Knee Flashcards
Function of the knee joint
Hinge
Does flex/ext and int/ext rotation when the knee is flexed
Articulations with the femur at the knee
Tibial plateau
Posterior patella
What is important to note about the fibula?
Not part of the knee joint
Does not bear any weight
There for attachments of biceps femoris and lateral collateral ligament
What type of bone is the patella considered
Sesamoid
What is the reason for the patella?
Acts as a pulley for the quadriceps and patellar tendon improving the angle of the pul
What is the Q angle?
Angle between:
ant. sup. iliac spine to the middle of the patella
a line straight though the tibial tuberosity
What attaches at Gerdy’s tubercle
Iliotibial band (IT band)
What is located at the prox ant. medial tibial surface
Pes anserine bursa
Why is it important to catch a prox. fibular head fx.
The common peroneal nerve runs just inferior to it
Where does the ant. cruciate ligament attach
Post. lat. femoral condyle to the ant. med. tibia
Where does the post cruciate ligament attach
med. femoral condyle posteriorly to lat. tibia
What do the menisci do and what are the differences between medial and lateral menisci
Cushion between bones for shock absorption
Medial: Bigger and less mobile; also attached to MCL and other structures so injured more often
Lateral: Smaller and more mobile
Important knee bursa to know
Suprapatellar
Prepatellar
Deep infrapatellar
Pes anserine bursa
What muscles do the femoral nerves innervate
EXTENSORS:
rectus femoris
vastus lateralis, intermedius,. medialis
What muscles does the sciatic nerve innervate
FLEXORS:
Tibial nerve: semitendinosus, semimembranosus, biceps femoris
Common peroneal nerve: short head of biceps femoris
What is the blood supply to the knee extensors
Lateral circumflex femoral artery which splits to ascending, transverse, and descending
What artery shows up as the BIG RED ONE on MRI
Popliteal artery
MOI for patellar/quadriceps tendonitis
40 y.o. caused by lifting, increased physical activity, and weight gain
Clinical signs/Physical exam for patellar/quadriceps tendonitis
Ant. knee pain following exercise, assoc w/ jumping or squatting
Tenderness at tendon attachment
Normal ROM, pain w/ hyperflexion
Tx of patellar/quadriceps tendonitis
rest,NSAIDs, immobilize/support
strengthening of quads/hamstrings
slow return to activity
PT referral if doesn’t get better
Patellar dislocation/subluxation Risk factors
Patella alta “high sitting patella”
Laxity of ligaments
Increased Q angle
IT Band tightness
Tx of patellar dislocation
Sedation
Reduction
Post reduction xray/immobilize
Refer to PT
Clinical signs of septic arthritis
Acute onset of pain, erythema, warmth, swelling, and reduced ROMFebrile
Most common organisms for septic arthritis
MRSA, MSSA, gram neg. bacilli
Organisms for knee infections of:
Diabetics
Arthroplasty
Tick bourne disease
Diabetics: salmonella
Arthroplasty: s pyogenes, group A B or G strep
Tick: Lymes
Organisms for knee infections of:
Sexually active
rheumatoid
endemic tb area
sexually active: n gonorrhoeae
rheumatoid: TB, fungal 2 TNF inhibitor
Endemic TB: TB
What labs to order with a knee infection
Synovial fluid aspiration»_space; gram stain and culture
Blood cultures
CBC, CRP, and ESR
Ottawa rules for knee xray
MUST HAVE 1 or more age >55 isolated tenderness of patella tenderness at the head of the fibula inability to flex 90 degrees inability to bear weight both immediately and in the ED for four steps
