The Knee Joint Flashcards
What type of Joint is the Knee
Synovial Hinge Joint
Bones of the Knee joint
Distal Femur
Proximal Tibia
(Patella)
(Fibula: not associated with knee joint- mainly just for muscle attachments)
Articulations at the knee
Medial Femorotibial
Lateral Femorotibial
Femoropatellar
Movements of the knee
Extension
Flexion
Medial/Lateral Rotation
When can knee rotation only occur
When knee is flexed and collateral ligaments are relaxed
Why is knee flexion not as strong when the hip is extended
Loss of tension of Hamstrings
Locking of the Knee
Femur rotates MEDIALLY when approaching full extension
Unlocking of the Knee
Popliteus LATERALLY rotates femur
Can’t flex the knee without first unlocking
Why is the knee least congruent in flexion
Round Femoral Condyles provide less contact upon the Tibial Plateau
Functions of the Menisci
Increase Joint Congruity (negligible)
Evenly distribute weight
Shock Absorption
Assist in Knee Locking
Which meniscus is attached to its collateral ligament
MEDIAL meniscus is attached to TIBIAL collateral ligament
Causes of a Meniscal Tear
Sports Injury
Degenerative Changes e.g Osteoarthritis
Symptoms of a meniscal tear
Locking of knee
Pain during movement
Reduced movement
As menisci may become trapped in joint
Repair of Meniscal tear
Repair or Resection is limited due to poor blood supply
Intra-articular ligaments
ACL and PCL
Inside the joint capsule
Extra-articular ligaments
Medial / Lateral (Tibial/Fibular) Collateral Ligaments
Origin/ Insertion of ACL
Anterior Intercondyle
->
Lateral Femoral Condyle
Function of ACL
Prevents Hyperextension/ Anterior displacement of tibia on femur
Injury to ACL
Hyperextension (anterior force)
Origin/Insertion of PCL
Posterior Intercondyle
->
Medial Femoral Condyle
Function of PCL
Prevents Hyperflexion/ Posterior displacement of tibia on femur
Injury to PCL
Landing on Tibial Tuberosity with a flexed knee
Which cruciate ligament is strongest?
PCL- main stabiliser of flexed knee e.g. walking downhill
Features/ attachments of Fibular/Lateral Collateral Ligament
Flat band, not attached to meniscus
Lateral Femoral Epicondyle
->
Head of Fibula
Function of LCL
Prevents Abduction and rotation during knee extension
Features/ attachments of Tibial/Medial Collateral Ligament
Cord like band, attached to medial meniscus
Medial Femoral Epicondyle
->
Medial Tibial Condyle
Function of MCL
Prevents adduction and rotation during knee extension
What is the Unhappy Triad
ACL Tear
MCL Tear
Medial Meniscus tear
Common when flexed knee is excessively laterally rotated
Bursae of the Knee
Prepatellar Bursa
Suprapatellar Bursa
Deep Infrapatellar Bursa
Superficial Infrapatellar Bursa
Muscles stabilising the patella
Rectus Femoris, Vastus Lateralis, Vastus Intermedius pull laterally
Vastus Medialis pulls medially and obliquely
Lip on Lateral Femoral Condyle
Why are patellar dislocations more common in females
Greater Q angle (wider and more shallow pelvis)
What is genu varum
Bow knee; Increased Q angle
Tibia adducted relative to femur
What is genu valgum
Knock knee; Decreased Q-Angle
Tibia abducted relative to femur
Changes in osteoarthritis
Reduced Joint Space
Osteophytes (abnormal bone remodelling)
Sclerosis (abnormal bone density)
