Knee- Soft Tissue Injuries Flashcards
Where do the menisci have a blood supply? What is the significance of this?
Only at their periphery- tears aren’t particularly painful and also won’t heal well
Knees pivot through what compartment during flexion and extension? What is the significance of this (regarding meniscal tears)?
Medial compartment, medial meniscus is more likely to tear
What way does the tibia rotate on flexion?
Internally
Which has a better blood supply, MCL or LCL?
MCL
What will be seen on clinical examination of a patient with a meniscal tear?
Effusion (following day), joint line tenderness, + Steinmann’s test (tibial rotation)
Where is a longitudinal meniscal tear?
Near the periphery
What is a bucket handle meniscal tear?
An extensive longitudinal tear, causing locking
What type of meniscal tear will cause the knee to click painfully?
Parrot beak
Why are medial meniscal tears more common?
The medial meniscus is more fixed and less mobile, force from pivoting movements is centred there
What will a locked knee in a displaced bucket handle meniscal tear present like?
15 degree springy block to extension
What is the mechanism of injury for a meniscal tear?
Usually as a sporting injury in young patients, or getting up from a squatting position (twisting force on a loaded knee)
Can meniscal tears occur spontaneously?
Yes, degenerate tears in older patients can (>40)
Rupture of what ligament is closely associated with meniscal tears?
ACL
What is the investigation of choice for a meniscal tear?
MRI
What features imply worse healing of a meniscal tear?
Radial tears, aged > 25, increased time from injury
What type of meniscal tears should be considered for repair?
Reasonably fresh bucket handle tears involving the outer 1/33rd of the meniscus in a younger patient
What happens in a meniscal repair?
The meniscus is sutured to its bed
What is the failure rate of meniscal tear repairs?
25%
When should an arthroscopic meniscectomy be considered?
In patients who still have pain or mechanical problems after 3 months
If meniscal repair surgery fails, what happens next?
Remove it (you only get one shot at repair)
An acute locked knee signifies what?
Displaced bucket handle meniscal tear
How soon must arthroscopic repair be done following a bucket handle meniscal tear?
6 weeks
If the knee remains locked following a meniscal tear, what may this result in?
Fixed flexion deformity
What do degenerate meniscal tears signify?
The first stage of knee OA
Will the Steinmann’s test be positive in degenerate meniscal tears? What other signs and symptoms will be associated with this?
No, Steinmann’s will be negative. There will be signs and symptoms of OA
What should you not treat degenerate meniscal tears with?
Arthroscopy
What may help control the symptoms in the early period of a degenerate meniscal tear?
Steroid injections
What is a grade 1 ligament injury?
Sprain- tearing of some fibres but macroscopically intact
What is a grade 2 ligament injury?
Partial tear, some fascicles disrupted
What is a grade 3 ligament injury?
Complete tear
Does the MCL heal well?
Yes
When would the MCL not heal well?
If associated with ACL or PCL rupture
How do you treat MCL rupture?
Bracing, early motion and physio
How long can it take for pain from an MCL rupture to settle?
Several months
What treatment can be used in chronic MCL instability?
Tightening or reconstruction with a tendon graft
Where may patients with an MCL rupture have laxity and pain?
On valgus stress, over the origin/insertion of the MCL
Do LCL ruptures happen alone?
Not often, they are usually part of multiple ligament injuries
What motions can cause LCL rupture?
Hyperextension or varus
Does the LCL heal well? What problems can you be left with?
It does not heal well- can be left with varus and rotatory instability (especially external)
Excessive stretch from varus/hyperextension in LCL ruptures can cause what nerve injury? What can this result in?
Damage to the common fibular nerve which can cause a permanent foot drop
LCL rupture is often found in combination with what other ligament ruptures?
PCL/ACL
If found within 2 weeks, how is an LCL rupture treated? What happens if it presents later than this?
Urgent repair. If late then reconstruction.
The ACL is the main stabiliser against what movement?
Internal rotation of the tibia
What is the principle complaint of ACL deficiency?
