copyright © 2013 wolters kluwer health | lippincott williams & wilkins knee conditions chapter...

Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Knee ConditionsKnee Conditions

Chapter 18


Anatomy Anatomy


Anatomy (cont.)Anatomy (cont.)


Tibiofemoral JointTibiofemoral Joint

• Condyles of femur with plateaus of tibia

• Hinge joint—flexion/extension

• Tibia does rotate laterally on femur during last few degrees of extension

– “Screw-home mechanism”

• Produces a locking of the knee in final degrees during extension

• Close-packed position of full extension


MeniscusMeniscus

• Fibrocartilaginous discs attached to tibial plateaus

– Medial and lateral

• Functions:

– Stabilize joint by deepening the articulation

– Shock absorption

– Provide lubrication and nourishment

– Improve weight distribution


Joint Capsule and BursaeJoint Capsule and Bursae

• Articular capsule – encompasses both tibiofemoral and patellofemoral joints

– Suprapatellar bursa

– Subpopliteal bursa

– Semimembranosus bursa

• Bursa outside capsule

– Prepatellar bursa

– Superficial infrapatellar bursa

– Deep infrapatellar bursa


LigamentsLigaments

• ACL

– Prevents:

• Anterior translation of tibia on femur

• Rotation of tibia on femur

• Hyperextension

– Discrete bands

• Knee full extension—posterolateral bundle is taut

• Knee full flexion—anteromedial bundle is taut


Ligaments (cont.)Ligaments (cont.)

• PCL

– Resists posterior displacement of tibia on femur

– Knee full extension—posterior fibers are taut; knee full flexion—anterior fibers are taut



• MCL

– Resist medially directed (valgus) forces

– Complete extension—tautmidrange—posterior fibers most tautcomplete flexion—anterior fibers most taut

• LCL

– Resist laterally directed (varus) forces



• Arcuate-popliteal complex

– Oblique popliteal ligament and arcuate popliteal ligament

– Supports posterior joint capsule

• Limits anterior displacement of tibia on femur

• Limits hyperextension and hyperflexion


Iliotibial BandIliotibial Band

• Extends from tensor fascia latae to Gerdy’s tubercle on lateral tibial plateau

• Lateral knee stabilizer


Patellofemoral JointPatellofemoral Joint

• Patella

– Superior, middle, and inferior articular surfaces

– Functions

• Protect femur

• Increase effective power of quadriceps


Q-AngleQ-Angle

• Q-angle

– Angle between line of resultant force produced by quadriceps and line of patellar tendon

– Males 13°; females 18°

– Q-angle— lateral patellofemoral contact Q-angle— medial tibiofemoral contact

• A-angle

– Measures relationship of patella to tibial tubercle

– 35° or greater linked to increased patellofemoral pain


MusclesMuscles

• Produce movement

• Stabilize the knee


NervesNerves

• Tibial nerve

– Hamstrings except short head of biceps

• Common peroneal

– Short head of biceps

• Femoral

– Quadriceps


Blood SupplyBlood Supply

• Femoral artery

• Popliteal artery

• Genicular arteries


KinematicsKinematics

• Knee flexion

– Hamstrings

– Assisted by:

• Popliteus

• Gastrocnemius

• Gracilis

• Sartorius


Kinematics (cont.)Kinematics (cont.)

• Knee extension – Quadriceps femoris muscle group

• Rectus femoris • Vastus lateralis• Vastus intermedius• Vastus medialis• Vastus medialis oblique (VMO)

– Screwing-home motion• Rotation and passive abduction and adduction

– Capability maximal at approximately 90° of knee flexion


Kinematics (cont.)Kinematics (cont.)• Knee motion during gait

– Midstance – flexed 20°, internally rotated 5°, and slightly abducted

– Swing phase – flexed 70°, externally rotated 15°, and 5° adduction

• Patellofemoral joint motion

– With knee flexion and extension, patella glides in the trochlear groove

– Tracking is dependent on the direction of the net force produced by the attached quadriceps


KineticsKinetics• Forces at the tibiofemoral joint

– Compression and shear during daily activities

• Extension—weight bearing and tension in muscles ↑ compression

• Flexion—as angle of joint ↑ to 90 → ↑ shear force produced by weight bearingshearing—tendency for the femur to displace anteriorly

• Forces at patellofemoral joint

– Compression during normal walking (50% body weight); increases with stair climbing


Prevention of Knee InjuriesPrevention of Knee Injuries

• Physical conditioning

– Strength

– Flexibility

• Rule changes

• Footwear

– Cleats vs. flat sole

– Position of cleats and size


ContusionsContusions

• Knee

– Mechanism: compression

– S&S

• Localized tenderness

• Pain

• Swelling

– Management: standard acute

– Caution: excessive swelling could mask other injuries


Contusions (cont.)Contusions (cont.)

