Chapter 5: The Knee and Patellofemoral Joints

Movements of the patella

The change of position of the patella occurs in relation to the femur; the patella slides down during flexion and up during extension within the femoral groove

Genu antecurvatum

"Hyperflexed knees"—knees that do not fully extend and appear bent • Changes can be achieved with very careful consistent stretching combined with dance technique modifications if it is soft tissue or neuromuscular in nature

Hyperextension can be learned to be controlled by 2 tactics

1. *Limiting the degree of knee extension* - principle of stopping the knee earlier as it extends -"pull the knees straight up"- co-contraction of hamstrings and quads will allow the knee flexors (hamstrings) to be recruited to slightly bend the knee 2. *Limiting the degree of femoral internal rotation* - focusing on using the ext rotators at the hip to limit this internal rotation of the femur and keep the knees facing directly forward rather than twisting inward can prevent undesired knee hyperextension - "pull up" the abdominals to create a neutral pelvis so that the femoral internal rotation associated with an anterior tilt of the pelvis is avoided

3 articulations of the knee

1. Between the medial condyle of the femur and slightly concave medial plateau of the tibia 2. B/t lateral condyle of femur and slightly concave lateral plateau of the tibia 3. B/t the backside of the kneecap and the underlying surface on the anterior femur, the femoral groove

Two possible mechanisms for decreased thigh development

1. Economy - learning how to work with less intensity but same effort 2. Altered muscle recruitment patterns

What 4 proper training techniques should be emphasized to lessen knee stress?

1. Emphasize the use of hip external rotation (DOR) to help direct the knee over the foot during movements such as pliés 2. Avoid shifting heels forward when the knee is flexed 3. Maintain as much external rotation as possible at the proximal end of the femur and avoid exaggerating the slight internal rotation of the femur relative to the tibia when extending the knees on movements such as rising from a plié 4. When the foot is non-weight bearing, emphasis should be on rotating the hip and carrying the external rotation down the leg such that the "heel comes forward"

Why is the knee joint so vulnerable to injury?

1. Knee is located between the longest bones of the body and has a very shallow articulation leaving potential injuries to the ligaments and menisci 2. Injury is heightened by the rotation allowed at the knee when it is in a flexed position 3. Anteriorly, the quads, patella, and patellar tendon (extensor mechanism) serve key antigravity, deceleration acceleration, and stability functions

Parts on the distal end of the femur

1. Medial and lateral condyles of the femur—distal end 2. Medial and lateral epicondyles of the femur—distal end—widest part of the femur (higher/more proximal than condyles) 3. Femoral groove 4. Intercondylar fossa (notch)

Meniscus (menisci pl)

1. Provide more surface area of contact b/t the bones 2. Help absorb shock 3. Decrease frictional wear 4. Facilitate knee movements Fibrocartilage discs on tibial plateau Further separation of the joint surfaces they provide allows for greater lubrication of the joint, and 20% increase in friction has been demonstrated to occur with removal of the meniscus

Muscles of the patellofemoral joint

1. Quadriceps femoris - rectus femoris, vastus intermedius, vastus medialis, vastus lateralis 2. Pes anserinus group - gracilis, sartorius, semitendinosus 3. Hamstrings - biceps femoris, semitendinosus, semimembranosus

Quadriceps femoris

1. Rectus femoris - only one that crosses the hip joint - knee extension and hip flexor 2. Vastus intermedius 3. Vastus medialis 4. Vastus lateralis All 4 act as prime movers to produce knee extension

Functions of the patella

1. Serves to increase the moment arm (increases torque) 2. Centralizes the divergent pulls of the four muscles of the quadriceps femoris complex 3. Serves as a retainer to help prevent the femur from sliding off the tibia anteriorly 4. Allows for a better distribution of compression stresses on the femur by increasing the surface area of contact 5. It provides a smooth gliding mechanism that reduces friction.

Why are grand pliés so controversial?

1. The large stresses applied to the menisci and posterior cruciate ligament 2. The dislocation force due to the approximation of the calf and back of the thigh and the parallel component of the hamstring muscles (angle of the muscle attachment) 3. The very high associated patellofemoral compression forces

What are some recommended approaches used to perform grand pliés correctly?

