2 - Clinical Conditions of the Hip Flashcards
What is the blood supply to the femoral head
artery of ligamentum teres
- Femoral head → acetabulum
- Located at fovea of femoral head
- Most important source in children
- Contribution to blood supply decreases with age, and is pretty insignificant in elderly patients
ascending cervical branches
- Arise from ring at base of neck, which goes to femoral head
- Formed by branches of the medial + lateral circumflex arteries
- Perforate bone just distal to articular cartilage
- Highly susceptible to injury with hip dislocation
Osteoarthritis risk factors
- Age (more common in elderly patients)
- Sex (more common in females)
- Ethnicity (more common and severe in Caucasians + African-americans)
- Nutrition
- Genetics (OA runs in families)
Primary and secondary osteoarthritis
primary
Cause is unknown
secondary
- Obesity
- Trauma (eg sports and occupation )
- Malalignment (eg developmental dysplasia)
- Infection (eg septic arthritis + tuberculosis)
- Inflammatory arthritis (eg rheumatoid arthritis)
- Metabolic disorders affecting joints (eg gout)
- Haematological disorders (eg haemophilia with bleeding into joints)
- Endocrine abnormalities (eg DM)
Pathology of osteoarthritis
- Precipitating risk factors → excessive loading of joint + damage to articular cartilage
- Increased proteoglycan synthesis (initial attempt to repair cartilage damage)
- Flaking + fibrillation of articular cartilage (meant to be smooth)
- Causes erosion of cartilage all the way down to subchondral bone (appears as lack of joint space on x-ray)
- Altered joint biomechanics lead to…
☞ vascular invasion + increased cellularity of subchondral bone (subchondral sclerosis)
☞ cystic degeneration of bone (subchondral bone cysts)
☞ osseus metaplasia of connective tissue (osteophytes)
Radiological features of osteoarthritis
- Lack of joint space (bone on bone)
- Sclerosis or hardening of the bone (looks more white)
- Cysts (ie in femur head)
Symptoms of osteoarthritis of the hip
- joint stiffness after getting out of bed / sitting still for long time
- pain + tenderness in hip joint
- swelling but this is not obvious in the hip
- crepitus is a sound or feeling of the bone rubbing against the bone
- reduced mobility which can be disabling or debilitating
- Trendelenburg sign (next card)
What is the Trendelenburg sign + gait
- Ask individual to stand on one leg
- If arthritis, affected hip will go up
- Shows lack of pelvic stability
Overview of management of hip osteoarthritis
- non pharmalogical management eg education, exercise, weight loss, appropriate footwear
- non pharmacological management eg physio, braces, simple analgesia
- pharmacological management eg NSAIDs, opioids (can be injected) or steorids injections for anti-inflammatory
-
surgery eg osteotomy, total joint replacement
☞ this all depends on the severity of the symptoms
Non-operative management of hip osteoarthritis
primary (by GP)
- Activity management (if it hurts, don’t do it → more detrimental for younger patients)
- Weight loss
- Stick/walker (improves biomechanics)
- Physiotherapy (strengthen muscles + improve recovery if operated on)
medications
- NSAIDs
- COX-2 inhibitors (eg celecoxib)
- Nutritional supplementation (glucosamine – works with 1/3 patients)
injections
Most commonly corticosteroids to reduce inflammation. Viscosupplementation may be beneficial but disputed.
Surgical management of hip osteoarthritis
total hip replacement
- Implants replace damaged surfaces
- Helps relieve pain + restore mobility
- Improved patient wellbeing
Symptoms + signs of hip fractures (proximal femur)
- Both intracapsular + extracapsular fractures present with a shortened, abducted + externally rotated leg at the hip
- Reduced mobility + sudden inability to bear weight on affected leg
- Pain in hip (sometimes also groin + knee)
Reasoning for external rotation of leg in hip fractures
- Hip fractures result in a shortened, abducted + externally rotated leg
- This is due to distal fragment being pulled upwards + rotated laterally
- Unopposed muscle pull, while femoral head remains in joint
Extracapsular vs intracapsular fractures
intracapsular
- Ie at neck or head of the femur
- More common in women + elderly (demographics with osteoporosis)
- Medial femoral circumflex artery is at risk of injury
- This can cause avascular necrosis (more details on sep card)
- Displaced fractures bring higher risk of this
- Treatment often involves full or partial hip replacement
extracapsular
- More common in young or middle aged people
- Avascular necrosis is much rarer (this is because the fracture is distal to the medial femoral artery, so blood supply remains intact)
Avascular necrosis – causes on separate card
- Death of bone tissue due to a lack of blood supply
- Can lead to tiny breaks in the bone
- This can eventually cause the bone to collapse
- Most common cause is a broken hip (proximal femur fracture in intracapsular region, due to disruption of blood supply)
- There are other causes (sep card)
Causes of avascular necrosis
- Most common cause is a broken hip (proximal femur fracture in intracapsular region, due to disruption of blood supply)
- Alcoholism
- Excessive steroid use
- Post trauma (injury)
- Thrombosis (blood clot)
- Hypertension (high blood pressure)
Hip dislocations overview
- Can be posterior (backwards), central (through socket) and anterior (forward)
- Hip dislocation occurs when the femoral head is no longer in contact with the acetabulum of the pelvis
- The pelvis is normally very stable, so a dislocation is due to a large force eg car accident
- Overall present with a flexed, adducted and internally rotated leg at the hip
Signs of hip dislocation (posterior, anterior + central)
posterior
- Shortened
- Internally rotated
- Adducted
- Flexed
- Sciatic nerve palsy in 10-20% due to pushing on the sciatic nerve
anterior
- Externally rotated
- Abducted
- Slightly flexed
- Rarely causes damage to femoral nerve (bit more room)
central
- Driven through socket
- Always a fracture dislocation
- Femoral head palpable per rectum
- Intrapelvic haemorrhage can be major problem
Complications of hip dislocation
- Avascular necrosis
- Post traumatic osteoarthritis
- Recurrent dislocation
- Sciatic nerve injury (if nerve stretched, compressed or transected)
- Infection
- Recovery is unpredictable
Which type of dislocation is the most common + why
Posterior as there is only one ligament posteriorly, whereas two anteriorly. Therefore, there is less stability posteriorly.
How to differentiate between neck of femur fracture and hip dislocation by presentation
hip dislocation = shortened + internally rotated (in posterior cases, which is 90%)
neck of femur fracture = shortened + externally rotated
