Knee Alignment and Common Deviations

Genu Valgum

-knock knees

-can’t stand with the feet together in closed parallel

-increased tension on the MCL and stress on lateral meniscus and excess foot pronation

-if someone is medially rotating femur it can appear to be genu valgum; or if have high femoral angle it can appear to be genu valgum

Genu Varum

-bow legs

-knees don’t touch in closed parallel

-increased tension on the LCL and stress on medial meniscus and excess foot supination

-could be from shape of tibia within knee joint (hyperextension can make it look bowed)

Genu Valgum

-knock knees

-can’t stand with the feet together in closed parallel

-increased tension on the MCL and stress on lateral meniscus and excess foot pronation

-if someone is medially rotating femur it can appear to be genu valgum; or if have high femoral angle it can appear to be genu valgum

Genu Varum

-bow legs

-knees don’t touch in closed parallel

-increased tension on the LCL and stress on medial meniscus and excess foot supination

-could be from shape of tibia within knee joint (hyperextension can make it look bowed)

Genu Recurvatum

-hyperextended knees; unequal pressure on menisci and ligaments; limit in weight-bearing

-could be from bony alignment, or capsular or ligament laxity (particularly popliteus ligament)

-lower extremity alignment altered, less balance and shock absorption and muscular imbalances

Tibial Torsion

-external tibial torsion= foot points outward in relation to knee facing forward, allows for more appearance of “turn-out” without causing torque on the knee, makes it difficult to have a parallel leg alignment causing torque on the knee

-internal tibial torsion= foot toes in in relation to the knee facing forward, poor turnout, more likely to try to turn out from the knee, causing torque on the knee

Knee Rotation

-little rotation possible when the knee is fully extended-most stable in extension

-20-30 degrees of internal/30-45 degrees of external rotation when flexed

Locking Mechanism

-”screw home”

-near full extension- slight rotation of the tibia or femur, allows the knee to “lock in”; minimal effort needed to stand over long periods of time

-open chain movement tibia laterally rotates

-closed chain movement femur medially rotates

Unlocking/Bending

-open chain movement (rond de jambe en l’air), popliteus rotates tibia medially

-closed chain movement (squat; plie) the popliteus laterally rotates the femur

Patellofemoral Joint and Functions

SEPARATE FROM KNEE JOINT

-has patella (sesamoid bone), floats over femur

-increases ability of quad to produce torque; acts as a pulley for the quads to protect knee joint

-helps prevent femur from sliding off the tibia anteriorly

-distributes force which protects the tendon

Movements of Patellofemoral Joint

-complex gliding movements'

-relationship to femur changes with flexion (slides down) and extension (slides up)

-stabilized by retinaculum, iliotibial band and patellar ligaments; balanced strength in quads critical; can be pulled on and not “ride the groove” smoothly

Patellofemoral Joint Angles and Compression Forces

-Q angle formed by the ASIS- through center of patella and tibial tuberosity

-Q angles larger than 15 degrees a risk factor for patellofemoral problems (more common in women-wider pelvis)- places stress on lateral side of patella, alignment issues- pronation creates a larger Q angle

-compression force in grand plie more than 7 times body weight

-large jumps can have compression forces of about 20 times body weight

Grand Plie Suggestions to Protect Knee

-consider dancer skill level

-use appropriate turn-out

-no sitting at bottom

-neutral pelvis

-recruit adductors to take some pressure off the quads

Hinge Suggestions to Protect Knee

-train with wall squats, then barre, then center; the backward angle of the torso makes it harder

How to avoid twisting of knee through forced rotation

-avoid forcing turn-out especially in plie because when legs straighten femur internally rotates and ligaments are taut which creates torsion

-avoid saying bring heel forward because rotation comes from hip not lower leg

-focus on hip rotation

-floor work square position or saddle in yoga requires supplemental stretching for hip and quads or will put torque on the knee

Forced Turn Out

-knees not aligned between 1st and 2nd toe

-decreased rotation at hip

-pronation of foot

-can lead to patellofemoral pain and meniscus tears

Hyperextended Knees

-limit extension and/or limit internal hip rotation

-co-contraction of quads and hamstrings

-neutral pelvis helps prevent

Overdeveloped Quads

-learning to work muscles other than the quads to assist

-ex: hip adductors, hamstrings at the proximal attachment, have torso more vertical; less use of quads

Medial Collateral Ligament Sprains/Tears

-Symptoms: pain on medial knee

-Common cause: decelerating, forced turnout, pivoting

-Treatment usually conservative; RICE (rest, ice, compression, elevation); NSAIDS (nonsteroidal anti-inflammatory drugs); taping/supporting; surgery required if rupture is complete

Anterior Cruciate Ligament Sprains/Tears

-Symptoms: pain on anterior knee; knee instability

-Common causes: deceleration, twisting, pivoting and jumping, more common in women

-Treatment: RICE; NSAIDS; taping/support; surgery required if rupture is complete

Meniscus Sprains/Tears

-usually medial section tears

-Symptoms: medial knee pain; knee locking in full flexion

-Common causes: repetitive forced turn-out may contribute to wearing down; twisting while in deep flexion

-Treatment: location determines healing; RICE; NSAIDS; strengthening quads/hamstrings; arthroscopic surgery may be necessary

Patellofemoral Pain Syndrome

-Symptoms: pain under the patella particularly with extended sitting

-Common causes: high impact and repetitive knee flexion, forced turn out; may also be anatomical; more frequent in women; pain with extended sitting

-Treatment: strengthen quadriceps and external rotators

Jumper’s Knee- Patellar Tendon Injury

-Symptoms: pain at the anterior knee

-Common causes: a lot of jumping and leaping; aggravated by hard floors

-Treatment: RICE; NSAIDS; strengthen quadriceps

Osgood-Schlatter’s Disease

-Symptoms: pain and inflammation of the area just below the knee where the patellar tendon attaches to the tibial tuberosity

-Common cause: injury to tibial tuberosity during growth spurt

-Treatment: RICE, NSAIDS; use knee pads, quad strengthening and stretching

What kind of dancers are more vulnerable to ligament sprains/tears?

dancers who are hypermobile