1. Use grand pliés judiciously in dancers with healthy knees 2. Limited consecutive repetitions 3. Close attention to technique and appropriate conditioning and skill level

How do you lessen the potential risks to knee? (ex. in grand pliés)

1. Utilize traditional use of music and counts to encourage a slow, controlled, and successive descent and rise from a plié 2. Use the directive to "lift out of your knees" as well as to avoid hesitating, or "sitting" at the bottom of the plié and to instead keep movement continuous 3. The use of a barre, which can aid with balance, as well as in some cases provide some "unweighting" of the knees 4. Do not use external weight so that only body weight is of concern 5. The use of turned out positions that may recruit other muscles such as the hip adductors and lessen the required magnitude of quadriceps contraction and resultant patellofemoral compression force

Number of muscles that act on the knee All either cross the hip joint or ankle joint except:

12 vasti group and the popliteus

Patellofemoral joint

3. B/t the backside of the kneecap and the underlying surface on the anterior femur, the femoral groove

ACL Healing Why is hamstring strength emphasized?

ACL tends to heal poorly because it is located within in the joint (intra-articular), where joint fluid interferes with fibrin clot formation essential for the healing process. The hamstrings pull the tibia posteriorly, aiding the ACL in its function

Femoral groove

Anterior femur b/t condyles—articulates with the patella

Tibial torsion

At the tibia, torsion is defined as an axial twist of the tibia or shinbone. The twist can occur internally or externally.

Hamstrings

Biceps femoris, semimembranosus, semitendinosus Attachments... proximally - ischial tuberosity distally - below the knee at the tibia and fibula All 3 produce knee flexion and prevent hyperextension Biceps femoris also acts as knee external rotation Semimembranosus and semitendinosus act as (internal) medial rotators

ACL injury

Cause... • Lateral blow to the knee • Landing involving the body's falling such that the hip is adducting and internal rotation, with the knee collapsing into valgus while the tibia translates forward from an externally rotated position - *the position of no return* Symptoms... • A pop and unable to continue to dancing at the time of injury • Knee feels unsteady with pain and swelling • The ligaments do not contain pain receptors, the degree of pain is not necessarily a good indicator of the degree of injury Treatment... • Initial immobilization with compression dressing and ice • If rupture is complete... surgery

MCL injury

Causes... • Results from a medially directed force against the lateral side of the knee (valgus force) that tends to open up the inside of the knee • Contact improv • Deceleration • Pivoting • Forcing turnout and pushing the knee forward relative to the foot Symptoms... • Pain on the inside of the knee where the MCL is located • Point tender • Swelling Treatment... • Initial bracing or immobilization • Limit dance activity... particularly 5th position • Quad strengthening

Varus Stress

Helps provide lateral stability to the knee and is the primary constraint to forces that tend to open up the lateral aspect of the knee—varus stress—70% of the varus stress is supported by the lateral collateral ligament

Genu recurvatum

Hyperextension—"back-knee" as the knees curve backward predominantly in the sagittal plane • More common in females than males • More common in individuals of any gender with joint laxity • Activity of the quadriceps is less in people with this condition (weak)

Intercondylar eminence

In anterior and posterior intercondylar areas - 2 small peaks/projections —serves as the attachment site for ligaments and helps stabilize the tibia and femur during weight bearing

The Patella

Inferior pole Superior pole Medial and lateral borders Underside surface - facets which articulate with the underlying femur

The Q angle (or quadriceps angle)

Is a static measurement of the angle that the patellar tendon makes relative to the shaft of the femur (the angle between the quadriceps muscle (primarily the rectus femoris) and the patellar tendon.) When assessed correctly, it supplies useful information concerning the alignment of the pelvis, leg, and foot. • It also provides useful information regarding the alignment of the knee in the frontal plane. Since large forces are transmitted through the patella during extension, misalignment will cause problems with knee function. • The angle provides an indication of the lateral force applied to the patella, which tends to make the patella track laterally in order to establish a straight line relationship between the proximal and distal attachments of the quadriceps femoris muscle group Females generally have a larger Q angle than men Females normal range—10-19° Males normal range—8-15° Q angles greater than 15° are considered abnormal and are a risk factor patellofemoral problems

