Knee Flashcards
What structure allows knees to function in its normal function with a short tibial plateau?
“Mueller’s 4 bar linkage” which describes how tension form the ACL and PCL direct movement at the knee
How does the ACL restrict motion at the knee?
by connecting the posterior femur to the anterior tibia and primarily hiccups the tibia from slipping forward; it also limits rotation
How does the PCL restrict motion at the knee?
by connecting the anterior femur to the posterior tibia it limits posterior tibial displacement
How does the PCL restrict motion at the knee?
by connecting the anterior femur to the posterior tibia it limits posterior tibial displacement
*commonly damaged by dashboard, fall, femur fracture
____ resists valgus and ___ resists varus.
MCL resists valgus and LCL resists varus
____ resists valgus and ___ resists varus.
MCL resists valgus (blow to lateral knee) and LCL resists varus (blow to medial knee)
How does the structure of ligaments damaged with sudden abrupt force?
tendons become increasingly stiff with increasing tension until they fail, sudden abrupt force often exceeds the ability of the ligament to cope with force
What motion causes injury of the ACL? What are other signs of a possible ACL tear?
when bones of the upper and lower leg twist in opposite directions under full body weight; which often means during a plant, cut or pivot
patients may hear an audible pop, they usually cannot continue to participate in athletics and there is an immediate tense effusion (will result in positive lachman test)
What are some of the complications of ACL tear? How are they treated?
50% have associated meniscal tears, recurrent episodes of knee giving way
late arthritis
treated with reconstruction of ACL and meniscus repair whenever possible
What is the most important function of the meniscus?
meniscus bears and distributes weight as evidenced by the fact that meniscectomy increases joint loads and increases risk of late DJD
What is the most important function of the meniscus?
meniscus bears and distributes weight as evidenced by the fact that meniscectomy increases joint loads and increases risk of late DJD
What characteristics of a meniscus are important for possible repair?
repair requires sufficient blood vessels and a good quality meniscus
What factors contribute to the development of DJD?
genetics old trauma to articular cartilage loss of meniscus chronic instability due to tendon damage malalignment obesity
How is DJD of the knee managed?
weight loss and activity modification
unloader brace, correct alignment
PT to improve motion, strength and balance
What is the limitation of arthroscopy to treat tendon or joint injury?
nearly all injuries include meniscal tears which are not treated well with arthroscopy
