Orthopaedic Applied Anatomy Of The Hip

Question 1

What are the 2 classes and causes of osteoarthritis?

Answer 1

PRIMARY
• Cause unknown
Risk Factors
• General• Age • Sex (female > male) • Ethnicity • Nutrition • Genetics (OA runs in families)

SECONDARY
• Causes include:
• Obesity • Trauma (including sports and occupational risk factors) • Malalignment e.g. Developmental dysplasia (congenital
dislocation) • Infection e.g. septic arthritis, tuberculosis • Inflammatory arthritis e.g. rheumatoid arthritis • Metabolic disorders affecting the joints (e.g. gout) • Haematological disorders (e.g. haemophilia with
bleeding into the joints) • Endocrine abnormalities (e.g. diabetes mellitus with neurovascular impairment)

Question 2

Describe the pathology of OA

Answer 2

• Precipitating risk factors (e.g. obesity, trauma) lead to excessive loading of joint and damage to articular cartilage
• Increased proteoglycan synthesis by chondrocytes (Initial attempt to repair cartilage damage)
• Flaking and fibrillation of articular cartilage
• Erosion of cartilage down to subchondral (lit. ‘below cartilage’) bone (reduced joint space on X-ray) (subchondral bone cysts)
• Altered joint biomechanics leads to:
• Vascular invasion and increased cellularity of subchondral bone (subchondral sclerosis)
• Cystic degeneration of bone
  
  • Osseous metaplasia of connective tissue (osteophytes)

Question 3

What are the radiological features of OA?

Answer 3

• sclerosis or hardening of the bone (looks more white)
• no joint space (bone on bone)
• cysts noted in bone of femur head
• new bone - osteophytes

Question 4

What are the symptoms of osteoarthritis?

Answer 4

• Joint stiffness that occurs getting out of bed
• Joint stiffness after sitting for a long time
• Pain, swelling, or tenderness in the hip joint
• Crepitus: A sound or feeling (“crunching”) of bone rubbing against bone
• Reduced ability to move the hip to perform routine activities such as putting on a sock, getting in and out of the car / the bath etc.
• OA hip is diagnosed on clinical presentation (symptoms and signs) supported by radiography (X-rays)

Question 5

What are non operative methods of managing OA?

Answer 5

• Activity Modification
• Weight Loss • Stick/walker
• Physical Therapy
• Medications:
• NSAIDs (naproxen, ibuprofen)
• COX-2 Inhibitors (celecoxib)
• Nutritional supplements (glucosamine)
• Injections:
• Corticosteroid
• Viscosupplementation

Question 6

Give a treatment overview for OA

Answer 6

Mild Non pharmacological management - education, excercise, weight loss, appropriate footwear
->
Physiotherapy, braces, paracetamol
->
Pharmacological management - NSAIDS, opioids (if effusion is present, aspirate and inject)
->
Surgery - osteotomy, total joint replacement
Severe

Question 7

What are the benefits of hip replacement surgery?

Answer 7

• Hip Replacement Surgery
• Reduced pain
• Improved patient well-being

Question 8

What is total hip replacement?

Answer 8

• Implants replace damaged surfaces
• Helps relieve pain and restore mobility
• 260,000 each year in the U.S.

Question 9

Where can a hip fracture occur?

Answer 9

Intracapsular - head and neck
Extracapsular - trochanteric area
Shaft fracture - shaft

Question 10

What are the consequences of hip fracture?

Answer 10

20% - die within one year
30% - permanent disability
40% - unable to walk independently
80% - unable to carry out at least one independent activity of daily living

Question 11

What are symptoms of fracture of the neck of the femur?

Answer 11

• Reduced mobility / sudden inability to bear weight on the limb
• Pain which may be felt in the hip, groin and/or knee

Question 12

What can cause avascular necrosis of the hip?

Answer 12

Mechanical disruption (fractured neck of femur)
Alcoholism
Excessive steroid use
Post-trauma (injury)
Thrombosis
Hypertension

Question 13

What are types of surgery that can be performed for hip fracture?

Answer 13

The site and displacement of the fracture, age and mobility of the patient, influence the surgery performed. Displaced intracapsular fracture →high risk of AVN → hemiarthroplasty (femoral head only) or total hip replacement (femoral head and acetabular cup)

Depending where the fracture is depends how you manage it
Number of different operations

• Intracapsular
◦ Screws holding it in place - intracapsular
◦ If you have an undisplaced intracapsular fracture you would want to hold it in place and hope it heals without avascular necrosis
◦ If you have a displaced intracapsular fracture. I.e. head come off, then it i is not going to heal - in this situation you would want to replace the head
◦ Someone really fit and healthy might get a total hip replacement - both sides of the joint replaced

• Extracapsular (trohanteric line or below)
◦ Sliding hip screw - screw with barrel over the top - as the fracture heals it collapses a bit - this allows for controlled collapse
◦ More complex fracture - intramedullary device

Question 14

Name some types of hip dislocation

Answer 14

Posterior
Anterior
Central

Question 15

What is a posterior dislocation

Answer 15

90% of cases Physical examination:
• Shortened (gluteus maximus, hamstrings, adductors)
• Internally rotated (anterior fibres of gluteus medius and minimus)
• Adducted
• Flexed Sciatic nerve palsy in 8-20% of cases

Question 16

What is anterior dislocation?

Answer 16

ANTERIOR DISLOCATION
• Externally rotated
• Abducted
• Slightly flexed
Rarely causes damage to femoral nerve

Question 17

What is central dislocation?

Answer 17

• Always a fracture dislocation
• Femoral head palpable per rectum
• Intrapelvic haemorrhage