Ortho Info

Question 1

Hereditary risks of anaesthetic?

Answer 1

1) Malignant hyperthermia (hyperpyrexia)
- Autosomal dominant condition
- Develops during or immediately after GA
- Likely result of defect in calcium channel regulation in muscle cell
- Continued contraction of muscle cell -> hypermetabolic state -> massive CO2 production, skeletal muscle rigidity, tachyarrhythmias, respiratory acidosis, hyperkalaemia, cyanosis, fever, lactic acidosis
- Testing for the condition - open muscle biopsy

2) Agranulocytosis
- Acute condition involving a severe and dangerous leukopaenia
- Most commonly - neutrophils

Question 2

Varus and Valgus alignment

Answer 2

• Valgus and varus refer to angulation (bowing) within the shaft of a bone or at a joint
• Determined by the distal part being more medial or lateral than it should be
• Valgus - distal part is more lateral
• Varus - distal part is more medial

Question 3

What are the 2 types of scars?

Answer 3

1) Hypertrophic
- Scar tissue is initially red and prominent
- Over several months a scar usually becomes flat and pale
- If there is a lot of tension on a healing wound, the healing area is thicker than usual = hypertrophic scar

2) Keloid
- Firm, smooth, hard growth, due to spontaneous scar formation
- May arise soon after injury or develop months later
- May be much larger than the original wound

Question 4

Radiographic features of OA

Answer 4

L - loss of joint space (asymmetrical)
O - osteophytes
S - subchondral sclerosis
S - subchondral cysts

Question 5

Avascular necrosis (osteonecrosis)

Answer 5

Definition:

• Degenerative bone condition characterised by death of cellular components of bone due to interruption of subchondral blood supply
• Usually affects epiphysis of long bones at weight-bearing joints (femoral head, humerus, knee)

Causes:
- Reduction of subchondral blood flow - due to: vascular interruptions from fracture +/- dislocation, intravascular occlusion due to thrombi or embolic fat

Risk Factors:
- Age, sex (m), glucocorticoid use, excessive ETOH, smoking, trauma and prior surgery involving the affected joint, radiation therapy,

Symptoms

• Pain at night, joint stiffness
• Worse with weight-bearing, relieved with rest

Question 6

Gonococcal Septic Arthritis

Answer 6

• Although Staphylococcus aureus is the most common cause of monomicrobial septic arthritis overall, among sexually active adults, N. gonorrhoeae is the most common causative organism
• The possibility of disseminated gonococcal infection (DGI) should be considered in sexually active individuals (particularly those younger than 40 years, those with multiple partners, and all men who have sex with men) who present with arthralgias or joint pain concerning for septic arthritis