Knee

Knee Joint Type

Synovial, hinge and rotation/ rolling and gliding

Major Bones of the Knee

Femur, Tibia, Patella, quad tendon connects the quad to patella and patella tendon connects patella to tibia

Tibiofemoral Articulation

Joint between femur and tibia.

Patellofemoral Articulation

Joint between patella and femur.

Knee Joint Stability Structures

Capsule, ligaments, menisci, muscle, tendons.

Knee Capsule

A sheet of dense fibrous connective tissue that surrounds the joint and surrounds the articulating bones. It is filled with synovial fluid for lubrication.

Anteriorly it, Extends upwards underneath patella for the infrapatellar fat pad and bursa/ Medially, forms the deep portion of the medial collateral ligament. Posteriorly, forms pouches that cover the femoral condyles and tibial plateau

It is extensive and redundant in that it covers a large area and There available space at the front of the knee as the area around the patella is more accessible and offers more space for fluid to gather as the capsule is loose around the patella to allow the movement of it

Medial Collateral Ligament (MCL) Function

• Short inner, long outer fibres

• Prevents inward rotation, or valgus movement

• Attaches at the medial epicondyle (femur) and medial condyle of the tibia

Lateral Collateral Ligament (LCL) Function

• Attaches to lateral epicondyle of femur and head of the fibular

• Prevents outward rotation or varus movement

Anterior Cruciate Ligament (ACL) Function

• Starts posteriorly on the femur and ends anteriorly on the tibial

• Prevents anterior displacement of tibia and prevents posterior displacement of femur

• Prevents hyperextension

• Stabilizes against excessive internal rotation and a secondary restrain for valgus or varus stress

Posterior Cruciate Ligament (PCL) Function

• Starts anteriorly on femurs and ends posteriorly

• Prevents Posterior displacement of tibia and Anterior displacement of femur

• Resists internal rotation of tibia and prevents hyperextension

Menisci Role in the Knee

• Fiber cartilage

• Medial and lateral

• Attached to tibial plateau

• Connects to the extracapsular ligaments by the coronary ligament

• Provides cushioning and stability

• Increase blood/nutrient circulation?

  • Maintains spacing between femoral condyles and tibial plateau

• Acts as a cushion

  • Cushions stress placed on the knee joint

• Acts as a sponge

  • It soaks up synovial fluid and when bending it squishes the fluid out to help circulate nutrients

Blood Supply Zones of Menisci

Outer 1/3 (red zone), Middle 1/3 (pink zone), Inner 1/3 (white zone).

Function of Quadriceps Muscles

• Rectus femoris

  • Originates at ilium at anterior inferior iliac spine

• Vastus medialis, vastus intermedias, vastus lateralis

  • Originates at the femur

  • All insert by the quadricep tendon and patellar tendon on the tibial tuberosity

  • Function is extension of the knee

  • Quad helps the PCL and prevents tibial posterior displacement

Hamstring Muscles

• Origins at the ischium

  • Bicep femoris

    • Inserts on the head of the fibula

  • Semimembranosus and Semitendinosus

    • Insert on the anterior medial tibia

• Flex lower leg on thigh at knee

• Extend thigh on trunk at the hip

• Helps ACL and prevents tibia anterior displacement

Bursae

• Prepatellar bursa

  • Anterior to the patella

• Suprapatellar bursa and fat pad

  • Superior to the patella on the femur

• Infrapatellar bursa and fat pad

  • Inferior to the patella on the tibia

• Inflammation of the bursa is bursitis

Valgus Stress Test

• Test the MCL

• Push the lower leg laterally

• Push the femur/knee joint medially

• Normal tests will see resistance from the knee

• Positive tests will see a considerable ROM of the knee

Meniscus Assessment Tests

• Apley's Compression

• Mcmurry

  • Compress and rotate the meniscus

  • Medial

    • Knee at 90 degree, push knee medially, rotate foot externally to apply stress

  • Lateral

    • Push knee lateral and foot internal rotation

• Joint line tenderness

Ottawa Knee Rules for X-ray

1. Age 55 or older

2. Isolated tenderness of patella (no bone tenderness of knee other than patella)

3. Tenderness of head of fibular

4. Inability to flex 90 degrees

5. Inability to bear weight both immediately and in the emergency department for 4 steps

   1. Unable to transfer weight twice onto each lower limb regardless of limping

Extracapsular ligaments

controls side to side movement and help with stability and direct movement in the correct path

