Orthopaedics 3 Flashcards
What is Meralgia paraesthetica?
Meralgia paraesthetica comes from the Greek words meros for thigh and algos for pain and is often described as a syndrome of paraesthesia or anaesthesia in the distribution of the lateral femoral cutaneous nerve (LFCN). It is an entrapment mononeuropathy of the LFCN, but can also be iatrogenic after a surgical procedure, or result from a neuroma.
What are the risk factors for meralgia paraesthetica?
- Obesity
- Pregnancy
- Tense ascites
- Trauma
- Iatrogenic, such as pelvic osteotomy, spinal surgeries, laparoscopic hernia repair and bariatric surgery. In some cases, may result from abduction splints used in the management of Perthe’s disease.
- Various sports have been implicated, including gymnastics, football, bodybuilding and strenuous exercise.
- Some cases are idiopathic.
What are the symptoms, signs and investigations for meralgia paraesthetica?
Patients typically present with the following symptoms in the upper lateral aspect of the thigh:
- Burning, tingling, coldness, or shooting pain
- Numbness
- Deep muscle ache
- Symptoms are usually aggravated by standing, and relieved by sitting
- They can be mild and resolve spontaneously or may severely restrict the patient for many years.
Signs:
- Symptoms may be reproduced by deep palpation just below the ASIS (pelvic compression) and also by extension of the hip.
- There is altered sensation over the upper lateral aspect of the thigh.
- There is no motor weakness.
Investigations:
- The pelvic compression test is highly sensitive, and often, meralgia paraesthetica can be diagnosed based on this test alone
- Injection of the nerve with local anaesthetic will abolish the pain. Using ultrasound is effective both for diagnosis and guiding injection therapy in meralgia paraesthetica
- Nerve conduction studies may be useful.
What are the features associated with a fat embolus?
Respiratory
- Early persistent tachycardia
- Tachypnoea, dyspnoea, hypoxia usually 72 hours following injury
- Pyrexia
Dermatological
- Red/ brown impalpable petechial rash (usually only in 25-50%)
- Subconjunctival and oral haemorrhage/ petechiae
CNS
- Confusion and agitation
- Retinal haemorrhages and intra-arterial fat globules on fundoscopy
What is Morton’s neuroma and what are the features?
Morton’s neuroma is a benign neuroma affecting the intermetatarsal plantar nerve, most commonly in the third inter-metatarsophalangeal space. The female to male ratio is around 4:1.
Features
- forefoot pain, most commonly in the third inter-metatarsophalangeal space
- worse on walking. May be described as a shooting or burning pain. Patients may feel they have a pebble in their shoe
- Mulder’s click: one hand tries to hold the neuroma between the finger and thumb. The other hand squeezes the metatarsals together. A click may be heard as the neuroma moves between the metatarsal heads
- there may be loss of sensation distally in the toes
How do you diagnose and manage a Morton’s neuroma?
Diagnosis is usually clinical although ultrasound may be helpful in confirming the diagnosis
Management
- avoid high-heels
- metatarsal pad
- CKS recommends referral if symptoms persist for > 3 months despite footwear modifications and the use of metatarsal pads
- orthotists may give the patient a metatarsal dome orthotic
- other secondary care options include corticosteroid injection and neurectomy of the involved interdigital nerve and neuroma
What is a comminuted fracture?
A break or splinter of the bone into more than two fragments
What are the different types of fracture?
Oblique fracture
Fracture lies obliquely to long axis of bone
Comminuted fracture
>2 fragments
Segmental fracture
More than one fracture along a bone
Transverse fracture
Perpendicular to long axis of bone
Spiral fracture
Severe oblique fracture with rotation along long axis of bone
How do you classify open fractures?
Gustilo and Anderson classification system:
1 Low energy wound <1cm
2 Greater than 1cm wound with moderate soft tissue damage
3 High energy wound > 1cm with extensive soft tissue damage
3 A (sub group of 3) Adequate soft tissue coverage, contaminated (farming injuries are at least 3a)
3 B (sub group of 3) Inadequate soft tissue coverage
3 C (sub group of 3) Associated arterial injury
What’s the most common part of the bone to be affected in osteomyelitis in children?
metaphysis
Haematogenous spread into the long bone is the most common source of infection for osteomyelitis in children. The location of infection depends on the age due to the changing vascular supply. In children, it frequently affects the metaphysis as it is a highly vascular area. In adults it tends to be the epiphysis.
What is a common cause of bilateral carpal tunnel syndrome?
Rheumatoid arthritis
When is carpal tunnel from acromegaly most likely to occur?
after age 50
What’s the most common place for osteoarthritis?
