Acute Knee Injuries Flashcards
What may cause an acute knee injury?
Fracture Acute on degenerate joint dx Meniscal injury Ligament injury Tendon injury
What are important things to ask in your history for an acute knee injury?
Environment - sport/work/recreation
Activity - sports tackle/jumping for e.g.
Energy - how fast, how heavy?
Systemic symptoms (rigors, fever - thinking infection?)
Chronology - quick/slow onset, prev injuries or events?
Hear/feel a pop/crack
Swelling - how fast the swelling came on
What would really fast swelling indicate?
Haemarthrosis (bleeding into the joint)
Examination of acute knee injury
Look: scars, bruising, swellings, joint lines
Feel: effusion, crepitus, heat (inflammation), tenderness, tissue/lump defects
Move: passive/active, straight leg raise, range of movement, ligament testing and dynamic testing
Why might it be difficult to examine a patient who you suspect as had a ligament injury but who is very muscly?
Muscles can compensate and stabilise the joint
What form of imaging must you always do in acute knee?
XRays
What can Xrays help you to identify?
Fractures Loose bodies Ligament avulsions Osteochondral defects Degenerative joint disease Lipohaemarthrosis (intra-articular fracture leads to bone/fat leakage from the bone marrow)
What other investigations can you use?
USS and MRI
When would you do an USS?
Not very often
Can be used to see tendon ruptures, some meniscal tears, swellings and cysts
When would you use an MRI?
For clinical conformation it is the test of choice
Can be used to see ligaments and menisci
Not good for DJD or mobile pathology
What would be a typical history of a meniscal injury?
Twisting movement on a loaded fixed knee
Squelch and pain
Gradual swelling
Painful to weight bear
Locked knee
Which of the menisci is most likely to tear and why?
Medial menisci - as it is relatively immobile
What is a typical history of a ACL tear?
Forward momentum on a fixed leg +/- rotation
Pop, immediate swelling
Often able to weight bear
Pain
What is the best test for diagnosing ACL tear?
MRI
How common is ACL tear?
1 in 3 people in high level sport will get this
What is a typical history for a collateral tear?
Force to the side of the knee
No/minimal effusion
Bruise on one side
Feel of crack
Lateralised, sharp pain
What is involved in the first aid care of an acute knee injury?
RICE, analgesia
What other non-pharmacological management may follow RICE & analgesia?
Physiotherapy
What is the goals of surgical treatment?
Joint preservation and to introduce as little to the joint as possible (which may fail)
Life-long care of joint
What are indications for surgical treatment?
Failure of conservative Rx
Demands of work/sport
Interferes with activities of daily living
Prevention of further injuries or prevention of falls
What are the three surgical methods of treating meniscal tears?
Meniscal repair
Partial Menisectomy
Meniscal transplant
What are the indications for meniscal repair?
Young, sporty
Fresh tears (up to 3 months)
Health meniscus
Red/red or red/white zone
Why does the tear need to be in the red/red zone or the red/white zone to qualify for meniscal repair?
These are the areas with higher vascularity and better chances of healing after repair
Why might arthroscopic meniscal repair be preferred over open meniscal repair?
You can reach more central tears (greater accessibility)
What are the various techniques for meniscal repair?
Open Outside-in Outside-out All inside Smith and Nephew
Describe the smith and nephew technique for meniscal repair
Device passed through portal and meniscus to a depth that enables the T to be deployed, then knot tied outside the joint
Knot pusher slides knots snuggly against meniscus
What is the success rate of meniscal repair?
90% when its done on the right joint (i.e. injuries that will heal)
1 in 5 will fail/need re-arthroscopy and probable partial meniscectomy
VAST majority of these tears are in the white zone
What would occur if you removed the whole menisci?
Predisposes to bad OA
What is involved in management of ACL tears?
1st line: ACL rehab
2nd line: ACL reconstruction
What is involved in ACL reconstruction?
Use tendon/fascia to fashion new ligament (allograft), feed this up through tibia and femur
OR can try to stitch ACL back together
What is involved in post-op care after ACL reconstruction?
Crutches, knee braces and physical therapy
What are indications for ACL reconstruction?
Prevention of further injury/OA
Back to work/sport
What is an osteochondral injury?
Injury to the cartilage and bone underneath
How can you surgically manage an osteochondral injury?
Debridement
Reattachment of loose bodies
Microfracture chondroplasty
Artificial cartilage implantation
What is involved in microfracture chondroplasty?
Puncture little holes into the bone and this causes bleeding –> clot formation and fibrous repair (not as good as cartilage)
What is involved in artificial cartilage implantation?
Grow cartilage in the lab and stitch it with a layer of periosteum covering to cover the defect - this will also stimulate chondrocytes to manufacture articular cartilage
What is the appearance of the medial meniscus?
Semicircular
What is the appearance of the lateral meniscus?
Circular
What are the menisci composed of?
Fibro and chondroblasts in matrix of type I collagen
How are the fibres of the menisci arranged?
Circumferential hoop fibres, superficially randomly orientated fibres, radially orientated tie fibres
What are the function of the menisci?
Spread the force over the articular cartilage and allow the joint to be more slack allowing for an increase in movement
Where does the perimeniscal capillary plexus originate from?
Branches of the inferior medial and lateral geniculate arteries
What vessels does the perimeniscal plexus form?
Circumferential vessels and penetrating radial vessels