Intracapsular Ligament

Helps for stability, control movement between femur and tibia and helps with rotational stability

Medial meniscus

• Takes valgus and torsional forces

• Will feel pain on external rotation of the tibia

  • Tibia rotates externally, meniscus moves under the femur condyle

• Like a C shape

Lateral meniscus

• Takes varus and tortional force

• Will feel pain on internal rotation of the tibia

• Like an O shape

Tensor Fascia Lata

• Originates at the ilium

• Inserts on the tibia and into the fascia of the thigh, the iliotibial band, IT band

• Helps flex and abduct thigh on trunk at hip

• Adds to lateral stability of the knee

Gracilis

• Origins at the ischium, insert on the anterior medial tibia

• Assists with knee flexion

Flexion and Extension

• Gliding of condyles on the plateau and meniscus

  • Flexion is anterior glide and posterior roll of femur

  • Condyles move forward and roll back

  • Extension is posterior glide and anterior roll of femur

  • Condyles move back and roll forward

Locking Mechanism

• Femur internally rotates to lock the joint

• When the knee extends from a flexed position, the tibia externally rotates relative to the femur or the femur internally rotates to complete full extension at the knee

• This can cause increased tension and shear force on medial meniscus and cause distortion

  • Tears, deformation, hypomobility

Popliteus

• Major stabilizing muscle of the knee

• Located on the back of the knee

• Knee flexion and external rotation of the femur

Knee Assessment

• Hx, PHx (prior knee injury? did it fully heal? Rehab?

• Ssx

  • Pain, tenderness

  • "snap", "pop"

• Examination

  • Observation

    • Limp or instability

    • Swelling (acute or delayed)

      • Swelling indicates intracapsular injury

• ROM

  • Functional tests

    • Compare both sides

  • Thigh circumference

    • Is there noticeably swelling

    • Long swelling will cause atrophy of the quads

  • Palpation

Knee Alignment

• Patellar malalignments

  • Check if the kneecaps have shifted out of the trochlear groove and are pulled toward the outside of the box

• Q angle

  • Angle between the Anterior superior iliac spine and the midpoint of the patella

  • Will indicate the alignment of the knee

  • An angle less than 15 degrees is normal

  • Angle greater than 20 degree is Genu Valgum, knock kneed

  • Less than 10 degrees is genu varum, bow-legged

  • Genu recurvatum

    • Hyperextension

  • Genu antecurvatum

    • Can't extend

Weight bearing Functional assessment

• Gait

• Squat

• Single leg squat

• Thessaly

  • Mensiscus

  • Bend and twist

• Duck walk, Childress Test

  • Meniscus

• 2 legged hop

• Single leg hop

Non weightbearing ROM

• Flexion/extension

  • Active

  • Passive

  • Resisted (strength)

Varus Stress Test

• Tests the LCL

• Push the lower leg medially

• Push the femur/knee joint laterally

• Positive test will see a considerable ROM

Intracapsular Swelling Test

• Patellar compression

  • Ballottement

  • Swipe Test

    • Swipe medially of the patella 5-6 times

    • Swipe laterally of the patella once, if there any movement of liquid going back to the medial side, it confirms swelling

ACL Assessment

• Anterior drawer

• Lachman's

• Pivot shfit

  • All assessments test for the anterior displacement of the tibia

• MRI accuracy for diagnosis of an ACL injury is 95% and more

PCL Assessment

• Posterior sag

• Posterior drawer

  • Tests for posterior displacement of the tibia

Contusion

• Direct blow and worse if muscle is relaxed

• Ssx

  • Pain, tenderness

  • Swelling, circumscribed

  • Discolouration

  • Limp

• Tx

  • POLICE for 2 days

  • ROM and padding

  • Physiotherapy and rehabilitation

• No massage, no heart over bruise

  • Myositis ossificans

Bursitis

• Direct blow or kneeling

• Overuse

• Ssx

  • Inflammation

    • Redness, heat, swelling, pain, loss of function

  • Tenderness

  • Painful on knee extension if infrapatellar or suprapatellar

• Tx

  • POLICE, padding, NSAIDs

  • Heat, physio, rehabilitation

  • Early aspiration if acute and traumatic

• Complications

  • Chronicity, recurrence, infection

Sprains

• Direct blow, valgus and anterior

• Torsion or hyperexteions

• Worse if foot is fixed (planted)

