip with a restricted range of movement.

Below is an image of his pelvic X-ray:

Given the most likely diagnosis, how would you manage this patient?

A. Antibiotics

B. External fixation

C. Internal fixation

D. Pavlik harness

E. Replacement arthroplasty

Answer 31

The above X-ray shows a widening of the physis of the right proximal femur and displacement of the epiphysis in the right hip joint which is consistent with a slipped capital femoral epiphysis.

C. Internal fixation is correct. The patient is presenting with slipped capital femoral epiphysis. It can occur with acute pain of the affected joint or with a more chronic onset. When patients are examined, there is a reduced range of movement and a loss of internal rotation on flexion. It should be managed with internal fixation.

A. Antibiotics is incorrect. Antibiotics are indicated if there are signs of septic arthritis or osteomyelitis. It may be prescribed for bursitis if this may be due to infection. These differentials should be considered with joint pain, especially if the patient is feverish, has signs of cellulitis, or if the joint is hot to the touch. However, the X-ray would not show the abnormality seen in this scenario and may show bone erosion in cases of osteomyelitis.

B. External fixation is incorrect. External fixation is where a device is used to keep the fracture aligned from the outside through the skin into the bone. It is usually used when the fracture would not be suitable for a cast. It can be used in paediatric patients, however, internal fixation is usually used in slipped capital femoral epiphysis.

D. Pavlik harness is incorrect. This is used in the management of developmental dysplasia of the hip. This condition should be picked up during neonatal checks or early on in childhood, and it is caused by the femur not aligning correctly with the acetabulum. This can affect the baby’s development, and they may not reach their milestones. The Pavlik harness holds the joint in an abducted and externally rotated position to correct the abnormality, therefore it is used in babies and would not be suitable to be used in a 12-year-old patient who is mobile.

E. Replacement arthroplasty is incorrect. This is the management for Perthe’s disease. This is a rare condition that affects the hip joint. The blood supply is lost leading to necrosis of the joint. The patient may present with a limp, short stature in pre-pubescence, and limited range of movement. Replacement arthroplasty can be used in the long-term management of patients with slipped capital femoral epiphysis due to the complications such as deformity and severe osteoarthritis. However, it is not the first-line treatment. The priority is the stabilisation of the joint by internal fixation.

Question 32

Perthe vs SUFE management differences:

Answer 32

If less than 6 years: observation

if more than 6 years: Replacement arthroplasty =for Perthe’s disease

Internal fixation=for SUFE

Question 33

associations with SUFE:

Answer 33

1. obesity
2. endocrine abnormalities eg hypothyroidism, renal faiure osteodystrophy,
   hypogonadism (eg GH deficiency, hypopituitarism)

Question 34

associations with Perthes:

Answer 34

1. hyperactivity (eg ADHD)
2. short stature
   -sometimes painless

Question 35

SUFE definition:

Answer 35

fracture through the epiphysis (growth plate) resulting in slippage of femur (icecream on cone appearance)

Question 36

Perthe’s definition:

Answer 36

avascular necrosis of femoral head

Question 37

difference between Barlow & Ortolani tests (mnemonic):

Answer 37

(BO DR : body odour doctor)
Barlow–> disclote
Ortlolani–> reduce

Question 38

what imaging should be done for DDH (different ages)

Answer 38

6 weeks–> USS of hips
>6months–> hip X-ray

Question 39

A 12 year old, fit boy presents to his GP complaining of a one week history of right hip pain. There seems to be no history of trauma. The family report they have had a general cold over the last two weeks. On examination, there is restricted internal rotation and extension of the right hip. He does not have a temperature and his past medical history is unremarkable. His immunizations are up to date. A hip radiograph is unremarkable. What is the most appropriate treatment?

A. Osteotomy

B. Hip x-ray

C. NSAIDs and bed-rest for up to 6 weeks

D. Hip ultrasound

E. Referral to social services

Answer 39

C. NSAIDs and bed-rest for up to 6 weeks

Transient synovitis is the most common cause of hip pain in children. It affects boys more than girls and is sometimes associated with minor trauma. Limited range of motion, specifically extension and internal rotation of the hip can be found. It is confirmed using a hip x-ray and ultrasound, which shows synovitis. It is treated using NSAIDs and bedrest. It usually clears in 7-10 days.