Locking mechanism of the knee

Is an energy-efficient mechanism that allows individuals to maintain the knee in extension over prolonged periods of standing without requiring muscular contraction The restraints of this mechanism are due to the cruciate ligaments and the shape of the surfaces articulating at the knee joint • Due to the different sizes of the lateral and medial condyles, when the knee extends in a standing position, the excursion of the lateral condyle is completed while that of the medial remains uncompleted. That is, the lateral surface has been used leaving about a ½ inch on the medial side—in order for the medial surface to have contact, internal rotation of the femur must be produced relative to the tibia • The knee cannot flex without being unlocked by the reversing the process where the Popliteus externally rotates the femur relative to the tibia

Jumper's Knee

Is an injury to the patellar tendon right at its junction with the inferior pole of the patella Causes... Factors that increase the risk for this injury in dancers include • A lot of jumping • Abrupt change in dance style • Performing on hard floors • Inadequate quadriceps strength • Growth spurts • Calf tightness leading to a limited plié Symptoms... • Pain is centered in the tendon just superior and inferior to the patella - "aching" in nature and usually goes away with rest Treatment... • Mild cases... heat or extra warm up prior to warm up • Ice after activity • Meds • Modalities • Modified activity • Quad strengthening • Correct poor landing mechanics

Valgus stress

Key for medial stability of the knee and is the principal restraint to forces that tend to open up the inside of the knee—valgus stress--@ 25-30 degrees of knee flexion, 80% of the valgus stress is supported by the medial collateral ligament—this occurs when the knee is allowed to fall inward relative to the foot

Knee mechanics

Knee joint mechanics are more complex than other true hinge joints b/c of 2 factors: 1. Flexion and extension at the tibiofemoral joint do not involve simple movement around one axis but rather incorporate rolling and gliding with a shifting axis at different degrees of flexion 2. Small amounts of transverse rotation also accompany flexion and extension

The 2 most common knee injuries in dancers are the

MCL and ACL

Meniscal injury

Medial meniscus has been reported to be torn 10 to 20 times more frequently than the lateral meniscus. Cause... • Repetitive forced turnout • Twisting when in a position of deep knee flexion Symptoms... • "popping" or "tearing" sensation • Pain • Point tender on the joint line • Swelling (delayed) • Grand pliés painful/limited ROM Treatment... • Limit activity • Ice • Compression • Elevation • Meds • Quad strengthening

Internal tibial torsion

Occurs when the tibia medially rotates; Prevents good turnout (this condition will adversely affect the ability of a dancer to achieve turnout. It is presumed that young dancers who have internal tibial torsion will self-select away from dance forms that require turnout due to frustration or pain in trying to achieve this goal. )

Lowering the Q angle

Orthotic supports - The most effective way to decrease a high Q angle and to lower the biomechanical stresses on the knee joint is to prevent excessive pronation with custom-made, flexible orthotics Adjustments and exercises - While no adjustment has been reported to reduce the Q angle, a search for pelvic and knee misalignments should be part of care. It is important that good biomechanical function be restored to all joints of both lower extremities. Stretching of tight muscles and strengthening of weak areas should be included. Muscles commonly found to be tight include: quadriceps, hamstrings, iliotibial band, and gastrocnemius. The vastus medialis obliques (VMO) is usually weaker than the opposing vastus lateralis muscle. Sometimes it is the coordination of these muscles that has become abnormal. Strengthening may require a special focus on the timing of muscle contractions. Closed chain exercises (such as wall squats) done only to 30 degrees of flexion are currently recommended

___ can contribute to a high Q angle

Overpronation

Connective tissue constraints on patella

Patellar ligaments and fibrous expansions of the vasti group and IT band provide lateral and medial stability for the patella and are key in preventing the patella from coming out of its groove

Intercondylar fossa (notch)

Posteriorly, deeper indentation separates the medial and lateral condyles

Anterior Cruciate Ligament (ACL)

Proximal attachment = lateral femoral condyle Distal = the anterior tibia 1. Important for preventing anterior displacement of the tibia relative to the femur, or posterior displacement of the femur relative to the tibia 2. ACL is responsible for 85% of the force that restrains anterior displacement of the tibia 3. ACL has secondary functions of helping to control rotation of the knee, varus and valgus stresses, hyperextension when the knee is fully extended 4. ACL plays a key role when large forces or deceleration is involved as with jumping, lowering the body down to the floor, or quick changes of direction in dance 5. Essential for joint integrity

Posterior Cruciate Ligament (PCL)

