What is a plica?
Remnants of synovial divisions from development; most common locations are the suprapetellar, mediopatellar plica, lateral synovial plica, infrapatellar plica (the most common plica and least symptomatic of all)
Describe symptoms of an irritated plica?
Most common symptoms location is along the medial (inside) of the knee. Symptoms mimic PFPS and can refer pain to the medial meniscus and cause paients pain "under the kneecap". Pain with prolonged sitting, prompting the term "moviegoer's sign" because it is less painful in ext; may cause pseudo-locking, may cause a pop beneath the patella or snap over the medial femoral condyle.
Describe the patellar trochlear groove contact from full ext to flexion:
0-20 no patellar femoral contact until 30 where the distal third contact the uppermost part of the femoral condyles; @45 the middle third contacts; @ 90 the distal third contacts; end range the odd facets contact
Patella baja may result from adhesions from what bursa?
infrapatellar bursa; most likely to occur after medialization of the tibial tuberosity or patellar tendon graft for an ACL repair
Describe the "lateral blow out" sign of the knee
the ant lateral portion of the capsule is thin and swelling will bulge outward in this area especially in knee flexion; may indicate lateral meniscus tear
Discuss the role of the posterior oblique ligament:
predominant ligamentous structure on the post-med corner of the knee; prevents posterior translational
What important does the arcuate complex provide:
each step at heel stroke with the near full ext exerts tremendous force across the posterior lateral knee (posterior one third of lateral supporting structures: LCL, arcuate lig an ext of the popliteus) helps control IR of the femur on a fixed tibia or ER during open chain
Function of the ACL
prevents recurvatum prevents IR of the tibia in open chain and and ER in closed chain, stops ant translation of the femur on the on the fixed tibia
Function of the PCL
stop posterior translation of the tibia of the tibia on the femur; decelerator of the femur
Function of the IT Band
aids in ext, but when the knee is bent past 30 degrees it slides back and becomes a flexor; also contribute to prevent pivot shift to aid the ACL
Anatomic reasons for patellar instability?
High Q-angle (norm for males 13 females 18), loose retinaculum, patella alta, weak or dysplastic vastus medialis obliquus muscle, flattened lateral femoral condyle
Do cruiciate ligaments really cross?
yes, the twist upon themselves during knee flexion and extension
What is the normal measurement of tibial torsion?
12-18 degress of lateral tibial torsion, so the lateral malleloi will be more posterior than the medial
Which meniscus is most commonly injured and why?
medial meniscus, it is adhered to the medial collateral ligament; there is also increased WB'ing on the medial portion of the knee
What is the function of popliteus?
unlocking and IR rotating the knee during flexion, aids with stabilization for balance, protects the latearl mensicus, prevents ant translation of the femur
What is the q-angle?
Angle from the ASIS to the center of the patella to the tibial tuberosity
What may increase a Q angle?
femoral anteversion, external tibial torsion, genu valgum, pes planus
What anatomic structures encourage lateral tracking of the patella
dysplastic patella, patella alta, shallow intercondylar groove, tight rentiaculum, tight IT band
Function of VMO
prevents subluxation of the patella, counter acts vastus laterallis; acting alone it is unable to ext the knee works harmoniously with the rest of the quad
What is lateral pressure syndrome?
A tight lateral retinaculum pulls and tilts the patella laterally, increases lateral facet
Define bipartite patella?
The patella will still have an intact ossification center, and may be mistaken as a fracture
What is the difference between Osgood-Schlatter disease and sinding larsen-johansson disease
Osgood is an apophysitis of the tibial tubercle and sinding larsen-johanssen disease is apophysitis of the inferior patellar pole
Since articular cartilage is anueral what tissues around the PF joint cause pain?
Define Hoffa's disease
Fat pad syndrome manifests as pain and swelling of the infrapatellar fat pad, usually from direct trauma to the anterior knee, particularly during activities
Treatment approach for instability?
avoid terminal knee ext, suggest ex from 90-30 degrees, use braces and tape
Tx for knee muscle and tendon injuries?
open and closed chain ex with emphasis on eccentrics, stretching
Tx for friction knee injuries
avoid repeated flexion and extension exercises, exercise in pain free ROM; exercise above and below painful ROM
Tx for knee articular injuries
increase quad function, pain free ROM in unloaded environment
Tests for plica syndrome
Stutter and Hughston's plica tests
Prepatellar bursitis either from blunt trauma over repetitive microtrauma over the anterior knee