Orthopaedics Flashcards
Describe the pathophysiology of osteoarthritis
Synovial joints
Combination of genetics and overuse and injury
Imbalance between cartilage wearing down and chondrocytes repairing it, leading to strucural issues
List some risk factors of osteoarthritis
Age Obesity Occupation Trauma Female FH
List the joints commonly affected by osteoarthritis
Hips Knees Sacroiliac joints DIPs CMC of the thumb Wrist Cervical spine - spondylosis
List the 4 key X-ray changes of osteoarthritis
Loss of joint space
Osteophyte formation
Subchondral cysts
Subchondral sclerosis
How does osteoarthritis present
Joint pain
Stiffness - worsens with activity
Deformity - bulky, bony enlargement of the joint
Crepitus on movement
Effusions around the joint
Instability
Reduced function/range of movement of the joint
Describe the signs of osteoarthritis in the hands
Heberden's nodes - DIP Bouchards nodes - PIP Squaring at the base of thumb - CMC Weak grip Reduced ROM
When can OA be diagnosed
Patient >45
Typical symptoms with activity
No morning stiffness
How is osteoarthritis managed
Patient education
Lifestyle change - weight loss, physiotherapy, OT, orthotics
Analgesia - oral paracetamol and topical NSAIDs, oral NSAIDs (PPI), opiates (codeine), topical capsaicin, intra-articular injection, joint replacement
What is a hemiarthroplasty
Replacing one half of the joint
What is a total joint replacement
Replacing both articular surfaces of the joint
Which organism is most common in prosthetic joint infections
Staphylococcus aureus
List some risk factors for prosthetic joint infection
Prolonged op time
Obesity
Diabetes
What are some symptoms of prosthetic joint infection
Fever Pain Swelling Erythema Warm
How is a prosthetic joint infection diagnosed
Clinical finding
X-ray
Blood tests - Inflammatory markers and cultures
How is prosthetic joint infection managed
Antibiotics and surgery - Joint irrigation, debridement complete replacement
What is a compound fracture
Skin is broken and broken bone is exposed to air
What is a stable fracture
Sections of bone remain in alignment at the fracture
What is a pathological fracture
Bone breaks due to an abnormality within the bone
What is a salter-harris fracture
Growth plate fracture - occurs only in children
What is a Comminuted fracture
Breaking into multiple fragments
What is a compression fracture
Affects the vertebrae in the spine
Describe a Colle’s fracture
Transverse fracture of the distal radius
Causes the distal portion to displace posteriorly (upwards)
Causes a dinner fork deformity
Commonly a result of a fall onto outstretched hand
Describe a scaphoid fracture
Fall onto outstretched hand
Scaphoid is a carpal bone at the base of the thumb
Key sign - tenderness in the anatomical snuffbox (groove between tendons when you extend thumb)
Why is it important to spot scaphoid fractures
Scaphoid bone has retrograde blood supply with blood vessels supplying the bone from only one direction
Avascular necrosis and non-union if blood supply cut off
List some bones which if fractured may result in avascular necrosis, impaired healing and non union due to vulnerable blood supplies
Scaphoid Femoral head Humeral head Talus Navicular and 5th metatarsal in foot
What is the name of the fibrous join between the tibia and fibula
Tibiofibular syndesmosis
What is the function of the tibiofibular syndesmosis
Stability and function of the ankle joint
What is the Weber classification
Used to describe fractures of the lateral malleolus - fracture is described in relation to the distal syndesmosis
Type A - below the ankle joint - syndesmosis in tact
Type B - at the level of the ankle joint - syndesmosis intact or partially torn
Type C - above the ankle joint - syndesmosis disrupted
Why is the weber classification of lateral malleolus fractures important
Decide management - surgery more likely if syndesmosis disrupted
What must you look for with pelvic ring fracture
Another fracture in the pelvic ring
Bleeding - shock
List some causes of pathological fractures
Pagets disease of bone
Osteoporosis
Cancer mets
List the cancers which commonly metastasise to bone
Prostate Renal Thyroid Breast Lung
What are fragility fractures
Fractures occuring due to weakness of the bone - usually due to osteoporosis
What tool is used to calculate a patients risk of fragility fracture over the next 10yrs
FRAX tool
What scan is done to measure bone mineral density
DEXA scan
Give the WHO criteria for osteoporosis and osteopenia
T score at hip
>-1 - normal
-1 to -2.5 osteopenia
What is the first line treatment for reducing the risk of fragility fractures
Calcium
Vit D
Bisphosphonates /denosumab
How do bisphosphonates work?
