Knee Flashcards
What meniscus is 10x more likely to tear and why?
Medial meniscus
More fixed than lateral and therefore less able to move
What is a classic presentation of a bucket handle tear?
Why does it occur?
True locking - Inability to fully extend knee even actively
Tear flips over and becomes stuck in the joint line
How would a patient present with a meniscus tear?
Pain and tenderness along joint line
~Inflammatory effusion
What meniscus tears are most likely to heal themselves?
Why?
Longitudinal in peripheral 1/3rd
Peripheral 1/3rd has a much better blood supply
Younger and older patients can both get meniscal tears. Under what circumstances is each group most likely to get one?
Younger - sport + squats (twisting force on loaded knee)
Older - sponateneous rupture (mostly asymptomatic)
How is a bucket handle tear treated?
If caught early - arthroscopic repair
If late and v problematic - meniscectomy
How are all knee ligament ruptures investigated?
MRI
can also be visible on CT
Name some mechanical symptoms that can come with meniscal tear
Catching sensation
“locking” of knee
What ligament acts as the main stabiliser against internal rotation of tibia?
As a result this is often damaged by twisting of upper body away from planted foot
ACL
A patient has collapsed in a netball match after hearing a “pop”. The knee is painful and there is an effusion.
What has she most likely damaged?
What is the explanation for the effusion?
ACL
Bleeding in the joint due to rupture of the ACL - haemarthrosis
How long may it take for a player to return to contact sport after ACL?
Up to a year
Rather than repair, reconstruction takes place on ACL. How is this done?
Graft ligaments from other places and use them
What ligament is most likely to be damaged in a motorbike crash?
PCL - when knee is flexed or hyperextended
Patient complains of instability walking down stairs and recurrent hyperextension. On inspection there is popliteal pain and bruising.
What further examinations would be done?
Posterior drawer test - +ve if sign of posterior tibial sag
PCL rupture
What is more likely to heal by itself. MCL or LCL?
Medial collateral ligament - rarely requires surgery
How would you examine for MCL injury?
Valgus laxity/discomfort = MCL injury
How are MCL injuries generally managed?
With a brace
How would knee dislocation be able to happen?
If all 4 ligaments are ruptured
What must regularly be done for a patient with recurrent knee dislocation?
Checks of peripheral pulses
High incidence of neurovascular injury
Match the following: Genu varum Genu valgus Affects lateral region of knee Affects medial region of knee
Genu varum - medial region of knee
Genu valgum - lateral region of knee
Knee replacements can cause explained moderate or severe pain. True or false?
True - up to 20%
Under what circumstances would a patient be considered for TKR?
SEVERE end-stage arthritis that is no longer controlled by conservative management causing SEVERE pain
Generally older patient
What kind of ligament damage in particular can lead to early OA?
Meniscal tear
What 5 parts make up the extensor mechanism?
Quadriceps muscle Quadriceps tendon Patellar Patellar tendon Tibial tuberosity
Match the following ages to what part of the extensor mechanism they are most likely to rupture:
<40 yo
>40 yo
How would each type of rupture appear on Xray?
> 40 yo - quadriceps tendon
<40 yo - patellar tendon
On Xray:
High patella -> patellar tendon rupture
Low patella - quadriceps tendon rupture
How is extensor mechanism rupture managed?
Surgery
If a patient presents with tendonitis, usually steroid injections can help. What part should not receive steroid injections as it can cause ruputre?
Extensor mechanism of the knee
What test is used to examine the function of the extensor mechanism?
Straight leg raise test
What is patellofemoral dysfunction?
A collection of conditions which can cause anterior knee pain
Alongside anterior knee pain what other symptoms may a patient with patellofemoral dysfunction complain of?
What can also make the pain worse?
Grinding/clicking sensation
“Pseudolocking” -> inability to fully extend leg when sitting for long periods of time (does correct tho unlike true locking in meniscal tears)
Pain worse when going downhill
What may a physio do to improve patellorfemoral dysfunction?
Try to strength medial quadriceps muscles
What are the knee Ottawa rules that indicate a need for an xray?
- Over 55
- Inability to bear weight immediately/in ED
- Inability to flex knee to 90 degrees
- Tenderness over patella
- Tenderness at head of fibula
What is the difference between patellar and knee dislocations?
What one is more concerning and why?
Patellar - just the patella becomes unstable
Knee - whole tibia+fibula moves
Knee - can severe popliteal artery (at back of knee) and cause huge neurovascular damage
What ligament ruptures in patellar dislocations?
What direction does this mean the patellar normally always moves?
Medial patellofemoral ligament
Laterally
What causes a patellar dislocation?
Sudden quad contraction with a flexing knee
A patellar dislocation is normally self-resolving. Why must the patient still come in to clinic?
To receive physio to prevent recurrence
Also sometimes given a velcro brace (think Amelia)
How must a patient with knee dislocation be managed if they have:
- Normal examination?
- Clinical concern in examination (poor neurovascular response)
Normal = observe in hospital
Clinical concern = arteriogram/MRI
Housemaid’s knee results from a bursitis of what?
Prepatellar bursitis
