Prevent & Treat Chapter 15

Knee extension

"screw home motion"

Patellar tendinitis (patellar condition)

*Patellar tendon frequently becomes inflamed and tender from repetitive or eccentric knee extension activities; these occur in running and jumping, hence the name "jumper's knee" -Due to repetitive or eccentric knee extension activities -Extrinsic factors that can lead to the condition include frequency of training, years of play, playing surface, type of training, stretching and warm-up practices, and type of shoe worn -Some intrinsic factors that may have a role in contributing to the condition include lower extremity malalignment, leg-length discrepancies, muscle imbalance, muscle length, and muscle strength

Patellofemoral pain (patellar condition)

*region most commonly associated with anterior knee pain May be caused by... -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 tracking disorders and instability within the joint, along with obesity, direct trauma, and repetitive motions, all contribute to a variety of injuries

PCL (posterior cruciate ligament)

*strongest -- runs from the posterior aspect of the tibial intercondyloid fossa in a superior, anterior direction to the lateral anterior medial condyle of the femur -consists of a large anterolateral and a smaller posteromedial bundle -- considered the primary stabilizer of the knee and resists posterior displacement of the tibia on a fixed femur

MCL (medial collateral ligament)

- deep fibers merge with the joint capsule and medial meniscus to connect the medial epicondyle of the femur to the medial tibia -resist medically directed forces

Superficial infrapatellar bursa

- located between the skin and patellar tendon

ACL (anterior cruciate ligament)

- stretches from the anterior aspect of the intercondyloid fossa of the tibia just medial and posterior to the anterior tibial spine in a superior, posterior direction to the posterior medial surface of the lateral condyle of the femur Prevents: -Anterior translation of tibia on femur -Rotation of tibia on femur -Hyperextension

S & S of dislocation (patellar condition)

-"Pop" -Violent collapse of the knee -Localized tenderness—medial extensor retinaculum -Loss of limb function -Effusion

Parrot-beak tear (meniscal condition)

-2 tears; commonly in middle segment of lateral meniscus

Iliotibial band friction syndrome can be the result of?

-A large Q-angle -Genu varum -Excessive foot pronation

Management of Iliotibia (IT) Band Friction Syndrome

-Acute -NSAIDs -Do not permit to continue activity until seen by a physician

S & S of Chondromalacia (patellar condition)

-Anterior knee pain and crepitus w/ walking stairs or deep knee bends -Pain and crepitus increase w/ active & resisted knee extension -Localized pain and tenderness on the medial and lateral patellar borders

Iliotibia (IT) Band Friction Syndrome

-Band drops behind lateral femoral epicondyle with knee flexion, then snaps forward over epicondyle during extension -Due to excessive compression and friction -Associated with overuse, abnormal biomechanics, and poor flexibility -common in runners, cyclists, weight lifters, and volleyball players -band drops posteriorly behind the lateral femoral epicondyle with knee flexion, then snaps forward over the epicondyle during extension; weight bearing increases compression and friction forces over the greater trochanter and lateral femoral condyle

Gait cycle

-Consists of alternating periods of single-leg and double-leg support -Requires a set of coordinated, sequential joint actions of the lower extremity

Chondromalacia (patellar condition)

-Degeneration in articular cartilage of patella, which results when compressive forces exceed the normal physical range, or when alterations in patellar excursion produce abnormal shear forces that damage the articular surface -Due to abnormal excursion & compressive forces *Articular cartilage does not contain nerve endings, so chondromalacia should not be considered the true source of anterior knee pain *Chondromalacia is a surgical finding that represents areas of hyaline cartilage trauma or aberrant loading, but is not the cause of pain

Horizontal tear (meniscal condition)

-Due largely to degeneration -Shearing from rotational forces -Tears the inner surface of the meniscus

Avulsion Fraction

-Due to direct trauma, excessive tensile forces, overuse -Ex: getting kicked on the lateral aspect of the knee may avulse a portion of the lateral epicondyle

S & S of Patellofemoral stress syndrome (patellar condition)

-Dull, aching pain, ↑ with sitting, squatting, and descending stairs -Point tenderness—lateral facet of the patella -Pain with manual patella compression into trochlear groove

Patellofemoral joint motion

-During 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

Infrapatellar bursitis

-Friction between patellar tendon and fat pad/tibia -May be associated with patellar tendinitis

