The Knee and Related Structures

The KneeBones

FemurPatella

Largest Sesamoid bone in human bodyTibiaFibula

Non-weight bearing bone

ArticulationsFour Articulations

Femur and Tibia Femur and Patella Femur and Fibula Tibia and Fibula

MeniscusTwo oval fibrocartilages that sit in the tibia

Semi-lunar (half moon shape)Stabilize the knee

Especially the medial, when the knee is flexed at 90 degreesMedial

C-shaped Attach to the tibia, joint capsule by the coronary ligament, and the

semimenbranous muscle (hamstring)Lateral

O-shaped Attached to the tibia, loosely to capsule, and popliteal tendon, and

ligament of WristbergBlood Supply

Divided into 3 circumferential zones Red –Red Red-White White-White

Avascular

3 Zones of Meniscus

Stabilizing LigamentsAccount for a considerable amount of knee

stabilityTwo ligamentous bands that cross one another

within the joint capsule of the knee Anterior Cruciate Ligament (ACL)

3 twisted bands Prevents the femur from moving posteriorly weight

bearing and anteriorly non-weight bearing. Stabilizes the tibia from excessive internal rotation

(IR) Posterior Cruciate Ligament (PCL)

Resists IR of the tibia Prevents hyperextension of the knee

ACL & PCL

Common Cause of ACL Tear

Common Cause of PCL Tear

Situations in which the PCL can tear include -excessive hyperflexion (forced bending), eg falling onto the shin with a bent knee and foot pointed dashboard injury in a car - where the knee is bent to a right angle and a sudden force drives the tibia backwards

Medial Collateral LigamentSuperficial ligament(MCL) is separate from the

deeper capsular ligament.Attaches above the join line on the medial epicondyle

of the femur and below on the tibia – Just beneath the attachment of the pes anserinus (hamstring tendons)

Deep medial capsular ligaments Primary purpose are to attach the medial meniscus to the

femur and to allow the tibia to move on the meniscus inferiorly

Lateral Collateral LigamentSize of a pencilAttached to lateral epicondyle of the femur and to the

head of the fibula.Taut during knee extension but relaxed during flexion

More Structures of the KneeJoint Capsule

Knee joint is surrounded by the LARGEST joint capsule in the body.

Contains: infrapatellar pouch, fat,pad, and bursae, MCL, and other ligaments.

Divided into Four regions – are reinforced by other anatomical structures Posterolateral & medial Anterolater al & medial

Knee Musculature13+ Muscles Movements of the Knee

Knee Flexion & Extension External & Internal Rotation

BursaeReduce friction2 dozen have been identified in the knee

Fat PadsSeveral pads located around the kneeInfrapatellar fat pad is the largest

Nerve & Blood Supply

Specific InjuriesMedial & Lateral Collateral Sprain

Hit from opposite side of legACL & PCL Sprain

ACL= lower leg is rotated while the foot is fixed (jumping) PCL=fall with full weight on the anterior aspect of the bent knee

with the foot in plantar flexion (sliding)Meniscal Lesions

Most common= weight bearing combined with a rotary force while running

Patellar Conditions Patellar orientation predisposes you to have certain types of

injuries Acute patellar subluxation or dislocation Chondromalacia

Softening and deterioration of the articular cartilage on the back of the patella

Three stages Patellofemoral Stress Syndrome

Some lateral deviation of the patella as it tracks in the femoral groove

MCL & LCL Sprain

Meniscal Lesions

Patellar Tracking

Patellar ExaminationThe Q-Angle

Quadriceps angle Normal is 10’ Males / 15’ Females20’ (+) predisposed to

patellar subluxation/dislocation

Extensor InjuriesOsgood-Schlatter Disease

Pain at the attachment of the patellar tendon to the tibial tubercle

Can lead to avulsion fractureLarsen-Johansson Disease

Occurs at the inferior pole of the patella Excessive repeated strain on the patellar tendon

Patellar Tendinitis (Jumper’s/Kicker’s Knee) Repetitive trauma Extreme tension on the knee extensor muscle complex Painful at patellar or quadriceps tendon

Iliotibial Band Friction Syndrome (runner’s knee)General expression for many repetitive and overuse

conditions Malalignment and structural assymetries of the foot

and lower leg.

Extensor Injuries

Patellar tendonitis can be classified by the following techniques: Stage 0 - No Pain Stage 1 - Pain only after intense sports activity; no undue functional impairment Stage 2 - Pain at the beginning and after sports activity; still able to perform at a satisfactory level Stage 3 - Pain during sports activity; increasing difficulty in performing at a satisfactory level Stage 4 - Pain during sports activity; unable to participate in sport at a satisfactory level Stage 5 - Pain during daily activity; unable to participate in sport at any level

Knee Joint Rehabilitation

General Body ConditioningWeight BearingKnee-Joint MobilizationFlexibilityMuscular StrengthNeuromuscular ControlBracing / TapingFunctional ProgressionReturn to Activity