Disorders Of The Knee Flashcards
Why do knee disorders have a massive impact on patients?
Major weight bearing joint needed for walking
Injury reduces mobility (reduces activity, leading to weight gain)
Cant work
Depressions
Socially isolated (cant participate in activities)
What sort of energy is required for a femoral shaft fracture?
High energy injuries
What type of incidents can lead to femoral shaft fractures?
RTA (Road traffic accidents)
Falls from height
Why are femoral shaft fractures dangerous?
Can lose immense amounts of blood leading to Hypovolaemic shock
How are femoral shaft fractures usually treated?
Traction splint
Surgical fixation
How do Tibial Plateau fractures usually occur?
Axial loading (falling from height landing on the feet)
What type of energy injury is a Tibial Plateau fracture?
High energy injury
What is usually damaged in Tibial Plateau fractures?
Tibial condyle(s)
Articular cartilage
What do Tibial Plateau fractures cause?
Instability in the joint (reduced accurate join surface)
How is a Tibial Plateau fracture fixed?
Fix articular segment to shaft in surgery
What is a patient at increased risk of with a Tibial Plateau fracture?
Post traumatic Osteoarthritis
What is a Bipartite patella?
A patella that functions normally but is in 2 parts
What test can you do to check if the patella is fractured?
Straight leg raise to see if the extensor mechanism is in tact
How is a displaced patella fracture fixed?
Reduced then surgically fixed
How is an undisplaced fracture of the patella fixed?
Splint
Protect
What do all fractures at joints put you at risk of?
Post traumatic osteoarthritis
What is the definition of a dislocation?
Loss of congruity of joints
What is Subluxation?
Partial loss of congruity of joint
Why does the knee tend to move laterally and therefore likely to laterally dislocate?
Q angle = The force of the pull of the quadriceps pulls the patella laterally strongly
What muscle pulls the patella medially helping prevent lateral patella dislocations?
Vastus medialis
What is the Q angle?
Angle between Quadriceps tendon and the patella tendon
How does size of the Q angle affect the patella?
The larger the Q angle, the more likely lateral dislocation is to occur
How is a dislocated or subluxated patella fixed?
Reduce it
Immobilise it
What type of cartilage is the menisci?
Fibrocartilage
How do meniscal injuries occur?
Twisting of knee in high Flexion
What are the signs of a meniscal injury?
Locking of the knee
Swelling
Localised pain
Why do meniscal injuries/tears often lead to locking?
The torn meniscus acts as an Intra articular foreign body mechanically blocking the space preventing the knee from fully extending
What is a menisectomy?
Removal of damaged cartilage
What are the static factors that determine joint stability?
Bones and ligaments
(Can not be changed)
What are the dynamic factors which can affect joint stability?
Muscles and tendon
(Can be changed by exercise, get stronger)
What factors strengthen the knee joint?
Menisci
2 Cruciate ligaments
2 collateral ligaments
Joint capsule
Quadriceps
Bones
Tendons
What is ValGUS strain?
Force that acts medially on the knee
Pushes from lateral to medial
What is Varus strain?
Force acting laterally pushing knee
From medial to lateral
Which ligament resists ValGUS strain?
Medial collateral ligament
Which ligament resists Varus strain?
Lateral collateral ligament
How are collateral ligament injuries remedied?
Surgical repair/reconstruction
How do people usually get collateral ligament injuries?
How are they normally treated?
Brace + Rehab
Contact/direct blow usually sport
What is the most common Cruciate ligament injury?
ACL (Anterior Cruciate Ligament)
When do ACL tears/injuries usually happen?
Non contact landing or changing direction
How are ACL injuries usually treated?
Rehab and or surgical reconstruction
What do ACL injuries lead to? (What type of movement is there instability with?)
Instability with twisting (anterolateral rotation)
How are PCL injuries caused?
Contact (falls onto knee or hyper extension))
Often the tibia dislocates posteriorly which avulses the PCL
How are PCL injuries fixed?
Brace + Rehab
For the knee joint to dislocate, how many ligaments must be ruptured?
At least 3 of 4
What is the danger with knee joint dislocations?
May damage popliteal arteries
How is a knee joint dislocation fixed?
Reduce
Stabilise
What is Osgood-Schlatters Disease?
Where you get bony swelling and inflammation around the knee at the tibial tuberosity (where the patella tendon inserts)
What is Grimers law?
