The PF joint is congruent or incongruent?
Why (3)?
What does it imply (2)?
- The shape of articular surface – different ++
- The patellar articular surface smaller than the femoral articular surface
- When knee in full ext – patella not in the groove
- Poor congruence = poor stability of the join
- Will need to rely on other static & dynamic structure for it’s stability
What are the dynamic stabilizer of the patella?
quads ts (VMO ms, vastus lateralis ms), patellar tendon, ITB, rectus femoris ms
What are the static stabilizer of the patella (2)?
Static stabilizer : med patellar retinaculum, lat patellar retinaculum
What is the insall -salvatti index ratio on lat x-ray?
What’s a normal and abnormal ratio?
What indicates an abnormal ratio?
o Ration patella td length: patella length
o Normal ratio = 1.25:1
o Abnormal ratio >2:1 = patella alta
Which bursa (knee joint) 1. communicate with the joint capsule
- Are affected by pronloged kneeling
- communicate with the joint capsule: suprapatellar & semimembranosus bursae
- Are affected by pronloged kneeling: prepatellar & superficial/subcut. infrapatellar bursae
MCL is preventing which mvt (2)? and stretched in which position (4)?
- prevent valgus stress, tibia ER
- stretched with knee in
o full ext
o flex 90°
o ER
o Valgus stress
T/F MCL is attaching to the medial meniscus and LCL is attached to lateral meniscus
MCL is attaching the medial meniscus.
LCL have no attachement to lateral meniscus
ACL is
- from ant/post & med/lat tibia
- to ant/post & med/lat femur
- intra/extra articular
- intra/extra synovial
ACL is
- from ant & lat tibia
- to post & lat femur
- intra articular
- extra synovial
What are the 3 primary function of the ACL?
- Restrain anterior translation of tibia on femur
- Backward sliding of the femur & hyperextension of the knee
- Control tibia IR on the femur in femoral ext of 0-30° (so with a extended knee 0&-30, IR)
Which mvt PCL restrains
Posterior translation of the tibia on femur
between medial and lateral meniscus
- which one is longer
- which one is C shaped and U shaped
- Which one has less mobility
- Which one covers more area
- Which side is more prone to OA
- which one is longer: medial
- which one is C shaped and U shaped: C = medial; U = lateral
- Which one has less mobility: medial (attached to MCL)
- Which one covers more area: lateral
- Which side is more prone to OA: medial
What are the functions of the menisci (8)?
- Jt congruence
- Vital for knee stability
- Lubrication, nutrition
- Improve weight distribution
- Reduce friction
- Prevent hyperextension
- Prevent capsule from getting into the jt
- Shock absorption: protects / minimizes the amount of stress on art cartilage
