Lecture 7 Flashcards
(29 cards)
What’re the most common injuries to the knee?
Patella fracture Patella dislocation ACL and PCL tears Collateral ligs sprains or tears Meniscal tears Tendon injuries
Name the ligs of the knee
ACL
PCL
LCL AND MCL
Meniscus
What’re the causes of LCL injuries?
Direct blow to medial aspect of knee creates an opening of lateral joint space causing tear or sprain to LCL
Symptoms
- knee swelling
- pain and tenderness over lateral knee joint
- stiffness progressing to locking of knee (grade 2 or 3)
- knee instability (grade 2 or 3)
Explain the classification of an LCL and MCL injury
Grade 1 = fibres stretched
Grade 2 = partial tear
Grade 3 =complete tear
Explain what’re injuries to the MCL
Direct blow to lateral aspect of knee creates opening on medial joint space causing a tear or sprain to MCL.
Can lead to pellegrini stedia syndrome = old calcified avulsion fracture of medial femoral condyle
Common and uses same grading system as LCL
Symptoms
- popping sound when MCL tears
- knee swelling
- pain and tenderness over medial knee joint
- knee locking (g2 or 3)
- knee instability (g2 or 3)
What’s a bursa and what’s its function?
Fluid-filled, saclike cavities
Located where muscles and tendons move over bony joint areas ie. knee
Function is to reduce friction caused by muscles and tendons moving against skin and bones, and therefore, facilitate smooth movement.
Name the bursa related to the knee
Suprapatellar bursa = between femur and quadriceps tendon
Prepatellar bursa = between patella and skin
Deep infrapatellar bursa = between tibia and ligamentum patella
Subcutaneous infrapatellar bursa = between tibial tuberosity and skin
Popliteal bursa = at the posterior aspect of the distal femur
What’s a lipohaemarthrosis in the suprapatellar bursa?
Bleeding into the joint space with fats
Suprapatellar bursa is in direct communication with synovial cavity of joint, hence, allowing for it to occur
It is indicative of a fracture of proximal tibia or distal femur
Less than 50% of proximal tibia and femur demonstrate lipohaemoarthrosis and the greater % only demonstrate haemarthrosis (which won’t be displayed in plain radiographs) but if they are seen, it will be shown as layering (separation of blood into serum)
Where is the Hoffas fat pad
Behind the infrapatellar bursa region
What’s an arcuate sign?
Basically when there’s an avulsion fracture from head of fibula from the avulsion of the arcuate lig complex at the head of fibula
It is commonly a subtle fracture fragment but is a significant injury and is associated with ACL ruptures
It can increase the lateral space of the knee joint Due to possible involvement of lateral collateral lig as well
It can even completely frvature the head of fibula
Can occur due to
- direct blow to tibia on extended knee
- sudden hyperextension of internally roasted leg
What’s a segond fracture?
Avulsion fracture from lateral surface of tibial condyle, where the inferior meniscal lig has been avulsed
Fragment lies parallel to lateral tibial border
Also associated with rupture of ACL and tears of lateral meniscus
Due to internal rotation of tibia on a flexed knee
What’s a reverse segond fracture and pelligrini steida syndrome?
Pelligrini steida syndrome
- Calcified avulsed fracture from medial aspect of femoral condyle, avulsion of MCL
Pt. Can be asymptomatic or have low grade knee pain
Reverse second fracture
- avulsion of medial tibial condyle where the MCL has been avulsed and the fragment lies parallel to medial border of tibia
- occurs due to external rotation of tibia on flexed knee
- also associated with rupture of PCL ant tear of medial meniscus
Explain what’re tibial plateau fractures
Marked change in height of joint
Density of bone, sclerotic appearance (non-linear lines)
Indentation of tibial plateaue
Ie. getting hit by a car on the lateral aspect of knee will cause lateral height of joint to decrease and increase of medial side. This can further be seen as haemarthrosis (looks like an egg on knee for presentation)
Usually should do oblique projection to see it (lateral aspect shown)
Explain the classification of ACL avulsion fractures
Type 1 = undisplaced but partially displaced tibial attachment
Type 2 = hinged (anteriorly) fragment. Hoffas fat lad has lost its triangular shape, and suprapatellar fossa bleeding seen.
Type 3 = a. Complete tibial detachment b. Avulsion involves entire tibial eminence
Type 4 = comminuted tibial attachment fragment (detached and inverted)
Explain what’s osgood schlatter disease
It’s a traction tendinitis of tibial tuberosity
Tenderness and swelling at attachment point of tendon to tibia
Limits movement, swelling
Unilateral
10-15 yo male dominated
Explain what’s sinding Larsen johansson disease
Traction tendinitis of distal pole (apex) of patella
Point tenderness at inferior pole of patella
Often bilateral, swelling
Limited movement
Resolved within 12 months
12-14 yo, male dominated
How does osgood schlatter disease look on a radiograph?
Fragmentation at tuberosity
Soft tissue elevation seen at tuberosity
Look for Hoffas fat pad being destroyed in terms of its triangular shape
How does Sinding Larsen Johansson disease show on a plain radiograph?
Look at inferior distal region of patella
Explain what’s osteochondritis dissects
12-16 yo. Intercom dealer region of femur
Causes cartilage and bone to disintegrate which can expand to area the size of a hazelnut
Affected area can break in to pieces or entire area can break away and become a loose body in joint and disrupt the movement of the cruciate ligaments and lead to knee locking
Pt. Has recurrent joint effusions, sometimes asymptomatic
Knee locking or giving away
What happens of the OCD is in the weight bearing condyle?
85% of patients will develop OA within 20-30 years
Condyles try to have even weight distribution but that’s no class
Why are knee dislocations of high concern?
Because they have high incidence of vascular complication with a popliteal artery injury in half the cases due to fixed position of the popliteal artery proximally and distally to knee joint
Therefore, vascular imaging is also performed
Explain what is anterior dislocation of the knee
Caused by forced hyperextension, rare but traumatic
The tibia and fibula move anteriorly and femur posteriorly (distal portion has moved anteriorly). Femoral condyle comes down and strikes the posterior portion of tibia and creates an indentation
Risk to popliteal artery, and possibly peroneus nerve
Can lead to lower leg amputation if displacement not reduced soon after injury
Explain what’s posterior knee dislocation
Direct blow to tibia when knee flexed ie leg stroking dashboard in MVA
Popliteal artery at risk but less risk to peroneal nerve
Explain what’s a rotary dislocation
Everything is rotated.
Ie. patella in unusual position, tibia and fibula region is lateral but the distal femur is quite off lateral thus, indicating a rotation
