Question What are some structures found in the knee?

The Knee Unit

the knee joint is the largest joint space in the body it is greatest at 30 degrees of flexion the knee is considered a synovial joint b/c it is aligned with the joint capsule the synovial layer secretes synovial fluid (like oil to a car) to help lubricate the joint and keep it moving purpose of synovial fluid –lubrication –nutrient rich

BONES

Femur largest bone in the body distal end makes up knee –forms convex medial and lateral condyles –medial condyle is larger and longer in the AP direction, which causes external tibial rotation

Tibia 2 tuberosities –concave in nature –separated by popliteal notch (Tibial Spine) ACL & PCL attach to the tibial spine ACL & PCL are named from their attachment on the tibia Tibia Fracture Tibia Fracture

Patella Sesmoid bone –largest one in the body –lies within the quad tendon to increase function Function –protect anterior knee –increase mechanical advantage

patella is most palpable in extension b/c it is above the trochlear groove at 30 degrees of flexion, the patella is in the trochlear groove patella is held in place by the retinaculum lateral retinaculum is stronger than medial retinaculum

Why patella dislocation happens laterally ? weak VMO shallow trochlear groove small or abnormal patella increased Q-angle tight IT band tight lateral retinaculum

Chondromalacia Patella

LIGAMENTS ALL STATIC STABILIZERS

MCL - Medial Collateral Ligament Injured by valgus force 2 parts –Deep close to bones; thin layer thickening of joint capsule, intracapsular injury causes effusion (joint swelling) attaches to the medial meniscus –Superficial forms the MCL palpableextracapsular injury causes edema (swelling outside the joint)

LCL - Lateral Collateral Ligament thickening of capsule does NOT attach to lateral meniscus attaches to fibular head and attaches to lateral epicondyle very palpable

ACL - Anterior Cruciate Ligament attaches on tibia and lateral femoral condyle (medial aspect) moves superior, posterior, lateral injury happens by anterior blow to femur or deceleration with rotation prevents the tibia from moving anteriorly

PCL - Posterior Cruciate Ligament attaches on tibia and medial femoral condyle (lateral aspect) moves superiorly, anteriorly, medially injury happens by anterior blow to tibia or posterior blow to femur

MENISCUS curved, wedged, fibrocartilaginous discs lies between the femoral condyles and tibial plateaus the outer edge is thicker than the inner edge

the inner 2/3 of menisci are avascular (no blood supply) the outer 1/3 is called the "red zone" because it is highly vascular (has blood supply) reasons for having the menisci –enhance stability of knee –assist with knee motion by decreasing friction –shock absorber

Menisectomy Menisectomy - removal of the meniscus Menisectomy the lateral and medial meniscus are connected by the transverse ligament located in front of the tibial spine Medial meniscus - "C" shaped Lateral meniscus - "O" shaped Medial meniscus is larger than lateral meniscus Medial meniscus is attached to entire periphery (outer edge), and intrachonduloar eminence (tibial spine), which is also the attachment for the ACL Lateral meniscus is loosely attached

Meniscal Tears Bucket Handle –occurs in the middle of the meniscus (red-white zone) –often times posterior –most common Peripheral Tear –red zone –responds extremely well to surgery Avascular Tear –white zone –must be removed and cleaned up on the edges –heals poorly because no blood supply

Hamstring Group

Quadricep Group

Bony Land Marks

Palpations Tibial Spine Head of fibula

Palpations Patella Patella Superior Pole

Palpations Tibial Tubercle Gerdy’s Tubercle

Palpations Patella Inferior pole Gastrocnemius

Palpations Patellar Tendon Quadriceps

Vastus Medialis Hamstrings

ROM Flexion and Extension Ab and Adduction Dorsiflexion and plantarflexion

Special Tests Valgus Stress Test (full extension) Steps Patient is supine with the involved leg close to the edge of the table and the knee in full extension Examiner supports the medial portion of the distal tibia with one hand while the other hand grasps the knee along the lateral joint line. Examiner applies a medial (valgus) force to the knee & the distal tibia is moved laterally while the knee is in complete extension Positive Test Increased laxity, pain, and guarding Positive Test Implications Injury to the MCL, medial joint capsule; probable ACL/PCL involvement if there is no endpoint

