What type of joint is the knee?
Compound, modified hinge
When is the knee most stable?
Extension
Who has the largest patella tracking?
Females
Where is the articular capsule attached?
Condyles of tibia and femur
What are the deficiencies of the capsule of the knee and what fills these?
Anterior: suprapatellar bursa
Posterior: popliteal tendon
What are the ligaments surrounding the knee joint?
Patellar, oblique, arcuate popliteal, medial collateral, ITB and coronary
What muscles provide support to the knee joint?
Hamstrings, popliteus and gastrocnemius
What does the synovial membrane in the knee reflect onto?
Cruciate ligaments, infra patellar fat and popliteal tendon
What are the communicating bursa of the knee and what is the significance of this?
Suprapatellar, gastrocnemius and semimembranosus - can spread infection
What are the collateral ligaments?
Medial (wider, attached to medial meniscus, resists abduction and ER)
Lateral (shorter, separated from lateral meniscus by popliteus tendon, resists adduction)
What are the cruciate ligaments?
Intracapsular but extrasynovial
Allow rotation and stabilise ant/post movement
What is the ACL?
Tightens and untwists in extension
Assits in IR of femur
Prevents backwards displacement of femur on tibia in WB and forward displacement during NWB
Prone to injury in hyperextension, flexion and rotation
What is the PCL?
Taut in full flexion
Prevents forward displacement of femur on tibia in WB and backwards displacement in NWB
Prone to injury with flexed knee
What are the other ligaments at the knee?
Oblique popliteal: posterior, extension of semimembranosus, inserts to tibia, fibres oblique superolateral
Arcuate popliteal: covers popliteal tendon
Transverse genicular: contact mensici anteriorly
*All work together to stabilise knee but don’t have strong individual roles
What are the menisci?
Fibrocartilage wedges
Improve congruency (increase 1/3) and stabilise knee
Bear weight and spread fluid
Lateral: more c shaped
Medial: larger, longer, less mobile due to MCL attachment
What is the mechanism of locking the knee joint?
Lateral condyle attaches (shorter)
Medial attaches and then rotates (longer and more oblique)
How can you test for knee joint injury?
Post/anterior draw test, keep femur stable and move tibia in desired direction, if it moves easily then ligaments are ruptured
What is the unlocking mechanism?
Rotation at beginning of flexion, in WB position of full extension popliteus draws lateral femoral condyle posteriorly, external rotation of femur on tibia
What is genu valgum?
Medial angulation of femur, lateral condyles touching, knock knee
What is genu varum?
Bow legged, lateral angulation of femur, medial condyles touching
What is the tibiofibular joint?
Proximal: plane
Distal: fibrous
Reinforced bby ant/post tibiofibular/interosseous ligaments
Provides shock absorption and stops bones from separating