• Infrapatellar fat pad – Entrapped between the femur and tibia– S&S

• Locking, catching, giving way• Palpable pain on either side of patellar tendon• Extreme pain on forced extension

– Management: standard acute


Contusions (cont.)Contusions (cont.)

• Peroneal nerve

– Mechanism: blow to the posterolateral aspect of the knee


Contusions (cont.)Contusions (cont.)– S&S

• Radiating pain down lateral aspect of leg and foot

• Severe cases

Initial pain—not immediately followed by tingling or numbness

As swelling ↑ within nerve sheath

Weakness in dorsiflexion or eversion

Loss of sensation in dorsum of foot, especially between 1st and 2nd toes

May progressively occur days or weeks later

– Management: standard acute; severe S&S—immediate physician referral


BursitisBursitis• Prepatellar

– Mechanism• Acute: direct blow to anterior patella• Chronic: repetitive blows

– S&S• Swelling• Pain with direct pressure• Pain with passive knee flexion• Localized swelling


Bursitis (cont.)Bursitis (cont.)

• Pes anserine– Mechanism:

• Friction between tendon and MCL• Direct trauma

– S&S• Pain with knee flexion


Bursitis (cont.)Bursitis (cont.)• Infrapatellar

– Mechanism: • Friction between patellar tendon and fat pad/tibia• May be associated with patellar tendinitis

– S&S• Point tender with possible swelling posterior to

patellar tendon• pain at end range of resisted knee extension and

passive flexion• Prolonged knee flexion may symptoms


Bursitis (cont.)Bursitis (cont.)

• Baker’s cyst– Posterior aspect of knee—most often:

semimembranosus– pain with full extension or flexion

• Bursitis management– Standard acute; aggravating activities


Ligamentous ConditionsLigamentous Conditions

• AAOS classifies ligamentous knee injuries according to:

– Functional disruption of a specific ligament

– Amount of laxity

– Direction of laxity

• Direction divides laxity into 4 straight and 4 rotatory laxities

• Knowing knee position at impact and direction the tibia displaces or rotates indicates the damaged structures


Ligamentous Conditions (cont.)Ligamentous Conditions (cont.)



• Straight medial laxity (valgus laxity)

– Involves MCL; posterior medial capsule—possibly PCL

– Lateral forces cause tension on medial aspect of knee

– 1st degree

• Mild pain medial joint line

• Little or no joint effusion/mild swelling at site

• Full ROM with minor discomfort

• Valgus @ 0°—stable; @ 30º—+



– 2nd degree• Valgus @ 30º—+ (with positive end feel)• Unable to fully extend the leg; often walk on the

ball of foot – 3rd degree

• Valgus @ 0—+ (with a soft or absent end feel)


Ligamentous Conditions (Cont’d)Ligamentous Conditions (Cont’d)

• Straight lateral laxity (varus laxity)

– Involves LCL, lateral capsular ligaments, PCL

– Medial forces produce tension on lateral aspect of knee

• Not usually isolated—presence of IT band, biceps femoris, popliteus



– S&S

• Similar to MCL

• Swelling minimal—no attachment to capsule

• + varus @ 30º

• Instability may not be obvious if other stabilizers are intact


• Straight anterior laxity (anterior instability)

– Anterior displacement of tibia on femur

– Involves ACL—rarely isolated

– Mechanism: cutting or turning maneuver, landing, or sudden deceleration




– S&S

• Pain

Minimal and transient to severe and lasting

Deep in knee difficult to pinpoint

• “Pop”

• Effusion within 3 hours; reports knee giving way—does not feel right



• Straight posterior laxity

– Tibia displaced posteriorly

– Involves PCL

– Mechanism

• Hyperextension force

• Fall on flexed knee (initial contact at tibial tuberosity)



