MSK & Orthopaedics Flashcards
What is Perthes’ disease?
A degenerative condition affecting the hips of children, typically between 4-8 years
What is the pathophysiology of Perthes’ disease?
Avascular necrosis of the femoral head, specifically the epiphysis - impaired blood supply eventually causes femoral necrosis
What is the epidemiology of Perthes’ disease?
5x more common in males, 10% of cases are bilateral
What are the features of Perthes’ disease?
- Hip pain: progressively over a few weeks
- Limp
- Stiffness and reduced range of hip movement
What are the diagnostic investigations for Perthes’ disease?
- Plain x-ray
- Technetium bone scan or MRI if normal x-ray and symptoms persist
What are the features of Perthes’ disease on x-ray?
- Joint effusion: widening of the medial joint space
- Asymmetrical femoral epiphyseal size
- Blurring of the physeal plate
- Radiolucency of proximal metaphysis
What are the complications of Perthes’ disease?
- Osteoarthritis
- Premature fusion of the growth plates
What staging is used to classify Perthes’ disease?
Catterall staging
What is the management of Perthes’ disease?
- Keep the femoral head with the acetabulum (cast, braces)
- If less than 6 years: observation
- Older/ if failed to respond to conservative measures: surgical management
- If severe deformities: surgical management
What is the prognosis of Perthes’ disease?
Most cases resolve with conservative management
Early diagnosis improves outcomes
What causes Perthes’ disease?
The trigger for avascular necrosis is unknown
What is muscular dystrophy?
Muscles appearing poorly nourished due to degeneration
Dys - bad
Trophy - nourish
How can muscular dystrophies and neuropathies be distinguished?
In muscular dystrophy, the neuromuscular junction is in tact but the muscles are dystrophied
In neuropathies that NMJs are not preserved
What are the dystrophinopathies?
Muscular dystrophies that occur due to mutations in the dystrophin gene (allelic disorders)
- Duchenne muscular dystrophy
- Becker muscular dystrophy
What mutation leads to duchenne muscular dystrophy?
Nonsense or frameshift mutation leading to no production of the dystrophin protein (one or both of the binding sites are lost)
What mutation leads to becker muscular dystrophy?
Misshapen dystrophin caused by missense mutations (both binding sites are preserved)
What is the difference between DMD and BMD?
DMD:
- More severe
- Symptoms tend to present by age 5
- Earlier onset complications
BMD:
- Less severe
- Symptomatic by age 10-20
What is the inheritance pattern of the dystrophinopathies?
X-linked recessive
2/3 of the time, the mother is a carrier
1/3 of the time, the mutation is sporadic
What is lyonization?
The inactivation of one x chromosome in females (as they inherit 2) to ensure that females only have one functional copy of the x chromosome in cells
What are manifesting carriers?
Carriers of an x-linked recessive genetic condition where more of the x-chromosomes with the functional copy of the gene undergo lyonization, leading to over-expression of the defective gene and manifestation of the disease
What is the function of the dystrophin protein?
It links intracellular actin to the dystrophin-associated protein complex on the muscle cell membrane, which links with the extracellular matrix, and provides structure (like a wooden support beam)
What happens to muscle cells without dystrophin?
The integrity of the sarcolemma (muscle cell membrane) is compromised leading to release of intracellular proteins eg. CK and cell death
What happens to muscle tissue in the short term, for a patient with dystrophinopathy?
Muscle regeneration:
- Cell death leads to muscle tissue loss
- Muscle fibres of different sizes are produced leading to some tissue regain
What happens to muscle tissue in the long term, for a patient with dystrophinopathy?
Muscle atrophy:
- Fat and fibrotic tissue infiltrates the muscle tissue
- Muscles become weak
How does Duchenne muscular dystrophy present?
- Progressive proximal muscle weakness from 5 years old
- Waddling gait
- Pseudohypertrophy of the calfs
- Gowers’ sign
- 30% of patients have intellectual impairment
What is Gower’s sign?
