Osteoarthritis Flashcards
What is the most common type of arthritis?
Osteoarthritis
What causes Osteoarthritis?
Results from disparity b/w stress applied to articular cartilage & ability of cartilage to withstand that stress
What joints are commonly affected by OA?
Hip Knee DIP PIP Thumb CMJ Hallux MTP
Which joint is classically spared in OA?
MCPJs
How does OA present?
Progressive pain -initially activity related, finally constant rest pain Stiffness -worse after periods of rest, lasts <30mins Waxing/waning course Later features -muscle wasting -loss of mobility -deformity/joint instability
What are the signs on examination of OA?
LOOK - bony swelling, muscle wasting
FEEL - joint line tenderness, possible effusion, crepitus
MOVE - limited range of movement
What are the risk factors for OA?
Age Obesity Family hx Gender (polyarticular Oa more common in women, esp post menopause) Hypermobility Prev trauma Occupation (miners, farmers etc.)
What are the protective factors for OA?
Osteoporosis
What are the causes of 2o OA?
Pre-existing joint damage -inflam/septic/crystal arthritis -AVN -trauma Metabolic disease -acromegaly -chondrocalcinosis -haemochromatosis Systemic disease -haemophilia -haemaglobinopathies -neuropathies
What are the two main types of OA?
Localised (hip/knee OA)
Generalised (affects many joints)
What is the aetiology of Hip OA?
More common in males
Unilateral at presentation
What are the signs on examination of Hip OA?
Painful & decreased internal/external rotation of hip
Trendelenburg +ve
What is the Trendelenburg test?
Indicates weakness in hip abductors
- pelvis drops on contralateral side during single leg stand on the affected side
- sound side sags
What is the prognosis of Hip OA?
Does poorly
Requires arthroplasty
What are the risk factors for Knee OA?
Obesity
Prev trauma
Knee soft tissue injuries
What are the signs on examination of Knee OA?
Often bilateral Moderate effusion Decreased range of movement Crepitus Quadriceps wasting Genu varus deformities due to medial disease
What are the common subtypes of generalised OA?
Nodal Generalised OA
Erosive OA
Crysal Associated OA
How does Nodal Generalised OA present?
Joints of hand affected over many years
-classically presents in postmenopausal women
First presents w/ painful swelling & impairment of funcn
What are the risk factors for Nodal Generalised OA?
Gender (f)
Post-menopause
Familial tendency (AI)
Which joints does Nodal Generalised OA commonly affect?
DIPS > PIPS
What is the natural hx of Nodal Generalised OA?
Joints in hands affected over many years
-painful swelling & impairment of function
Inflammatory phase settles after months/yrs
-leaves bony swellings posterolaterally
-Heberdens (DIPS) & Bouchards (PIPS) nodes
-function still generally good
What joints are affected to cause the classical ‘squared hand’ of OA?
CMC & MCP joints of thumb
Bony swelling
Fixed adduction
What is Erosive OA?
Rare type of OA
Characteristic cysts seen on XR
Poor prognosis
What is Crystal Associated OA?
Calcium pyrophosphate deposition in cartilage leading to chondrocalcinosis (pseudogout)
- can be asymptomatic/lead to sx of OA
- knees/wrists most commonly affected
What is the best predictor of pain in OA?
Poor quadriceps strength & depressed mood
-better than radiological severity
How does Early OA present?
Rarely symptomatic
-unless accompanied by effusion
What is the underlying pathophysiology of OA?
Wear/tear splits/erodes articular cartilage
-narrows joint space
Associated inflammation
-thickening of joint capsule/synovium
-capsular fibrosis
Progressive loss of cartilage leads to eburnation
Cysts develop beneath abnormal bone surface
Osteophytes form on peripheral, unstressed, cartilage
2o atrophy of associated muscles
What is Eburnation?
Constant friction of two naked bone surfaces rubbing together
What are the four cardinal changes of OA on X-ray?
Joint space narrowing
Sclerosis
Osteophyte formation
Cystic formation
What investigations may be appropriate in suspected OA?
Bloods - CRP/ESR, RF, ANA (rules out other dx)
XR - 2 views to confirm dx
CT/MRI - if XR doesn’t match clinical picture
What is the conservative management of Early OA?
Pt education Wt loss Physiotherapy Reduction of mechanical factors (cushioned footwear, walking aids) Splints for ankles/wrists Offset bracing of knee
What is the medical management of OA?
Pain-relief
- paracetamol & topical NSAIDs
- oral NSAIDs (+PPI) & topical capsaicin
What are the surgical management options for OA?
Total replacement arthroplasty -common in knee/hip -delayed for longer in knee (poor outcomes) One compartment arthroplasty -can occur in knee if just one side of articular surface is diseased Arthroscopy & joint washout -for young pts -delays definitive management for mo/yrs Arthrodesis -ankle/spine/hand Realignment osteotomies -hip/knee
What are the indications for large joint replacement surgery?
Pain/stiffness leading to loss of function
What are the absolute contraindications to large joint replacement surgery?
Untreated joint sepsis
What are the relative contraindications to large joint replacement surgery?
Young age
Co-morbid disease inc obesity
What are the potential complications of total hip replacement?
Leg length discrepancy (15%)
Dislocation (3%, highest in 1st 3mo, can be due to infec)
Infection (0.5-1%)
Periprosthetic fracture
Persistent pain (1%)
Polyethene wear of acetabular compartment
Neurovascular injury (0.1%)
How does infection post total hip replacement present?
Subclinically w/ little systemic upset
How is suspected infection post total hip replacement confirmed?
Aspiration in aseptic conditions
-ideally on 3 occasions
How is infection post total hip replacement managed?
Removal of prosthesis
Lengthy courses of a/b
What is the prognosis of infection post total hip replacement?
Rare but devastating
Joint salvage rates around 30%