Proximal attachment = medial femoral condyle Distal = posterior tibia 1. Key in preventing the femur from sliding during knee flexion 2. PCL provides 95% of the total restraining force to posterior movement of the tibia—posterior drawer 3. PCL becomes taut with knee flexion versus knee extension 4. 50% stronger than the ACL and less commonly injured

Medial collateral ligament (MCL)

Proximal attachment = medial femoral condyle and merges with the margins of the medial meniscus to the edge of the distal attachment = tibial condyle 1. Stronger than the lateral collateral; but more prone to injury 2. Taut with knee extension and external rotation 3. MCL is the key restraint for external rotation of the tibia whether the knee is flexed or extended—cause of the injury to medial collateral

Lateral Collateral Ligament (LCL)

Proximal attachment = the lateral femoral condyle Distal = the fibular head 1. Taut with knee extension 2. Helps provide lateral stability to the knee and is the primary constraint to forces that tend to open up the lateral aspect of the knee—varus stress—70 % of the varus stress is supported by the lateral collateral ligament 3. Both ligaments slacken with knee flexion, and lessening of these constraints is vital for allowing functional rotation of the tibia used in movements such as pivoting.

Roll and glide movements of the femoral condyle

Pure rolling motion: the femur rolls off the tibial plateau before full flexion is complete. Pure sliding motion: the femur impinges the posterior tibial plateau before full flexion is achieved. (True motion): Combined rolling and gliding of the femoral condyles allows full range of flexion.

Pes Anserinus

Sartorius, gracilis, and semitendinosus all join together distally to form a tendinous expansion • ...insert on the medial aspect on the proximal tibia

Genu valgum

The angle between the tibia and femur is less than 170⁰

Bones that take part in the knee joint and patellofemoral joint

The femur, tibia, and patella

Normal Knee alignment

The femurs are not totally vertical but angle slightly inward and knees are medial to the femoral heads forms a valgus angle, or valgus angulation. In adults, the angle of 170⁰ to 174⁰ is considered normal. Normal alignment is termed genu rectum

Vascularity of meniscus

The inner 1/3 of the meniscus structures are avascular, meaning there is no blood supply. The middle 1/3 is partially vascular, and the outside 1/3 is fully vascular. During a tear of the meniscus, if the inner 1/3 is damaged, healing will be impossible. As a result, a procedure to remove part of the meniscus will be necessary. If the tear occurs on a vascular zone, it will have the capacity to heal (although surgery still may be required to speed up the healing process).

Knee joint capsule

The knee is surrounded by an irregular joint capsule lined with the largest synovial membrane found in the body

Knee rotation further explanation

The knee will not allow rotation unless it flexed 20 to 30 degrees or more - Internal and external rotators of the knee are key for controlling twisting or pivoting movements of the body when the foot is on the ground - Subtle rotations of the tibia are also sometimes used when the foot is in the air to enhance the aesthetics of a movement—attitude derrière

Why is the knee joint called a "modified hinge joint"

The primary joint actions are flexion and extension; in addition, the joint can also incorporate slight internal and external rotation

Knee extension

The quadriceps are used concentrically to extend the knee both when the foot is free and when it is weight bearing • The knee extensors can be used concentrically to produce a straight position of the knee in the gesture leg in the développé or isometrically to maintain a straight position of the knee of the gesture leg in tendu, battement tendu jetés, and grand battement jetés • When weight bearing the quads are used concentrically to extend the knee- rising from a plié or fondu. Isometrically used when extended knee on support leg.

Why does a dancer experience discomfort or cramping in the rectus femoris when performing a développé to the front?

The rectus femoris has two actions in the développé - hip flexion and knee extension - these two actions shorten the muscle across the 2 joints and causes active insufficiency. So when working on increasing the leg height the rectus femoris is overworked. To prevent the cramping, the iliopsoas must be strengthened adequately

The Terrible Triad

This combination injury involves the following structures: 1. ACL 2. Medial Meniscus 3. MCL

Genu varum

When the angle between the tibia and femur gets larger (than 170°)

Tibiofemoral joint

between the femoral condyles and tibia referred to as the knee joint

Tibial plateau

superior surface of the tibia

Patellofemoral compression force

the force pressing the kneecap back against the underlying femur 2 important determinants of patellofemoral compression forces are: 1. The amount of quadriceps contraction 2. The angle of knee flexion - The harder the quads contracts the greater the compression force + farther the knee bends = greater the compression force

