Knee Flashcards
Why is popliteal artery prone to injury in knee dislocations?
Popliteal artery is tethered to popliteal fossa and is relatively immobile
What to suspect if LL pulses diminished after knee dislocation?
thrombosis from intimal tear of popliteal artery. Confirm reduction of joint, put on regular vascular charting KIV angiography with angioplasty
How do patella dislocations happen?
More commonly lateral, during sudden contraction of quads with knee in extension and valgus
How to differentiate btw fracture, ligament and meniscus?
Cannot weight bear = fracture
Cannot weight bear within 1-2 weeks + immediate swelling = ligament
Can weight bear within 1-2 weeks + delayed swelling = meniscus
how to differentiate compartments of knee OA?
Medial pain when walking flat ground = medial compt OA
Lateral pain when walking flat ground = lateral compt OA
Ant pain when walking up and down stairs = patellofemoral OA
Difference btw motions that cause instable knee?
ACL / PCL = turning tight angles, squatting, going up/down stairs
MCL / LCL = side stepping
How to differentiate ligamentous and meniscus injury from the swelling?
Acute trauma+ immediate swelling = ligament
Acute trauma + delayed swelling = meniscus
Which knee ligaments are intracapsular and extracapsular?
Intracapsular = ACL, PCL
Extracapsular = MCL, LCL
What keeps knee joints stable?
Strong fibrous capsule
Ligaments
Quadriceps
How to differentiate ligament or meniscus injury from Hx?
Ligament = Immediate swelling, pop sound, chronic instability e.g. angles, squats, stairs
Meniscal = Delayed swelling, locking sensation, instability e.g. side stepping
What can be seen in XR of ACL tear?
Segond fracture
Deep sulcus sign
What is usually injured with PCL injury?
Posterolateral Corner injury
How to classify tears of knee ligaments?
Partial tear = no abnormal movement, but severe pain on attempted abnormal movement
Complete tear = Abnormal movement, but little/no pain
Different grades of knee ligament sprain?
1 = mildly stretch LIG, can stabilize knee joint
2 = Loose LIG, partial tear
3 = LIG torn into 2, complete tear
PCL posterior translation extent by sprain grade
1 = 0~5mm
2 = 5~10mm
3 = More than 10mm posterior translation
Functions of meniscus?
Increase knee stability
Control complex gliding joint movements
Distribute load during movement
Why does meniscus not repair well?
Most of meniscus is avascular and does not repair
ROM in meniscal injury of knee?
Stiffness
Full flexion but limited extension
Clicking and locking esp when squatting
Characteristic of IT band syndrome?
Lateral knee pain. Due to friction of IT band against femoral epicondyle
What causes IT band syndrome?
Overuse and repetitive flexion and extension of knees
What test for IT band syndrome?
Ober’s test
What is Osteochondral lesion?
Also known as Osteochondritis Dessicans
Cartilage disorder on** LATERAL SIDE **of medial fermoral condyle of knee.
Commoner in youths
How to compare with SONK?
What is SONK?
Spontaneous Osteonecrosis of Knee
On medial side of medial femoral condyle of knee.
Commoner in middle aged and elderly, esp females.
SONK shows **crescent shape on XR. **
Unhappy triad for knee injury?
MCL tear
Medial meniscus damage
ACL tear
How to classify patella dislocation?
patellar dislocation mostly lateral
By quadrants according to extent of lateral translation. 1 quarter, half, 3 quadrants etc
What is trochanteric bursitis?
Common source of lat hip pain caused by repetitive trauma 2! to IT Band tracking over trochanteric bursa
Point tenderness over GT.
Differentials for popliteal fossa swelling?
Baker’s cyst [popliteal cyst]
Semimembranosus bursitis
Popliteal artery aneurysm
Lipoma, Schwannoma
Saphena varix at saphenofemoral junction
Alw flex joint when palpating!
Tethered to skin? Cross-fluctuant? Pulsatile? Slip sign? Foucher’s sign?
What XR view to use in Knee OA?
Weight bearing view
Skyline view optional
