Disorders Of The Hip

Question 1

Describe the pathology of OA in the hip

Answer 1

Degenerative disorder
Break down of articulations hyaline cartilage
Clinical syndrome comprising of joint pain
Functional limitation and reduced QoL

Question 2

What is ankylosis

Answer 2

Bony fusion across a joint

Very rarely seen in OA

Question 3

What is the different between primary and secondary OA

Answer 3

Primary = cause unknown

Secondary = there is a known precipitating cause

Question 4

What are the risk factors for OA

Answer 4

Age
Female
Ethnicity - African America,, American Indian, Hispanic
Genetics
Nutrition

Question 5

Give some examples of some secondary causes of OA

Answer 5

Obesity
Trauma
Malalignment eg developmental dysplasia
Infection - septic arthritis, tb
Inflammatory arthritis - RA, ankylosing spondylitis
Metabolic disorders of the hip - gout
Haematological disorders - haemophilia
Endocrine abnormalities

Question 6

What are the symptoms of OA in any joint

Answer 6

Deep aching pain exacerbated by use
Reduced range of motion
Crepitus
Stiff during rest

Question 7

Describe the pathology fo OA

Answer 7

Hyaline cartilage becomes swollen due to increased proteoglycan synthesis by chondrocytes

This is an attempt to repair damage

Over may years, the proteoglycan content decreases
Cartilage softens and loses elasticity
Flaking and fibrillation develop along the articulations surface
Cartilage becomes eroded down to subchondral bone
Loss of joint space
Subchondral bone responds with vascular invasion and increased cellularity, becoming thickened and denser at areas if pressure
This is known as eburnation
Shows at subchondral sclerosis on X-rays

Traumatised subchondral bone - cystic degeneration

Question 8

What are the 4 cardinal signs of OA on an X-ray

Answer 8

Reduced Joint space
Subchondral sclerosis
Bone Cysts
Osteophytes

Question 9

In OA, the patient feels pain in the hip, gluteal and groin regions radiating to the knee. What nerve is involved

Answer 9

Obturator nerve

Question 10

Treatment for OA

Answer 10

Weight loss - force equivalent to 6x bod weight passes through hips and knees
Walking aid
Orthotic shoes
Muscle strengthening
Analgesia
Anti-inflammatories
Total hip replacement

Question 11

Define a fractured neck of femur

Answer 11

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

Question 12

What are the two classifications of a neck of femur fracture

Answer 12

Intra capsular

Extracapsular - can be intertrochanteric and subtrochanteric

Question 13

An intracapsular fracture is likely to disrupt what blood vessels?
And why can this lead to avascular necrosis

Answer 13

Ascending cervical branches of the medial femoral circumflex artery

The artery of ligamentum teres cannot sustain the metabolic demand of the femoral head. This risk is increased if the fracture is displaced

Question 14

Intracapslar fractures are most common in?

Answer 14

Post menopausal women with osteoporotic bone, after a minor fall

Question 15

Extra capsular fractures tend to affect?

Answer 15

Young and middle aged people after significant trauma eg RTA

Question 16

Upon examining a displaced neck of femur fracture, the leg is in what position?

Answer 16

Shortened
Abducted
Externally rotated

Question 17

What muscles cause the external rotation presentation of a displaced neck of femur fracture

Answer 17

The small lateral rotators:
Piriformis
Obturator internus
Superior and inferior gemelli
Quadratus 

Contracts

The abductors that attach to the greater trochanter. - gluteus minimum and maximus abduct the femur distal ti the fracture site

Question 18

In a neck of femur fracture, what causes shortening of the limb?

Answer 18

The strong muscles of the thigh pull the distal fragment of the femur upwards
Rectus femoris, adductor Magnus and the hamstrings

Question 19

What is dislocation of the hip

Answer 19

The head of the femur fully displaced out if the cup shaped acetabulum of the pelvis

Question 20

What percent of hip dislocations are posterior

Answer 20

90%

Question 21

What is the most common cause of a posterior hip dislocation

Answer 21

The knee impacting on the dashboard during a road traffic collision

Question 22

In a posterior dislocation, what position will the limb be in?

Answer 22

Shortened, in a position of flexion, adduction and internal rotation

Question 23

What is the position of the limb in an anterior hip dislocation

Answer 23

External rotation
Abduction
Slight flexion

Question 24

What happens in a central dislocation of the hip

Answer 24

Head of femur driven into pelvis through the acetabulum
It is always a fracture dislocation
Femoral head is palpable on rectal exam
High risk of intrapelvic haemorrhage

Question 25

Decribe the Trendelenburg sign

Answer 25

When a person with a superior gluteal nerve palsy is asked to stand on their injured lower limb, the pelvis on the unsupported side descend as gluteus medius and minimus of the supporting lower limb would normally contract