Not B: Hip X-ray

This is a case of transient synovitis. Whilst a hip x-ray may be indicated, it is not involved in the treatment

Question 40

Answer 40

DDH

Question 41

A 3-year-old boy is brought into the Emergency Department by his parents who are worried about his walking. He has been refusing to weight-bear for the past day and has been more irritable than usual. His parents inform you that the child has had two doses of Calpol today after they recorded his fever as 38.5 °C in the morning.

On examination, the child is noted to have a red and swollen left hip joint.

What is the most appropriate next step in the management of this patient?

A. Commence empirical intravenous (IV) antibiotics

B. Joint aspiration

C. Osteotomy

D. Surgical drainage of the hip joint

E. Non-steroidal anti-inflammatory drugs (NSAIDs) and bed rest

Answer 41

B. Joint aspiration

This patient is presenting with fever alongside an acutely inflamed and swollen joint and he is unable to weight bear, which points towards the diagnosis of septic arthritis. Septic arthritis describes infection of the joint caused by bacteria or a virus which spreads into the synovial fluid surrounding the joint. It is an emergency, as the infection can progress to destroy the joint and cause systemic illness and therefore it must be diagnosed and treated promptly. The joint should be aspirated and the sample sent for crystal microscopy, Gram staining, culture and antibiotic sensitivities. Once the joint has been aspirated, intravenous empirical antibiotics should be started immediately in all cases of suspected or confirmed septic arthritis.

Not A: Commence empirical intravenous (IV) antibiotics

IV antibiotics are the mainstay of the management of septic arthritis. However, it is important to perform a joint aspiration of the affected joint before antibiotics are commenced, so that the antibiotics do not interfere with the results of the synovial fluid analysis. Once the joint aspiration has been taken, empirical antibiotics are commenced intravenously until the microbial sensitivities are commenced, at which stage more targeted antibiotics can be given.

Not E: Non-steroidal anti-inflammatory drugs (NSAIDs) and bed rest

This is the correct management for cases of transient synovitis. Transient synovitis is a self-limiting condition resulting from inflammation of the synovial lining of the hip joint. Both transient synovitis and septic arthritis cause acute-onset limp and problems weight-bearing. However, symptoms in transient synovitis are milder than those found in septic arthritis. The high-grade fever in this presentation necessitates immediate exclusion of septic arthritis as a diagnosis.

Not B: Osteotomy

Osteotomy describes surgical reshaping of the joint, such as shortening of lengthening the bones to change their alignment. Osteotomy is performed in severe cases of Perthes’ disease if more than 50% of the femoral head is involved.

Not D: Surgical drainage of the hip joint

Surgical drainage and washout of the joint to clear the infection is reserved for severe cases of septic arthritis in which IV antibiotics alone has not been effective in clearing the infection. For this reason, it is not the next step in the management of this patient.

Question 42

when do you aspirate the joint?

Answer 42

suspected septic arthritis

Osteomyelitis; no need to aspirate (do blood culture instead)

Question 43

RFs for septic arthritis and osteomyelitis:

Answer 43

Diabetes mellitus
Peripheral vascular disease
Malnutrition
Immunosuppression
Malignancy
Extremes of age
Local factors e.g chronic lymphedema, vasculitis, neuropathy etc.

Question 44

bacterial etiology of septic arthritis and osteomyelitis

Answer 44

Question 45

Investigations of septic arthritis vs osteomyelitis:

Answer 45

Imaging:
1. X-ray - may be negative early on as periosteal reaction cannot be seen until about 7 days and bone necrosis after 10 days. It is useful in the diagnosis of chronic osteomyelitis.

2. MRI - good for viewing bone and soft tissue. Imaging modality of choice (*preferred: An MRI does not involve radiation so is particularly useful in children where the radiation burden is more significant)
3. CT - good for identifying necrotic bone and for guiding a needle for biopsy.

Question 46

management of septic arthritis/osteomyelitis:

Answer 46

Antibiotics for a minimum of 4-6 weeks (at least 12 weeks, usually 3-6 months, in chronic osteomyelitis):

1. Empirical: flucloxacillin plus fusidic acid/rifampicin, vancomycin is MRSA suspected
   I2. f penicillin allergic: give clindamycin
2. Start IV and switch to oral antibiotics when patient stable and/or 2 weeks post surgery

For chronic osteomyelitis, treatment is usually delayed until culture and sensitivity results have been obtained.

Surgical debridement

1. The mainstay of treatment for chronic osteomyelitis
2. Acute infections can be treated with extensive surgical cleaning early on together with antibiotics

Question 47

what does joint aspiration look for?

