Hip (Session 3) Flashcards
Which muscles in the hip does the superior gluteal nerve supply?
Hip ABDUCTORS: Gluteus medius and minimus
How can the superior gluteal nerve get injured?
Complication of hip surgery
Buttock injections
Greater trochanter fracture
Hip dislocation
What is the ‘Trendelenburg sign’?
Clinical sign- superior gluteal nerve damage. If patient standing on one leg and hip drops on the raised leg- as gluteus medias and minimum of other limb not contracting so pelvis not supported on that side
Where do the hamstring muscles originate?
ischial tuberosity
What population is most commonly affected by osteoarthritis?
Elderly (20-30% of people over 70 suffer from OA of hip)
Define osteoarthritis.
1) Degenerative disorder arising from breakdown of articular hyaline cartilage
2) Clinical syndrome comprising joint pain and functional limitation+ reduced quality of life
3) chronic disease of MSK system= non inflammatory
What are the most common joints affected by osteoarthritis?
Hips, knee, cervical spine, lumbar spine, small joints in hands
What is ankylosis?
Bony fusion across a joint
What’s the difference between primary and secondary OA?
Primary: cause is unknown, Secondary: known cause
What are some risk factors for primary osteoarthritis?
Age, female sex, ethnicity, genetics, nutrition
What are some specific causes of secondary osteoarthritis?
Obesity, trauma, malalignment, infection, inflammatory arthritis (e.g. rheumatoid), metabolic disorders, haematological disorders, endocrine abnormalities
What are some symptoms of osteoarthritis?
Deep+ aching joint pain
Reduced range of motion
Crepitus (grinding)
Stiffness during rest
How does excessive/uneven loading of the joint increase someones risk of osteoarthritis?
Damages hyaline cartilage- hyaline cartilage= swollen (increase proteoglycan synthesis by chondrocytes)- attempt to repair cartilage- eventually cartilage softens and loses elasticity- eroded down to bone, loss of joint space
What is eburnation?
Subchondral bone–>thicker denser bone
Process in which subchondral bone responds to cartilage surface changes
What are the 4 cardinal signs of OA on an X-ray?
LOSS:
Loss of joint space
Osteophytes
Subchondral sclerosis
Subchondral cysts
In what population is osteoarthirits of the hip most common?
Males over 40
What symptoms will be experienced by those sufferring from osteoarthritis of the hip? (5)
- Joint stiffness
- Pain in:
- Hip
- Gluteal region
- Groin region–> radiating to knee (via obturator nerve)
- Mechanical pain
- Crepitus
- Reduced mobility
How is osteoarthirits of the hip diagnosed?
Clinical presentation
Supported by x-ray changes
How is osteoarthritis of the hip treated? (conservative) (9)
- Weight reduction (if overweight)
- Activity modification
- Walking stick/frame -reduce load
- Muscle strengthening exercises/orthotic footwear
- Analgesia
- Anti-inflammatories (NSAIDs)
- Nutritional supplements
- Steroid injections-reduce swelling
- Hyaluronic acid injections- increase lubrication
What is the only ‘cure’ for hip osteoarthritis?
Total hip replacement
Roughly how many hip replacements are performed in the UK each year and what is the average age?
about 100,000
Average age: 68yrs
What is a fractured neck of femur (NOF#) defined as? (as in where fracture is classified as NOF#)
- Fracture of proximal femur
- Up to 5cm below lesser trochanter
What are the 2 types of neck of femur fractures?
Intracapsular
Extracapsular
What can the extracapsular fractures be divided into?
- Intertrochanteric
- Subtrochanteric
Why is there a high risk of avascular necrosis with an intracapsular #NOF, particularly if the fracture is displaced?
- Fracture=likely to disrupt: Medial femoral circumflex artery (MFCA)
- Artery of ligamentum teres- unable to sustain metabolic demands of femoral head
Which populations do intracapsular and extracapsular fractures commonly affect?
Intracapsular:
- More common in elderly
- (esp post-menopausal women w./ osteoporotic bone)
Extracapsular:
- Young and middle aged
What are the common mechanisms of injury for intracapsular and extracapsular fractures?
Intracapsular: Minor fall
Extracaspsular: Significant trauma eg road traffic collision
Why is a displaced intracapsular fracture in an older person usually treated by surgical replacement of:
- Hemiarthroplasty (Femoral head only)
- Total hip replacement (Femoral head and acetabular cup)
High risk of avascular necrosis
What is the prognosis like following a #NOF?
- 20% one year mortality (many of patients=elderly and have co-morbidities)
- 30% one-year post #NOF permanent disability
- 40% unable to walk independently
- 80% unable to carry out at least one independent activity of daily life
What are the symptoms of a neck of femur fracture?
- Reduced mobility
- Pain (may be felt in hip, groin, knee)
How will a patient with a neck of femur fracture present if the fracture is displaced? (position of leg)
Affected leg:
- Shortened
- Abducted
- Externally rotated
Exacerbation of pain on:
- Palpation of greater trochanter
- Rotation of hip
Why is the hip shortened, abducted and externally rotated in a displaced #NOF?
- Shaft of femur can now move independently to hip joint
- Short lateral rotators of hip: piriformis, obturator internus etc contract and laterally rotates femoral shaft
- Iliopsoas pulls on lesser trochanter- laterally rotates femoral shaft
- Strong abductors attach to greater trochanter abduct femur distal to fracture site
- Rectus femoris, adductor magnus, hamstring muscles- pull distal fragment of femur upwards- shorten limb
Define ‘dislocation of the hip’.
Head of femur- fully displaced out of cup-shaped acetabulum of pelvis
What are the 2 main causes of hip dislocations?
- Congenital
- Traumatic
What is DDH? (MSK)
Developmental dysplasia of the hip
(can be congenital/develop after birth)
In what population is an acute traumatic hip dislocation most commonly seen?
16-40 year olds
(in high speed road traffic collision)
What % of hip dislocations are posterior?
90%
What is the most common cause of a posterior hip dislocation?
Knee impacting dashboard during road traffic collision
How will the patients affected limb be held is they have experienced a posterior hip dislocation?
- Flexed
- Adducted
- Internal (medial) rotation
(Due to:
Femoral head lying on surface of ilium
Head of femur pulled up by strong extensors and adductors of hip
Anterior fibres of glut medius and minimus pull on greater trochanter- cause femur to rotate internally
In what % of cases of posterior hip dislocations is sciatic nerve palsy present?
8-20% of cases
What position is the limb held in in an anterior dislocation?
External rotation
Abduction
Slight flexion
Why is a central dislocation of the hip a life threatening injury?
- Head of femur driven into pelvis through acetabulum
- Always= fracture dislocation
- Femoral head=palpable on rectal examination
- High risk- intrapelvic haemorrhage
- disruption of pelvic venous plexuses
