Disorders Of The Knee Flashcards
What is septic arthritis?
Invasion of joint space by microorganism
What microorganism most commonly causes septic arthritis?
What its gram stain?
Staphylococcus aureus
Gram positive cocci
Risk factors of septic arthritis
Extremes of age
RA
Diabetes mellitus
Immunosuppression
IV drug use
What can cause septic arthritis?
Recent surgery - prosthetic joints
Knee effusion secondary to bacterial infection
Articular cartilage damage
Symptoms of septic arthritis and what to examine for
- fever
- pain
- reduced ROM
Examine for:
- erythema
- swelling
- warmth
- tenderness
- ROM
What needs to be done if septic arthritis is suspected?
- Aspiration of joint - use ultrasound to help
- Send aspirate for urgent microscope, culture + sensitivities
Risk factors for knee osteoarthritis
Age
Sex female > male
Weight
Post traumatic
Genetics
Treatment of osteoarthritis
Weight loss
Strengthening exercises
Surgery
NSAIDs
How is sclerosis seen on an x ray?
Increased whiteness as bone is more dense
What is Osgood-Schlatter’s disease?
Inflammation of the apophysis of patella ligament into tibial tuberosity
Treatment of Osgood-Schlatter’s disease
Resolves with rest + ice
What bursae is inflamed in housemaid’s knee?
Pre-patellar bursitis
Leaning forward on knee
What bursa is inflated in clergyman’s knee?
Intra-patellar bursitis
Kneeling
What bursa is inflamed in Baker’s/popliteal cyst?
Semimembranosus bursa
What is another name for semimembranosus bursitis?
Baker’s/popliteal cyst
What is another name for pre-patellar bursitis?
Housemaid’s knee
What is another name for infra-patellar bursitis?
Clergyman’s knee
What is fluid inside a joint called?
Effusion
`What is fluid outside a joint called?
Soft tissue haematoma
When is a knee effusion normal?
Never normal
What are the types of knee effusion and what is suspected until proven otherwise?
Haemarthrosis - blood in joint
- ACL injury until proven otherwise
Lipo-haemarthrosis- fat and blood in joint
- fracture until proven otherwise
What is haemarthrosis in the knee thought to be caused by until proven otherwise?
ACL injury
What is lipo-haemarthrosis in the knee thought to be caused by until proven otherwise?
Fracture
Causes of knee swelling
VITAMIN C+D
Vascular - haemarthosis
Inflammatory - bursitis
Trauma - meniscal tear»_space; effusion
Autoimmune - RA
Metabolic - gout
Iatrogenic - infected prosthetic joint
Neoplasia - rare
Cancer - rare
Degernative - OA
How many ligaments are ruptured in a knee joint dislocation?
3/4
Cause of knee joint dislocation
High energy trauma
Mechanism of collateral ligament injury
Contact/direct blow e.g. sport
What type of strain is there if the medial collateral ligament is injured?
Valgus strain }{
What type of strain is there if the lateral collateral ligament is injured?
Varus strain {}
What is the unhappy triad?
ACL
Medial collateral ligament
Medial meniscus
Treatment of collateral ligament injury
Brace + rehabilitation
Surgical repair + reconstruction
What crucial ligament is more common to injury?
ACL
Mechanism of ACL injury
Non contact - landing or direction change
Mechanism of PCL injury
Contact - falls + hyperextension
What tests can be used to examine the cruciate ligaments
Lachman’s test
Anterior and posterior drawer test
What do normal menisci look like on an MRI?
Black triangle
Mechanism of meniscal injures
Twisting injury
Symptoms of meniscal injuries
Catching
Jamming
Locking - unable to straighten knee
Localised pain
Swelling
Treatment of traumatic meniscal injury
Meniscal repair
Menisectomy
Treatment of degenerative meniscal injury
Leave alone
Rehabilitate
What helps to prevent patella dislocation?
Vastus medialis obliquus
Function of VMO
Stabilise patella in trochlea groove
Control tracking in flexion + extension
Prevents patella dislocation
Mechanism of patella dislocation
Twisting action in slight flexion
Trauma
Direct blow to knee
Predisposition of patella dislocation
Previous dislocation
Long patellar ligament
Shallow trochanter grove
Ligament laxity
Weakness of Vastus medialis obliquus
Treatment of patella dislocation
Reduce + immobilise
Soft tissue reconstruction
How to check for a patella fracture
Ask patient to raise a straight leg
Inability to is indicative of a patella fracture
Inability to raise straight leg is indicative to what?
Patella fracture
What risk if there after a patella fracture?
Post traumatic OA
Treatment of displaced patella fracture
Reduce + fix
Treatment of undisplaced patella fracture
Splint + protect
Sites of femoral shaft fractures
Proximal
Mid shaft
Supracondylar
Risk after femoral shaft fracture
Hypovolaemic shock
Mechanism of femoral shaft fracture
High energy injury - RTA + falls from height
Significant force needed
Treatment of femoral shaft fracture
Traction splint - stabilises bone
Surgical fixture
Mechanism of distal femoral fracture
Young - high energy sport
Older - fall from standing
What is at risk of damage in a distal femoral fracture?
Popliteal artery
