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
