Lecture 6 - Disorders of the hip

Question 1

Osteoarthritis

Answer 1

Degenerative disorder due to the breakdown of articular hyaline cartilage.

Clinical syndrome:

• Joint pain
• Functional limitation
• Reduced quality of life

Non-inflammatory without systemic involvement

Question 2

Primary osteoarthritis

Answer 2

Unknown cause

Question 3

Secondary osteoarthritis

Answer 3

Has a known precipitating cause

Question 4

Risk factors of osteoarthritis

Answer 4

Age
Female 
Nutrition - diet rich in vitamin C and E can reduce the risk 
Ethnicity 
Genetics

Question 5

Causes of secondary osteoarthritis

Answer 5

Obesity - BMI 30+
Trauma - sports or occupation risk factors
Malalignment - developmental dysplasia of the hip
Infection - septic arthritis, tuberculosis
Inflammatory arthritis - rheumatoid, ankylosing spondylitis
Metabolic disorders affecting the joint - gout
Haematological disorder - haemophilia with haemarthrosis (bleeding in joints)
Endocrine abnormalities- Diabetes with neurovascular impairment - chronic malalignment (Charcot joint)

Question 6

Symptoms of osteoarthritis

Answer 6

Deep aching joint pain exacerbated by use
Reduced range of movement
Crepitus - grinding
Stiffness during rest - morning stiffness

Question 7

Pathology of osteoarthritis

Answer 7

1. Excessive or uneven loading of the joint
2. Damage to articular hyaline cartilage
3. Hyaline cartilage becomes swollen due to increased proteoglycan production by chondrocytes.
4. Increased chondrocytes are produced from the differentiation of chondroprogenitor cells

Can last several years - attempt to repair itself

5. Proteoglycan content decreases
6. Cartilage softens and loses its elasticity
7. Flaking and fibrillation (vertical clefts) along the normally smooth cartilage
8. Over time the cartilage becomes eroded to the subcondral bone
9. Loss of joint space
10. Surface changes alter the distribution of forces

Question 8

Affect of osteoarthritis on subchondral bone

Answer 8

Vascular invasion

Eburnation: increased cellularity - thicker and denser at areas of pressure

Cystic degeneration forming subchondral bone cysts due to osseus necrosis secondary to chronic impaction (pressure) or intrusion of synovial fluid

Osseus metaplasia of CT occurs therefore outgrowths of new bone - osteophytes

Question 9

Presentation of osteoarthritis on an Xray

Answer 9

Loss of joint space
Osteophytes
Subchondral sclerosis
Subchondral bone cysts

Question 10

Eburnation

Answer 10

Increased cellularity of subchondral bone therefore it is thicker and denser at areas of pressure

Question 11

Symptoms of osteoarthritis in the hip

Answer 11

Joint stiffness - especially after rest
Pain in the hip - gluteal and groin region radiating to the
knee (obturator nerve)
Mechanical pain - when weight bearing or moving
Crepitus
Reduced mobility - difficulty walking, putting on socks, tying shoelaces, getting in and out pf the car/ bath

Question 12

Treatment of osteoarthritis

Answer 12

1. Weight reduction
2. Activity modification
3. Walking stick/frame - reduce load through joint
4. Muscle strengthening exercises ( deep gluteal muscles)
5. Orthotic footwear - realign joint
6. Analgesia and NSAIDS (anti-inflammatory)
7. Steroid injections - into the joint to reduce swelling
8. Hyaluronic acid injection - increase lubrication and promote cartilage repair (limited evidence)
   Cure = total hip replacement

Question 13

Location of a fractured neck of femur

Answer 13

Fracture of the proximal femur up to 5 cm below the lesser trochanter

Question 14

2 types of classification of NOF

Answer 14

Intracapsular

Extracapsular - intertrochanteric and subtrochanteric

Question 15

Intracapsular fractures

Answer 15

Likely to disrupt the ascending cervical (retinacular) branch of the MFCA

The ligamentum teres is unable to sustain the blood supply to the femoral head therefore there is a high risk of avascular necrosis

Increased risk in dispaced NOF and adults

Question 16

Who commonly gets intracapsular fractures

Answer 16

Elderly

Post- menopausal women - osteoporosis

Question 17

Who commonly gets extracapsular fractures

Answer 17

Young and middle-aged population

Requires significant force e.g. RTA

Question 18

How to treat intracapsular fractures

Answer 18

Surgical replacement of the femoral head:

• hemiarthroplasty
• total hip replacement (head and acetabular cup)

Question 19

Symptoms of NOF

Answer 19

Reduced mobility
Sudden inability to bear weight on the limb
Pain in hip, groin and knee

Question 20

Presentation of a displaced fracture

Answer 20

Leg is:
Shortened
Abducted
Externally rotated

Exacerbation of pain when the greater trochanter is palpated and when the hip is rotated

Question 21

Traumatic dislocation of the knee

Answer 21

Head of the femur fully dispaced out of the acetabulum

Can be congenital - developmental dyslpasia
Traumatic

Question 22

Who commonly gets traumatic hip dislocations

Answer 22

16- 40 yrs old
Requires significant force - RTA

• Extremely painful
• Resists any attempt to move the limb
• 90% posterior

Question 23

Presentation of a posterior dislocated hip

Answer 23

Affected limb will be:

• Shortened
• Flexed
• Adducted
• Internal rotated
• Sciatic nerve palsy - 8- 20% of cases

Question 24

Presentation of an anterior dislocated hip

Answer 24

The affected limb will be:

• Shortened
• slightly flexed
• Abducted
• Laterally rotated
• Femoral nerve palsy (uncommon)

Question 25

Presentation of central dislocated hip

Answer 25

Femoral head driven into the acetabulum
Always a fracture-dislocation
Life-threatening

Femoral head palpable on rectal examination
High risk of intrapelvic haemorrhage (disruption of pelvic venous plexuses)

Question 26

Risk factors for congenital hip dislocation

Answer 26

Female 
Breech presentation 
FHx
First born 
Oligohydramnios