Pes anserine bursitis

-Friction between tendon and MCL -Direct trauma

S & S of Knee Dislocation/Subluxation

-Individual describes severe injury -"Pop" -Deformity (unless spontaneously reduced)

S & S of Osgood- Schlatter disease (patellar condition)

-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

Osgood- Schlatter disease (patellar condition)

-Inflammation or partial avulsion of tibial apophysis due to traction forces *typically develops in girls between the ages of 8 and 13, and in boys between ages 10 and 15 at the beginning of their growth spurt *estimated that the condition occurs in 21% of adolescent athletes as compared with 4.5% of age-matched non-athletes

S & S of a meniscal condition

-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

S & S of Patellar tendinitis (patellar condition)

-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; eventually pain both during and after activity -Pain ascending and descending stairs; pain after prolonged sitting

Straight lateral laxity ligament condition

-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

Straight medical laxity ligament condition

-Involves MCL; posterior medial capsule—possibly PCL -Lateral forces cause tension on medial aspect of knee

Contributions to a Stress Fractures

-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 of an Avulsion Fraction

-Localized pain and tenderness over the bony site -If a musculotendinous unit is involved, muscle function will be limited -If ACL is involved, the bony fragment may lodge in the joint, causing the knee to "lock"

S & S of a Infrapatellar fat pad contusion

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

1st degree of straight medial laxity ligament condition

-Mild pain medial joint line -Little or no joint effusion/mild swelling at site -Full ROM with minor discomfort -Valgus @ 0°—stable; @ 30º—+

Knee Dislocation/Subluxation

-Minimum of 3 ligaments torn for knee to dislocate -Most often—ACL, PCL, and one collateral ligament -Concern: damage to other structures; especially neurovascular -MOI: cutting, twisting, or pivoting maneuver -Dislocations may occur in any directions: most common in an anterior or posterior direction * Posterior knee dislocations are associated with the highest incidence of damage to the popliteal artery, with posterolateral rotary dislocations having the highest incidence of nerve injury

S & S of a Straight anterior laxity ligament condition

-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

S & S of Iliotibia (IT) Band Friction Syndrome

-Pain with running progresses from not restrictive to restrictive even with ADLs -Initial lateral ache progresses into a more painful, sharp, and localized discomfort over the lateral femoral condyle just above the lateral joint line -Flexion and extension of the knee may produce a creaking sound

S & S of Epiphyseal and apophyseal fracture

-Pain, ecchymosis, swelling, and tenderness -Difficulty going up and down stairs -Knee extension painful and weak -Larger fractures involving extensive retinacular damage -Patella rides high -Knee extension is impossible

S & S of a Osteochondral fracture

-Painful "snap" -Considerable pain & rapid swelling -Displaced fracture: locking; crepitus

S & S of an Extensor tendon rupture (patellar condition)

-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

S & S of Infrapatellar bursitis

-Point tender with possible swelling posterior to patellar tendon -Increased pain at end range of resisted knee extension and passive flexion -Prolonged knee flexion may increase symptoms

Patellofemoral stress syndrome (patellar condition)

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

S & S of a Peroneal nerve contusion

-Radiating pain down lateral aspect of leg and foot -Sever cases: Initial pain—not immediately followed by tingling or numbness, as swelling ↑ within nerve sheath there is a weakness in dorsiflexion or eversion, loss of sensation in the foot

S & S of a Straight posterior laxity ligament condition

-Sense of stretching to posterior knee -"Pop" -Rapid joint effusion -Decrease in knee flexion due to effusion

S & S of a Straight lateral laxity ligament condition

-Similar to MCL -Swelling minimal—no attachment to capsule -Instability may not be obvious if other stabilizers are intact

Management of a Knee Dislocation/Subluxation

-Spontaneous reduction—physician referral -Not reduced—activate emergency plan, including summoning EMS

Management of a Infrapatellar fat pad contusion

-Standard acute -If symptoms persist > 2-3 days, physician referral -Protect the area during activity

Management of Patellar instability and dislocation (patellar condition)

-Standard acute -Immediate physician referral -Coach should not attempt to reduce

Management of a ligament condition

-Standard acute -Unable to walk normally - crutches should be used -Physician referral -Not typically an ER, but seen by physician 1-2 post-injury *Injuries involving minimal ligament failure are managed conservatively with ice application, compression, elevation, and protected rest until acute symptoms subside