– S&S• Sense of stretching to posterior knee

• “Pop”

• Rapid joint effusion

• ↓ knee flexion due to effusion

• + reverse Lachman’s test; posterior sag



• Anteromedial instability

– Anterior external rotation of medial tibia condyle on femur

– Involves MCL and oblique popliteal ligament, potentially ACL and medial meniscus

– S&S

• + valgus @ 0 & @ 30°

• + Slocum drawer test; + Lachman’s test

• ↑ anterior translation of the medial tibial plateau (w/ special tests)



• Anterolateral instability– Anterior internal subluxation of lateral tibial condyle on

femur– Caused by a sudden deceleration and cutting maneuver – Involves ACL, IT band, lateral capsule– S&S

• ↑ anterior translation of the lateral tibial plateau (with special tests)



• Posteromedial instability

– Medial tibial plateau shifts posteriorly on the femur and opens medially

– Involves superficial MCL, ACL, PCL, posteromedial capsule, and oblique popliteal ligament

– S&S: + posteromedial drawer test and posteromedial pivot shift test



• Posterolateral instability– Lateral tibial plateau rotates posteriorly– Due to hyperextension with varus– Involves PCL, arcuate–popliteal complex, posterolateral

capsule, and LCL – S&S

• Soft end point with varus stress at 0° and 30° • + posterolateral drawer and external rotation

recurvatum tests


Instabilities of the KneeInstabilities of the Knee



• Management

– Standard acute; NSAIDs

– Physician referral—timing dependent on severity


Knee Dislocation/SubluxationKnee Dislocation/Subluxation• Minimum of 3 ligaments must be torn for knee to dislocate

– Most often—ACL, PCL, and one collateral ligament

• Concern: damage to other structures; especially neurovascular

• S&S

– Individual describes severe injury

– “Pop”

– Deformity (unless spontaneously reduced)

• Management: standard acute

– Spontaneous reduction—physician referral

– Not reduced—activate EMS


Meniscal ConditionsMeniscal Conditions

• Classified according to location

• Involve compression, tension, shearing forces

• Longitudinal

– Twisting motion when foot fixed and knee flexed

• Produces compression and torsion on posterior peripheral attachment

– Bucket-handle tear

• Longitudinal segment displaced medially toward center of tibia


Meniscal Conditions (cont.)Meniscal Conditions (cont.)

• Horizontal tear– Due largely to degeneration – Shearing from rotational forces

• Tears the inner surface of the meniscus– Parrot-beak tear

• 2 tears; commonly in middle segment of lateral meniscus


Meniscal Conditions (cont.)Meniscal Conditions (cont.)• S&S

– Initial symptoms may be vague or limited

• Limited sensory nerve supply—minimal pain

• Minimal disability

• Minimal swelling

– Understand mechanism

– Delayed swelling

– Joint line pain

– Classic: clicking/locking (not acutely) leads to knee buckling or giving way

– + McMurray; Apley’s compression; “bounce home” test


Meniscal Conditions (cont.)Meniscal Conditions (cont.)

• Management

– Standard acute; treat symptoms

– Physician referral


Patellar ConditionsPatellar Conditions• Patellofemoral pain

– Causes

• Mechanical (e.g., patellar subluxation or dislocation)

• Inflammatory (e.g., prepatellar bursitis, patellar tendinitis)

• Other causes (e.g., reflex sympathetic dystrophy, tumors)

– Dynamic stabilizer— extensor mechanism


Patellar Conditions (cont.)Patellar Conditions (cont.)

• Patellofemoral stress syndrome

– Mechanism

• Poor patellar tracking due to weak VMO or tight lateral structures

– S&S

• Dull, aching pain, ↑ with sitting, squatting, and descending stairs

• Point tenderness—lateral facet of the patella

• Pain with manual patella compression into trochlear groove



– Management:

• Standard acute; NSAIDs

• Lower extremity assessment


Patellar Conditions (cont.)Patellar Conditions (cont.)• Chondromalacia

– Degeneration in articular cartilage of patella

– Due to abnormal excursion and compressive forces

– S&S: • Localized tenderness • Anterior knee pain• + Clarke’s test; + Waldron

test– Management

• Standard acute• Activity modification



• Patellar instability and dislocation

– Displacement of patella due to internal or external forces

– Mechanism: deceleration combined with a cutting motion

– S&S subluxation

• Transient partial displacement; acute or intermittent with spontaneous reduction