Interfere with osteoclasts, reducing their activity and preventing the reabsorption of bone
List some important side effects and patient info for bisphosphonates
Reflux and oesophageal erosison - taken on empty stomach, stand up for 30 mins after
Osteonecrosis of jaw an external auditory canal
Atypical fractures - femoral
Describe the action of denosumab
Monoclonal antibody that works by blocking the activity of osteoclasts
What is the investigation of choice for fractures
X-ray - 2 views - AP and lateral
CT if X-ray inconclusive and more info required
What are the principles of fracture management
Mechanical alignment
Relative stability
How is mechanical alignment achieved
Closed reduction via manipulation of the limb
Open reduction via surgery
How is relative stability of a fracture achieved
External casts K wires IM nails IM wires Screws Plates and screws
Describe the management of fractures
Pain management
Closed reduction and plaster cast with FU in fracture clinic
Refer to on call trauma and ortho team, admit, NBM, trauma meeting
List some early complications of a fracture
Damage to local structures Haemorrhage - shock and death Compartment syndrome Fat embolism DVT
List some longer term complications fo fractures
Delayed union - slow Malunion - misaligned Non-union - failure to heal Avascular necrosis Infection - osteomyelitis Joint instability Joint stiffness Contractures Arthritis Chronic pain Complex regional pain syndrome
What is a fat embolism
Fat globule from long bone fracture travels through systemic circulation and causes blood flow obstruction
Causes systemic inflammatory response
Presents 24-72hrs after fracture
Which criteria is used for Fat embolism syndrome
Gurd's criteria Major criteria - Resp distress - Petechial rash - Cerebral involvement Minor criteria - Jaundice - Thrombocytopenia - Fever - Tachycardia
How is fat embolism syndrome treated
Supportive
Operate early to prevent this occurring
Give some risk factors for hip fractures
Osteoporosis
Female
Age
What are the two classes of hip fracture
Intracapsular
Extracapsular
What is the capsule of the hip joint
Strong fibrous structure
Attaches to the rim of the acetabulum on the pelvis and the intertrochanteric line on the femur
Surrounds the head and neck of the femur
Describe the blood supply of the femoral head
Retrograde supply
Medial and lateral circumflex femoral arteries join the femoral neck just proximal to the intertrochanteric line and branches run up toward the femoral head
What is the intertrochanteric line
Line between greater and lesser trochanter of femur
Which classification is used for intra-capsular neck of femur fractures
Garden classification Grade 1-4 1 - partial # and no displacement 2 - complete # and no displacement 3 - partial displacement 4 - full displacement
How are non-displaced intracapsular femur fractures managed
Blood supply still intact - Internal fixation (screws)
How are displaced intracapsular femur fractures managed
Risk of avascular necrosis
Head of femur needs to be replaced
Hemiarthroplasty - co-morbidity or limited mobility
Total hip replacement for those mobile and fit for surgery
What are the two types of extra-capsular hip fractures
Intertrochanteric - occurs between greater and lesser trochanters
Sub trochanteric - distal to lesser trochanter
How are extra-capsular fractures treated
Intertrochanteric - Dynamic hip screw
Sub trochanteric - IM nail (through greater trochanter)
Describe the presentation of a hip fracture
Pain in groin or hip
Not being able to weight bear
Shortened, abducted and externally rotated leg
Cause of fall - anaemia, electrolytes, arrhythmia, HF, MI, Stroke, infection
What is shentons line and how is it used
Shentons line seen on AP hip X-ray
One continuous line formed by medial border of femoral neck to inferior border of superior pubic ramus
Disruption to shentons lone indicates fractured neck of femur
When should hip fracture surgery be carried out
<48hrs of # occurring
When should patients weight bear after surgery
Right away
How does trochanteric bursitis present
Lateral hip/thigh pain with tenderness over the greater trochanter
Describe compartment syndrome
Abnormally elevated pressure in a fascial compartment cuts off blood flow to the contents of that compartment
What is fascia
Strong fibrous connective tissue
Not able to stretch or expand
What do fascial compartments contain
Muscle
Nerve
Blood vessels
What causes acute compartment syndrome
Injury - oedema and bleeding
Bone fracture
Crush injuries
How does compartment syndrome present
5Ps Pain disproportionate to underlying injury - worsened by passive stretching of muscle Paraesthesia Pale Pressure - high Paralysis is a late sign
How is compartment syndrome managed
Needle manometry - measure the compartment pressure
Escalate to ortho reg or consultant
Remove bandages and dressings
Elevate leg to heart level
Maintain good BP
Definitive treatment - emergency fasciotomy - operation to cut through fascia down entire length of compartment to release pressure then debride necrotic tissue - wound left open and covered with dressing. May require skin graft later
Describe chronic compartment syndrome
Increased pressure with exertion
Pain, numbness and paraesthesia stops with rest
Needle manometry for diagnosis
Fasciotomy for treatment
What is osteomyelitis and how is it caused
Inflammation of bone/bone marrow
Usually caused by bacterial infection
Acute/chronic
Haematogenous osteomyelitis - pathogen carried through blood and seeded in bone or direct contamination
Which bacteria commonly causes osteomyelitis
Staphylococcus aureus
List some risk factors for osteomyelitis
Open # Ortho op DM PAD IVDU Immunosuppression
How does osteomyelitis present
Fever Pain and tenderness Erythema Swelling Non-specific - fatigue, nausea, fever, muscle ache
How is osteomyelitis investigated
X-ray - not too helpful but some changes are periosteal reaction, localised osteopenia and destruction
MRI is best imaging modality
Bloods - WCC, Inflammatory marker, blood cultures
How is osteomyelitis managed
Surgical debridement
Antibiotics therapy - prolonged course, 6 weeks flucloxacillin with rifampicin or fusidic acid in first 2 weeks or clindamycin in pen allergic or vancomycin/teicoplanin in MRSA
Chronic osteomyelitis - 3 months antibioitcs
If due to prosthesis - complete revision surgery
What is a charcot joint
One which has become disrupted and damaged secondary to a loss of sensation - seen in diabetes
What are sarcomas
Cancers of muscle, bone and other connective tissue
How do sarcomas present
Soft tissue lump - growing, painful or large
Bone swelling
Persistent bone pain
How should you investigate sarcomas
Xray - bone lump/persistent pain
Ultrasound - soft tissue lump
CT/MRI - lesion in more detail and look for metastatic spread
Biopsy for histology
Where does sarcoma commonly spread to
Lungs
What causes Kaposi’s sarcoma (red/purple skin lesions)
HSV8
HIV