Management of Patellofemoral stress syndrome (patellar condition)

-Standard acute -Physician referral

Management of a Peroneal nerve contusion

-Standard acute, but caution with compression -Severe S&S—immediate physician referral

Bursitis management

-Standard acute; decrease aggravating activities or total rest -Protect area during activity

Management of a meniscal condition

-Standard acute; treat symptoms -Physician referral

Patella

-Superior, middle, and inferior articular surfaces -protects the femur -increases effective power of quadriceps

S & S of Prepatellar bursitis

-Swelling -Pain with direct pressure -Pain with passive knee flexion -Localized swelling

Straight anterior laxity ligament condition

-The rate of ACL injuries is higher in women, particularly for those in jumping and pivoting sports -Anterior displacement of tibia on femur -Involves ACL—rarely isolated -MOI: cutting or turning maneuver, landing, or sudden deceleration

Straight posterior laxity ligament condition

-Tibia displaced posteriorly -Involves PCL -MOI -Hyperextension force -Fall on flexed knee (initial contact at tibial tuberosity)

Epiphyseal and apophyseal fracture

-Tibial tubercle fracture -Adolescents in contact sports are particularly susceptible to epiphyseal fractures in the knee region -Forced flexion of knee against a straining quadriceps contraction -Violent quadriceps contraction against a fixed foot

S & S of subluxation (patellar condition)

-Transient partial displacement; acute or intermittent with spontaneous reduction -Feeling of patella slipping when cutting, twisting, or pivoting

Longitudinal tear (meniscal condition)

-Twisting motion when foot fixed and knee flexed -Produces compression and torsion on posterior peripheral attachment

Q angle

-angle between the line of resultant force produced by quadriceps and the line of the patellar tendon -males 13 degrees, females 18 degrees -increasing the Q-angle increases lateral patellofemoral contact pressures and could promote lateral patellar dislocation -decreasing the Q-angle could increase the medial tibiofemoral contact pressure

Medial meniscus

-attached to the deep MCL and fibers from the semimembranosus (medial side of hamstring) -injured more frequently than lateral meniscus because it is more securely attached to the tibia, therefor less mobile

Peroneal nerve contusion

-blow to the posterolateral aspect of the knee -may also be injured by prolonged compression from a knee brace or elastic wrap, prolonged squatting (e.g., baseball or softball catcher), or by traction due to a varus stress or hyperextension at the knee -if the actual nerve is not damaged, tingling and numbness may persist for several minutes

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 -"screwing-home mechanism" -produces a locking of the knee in final degrees during extension

LCL (lateral collateral ligament)

-connects the lateral epicondyle of the femur to the head of the fibula -resist laterally directed forces

What are the functions of the meniscus?

-dissipation of forces -improved joint congruency -provide lubrication to promote gliding

Blood supply

-femoral artery -popliteal artery -genicular arteries

Meniscus

-fibrocartilaginous discs attached to tibial plateau -thicker along the lateral margin and thinner on the medial margin -medial and lateral meniscus

Meniscal conditions

-involves compression, tension, shearing forces *medial meniscus damage is more common than lateral meniscus damage *meniscal injuries are difficult to assess because they are not innervated by nociceptors, and only 10% to 30% of the peripheral medial meniscus border and 10% to 25% of the lateral meniscus border receive direct blood supply

Suprapatellar bursa

-lies between the femur and quadriceps femoris tendon -reduces friction between the two structures

Subpopliteal bursa

-lies between the lateral condyle of the femur and the popliteal muscle

Semimembranosus bursa

-lies between the medial head of the gastrocnemius and the semitendinosus tendon

S & S of a knee contusion

-localized tenderness -pain -swelling

Prepatellar bursa

-located between the skin and anterior surface of the patella -allows free movement of the skin over the patella during flexion and extension

Deep infrapatellar bursa

-located between the tibial tubercle and the infrapatellar tendon -separated from the joint cavity by the infrapatellar fat pad -reduces friction between the ligament and the bony tubercle

Patellar instability and dislocation (patellar condition)

-occurs when the patella has normal or abnormal alignment in the trochlear groove but is displaced by internal or external forces -MOI: deceleration combined with a cutting motion -displacement can range from microinstability to subluxation or gross dislocation

Prevention of a knee injury?