• Feeling of patella slipping when cutting, twisting, or pivoting

• + apprehension test



– S&S dislocation

• “Pop”

• Violent collapse of the knee

• Localized tenderness—medial extensor retinaculum

• Effusion

– Management: standard acute; immediate physician referral


Patellar Conditions (cont.)Patellar Conditions (cont.)• Patella plica syndrome

– Asymptomatic until trauma

– S&S

• Gradual onset of anterior knee pain

• Pain with prolonged sitting; individual stands and begins to walk, sharp pain for 8–10 steps, then disappears

• Slight joint effusion

• Palpable pain and crepitus – medial and lateral retinacular regions

• + medial synovial plica and stutter tests

– Management: treat symptoms; activity modification


Patellar Conditions (cont.)Patellar Conditions (cont.)• Patellar tendinitis

– Due to repetitive or eccentric knee extension activities

– S&S

• Initial—pain after activity on inferior pole of patella or distal attachment of patellar tendon

• Progression—pain at start of activity, subsides with warm-up, reappears after activity

• Pain ascending and descending stairs

• Pain with passive knee flexion beyond 120° and resisted knee extension

– Management: standard acute; NSAIDs


Patellar Conditions (cont.)Patellar Conditions (cont.)• Osgood- Schlatter disease

– Inflammation or partial avulsion of tibial apophysis due to traction forces

– S&S• Individual points to tibial tubercle as source of

pain • Tubercle appears enlarged • Pain during activity and relieved with rest• Pain at extreme knee extension and forced

flexion – Management: treat symptoms; self-limiting



• Sinding-Larsen-Johansson disease– Inflammation or partial avulsion of apex of patella due to

traction forces – S&S

• Gradual onset of pain• Pain with palpation of inferior patellar pole with

patient’s knee extended and patellar tendon relaxed– Management: treat symptoms; self-limiting



• Extensor tendon rupture

– Due to powerful eccentric muscle contractions

– S&S

• Partial rupture—pain and weakness in knee extension

• Total rupture distal to patella

High-riding patella

Palpable defect over the tendon

Inability to extend knee extension or perform a straight leg raise



• Total rupture from superior pole with extensor retinaculum still intact

Knee extension is possible, but weak and painful

– Management: standard acute; knee immobilizer and crutches; immediate referral to a physician


Iliotibial Band Friction SyndromeIliotibial Band Friction Syndrome• Band drops behind lateral femoral epicondyle with knee

flexion, then snaps forward over epicondyle during extension


Iliotibial Band Friction Syndrome (cont.)Iliotibial Band Friction Syndrome (cont.)

• Due to excessive compression and friction

• Associated with overuse, abnormal biomechanics, and poor flexibility

• S&S

– Pain with exercise progresses from not restrictive to restrictive even with ADLs

– Extreme point tenderness 2–3 cm proximal to lateral joint line over epicondyle with leg flexed at 30°

– + Noble’s and Ober’s compression tests

• Management: standard acute; NSAIDs; preventative conditioning program


Fractures and Associated ConditionsFractures and Associated Conditions• Avulsion fracture

– Due to direct trauma, excessive tensile forces, overuse

– S&S: localized pain and tenderness over the bony site

• Epiphyseal and apophyseal fracture

– Tibial tubercle fracture

• Mechanism

Forced flexion of knee against a straining quadriceps contraction

Violent quadriceps contraction against a fixed foot


Fractures and Associated Conditions (cont.)Fractures and Associated Conditions (cont.)

