Hip and Knee Flashcards
What is the normal angle of inclination for the hip?
~125°
what is coxa valva?
pathological increased angle of inclination (>125°)
what is coxa vara?
pathological decreased angle of inclination (<125°)
what are some factors that can contribute to an increased risk of slipped capital femoral epiphysis?
high BMI
coxa vara
how does a high BMI and coxa vara increase the risk for slipped capital femoral epiphysis?
Coxa vara results in the head and neck being closer to a right angle which decreases the dispersion of force resulting in more force coming down onto the head of the femur. A high BMI enhances that because it is even more force coming down.
what is considered a normal degree of anteversion at the hip?
8-20°
excessive anteversion reduces _________
hip stability
what is excessive anteversion associated with? (mobility)
increased hip IR
decreased hip ER
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excessive retroversion may cause __________
hip impingement
excess retroversion is associated with what? (mobility)
increased hip ER
decreased hip IR
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List some common acetabular abnormalities
- acetabular dysplasia
- coxa profunda (acetabular over coverage)
- anteversion
- retroversion
what is a CAM lesion?
extra bone at anterior-superior region of femoral head and neck junction
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what is a pincer deformity?
abnormal bony extension of anterior lateral rim of acetabulum
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what motions would provoke an impingement with either a CAM lesion or a Pincer deformity?
Hip IR with flexion
List structures that support the hip
- strong joint capsule
- iliofemoral ligament
- pubofemoral ligament
- Ischiofemoral ligament
- transverse acetabular ligament
- acetabular labrum
- ligamentum teres
which ligaments of the hip provide protection to blood vessels?
transverse acetabular ligament
ligamentum teres
what is the trabecular system? Why do we have it?
it is a structural adaptation to weight bearing.
it allows us to provide structural resistance to bending force
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where is the joint capsule strong and weak at the hip?
strong = anterosuperiorly
weak = posterior and inferiorly (dislocations are more common in these directions)
what is the role of the acetabular labrum?
since it is wedge shaped it deepens concavity and improves congruency at the hip
acts as a seal to maintain negative intraarticular pressure
what motion can potentially injury the ligamentum teres?
excessive ER can strain/potentially tear it
describe the arthrokinematics of the hip during an OKC motion
Convex on Concave
opposite roll and slide
describe the arthrokinematics of hip IR/ER during an OKC motion
IR = anterior roll, posterior glide
ER = posterio roll, anterior glide
describe the arthrokinematics of the pelvic during an CKC movement
Concave on Convex
roll and glide in same direction
What osteokinematic movements are available at the pelvis?
A/P pelvic tilt
lateral pelvic tilt (pelvic hike/drop)
Forward/backward rotation
describe the motion of both the contralateral and ipsilateral femur when the pelvis is hiked to the R
ipsilateral (R) = adducted
contralateral (L) = abducted
describe the motion of both the ipsilateral and contralateral femur when the pelvis drops to the R
ipsilateral (R) = abduction
contralateral (L) = adduction
describe the open pack and capsular pattern of the hip joint
open pack = 30° flexion, 30° abduction, neutral to slight ER
capsular pattern: equal loss of IR w/flexion and abduction
what muscles help with performing an anterior pelvic tilt?
hip flexors
back extensors
what muscles help with performing a posterior pelvic tilt?
abdominal muscles
hip extensors
T/F: when performing a single leg raise, your abdominals are not involved. Why/Why not?
FALSE
abdominal wall muscles contract to neutralize the hip flexor’s pull on the pelvis into an anterior tilt.
This is important in preventing a lordotic curve in the lumbar spine during a straight leg raise
what is the Tredelenberg sign?
contralateral hip drop during walking
indicates glute medius weakness on the stance leg
in order to maximze a hamstring stretch, what should be done at the pelvis?
an anterior pelvic tilt
in order to maximze a rectus femoris stretch, what should be done at the pelvis?
posterior pelvic tilt
what is considered normal for tibiofemoral alignment?
femoral shaft 170-175° laterally from tibial shaft
what is genu varum?
bowlegged
angle is >180°
what is genu valgus?
knock knees
angle is <165°
during genu varum, what tibiofemoral compartment is compressed?
medial compartment
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during genu valgus what tibiofemoral compartment is compressed?
lateral compartment
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what factors can lead to genu valgus?