When lying on their stomach, the child will use their arms to help themselves stand due to muscle weakness in the legs and upper hips
What are the later symptoms of dystrophinopathies?
- Wheelchair use
- Respiratory failure - diaphragmatic weakness
- Scoliosis
- Dilated cardiomyopathy
- Arrhythmias
What is the cause of the cardiac symptoms in dystrophinopathies?
Dystrophin is expressed in cardiac muscle
How are dystrophinopathies diagnosed?
- High serum creatine kinase
- Genetic testing: DNA test, Western blot
- Muscle biopsy: staining for dystophin (genetic testing has replaced this as the way to achieve a definitive diagnosis)
What is the medical management for dystrophinopathies?
- Glucocorticoids - slow the degeneration, but there are side effects eg. weight gain
- Ataluren - restores dystrophin synthesis (>=5 years old)
What is the prognosis for DMD?
- Most children can’t walk by the age of 12
- Patients typically survive to 25-30 years
- Associated with dilated cardiomyopathy
What is the physiotherapy for Perthe’s disease?
Stretching of the quadriceps and hamstring muscles, strengthen quads and encourage hip abduction
Continue activity
What is the supportive care for acute pain in Perthe’s?
- Simple analgesia
- Ice packs
What is the supportive management for DMD?
- Physiotherapy (prevent contractures)
- Exercise and psychological support
- Dietician (gastric feeding in some patients, vitamin D and calcium supplementation if bone fragility)
Why can DMD lead to nocturnal hypoxia?
Weakness of the intercostal muscles
What is the management for DMD with nocturnal hypoxia?
Overnight CPAP
What is the management for DMD if left ventricular fraction drops?
Cardioprotective drugs (eg. carvedilol) and left ventricular assist devices
What is the managment for DDH in <6 months old?
1st line
- Observation: monitor via repeat USS or X-ray
2nd line
- Splint/ Pavlik’s harness to keep hip flexed and abducted (follow up with x-ray at 6 months)
3rd line
- Surgery if conservative measures fail
What is the surgery for DDH?
Reduction with spica casting
What are the indications for USS at 6 weeks to check for DDH?
- Breech presentation (36/40)
- Breech delivery (including <36/40)
- Family hx DDH
What imaging is better for DDH >6 months?
Hip x-ray
Which sex is at greater risk of DDH?
Female
Does DDH tend to resolve?
Most resolve spontaneously by 3-6 weeks
What is the initial management of fractures?
Initial pain management and immobilisation
- Oral ibuprofen and/or paracetamol
- IV opiods for severe pain
- Acute stage assessment and diagnostic imaging
What is the management of distal radius fracture in ED?
Manipulation
Consider:
- A below-elbow plaster cast
- K-wire fixation if the fracture is completely displaced
What is the first step in management of femoral fracture in ED?
Admit all children
Femoral fracture managment 3-18 months?
Gallows traction
Femoral fracture managment 1-6 years?
Straight leg traction with possible conversion to hip spica cast to enable early discharge
Femoral fracture managment 4-12 years?
Elastic intramedullary nail
Femoral fracture managment >11 years (weight >50kg)?
- Elastic intramedullarly nails supplemented by endcaps
OR
- Lateral entry antegrade rigid intramedullary nail
OR
- Submuscular plating
Who should patients with JIA be managed by?
Specialist paediatric rheumatology MDT
Why should patients with JIA continue activity?
Inactivity leads to deconditioning, disability and decreased bone mass (continue activities like swimming and cycling)
What is the management of JIA?