• 1st degree

  • Mild pain and swelling

  • No limp or effusion or increase laxity

  • Tx

    • POLICE, physio

    • Brace

• 2nd Degree

  • Pain, tenderness, snap

  • Swelling and effusion if intraarticular

  • Limp

  • Increased laxity with a firm endpoint

  • Tx

    • Same as 1st degree and see MD

    • Longer recovery period

• 3rd Degree

  • Complete rupture of the ligaments

  • Ssx

    • More pain, tenderness, snap

    • Marked swelling and effusion

    • Unstable or won't bear weight

    • Increase laxity with a soft endpoint

  • Tx

    • NPO

    • Stabalize, get to hospital

    • Need brace and/or surgery

    • Follow with extensive physio and rehab

Meniscal Tear

• Torsions and hyperextension

• Rotation of the femur will cause the condyle to glide on top of the tear

• Ssx

  • Acute

    • Pain or tenderness

    • Effusion

  • Chronic or acute

    • Locking or buckling

    • Intermittent pain, swelling, effusion

    • Positive McMurray's and Apley's test

• Tx

  • Physio

  • Arthroscopic repair or excision

Capsular Tear

• Connective tissue tears

• Torsion

• Hyperextension

• Ssx

  • Pain, swelling maybe

  • Tenderness

  • Cause rotary instability

  • Mimix torn meniscus or tendon injury

• Tx

  • Rest, physio, rehab

  • Surgery if symptoms persists

Patellofemoral Pain syndrome

• Pain around the patellofemoral joint

• Related to abnormal tracking of patella in the femoral groove

  • Cause of the track can be from genu valgum, external tibial torion, over pronation, greater than normal Q angle

  • Tight quad musculature

  • Tight of adductors

It breaks down into chondromalacia patellae or patellofemoral stress syndrome

Chondromalacia Patellae

• Softening and deterioration of cartilage on the back of the patellae

• SSx: pain walking up or down, running and squatting

• Tx: Conservative (POLICE, NSAIDS, active modification, strengthening, orthoticts)

  • Surgery is last option

    

Patellofemoral stress syndrome

• Lateral tracking of patellae in femoral groove

• Tight lateral musculature, weak hip adductors/stabilizers

• Ssx: pain lateral patellae, crepitus with patellar compression

• Tx: POLICE, avoiding aggravating activities, strengthening VMO over VL. Stretching lateral soft tissues, Mcconell taping/bracing

Patellar Sublux/Dislocation

Patella is out of place and not in femoral groove

Unhappy Triad

• Seen more in female sex, could be hormonal

• Acl Tear

  • Positive anterior drawer, Lochmann's test, pivot shift

  • Effusion

  • Snap

• MCL tear

  • Valgus instability, point tenderness

• Mensical Tear

  • Tenderness

  • Locking or buckling

• Capsular tear

• Tx

  • Reconstructive surgery

  • Brace, physio, rehab

• NB, effusion? Get to hospital

Osteochondritis dissecans

• Damage to cartilage and subchondral bone

• Most commonly in knee, medial femoral condyle 70% of the time

• Cause could be hereditary, traumatic, vascular

  • Progression: softening of cartilage

  • Early cartilage separation from bone

  • Partial detachment of cartilage

  • Osteo chondral separation with loose bodies

ACL post Surgical Rehab

• Quad and hamstring activation

• ROM focusing on full extension

  • No extension you can't walk

• 3-4 months post surgery must proceed with caution

  • Graft is still weak and adapting to environment

• Start with Closer kinetic chain than open kinetic chain

  • Close is the foot in contact with the round

  • Open creates shear force, knee extension must be avoided

• Strengthening hamstring and quad is balanced

• 6 months on, increase load, jogging and running

• Neuromuscular training

• Return to sport, education/technique modification

• Return to sport functional testing

• Use a brace?

Prevention of ACL injury, Neuromuscular Training Fifa 11

• All youth athletes should do straining that work balance, proprioception and strenghtening

• 1/3 decrease of ACL injuries with FIFA 11

• Running exercise with change of directions

• Strength, plyometric and balance

• End with harder intensity running

Screening for risk of knee injuries by doing drop vertical jump test

Open and closed chain exercises

Open kinetic chain has the foot or hand free and not fixed to an object.

Closed will be fixed, or stationary