Rotatory instability which gives way on turning
How are ACL ruptures usually acquired?
Sports injury- football/rugby/skiing turning the upper body laterally on a planted foot
How are ACL ruptures treated?
Reconstruction
What will examination of an ACL rupture reveal?
Knee swelling with excessive anterior translation of the tibia on anterior drawer test and Lachmann’s test
To give stability, the ACL can be stuck to which other ligament?
PCL
Recovery from ACL rupture comes under the rule of thirds, what is this?
1/3rd compensate and function well, 1/3rd avoid instability by avoiding certain movements, 1/3rd have frequent instability
When should surgery be considered for an ACL rupture?
Rotatory instability, no response to physio, protect a meniscal repair, return to professional sport, multi-ligament damage
After surgery for ACL repair, what is the recovery like?
Can be up to 1 year of intense rehab, some never get back to sport, often have arthritis within 10 years
What is the mechanism of injury of a PCL rupture?
Direct blow to the anterior tibia or hyperextension
How will a PCL rupture occur?
Popliteal pain and bruising
Is isolated PCL rupture common?
No
When is reconstruction used for PCL rupture?
If part of multi-ligament injury or if severe instability
What can PCL ruptures cause long term?
Instability, recurrent hyperextension, feeling unstable going downstairs
How would you describe a knee dislocation?
High impact injury with a high incidence of complications
What are some complications of knee dislocation?
Popliteal artery injury, nerve injury, compartment syndrome
What is the treatment for a knee dislocation?
Emergency reduction with possible external fixation, multiple ligament reconstruction
The patella will almost always dislocate in what direction?
Laterally
When the patella dislocates, what ligament is torn?
Medial patellofemoral ligament
As well as the torn ligament, what else may happen alongside patellar dislocations?
Osteochondral fracture (small opacification on x-ray)
What movements can cause a patellar dislocation?
Rapid turn or direct blow
What are some factors which predispose to patellar dislocations?
Female, adolescent, ligamentous laxity, values knees, high patella, femoral neck ante version, shallow trochlear groove
What % of people will have a recurrent patellar dislocation?
10%
What is the treatment for recurrent patellar dislocations?
Surgical stabilisation
What occurs following a patellar dislocation which causes a characteristic x-ray appearance?
Lipo-haemarthrosis
After a patellar dislocation, physiotherapy to strengthen which muscles may help?
Quadriceps
What components make up the extensor mechanism of the knee?
Tibial tuberosity, patellar tendon, patella, quadriceps tendon, quadriceps muscles
What is the mechanism of injury for an extensor mechanism rupture?
Fall onto a flexed knee with quadriceps contracted
What are some risk factors for extensor mechanism rupture?
Previous tendonitis (quinolones), steroids, chronic renal failure, diabetic, RA
What are the clinical signs of an extensor mechanism rupture?
Unable to straight leg raise and a palpable gap
What treatment should be avoided in an extensor mechanism rupture?
Steroid injections
At what ages are a) patellar tendon ruptures and b) quadriceps tendon ruptures more common?
a) < 40 b) > 40
On an x-ray, where will the patella lie in a) patellar tendon ruptures and b) quadriceps tendon ruptures?
a) high lying patella b) low lying patella
If a patient is obese and there is no palpable gap, what test can be used to assess for extensor mechanism rupture?
Ultrasound
What is the treatment for an extensor mechanism rupture?
Tendon to tendon repair or reattachment of the tendon to the patella
If there is a loose mechanical fragment in a meniscal tear, how may this present?
Feeling like the knee is going to give way
Is it possible to have a meniscal tear without locking?
Yes
Is pseudo-locking a sign of meniscal injury?
No
How soon after an ACL rupture will a haemarthrosis develop?
An hour
Valgus stress injuries usually tear which ligament? What other injuries may occur?
MCL - can also cause ACL damage and lateral tibial plateau fracture
A varus stress injury will usually damage what ligament? What other ligament may or may not be involved?
LCL +/- PCL
If a knee injury is though to be significant, what is the best test to do?
MRI