- previous injury
- genetic predisposition
- high BMI
- laxity of ligaments
- abnormal alignment and muscle weakness at either end of the LE
what factos can lead to genu varum?
- previous injury
- genetic predisposition
- laxity of ligaments
- abnormal alignment and muscle weakness at either end of the LE
- thinning of articular cartilage on medial side
what might result from genu varum?
- increased medial compartment loading
- greater loss of medial joint space
- increased strain on LCL
what might result of genu valgum?
- increased stress on MCL
- increased stress on lateral comparment
- excessive lateral tracking of patella
- increased stress on ACL
what is genu recurvatum?
tibiofemoral hyperextension greater than 10°
stress is placed on posterior capsule and knee flexors
where does the M/L meniscus attach?
medial = MCL, ACL, PCL and semimembranosus
lateral = ACL, PCL, popliteus
what is the function of the meniscus?
- distribute weight bearing forces
- increase joint congruency
- shock absorption
what motions does the ACL restrict?
- anterior translation of the tibia on femur
- knee hyperextension
- varus and valgus stresses
- tibial rotation medially and laterally
what motions does the PCL restrict?
- posterior translation of the tibia on femur
- varus and valgus stresses
- tibial rotation medially
what motions does the MCL restrict?
- valgus force
- lateral tibial rotation
- anterior translation of tibia on femur
what motions does the LCL restrict?
- varus stresses
- tibial lateral rotation
what osteokinematic motions are available at the tibiofemoral joint?
- flexion/extension
- abduction/adduction
- IR/ER
describe the arthokinematics of the tibiofemoral joint during a CKC motion
convex femoral condyle moves on concave tibial plateau
opposite roll and glide
describe the arthrokinematics of the tibiofemoral joint during an OKC movement
concave tibial plateau moves on convex femoral condyle
roll and glide in same direction
what occurs during the screw home mechanism at the knee?
10° of tibial ER
needed for terminal knee extension
what occurs during the unlocking mechanism of the knee joint?
popliteus IR the tibia prior to flexion
what is the open pack position and capsular pattern of the tibiofemoral joint?
open pack = 25° flexion
capsular pattern = loss of flexion before extension
prior to knee flexion, describe the joint congruency of the patella and femur
minimal joint congruency as the patella lies in the femoral sulcus during full extension
how does the joint congruency of the patella and femur change as the knee flexes?
once it gets above 90° the middle portion of the patella isn’t making contact with the femur anymore, its mostly medial and lateral surfaces
how is the patella a necessary and significant structure?
it functions as pulley for the quad
it increases the internal moment arm of the knee extensor mechanism = we need less force to extend
what static structures support the patella?
- M/L patellofemoral ligament
- M/L patellotibial ligament
- Trochlear groove
describe the motions of the patella
- S/I glide
- M/L glide
- M/L tilt
- M/L rotation
when does S/I glide of the patella occur?
superior = knee extension
inferior = knee flexion
List from least to greatest, which movements put the greatest amount of compressive force on the patellofemoral joint
- walking (1.3x BW)
- climbing stairs (3.3x BW)
- squatting (7.8x BW)
what is the Q angle?
an estimation of the line of pull of the quads
normal = 13-15°
increased Q angle ___ ____ _____on the patell
increases lateral force
list some local factors that limit lateral pull of the patella
- raised lateral facet of trochlear groove
- quadriceps (VMO in particular)
- medial patellar retinaculum fibers
- medial passive structures
list some local factors that contribute to lateral pull of the patella
- tight IT band
- excession tension in lateral patellar retinacular fibers
- excessive tension in lateral passive structures
list some global factors that contribute to lateral patellar pull
- excessive genu valgum increases Q angle
- weakness of hip ER or abductor muscles
- tightness of hip IR or adductor muscles
- excessive pronation of subtalar joint
what is a recommendation for weight bearing exercises for someone with patellofemoral pain syndrome?
avoid deep flexion
what is a recommendation for non-weight bearing exercises for someone with patellofemoral pain syndrome?
avoid final 30° of extension
what forms the Q angle?
line connected ASIS to middle of patella
line connecting tibial tuberosity to middle of patella