Knee Conditions

Knee Conditions

Chapter 18

Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Anatomy


Anatomy (cont.)


Anatomy (cont.)


Tibiofemoral 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


Meniscus

• 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 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


Ligaments

• 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.)

• 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—taut midrange—posterior fibers most taut complete 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 Band

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

• Lateral knee stabilizer


Patellofemoral Joint

• Patella

– Superior, middle, and inferior articular surfaces

– Functions

• Protect femur

• Increase effective power of quadriceps


Q-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



Muscles

• Produce movement

• Stabilize the knee


Nerves

• Tibial nerve

– Hamstrings except short head of biceps

• Common peroneal

– Short head of biceps

• Femoral

– Quadriceps


Blood Supply

• Femoral artery

• Popliteal artery

• Genicular arteries


Kinematics

• Knee flexion

– Hamstrings

– Assisted by:

• Popliteus

• Gastrocnemius

• Gracilis

• Sartorius


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.)

• 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


Kinetics

• 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 bearing shearing—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 Injuries

• Physical conditioning

– Strength

– Flexibility

• Rule changes

• Footwear

– Cleats vs. flat sole

– Position of cleats and size


Contusions

• Knee

– Mechanism: compression

– S&S

• Localized tenderness

• Pain

• Swelling

– Management: standard acute

– Caution: excessive swelling could mask other injuries


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



• Peroneal nerve

– Mechanism: blow to the posterolateral aspect of the knee



– 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


Bursitis

• 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.)

• Pes anserine

– Mechanism:

• Friction between tendon and MCL

• Direct trauma

– S&S

• Pain with knee flexion



• 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



• Baker’s cyst

– Posterior aspect of knee—most often: semimembranosus

–  pain with full extension or flexion

• Bursitis management

– Standard acute;  aggravating activities


Ligamentous 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.)





• 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)

• 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 Knee



• Management

– Standard acute; NSAIDs

– Physician referral—timing dependent on severity


Knee 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 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.)

• 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




• 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



• Management

– Standard acute; treat symptoms

– Physician referral


Patellar 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.)

• 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



• 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




• 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 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



• 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 Syndrome

• Band drops behind lateral femoral epicondyle with knee flexion, then snaps forward over epicondyle during extension


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 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



(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



(cont.)

• Stress fractures

– Common areas

• Femoral supracondylar region

• Medial tibial plateau

• Tibia tubercle



(cont.)

– 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



(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



(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




(cont.)

• Fracture management

– Standard acute

– Immobilization

– Immediate physician referral

• Stress fracture management

– Physician referral

– Rest


Assessment

•

History

•

Observation/inspection

•

Palpation

•

Physical examination tests


Patella Palpation

• Patellar glide

– Hypomobile

• < 1 quadrant of displacement

– Hypermobile

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


Palpation for Swelling

• Brush or stroke test

(milking)

• Patellar tap test

(“ballotable patella”)


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.)

• RROM


Stress Tests

• Anterior drawer test

• Lachman’s test


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 Tests

• Meniscal tests

– McMurray’s test

– Apley’s compression/ distraction test

– “Bounce home” test


Special Tests (cont.)

• Tibiofibular instability

– Proximal tibiofibular syndesmosis test

• Plica tests

– Mediopatellar plica test

– Stutter test

– Hughston’s plica test



• Tests for patellofemoral dysfunction

– Patella compression or grind

– Clarke’s sign

– Waldron test

– Patellar apprehension



• IT band syndrome tests

– Noble compression test

– Ober’s test


Neurologic 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.)

• Reflexes

– Patella—L3, L4

– Achilles tendon—S1


Neurologic Tests (cont.)

• Dermatomes

• Peripheral nerve distribution


Rehabilitation

• Restoration of proprioception and balance

– Closed-chain exercises

• Muscular strength, endurance, and power

– Open-chain exercises

– PNF-resisted exercises

• Cardiovascular fitness


Rehabilitation (cont.)

•

Range of motion



•

Patellar self-mobilization



•

Closed-chain terminal extension


Knee Conditions

test

History

Observation/inspection

Palpation

Physical examination tests

Range of motion

Patellar self-mobilization

Closed-chain terminal extension

Related documents

Products

Support

Knee Conditions

test

History

Observation/inspection

Palpation

Physical examination tests

Range of motion

Patellar self-mobilization

Closed-chain terminal extension

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