Answer 47

1. gram staining
2. crystal microscopy
3. culture
4. antibiotic sensitivities

(MC &S: microscopy, culture and sensitivity)

Question 48

management of SUFE:

Answer 48

Surgery (S for surgery and SUFE) is required to return the femoral head to the correct position and fix it in place to prevent it slipping further.
-operative internal fixation

Question 49

SUFE presentation:

Answer 49

The typical exam presentation is an adolescent, obese male undergoing a growth spurt. There may be a history of minor trauma that triggers the onset of symptoms. Suspect SUFE if the pain is disproportionate to the severity of the trauma.

Presenting symptoms can be vague. These can be:

1. Hip, groin, thigh or knee pain
2. Restricted range of hip movement (loss of internal rotation of the leg in flexion)
3. Painful limp
4. bilateral slip in 20% of cases

When examining the patient, they will prefer to keep the hip in external rotation. They will have limited movement of the hip, particularly restricted internal rotation.

Question 50

SUFE investigations:

Answer 50

The initial investigation of choice in SUFE is xray (AP and lateral (typically frog-leg))

Other investigations that can be helpful in establishing the diagnosis are:

1. Blood tests are normal, particularly inflammatory markers used to exclude other causes of joint pain
2. Technetium bone scan
3. CT scan
4. MRI scan

Question 51

complications of SUFE:

Answer 51

1. osteoarthritis
2. avascular necrosis of the femoral head
3. chondrolysis (rapidly progressive loss of articular cartilage from both the femoral and acetabular sides of the hip)
4. leg length discrepancy

Question 52

what does this show?

Answer 52

Posterior migration (slip) of left femoral capital epiphysis in relation to metaphysis

Frog lateral view confirms posterior slip of the left femoral capital epiphysis. Slippage is usually posteromedial and may be hard to detect on frontal, A-P, views only.

Question 53

what is a greenstick fracture?

Answer 53

A greenstick fracture occurs when a bone bends and cracks, instead of breaking completely into separate pieces

Question 54

management of greenstick fracture:

Answer 54

When not displaced fractures in children do not require any specific treatment other than splinting.

An angulated greenstick fracture would need manipulation and plaster immobilisation.

Question 55

pain management for fractures in children (& what is contraindicated):

Answer 55

Pain management in children is slightly different than adults. The World Health Organisation have a pain ladder for children that has only two steps:

Step 1: Paracetamol or ibuprofen
Step 2: Morphine
If a child requires morphine they generally need admission for a serious illness.

TOM TIP: Examiners like to test your knowledge on the pain medications that are not used in children. Codeine and tramadol are not used in children as there is unpredictability in their metabolism, so the effects vary too greatly to make them safe and effective options.

Aspirin is contraindicated in children under 16 due to the risk of Reye’s syndrome (a rare disorder that affects all organs of the body but is most harmful to the brain and the liver—causing an acute increase of pressure within the brain and, often, massive accumulations of fat in the liver and other organs) (aspirin is used in certain circumstances such as Kawasaki disease).

Question 56

what is a positive Trendelenburg test?

Answer 56

A positive Trendelenburg test where the pelvis tilts towards the unaffected side when standing on the affected leg.

Question 57

Osteomyelitis Investigations:

Answer 57

1. Blood cultures
2. Full blood count
3. Inflammatory markers (CRP)
4. X-ray knee
5. Bone scan
6. MRI knee

Question 58

when is surgical drainage of osteomyelitis carried out?

Answer 58

If the child does not respond within the first 24 to 48 hours

Question 59

what is the most common organism in osteomyelitis and septic arthritis?

Answer 59

staphylococcus aureus

Question 60

osteomyelitis causes in adults, children, sickle cell patients, immunocompromised & congenital:

Answer 60

Question 61

what is the most common organism in septic arthritis patients with sickle cell disease?

Answer 61

It is the most common organism in patients with sickle cell disease, although salmonella infection is commonly associated with these patients.

Question 62

most common site of septic arthritis:

Answer 62

The most common site of infection is the hip (75%).

Question 63

when do plain xray film changes appear in septic arthritis:

Answer 63

Plain film changes are not usually evident for 2-3 weeks
-When positive, they may show the joint space widening and ill-defined articular margins. If there is a high index of suspicion, MRI should be performed as soon as possible.

• Septic arthritis is often diagnosed late due to poor localisation of symptoms and normal plain X-ray findings at presentation