Knee Lecture Flashcards
(19 cards)
Concentric Contraction
shortening muscle
Eccentric contraction
lengthening muscle (much more sore!)
Isometric contraction
holding a contraction in a stationary position (ie hold quad flex when sitting in chair)… Great for immobilized patients
Why do you want to increase core stability?
to relieve back pain/stabilize hips and shoulders…
Increased lordosis in back can be do to weakened abdominal muscles!
Route of ACL
anteromedial on tibia across joint to posterolateral on femur
Route of PCL
from medial on femur to more lateral on tibia but STAYS on posterior aspect, doesn’t really cross the joint like the ACL does!
What is the unhappy triad?
MCL tear, medial meniscal tear (MCL attaches to medial meniscus), and ACL… all caused by a blow to the side of a planted knee
What is one bad thing about playing sports?
it increases the rate of osteoarthritis in the knee
How do you typically dislocate the patella?
Sudden cutting movement or sudden contraction of quads during deceleration… HOWEVER, the patella typically reduces itself spontaneously with knee straightening (high recurrence rate)
Patellar femoral syndrome
Pain as a result of posterior side of patella rubbing against femur… if this occurs in presence of cartilage damage = “chondromalaciae patellae”
occurs in connective tissue disorders like ehlers dahnlos, marfans etcs.
DUE TO: Elevated Q-Angle! More common in women as they have a wider pelvis so their femur has to come in at a more “valgus” angle to the tibial plateau
Bakers cyst
popliteal (back of knee) bursa that communicates with knee joint and thus becomes more prominent with intra-articular pathology (due to inflammation).
These can burst and cause calf swelling which can be mistaken for deep vein thrombotic-induced edema
“knee locking” is a clue for what pathology? what test should be performed
meniscal tear… use McMurray’s test!
McMurray = suppine, hyperflex knee with finger on medial aspect then apply varus pressure while extending leg… feeling a “pop” with associated pain is a positive test! can also do same thing the other way with hand on lateral knee with valgus pressure
What is a common cause of PCL tear / what movement does the PCL act to protect against
PCL prevents posterior movement of tibia relative to femur.
Frequently caused by car accidents when the dash presses into tibia while femur continues to move forward.
What is the only isolated injury to cause ACL tear?
What do you see after the tear?
Tibial femoral compression!!! As in with jumping/landing the ACL “shoots forward”…
It also occurs with internal twisting of tibia… which is followed by *Excessive external tibial rotation with valgus bending!!!
What bone geometry puts an athlete at an increased risk for ACL tear?
1) A shallow, or concave tibial plateau (compared to convex!!!)
2) A steep posterior tibial slope (allows the femur to slide down posteriorly easier)
What is the goal of ACL braces?
shift tibiofemoral compression from the lateral to medial compartment by creating a varus bending moment on the knee during large axial forces
What is injured in a high ankle sprain?
anterior tibiofibular ligament
What 2 things could be injured in a lateral ankle sprain?
hyper-inversion of foot (sole of foot facing inward)
1) could damage anterior tibiofibular ligament
2) Calcaneofibular ligament
What is injured in a medial ankle sprain?
hyper-eversion (sole of foot facing out)… name for side of ligamentous damage
anterior deltoid ligament (aka posterior tibiotalar ligament)