• S&S

Pain, ecchymosis, swelling, and tenderness

Difficulty going up and down stairs

– Distal femoral epiphyseal fracture

• Mechanism: varus or valgus stress applied on a fixed, weight-bearing foot

• S&S: pain around knee; unable to bear weight



• Stress fractures

– Common areas

• Femoral supracondylar region

• Medial tibial plateau

• Tibia tubercle



– Occur when:• Load on the bone is increased • Number of stresses on the bone increases (e.g.,

changes in training intensity, duration, frequency)• surface area of the bone receiving load decreases

– S&S: localized pain before and after activity, relieved with rest and non–weight bearing


Fractures and Associated Conditions (cont.)Fractures and Associated Conditions (cont.)• Chondral fracture (involves

articular cartilage)• Osteochondral fracture (involves

articular cartilage and underlying bone)

– Due to compression from direct blow to knee causing shearing or forceful rotation

– S&S • Painful “snap” • Considerable pain and

rapid swelling• Displaced fracture:

locking; crepitus


Fractures and Associated Conditions (cont.)Fractures and Associated Conditions (cont.)• Osteochondritis dissecans

– Bone fragment due to localized area of avascular necrosis

– Due to:

• Direct and indirect trauma

• Skeletal abnormalities

• Prominent tibial spine

• Generalized ligamentous laxity

– S&S

• Aching, diffuse pain, or swelling with activity

• As disease progresses, knee locking or giving way



• Fracture management

– Standard acute

– Immobilization

– Immediate physician referral

• Stress fracture management

– Physician referral

– Rest


AssessmentAssessment• History

• Observation/inspection

• Palpation

• Physical examination tests


Patella PalpationPatella Palpation

• Patellar glide

– Hypomobile

• < 1 quadrant of displacement

– Hypermobile

• 3+ quadrants (greater than one-half of patellar width)


Palpation for SwellingPalpation for Swelling• Brush or stroke test

(milking)

• Patellar tap test(“ballotable patella”)


Range of Motion (ROM)Range of Motion (ROM)• AROM

– Flexion (0–135°)

– Extension (0–15°)

– Medial rotation of tibia on femur (20–30°) with knee flexed at 90°

– Lateral rotation of tibia on femur (30–40°) with knee flexed at 90°

• PROM

– Normal end feel

• Flexion—tissue approximation

• Extension; medial and lateral rotation—tissue stretch


ROM (cont.)ROM (cont.)


ROM (cont.)ROM (cont.)• RROM


Stress TestsStress Tests

• Anterior drawer test

• Lachman’s test


Stress Tests (cont.)Stress Tests (cont.)

• Modified Lachman’s



• Posterior sag (gravity) test

• Posterior drawer test

• Reverse Lachman’s test



• Valgus stress

• Varus stress



• Slocum drawer test

– Anteromedial rotary instability

– Anterolateral rotary instability



• Lateral pivot shift



• Jerk test



• Slocum ALRI test

• Cross-over test



• Flexion–rotation drawer

• Posteromedial drawer

• Posteromedial pivot shift

• Posterolateral drawer



• Reverse pivot shift



• External rotation recurvatum


Special TestsSpecial Tests

• Meniscal tests

– McMurray’s test

– Apley’s compression/ distraction test

– “Bounce home” test


Special Tests (cont.)Special Tests (cont.)

• Tibiofibular instability

– Proximal tibiofibular syndesmosis test

• Plica tests

– Mediopatellar plica test

– Stutter test

– Hughston’s plica test


Special Tests (cont.)Special Tests (cont.)• Tests for patellofemoral dysfunction

– Patella compression or grind

– Clarke’s sign

– Waldron test

– Patellar apprehension


Special Tests (cont.)Special Tests (cont.)

• IT band syndrome tests

– Noble compression test

– Ober’s test


Neurologic TestsNeurologic Tests

• Myotomes

– Hip flexion—L1, L2

– Knee extension—L3

– Ankle dorsiflexion—L4

– Toe extension—L5

– Ankle plantarflexion, foot eversion, or hip extension—S1

– Knee flexion—S2


Neurologic Tests (cont.)Neurologic Tests (cont.)

• Reflexes

– Patella—L3, L4

– Achilles tendon—S1


Neurologic Tests (cont.)Neurologic Tests (cont.)

• Dermatomes

• Peripheral nerve distribution


RehabilitationRehabilitation

• Restoration of proprioception and balance

– Closed-chain exercises

• Muscular strength, endurance, and power

– Open-chain exercises

– PNF-resisted exercises

• Cardiovascular fitness


Rehabilitation (cont.)Rehabilitation (cont.)

• Range of motion



• Patellar self-mobilization



• Closed-chain terminal extension

copyright © 2013 wolters kluwer health | lippincott williams & wilkins knee conditions chapter...

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femur limits hyperextension