- knee
2. hip
What are the risk factors for OA?
- increasing age
- female gender (twice as common)
- obesity
- developmental dysplasia of the hip
What’s the appropriate management for OA?
What are the complications of surgery and when should surgical revision take place?
Management
- oral analgesia
- intra-articular injections: provide short-term benefit
- total hip replacement remains the definitive treatment
Complications of total hip replacement
- venous thromboembolism
- intraoperative fracture
- nerve injury
Reasons for revision of total hip replacement
- aseptic loosening (most common reason)
- pain
- dislocation
- infection
What are the features of paget’s disease and how do you treat it?
- Focal bone resorption followed by excessive and chaotic bone deposition
- Affects (in order): spine, skull, pelvis and femur
- Serum alkaline phosphatase raised (other parameters normal)
- Abnormal thickened, sclerotic bone on x-rays
- Risk of cardiac failure with >15% bony involvement
- Small risk of sarcomatous change
Bisphosphonates
What are the features of osteoporosis and how do you treat it?
- Excessive bone resorption resulting in demineralised bone
- Commoner in old age
- Increased risk of pathological fracture, otherwise asymptomatic
- Alkaline phosphatase normal, calcium normal
Bisphosphonates, calcium and vitamin D
What are the features of secondary bone tumours and how do you treat them?
- Bone destruction and tumour infiltration
- Mirel scoring used to predict risk of fracture
- Appearances depend on primary (e.g.sclerotic - prostate, lytic - breast)
- Elevated serum calcium and alkaline phosphatase may be seen
Radiotherapy, prophylactic fixation and analgesia
Is a high fever common in transient synovitis?
No, think septic arthritis
What are the risk factors for avascular necrosis of the hip? What are the symptoms?
- long-term steroid use
- chemotherapy
- alcohol excess
- trauma
- initially asymptomatic
- pain in the affected joint
How would you investigate and manage avascular necrosis of the hip?
Investigation
- plain x-ray findings may be normal initially. Osteopenia and microfractures may be seen early on. Collapse of the articular surface may result in the crescent sign
- MRI is the investigation of choice. It is more sensitive than radionuclide bone scanning
Management
- joint replacement may be necessary
What’s the imaging of choice for osteomyelitis?
MRI
What are the red flags for back pain and what investigations should you perform?
Thoracic pain Age <20 or >55 years Non-mechanical pain Pain worse when supine Night pain Weight loss Pain associated with systemic illness Presence of neurological signs Past medical history of cancer or HIV Immunosuppression or steroid use IV drug use Structural deformity
Patients with red flags should have blood tests for FBC, ESR, Calcium, Phosphate, Alkaline phosphatase and PSA if appropriate. X-ray imaging should also be arranged.
What is the Gartland scale used for?
to classify supracondylar fractures in children
Which single clinical finding best supports the diagnosis of a dislocated hip?
- asymmetrical skin creases on the thighs
- clicking on abduction of the hip
- a dimple at the base of the spine
- leg length discrepancy
- limited abduction of the hip
Limited abduction of the hip. This means that the hip is out posteriorly (positive Ortolani)
What should you do if you suspect cauda equina?
First: history and examination including DRE
Then: MRI
When do children in the UK have their hips checked?
6 weeks
8 months
2 years
What are the risk factors for DDH?
- female gender
- first born
- foot first (breech)
- FH
- further bony abnormalities (e.g talipes equinovarus)
What’s the most common elbow fracture in paeds?
Supracondylar
At what age does the elbow ossify?
1 Capitellum 3 Radial head 5 Internal epicondyle 7 Trochlear 9 Olecranon 11 Lateral epicondyle
What structures are at risk from a supracondylar fracture?
median and ulnar nerves
brachial artery
How do you treat a supracondylar fracture?
- rest and immobilise while NV status assesses
- if NV compromised then emergency
Gartland classification
I- non displaced, subtle, intact anterior humeral line (may only have posterior fat pad sign)- splint, non operative
II- displaced, posterior cortex intact, anterior humeral line not through middle 1/3 of capitellum, likely operative
III- completely displaced, rotation and comminution, operative
What is a medial epicondyle fracture associated with?
50% elbow dislocation
How do you treat a medial epicondyle fracture?
- If < 5mm then back slab at 90 degrees flexion for 3 weeks
- If 5-15mm then need reduction (either open or closed)
- If >15mm then dislocation likely, need urgent reduction
How do you treat a lateral mass fracture?
- undisplaced- back slab
- minimal displacement- immobilise or closed reduction with percutaneous pins
- if >2mm then need to go to theatre
How do you treat a triplane fracture?
> 2mm displaced then reduce
< 2mm displaced then above knee cast