Varus Stress Test Steps: Patient is supine with the involved leg close to the edge of the table and the knee is in full extension. Examiner supports the lateral portion of the distal tibia with one hand while the other hand grasps the knee along the medial joint line. Examiner applies a lateral (varus) force to the knee & the distal tibia is moved medially while the knee is in complete extension Positive Test Increased laxity, pain, and guarding Positive Test Implications Injury to the LCL, lateral joint capsule, & arcuate ligament; probable PCL (& maybe ACL) involvement if there is no endpoint

Lachman’s Patient is supine with his/her knee passively flexed to approximately 20 degrees & hands crossed across his/her chest. Examiner's thumb of the same–side hand as the knee to be examined is placed at the anterior medial tibial plateau/joint line, while digits 2–5 are positioned posterior, slighty distal to the popliteal fossa. Examiner's contralateral hand is placed laterally around the distal femur, just proximal to the patella with the thumb anterior & the digits 2–5 are positioned posteriorly. Examiner sets the tibia by pushing posterior (to make sure the PCL is in tact). Examiner provides an anterior force to the tibia while applying posterior pressure to the femur; repeats the process 2–3 times Positive Test Increased anterior tibial translation, pain Positive Test Implications ACL tear (primary posterolateral bundle but also the anteromedial bundle)

Positive Laahman’s ODKJwk ODKJwk

Anterior Drawer StepsPatient is lying supine with his/her hip flexed 45 degrees & knee flexed 90 degrees Examiner sits on the patient's foot & grasps the tibia just below the joint line Examiner's thumbs are placed along the joint line on either side of the patellar tendon & the index fingers are used to palpate the hamstring tendons Examiner ensures that the patient is relaxed, esp. the hamstring tendons Examiner draws the tibia straight forward (no rotation) Positive Test Increased anterior tibial translation, pain Positive Test Implications ACL tear (mainly the anteromedial bundle because the posterolateral bundle is basically laxed in this position) Mmj0 Mmj0

Posterior Drawer Steps Patient is lying supine with his/her hip flexed to 45 degrees & knee flexed to 90 degrees Examiner sits on the patient's foot & grasps the tibia just below the joint line Examiner's thumbs are placed along the joint line on either side of the patellar tendon Examiner ensures that the patient is relaxed, esp. the quadriceps Examiner pushes the tibia posteriorly Positive Test Increased posterior tibial translation, pain Positive Test Implications PCL tear

McMurry’s Test StepsPatient is supine Examiner stands lateral & distal to the involved knee with one hand supporting the lower leg Examiner positions thumb & index finger of the opposite hand in the anteromedial & anterolateral joint lines on either side of the patellar tendon Examiner keeps the tibia in the neutral position, applies a valgus stress through knee flexion & varus stress through knee extension Examiner internally rotates the tibia & applies a valgus stress through knee flexion & a varus stress through knee extension Examiner externally rotates the tibia & applies a valgus stress through knee flexion & a varus stress through knee extension Positive Test Popping, clicking, or locking of the knee; pain from within the joint Positive Test Implications Possible meniscus tear

Apley’s Compression Steps - Patient is prone with his/her knee flexed to 90 degrees Examiner applies pressure to the plantar aspect of the heel, applying an axial load to the tibia while simultaneously internally & externally rotating the tibia Positive Test Pain; possible clicking Positive Test Implications Possible meniscus tear

Ober’s test Steps - Patient is lying on the side opposite that being tested Examiner stabilizes the pelvis with one hand and the lateral side of the examiner's hip against the patient's pelvis Examiner grasps the femur above the knee with the other hand & abducts & extends the hip Examiner allows the hip to passively adduct to the table with the knee straight Positive Test Leg does not adduct past parallel Positive Test Implications IT Band tightness