Pharmacological
WHO Pain ladder
- Simple analgesia
- NSAIDs (controlling pain and stiffness)
- Consider weak opiates
Intra-articular corticosteroids (or oral/IV)
- Adjunctive agents (avoided if possible due to growth suppression and osteoporosis)
DMARDs (when disease fails to respond to conventional treatment)
- 1st line: oral or SC methotrexate
- 2nd line: sulfasalazine
Other (biologics)
- Inflammatory cytokine blockage eg. TNF-alpha inhibitors, IL receptor antagonists, anti-emetics
What are the complications of JIA?
- Joint damage
- Anterior uveitis
- Osteoporosis
- Growth failure
When is Osgood-Schlatter referred to orthopaedic surgeons?
If symptoms don’t improve or worsen or persist to adulthood despite management
What is the management of Osgood-Schlatter?
Pain relief
- Analgesia (paracetamol/ NSAIDs)
- Ice packs over tibial tuberosity (10-15 mins up to x3 per day)
- Protective knee pads (pain when kneeling)
Should sporting activity be stopped in Osgood-Schlatter?
- Reduce sporting activity
- Change type of exercise to limit running and jumping
- As sx decrease, gradually increase exercise levels
- Low impact quadriceps exercises (cycling, swimming, straight leg raises)
What is the management for osteochondritis dissecans?
- Pain relief
- Rest and quads exercises
- Sometimes surgical intervention needed to remove intra-articular loose bodies
What is the management for acute osteomyelitis?
- High dose IV empirical abx (usually 2-4 weeks)
- Clinical recovery (acute phase proteins normal) switch to oral abx
- Alter abx regimen when blood cultures are back
- Affected limb immobilised, analgesia given
When should blood cultures be taken for osteomyelitis?
Before starting abx
When can early transition to oral abx be started for children with osteomyelitis?
If they respond well, early transition to oral abx (after 3 days- 1 week) can be considered
How long is the course of oral abx for osteomyelitis?
6 weeks
When is surgical debridement considered for osteomyelitis?
If there’s dead bone or a biofilm
How is chronic osteomyelitis staged?
Using Cierney-Mader classification
What is the management for chronic osteomyelitis?
- Surgical debridement
- IV abx
- Functional rehabilitation
What is the management for reactive arthritis?
- Self-resolving
- Symptomatic relief: NSAIDs, steroids (severe), DMARDs (ongoing)
What is the management of Rickets?
Calcium and vitamin D deficiency
- Daily calcium
- Daily ergocalciferol (V D2)/ cholecalciferol (V D3)
Pseudo-vitamin D deficiency (defect in 1-alpha hydroxylase)
- Calcitriol/ 1-alfacalcidiol
Dietary
- Oily fish, egg yolk
What is given in hypophosphataemic rickets?
Phosphate salts
What is the antibiotic course length for septic arthritis?
Initially IV for 2 weeks, followed by 4 weeks of oral abx
Which abx are used for septic arthritis in a neonate <3 months?
IV cefotaxime
Which abx are used for septic arthritis 3 months - <=5 years?
- IV ceftriaxone
- If penicillin allergic, give clindamycin
Which abx are used for septic arthritis >=6 years?
- IV flucloxacillin
- If penicillin allergic, give clindamycin
What are the oral step-down abx for septic arthritis?
- Co-amoxiclav
- Flucloxacillin
Which methods are used for joint aspiration in septic arthritis?
Joint aspirated to dryness
- Closed needle aspiration
- Arthroscopically
What is the management of SUFE?
- Patient remains non-weight bearing, analgesia and IMMEDIATE ORTHO REFERRAL
- Surgical repair: in situ fixation across the growth plate
What are the x-ray findings of SUFE?
Trethowan’s sign: Klein line doesn’t intersect superior femoral epiphyses/ asymmetry between Klein line on either side
What is the managment of transient synovitis?
- Bed rest
- Pain relief (paracetamol or NSAIDs)
- Usually resolves after a few days
What is the management of femoral fractures at birth or due to prematurity?
Simple padded splint
What is the management of femoral fractures 0-6 months?
Pavlik’s harness or Gallows traction