-physical conditioning (strength & flexibility) -rule changes -footwear (cleats vs. flat sole)/(position of cleats & size)

Lateral meniscus

-smaller and more freely moveable structure

Functions of the meniscus

-stabilizes joint by deepening the articulation -shock absorption -provide lubrication and nourishment -improve weight distribution

Management of a knee contusion

-standard acute; extreme point tenderness physician referral

Grade I Osgood- Schlatter disease (patellar condition)

1 - Pain after activity that resolves within 24 hours

Grade 2 Osgood- Schlatter disease (patellar condition)

2 - Pain during and after activity that does not hinder performance and resolves within 24 hours

Grade 3 Osgood- Schlatter disease (patellar condition)

3 - Continuous pain that limits sport performance and daily activities

Prepatellar bursitis

Acute: direct blow to anterior patella Chronic: repetitive blows

Changing direction during deceleration is a common mechanism of injury for what ligament?

Anterior cruciate ligament

A condition caused by abnormally high shear forces that damage the articular surface of the patella is called?

Chondromalacia

Stress Fractures

Common areas: Femoral supracondylar region Medial tibial plateau Tibia tubercle *Localized tenderness and edema are present, but initial radiographs of the stress fracture may be negative

A blow to the posterolateral aspect of the knee can contuse the what?

Common peroneal nerve

Management of Osgood- Schlatter disease (patellar condition)

Do not permit to continue activity until seen by a physician

Extensor tendon rupture (patellar condition)

Due to powerful eccentric muscle contractions *Extensor tendon ruptures can occur at the superior or inferior pole of the patella, tibial tubercle, or within the patellar tendon itself

Articular capsule

Encompasses both tibiofemoral and patellofemoral joints

Infrapatellar fat pad contusion

Entrapped between the femur and tibia

Knee flexion is performed by?

Hamstrings Popliteus Gastrocnemius Gracilis Sartorius

Which of the following structures is associated with jumper's knee

Infrapatellar tendon

Chondral Fracture

Involves articular cartilage

Osteochondral fracture

Involves articular cartilage and underlying bone -Due to compression from direct blow to knee causingshearing or forceful rotation

S & S of a Stress Fractures

Localized pain before and after activity Relieved with rest and non-weight bearing

Bucket-handle tear (meniscal condition)

Longitudinal segment displaced medially toward center of tibia

Inability to fully extend the leg, walking on the ball of foot, and inability to keep heel flat on the ground are signs of injury to what ligament?

MCL (medial collateral ligament)

Distal femoral epiphyseal fracture

MOI: varus or valgus stress applied on a fixed, weight-bearing foot -- 10 times more common than proximal tibial fractures and are more serious because of possible arterial damage to the growth plate -- may occur at any age, but are often seen in boys aged 10-14

S & S of Distal femoral epiphyseal fracture

Pain around knee Unable to bear weight

S & S of Pes anserine bursitis

Pain with knee flexion

A traction-type injury to the tibial apophysis where the infrapatellar tendon attaches onto the tibial tuberosity is called?

Patellar tendinitis

Stress fracture management

Physician referral

The strongest ligament at the knee?

Posterior cruciate ligament (PCL)

Tracking of the patella against the femur is dependent on the direction of the net force produced by?

Quadriceps

What muscles comprise the quadriceps?

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

Management of Chondromalacia (patellar condition)

Standard acute Physician referral

Fracture management

Standard acute Use of crutches Immediate physician referral

Management of an Extensor tendon rupture (patellar condition)

Standard acute; crutches; immediate referral to a physician

Management of Patellar tendinitis (patellar condition)

Standard acute; physician referral

In the knee region, the most common site for an apophyseal fracture in boys is the?

Tibial tuberosity

What is considered the knee joint?

Tibiofemoral joint

Peak incidence of meniscal injuries has been found to occur in men and women between the ages of 21 and 40?

True

2nd & 3rd degree of straight medial laxity ligament condition

Unable to fully extend the leg; often walk on the ball of foot; unable to keep heel flat on the ground

The screwing-home mechanism occurs when?

When the tibia rotates laterally on the femur during the last degrees of knee extension

Major muscle action of quadriceps femoris muscle group (rectus femoris, vastus lateralis, vastus intermedius, vastus medialis, vastus medialis oblique)

knee extension

Major muscle action of hamstrings?

knee flexion