Patellofemoral pain syndrome

• A term used to describe pain originating from the region of the patella (kneecap) and femur (thigh bone). Other names for this syndrome include: retropatellar pain, anterior knee pain, and chondromalacia patellae Causes... • Activities involving high-impact or repetitive knee flexion • Anatomical and biomechanical factors such as genu recurvatum, weak vastus medialis, genu valgum, excessive femoral anteversion, increased Q angle, or tight IT band • More common in females than in males Symptoms... 1. Generalized pain behind or around the patella 2. Pain with knee flexion such as in grand pliés 3. Pain with extending sitting - most distinguishing symptom 4. Pain going down stairs 5. Weakness, swelling, and pain during or after activity Treatment... • Ice after activity • Modified activity • Meds • Quad strengthening exercises using isometric and small arc exercises • Stretch IT band • Correct technical errors • Taping techniques

Knee extensor strengthening...

• Adequate quad strength plays an important role in knee joint stability, the prevention or progression of knee osteoarthritis and proper tracking of the patella • Dancers with a history of kneecap problems or who experience knee discomfort with grand pliés should begin with the quad set and straight leg raise in which the knee is isometrically maintained in a position of extension so that patellofemoral compression forces are low

The law of valgus

• Because the femur normally runs slightly inward, the patella has a tendency to be pulled laterally... the lateral motion of the patella is referred to as this • Lateral tracking causes the patella to lie alongside the lateral portion of the femoral groove. The resultant excessive shear forces can damage the cartilage lining the underside of the patella and cause Patellofemoral dysfunction and pain. • Adequate and balanced strength of the quadriceps is an essential measure for promoting sound patellar mechanics and preventing Patellofemoral injuries.

Popliteus

• Deep to the Gastrocnemius and attaches proximally to the lateral femoral condyle, lateral meniscus, and fibula, and distally to the posteromedial aspect of the tibia Function: Weight bearing...popliteus acts to externally rotate the femur which is important to unlock the knee and allow flexion to occur When the tibia is free...the femur acts as the fixed segment and the popliteus acts on the tibia producing internal rotation of the tibia

What is the proper technique for performing knee extension exercises?

• Due to the prevalence of knee hyperextension in dancers, it is important to take care that the knee is brought only to a straight position and not beyond. The persistence use of hyperextension in these exercises can actually decrease knee stability and irritate tissues rather than provide the desired increase in joint stability and muscle strength.

Closed-chain and open chain movement of locking mechanism

• Femur on Tibia : closed-chain mvt o Femur rotates internally to "lock" o Femur rotates ext to "unlock" • Tibia on femur: Open-chain movement o Tibia ext rotates to "lock" o Tibia int rotates to "unlock"

Knee flexion

• Hamstrings are used concentrically when flexion is occurring against gravity or resistance, to shorten the length of the limb, to effect a desired shape such as in a retiré, attitude or the back leg of the stylized stag leap • Weight bearing, such as a demi plié, gravity becomes the 1° force creating further flexion of the knee, therefore.... The knee extensors (quadriceps femoris) are working to eccentrically to control further flexion or isometrically to maintain the angle of knee flexion

Osgood-Schlatter Disease

• Involves the quads tendon and the inferior attachment of the patellar tendon where it joins to the tibial tuberosity • Not really disease...it involves an injury to the growth center of the tibial tuberosity due to traction produced by the quads via the patellar tendon • Occurs in 8 to 15 years of age • More prevalent in males than females Symptoms... • Characterized by pain and swelling over tibial tuberosity Treatment... • Ice after activity • Anti-inflammatory meds • Dance modified - grand plié, deep fondu, and jump • Quad strengthening and stretching

Why is it dangerous to shift the heels forward at the bottom of a demi plié?

• Knee flexion allows more rotation of the tibia due to slackening of ligamental constraints, as well as external rotation of the femur associated with unlocking the knee • This should be avoided b/c when the knee straightens, the femur internally rotates and the ligaments become taut, and an undesired torsional stress will occur at the knee if the foot is positioned excessively outward. • Also, when extending the knee it is easy to exaggerate the associated internal rotation of the femur if external rotation is not maintained at the hip joint. o That is, the distal tibia is being held externally rotated by the foot against the floor as the femur internally rotates, resulting in torsional stress at the knee • The Q angle and patellofemoral stress increases.