Anything bigger than a golf ball and painful is likely a soft tissue Sarcoma
What is a soft tissue sarcoma?
Cancers that start in soft tissue
What is knee effusion??
When fluid fills the knee joint
What are 2 types of Acute Knee effusions?
Haemarthrosis
Lipo-haemarthrosis
What happens during haemarthrosis?
Bleeding into the knee joint causes swelling
What is Lip-haemarthosis and what does it usually indicate?
When fat has filled in the joint
Fat usually comes from a fractured bone
What does a pop while playing sports indicate?
Torn ACL
(Until proven otherwise)
What are Bursae?
Fluid filled sacks protecting bony prominences
What is bursitis?
Inflammation and fibrosis of a bursa
What is prepatellar bursitis also called?
Where is the prepatellar bursa?
Housemaids knee
Imagine kneeling and scrubbing floors far away
In front of the patella
What is a Semimembranosus bursitis also called?
Where is the Semimembranosus bursa?
Popliteal cyst/bakers cyst
Behind the patella deep to the popliteal fossa
What is osteoarthritis?
The wear and tear damage caused to joints
Articular cartilage wears away leading to the damage of the bones too
What may indicate Knee arthritis?
Synovitis
Pain and stiffness
Deformity (Varus or ValGUS)
How is knee osteoarthritis treated?
Strengthening exercises for the muscles
Analgesia (pain reduction)
Weight loss
Activity modification
What 4 things indicate osteoarthritis on a radiograph?
LOSS
Loss of Joint space
Osteophytes
Subchondral sclerosis
Subchondral cysts
What is sclerosis?
More dense bone indicated by increased whiteness
Why is it thought that osteophytes form in osteoarthritis?
Trying to increase the SA of the bone when it gets damaged
Trying to repair and replace the damaged bone and cartilage
What are the signs of septic arthritis?
What is the triad of signs patients present with in septic arthritis?
Pain
Swelling (MOST have this))
Redness and warmth
Recent surgery
Knee effusion bacterial infection
Triad:
-Fever
-Pain
-Reduced range of motion
What should be immediately done if septic arthritis is suspected?
Aspirate to confirm diagnosis of infection by sending aspirate for microscopy, culture and sensitivities
IV Antibiotics and surgical wash out
SEPSIS Pneumonic
Slurred speech or confusion
Extreme shivering or muscle pain
Passing no urine in the day
Severe breathlessness
I’m going to die
Skin mottled or discoloured
Where is the suprapatellar bursa?
What is suprapatellar bursitis a sign of and why?
Above the patellar
The suprapatellar bursa is an extension of the synovial cavity of the knee joint. So a KNEE EFFUSION often presents with swelling in the suprapatellar pouch
What are some possible pathologies causing knee effusion?
Osteoarthritis
Rheumatoid arthritis
Infection/septic arthritis
Gout
Which of the 2 infrapatellar bursae are most commonly involved in bursitis?
Where is this bursa?
What is this bursitis also called and why is it called this?
Superficial infrapatellar bursa
Just below the patella
Clergyman’s knee (injury caused by the repetitive upright kneeling a religious clergyman would do)
What is damaged in septic arthritis ?
How is this damaged?
Articular cartilage damaged
Bacterial invasion and their virulence factors like proteases break it down
Or
Host immune response
Neutrophils make cytokines and other inflammatory products resulting in hydrolysis of collagen and Proteoglycans
Where is the bipartite part of the patella always visible?
What causes it?
Superolateral aspect
Failure of union of a secondary ossification centre
What is the mnemonic to remembering how the ACL and PCL ligaments run?
Using this mnemonic how are they orientated?
What is another way of remembering it?
PAMs APpLes (orientation from the bottom of the ligament up, so distal to proximal)
Posterior (PCL) passes to the Anterior inserting Medially
Anterior (ACL) passes to the Posterior inserting Laterally
Or think of the ACL running the same way as when you put your hands in your pockets
What is the mnemonic use to categories the potential pathology of a knee effusion?
What does this stand for?
VITAMIN C&D
Vascular (haemarthrosis)
Inflammatory/infective (bursitis, septic arthritis)
Trauma (meniscal tear)
Autoimmune (rheumatoid arthritis)
Metabolic (Gout)
Iatrogenic (infected prosthetic joint, infection following injection but this is septic arthritis)
Neoplasia (rare)
Congential (rare)
&
Degenerative (osteoarthritis)