Medial and lateral meniscus

• Medial meniscus is "C" shaped and the lateral meniscus is "O" shaped and joined to each other anteriorly via the *transverse ligament* • Medial meniscus is attached to the medial collateral ligament and of the medial hamstring muscles (Semimembranosus), making medial meniscus less movable than the lateral meniscus • During knee flexion, the menisci move posteriorly with the femur, with the more movable lateral meniscus traveling approximately twice as far as the medial. • During knee extension, the menisci move anteriorly with the femur

Bursae

• More than 20 bursae are present around the knee joint - superficial infrapatellar bursa - gets strains most (can easily get injured or have to get it aspirated)

Knee flexion and extension

• Occurs primarily in the sagittal plane b/t the condyles of the femur and tibia • In flexion, the femoral condyles roll backwards and would roll off the back of the tibia without an anterior sliding motion that occurs after about 25 degrees of flexion. • The opposite occurs with extension, with the femoral condyles first rolling forward and then sliding backward to offset the forward motion associated with rolling. • The simultaneous use of rolling and sliding allows for the desired surfaces to stay in contact during flexion and extension and prevents excessive relative movement of the associated bones that could jeopardize joint integrity.

Q angle

• Shape, height, mobility, and facing of the patella in the femoral groove, as well as its angular relationship to the tibia, are important for determining stability and tracking of the patella Patellofemoral alignment

Prevention of Knee Injuries

• Supplemental quad and hamstring strengthening included in training regimes can help reduce injury o Plyometric training develops functional strength • Adequate flexibility of the quads and paying close attention to technique may also help reduce injury risk

Iliotibial band

• Tensor fasciae latae inserts into this band, so when the muscle contracts it tightens the IT band • Can work as a knee extensor when the knee is lightly flexed (30⁰) • Provides key lateral support to the knee as well as the hip • Acts as a flexor of the knee when the knee is flexed greater than (40⁰)

Knee rotation

• The 2 condyles at the distal end of the femur are different in shape and size and not quite parallel necessitates slight transverse rotation • The degree of rotation permitted varies with the degree of knee flexion and is strongly influenced by ligaments—when the knee is bent, the collateral ligaments are more slack, and 20-30 degrees of internal rotation and 30-45 degrees of external rotation of the tibia are possible. The increased rotation permitted as the knee bends enhances movement possibilities. It allows for quick changes in directions and in non-weight bearing conditions such as "presenting the heel forward"

How do you effectively stretch the vasti group?

• The knee must be brought into full flexion and the position of the pelvis is irrelevant since these muscles do not cross the hip • The rectus femoris slackens and the stretch decreases effectiveness with an anterior tilt so the pelvis must stay in neutral or tucked position. B/c the rectus femoris is a hip flexor, bringing the hip into hyperextension prior to bringing the knee toward the buttocks will also increase the stretch of the rectus femoris.

Why has closed kinematic chain exercises gained popularity in fitness and rehabilitation?

• They better replicate functional movements in terms of the loads place upon the joints and the complex muscles contraction involved in coordination multiple joints. • They place less stress on the ACL and are associated with less patellofemoral compression forces in the angles of 0-53° of knee flexion • Open kinematic chain exercises may offer advantages in terms of producing effective overload with less resistance, help correct muscle imbalances, and replicating dance demands of the gesture leg. Therefore, it is recommended to include a combination of open and closed kinematic chain strengthening exercise in supplemental conditioning programs for dancers.

Tight muscles that affect the knee

• Tightness in the iliotibial band can exert lateral forces on the patella and increase knee injury risk. • Adequate flexibility in the hip adductors is important for correct placement of the knees over the feet in positions such as turned-out second. • Tightness in the calf muscles limits the depth of the demi plié and can contribute to compensatory foot pronation and resultant suboptimal knee mechanics • Knee extensor stretches: • Tight quads muscles may increase the risk for patellofemoral problems, so it is important that adequate flexibility be achieved and maintained.

External tibial torsion

• has been measured as widely varied as 16-60 degrees. • Dancers tend to have differing amounts of tibial torsion in each leg. This will mean that turnout on each leg will be varied. • Most health care practitioners advise that one assumes the rotation of the less turned out leg for symmetry and injury prevention - longevity o External torsion= toeing out - hard to keep parallel