77 and 78 - Pediatric Hip, Knee and Leg Flashcards
Angle of Inclination of Femur
- Angle of Inclination of Femur: angle in the frontal plane formed by the axis of the head and neck of the femur and shaft of the femur
- Infant-150°
- Adult-125°
Coxa vara
- Coxa vara: a decrease in the angle of inclination so that the distal femur is directed towards the midline and the knees are closer together (causes genu valgum)
Coxa valga
- Coxa valga: an increase in the angle of inclination so that the distal femur is directed away from the midline and the knees are farther apart (causes genu varum)
Purpose of normal inclination angle
- The inclination angle allows abductors to function with a mechanical advantage as they counterbalance body weight in one-legged stance
- If you didn’t have this, you would develop a Trendelenburg gait (unaffected side would tilt down when standing on the affected side)
- Hip abductors should be as far laterally from the hip as possible to achieve muscle stability which is greatest when the child begins to stand
Deformities of inclination angle
- Coxa vara: caused by overgrowth of the femoral epiphysis (femoral head) which leads to limb shortening and limitation of passive hip abduction*** - causes GENU VALGUM
- Coxa valgum: very uncommon
- An abnormal angle of inclination will cause a child to:
o Stand with the pelvis tilting down on the contralateral side
o Stand with the pelvis tilting down on the ipsilateral side
o Stand with the pelvis tilting down on the contralateral side
Angle of declination of femur
- Angle of Declination of Femur: angle in the transverse plane formed by the axis of the neck of the femur and the transcondylar axis of the knee with the apex of the angle lateral when looking from proximal to distal through the femur
- Infant: 30° (up to 60°) of internal rotation
- Adult: 8° to 12° of internal rotation
- Therefore, angle decreases about 20° (up to 50°) by rotating
externally, but still remains internally rotated by about 10° in the adult - NOTES: the femur at birth is naturally twisted internally, but not in the shaft, but in the NECK of the femur – as you age the internal twist of the femur will gradually externally rotate, but will stop at 10 degrees of internal rotation – This can be measured by CAT SCAN
Normal fetal position
- Normal fetal position is sitting like “Buddha”; hips and knees flexed, hips externally rotated, legs and feet internally rotated
- When the HIP is flexed in utero, it is also externally rotated
- When the LOWER LIMB is flexed in utero, it is also internally rotated
- BOTH are flexed, but hip is EXTERNALLY rotated and lower limb is INTERNALLY rotated
- NOTES: in order for the child to sit comfortably in the womb, they sit in “Buddha” but you will need to change in order to eventually stand upward
Version vs Torsion
- 1979 Subcommittee on Torsional Deformity of the Pediatric Orthopedic Society
- Standardized the terms “version” and “torsion” as it relates to rotational problems of lower limb
- Version means NORMAL – the amount of twist you see in the bone is NORMAL
- Torsion means ABNORMAL – the amount of twist in the bone is ABNORMAL
- BOTH refer to how much TWIST is in the bone
Version
- Version: angular difference between the transverse axis of motion of each end of a long bone (does NOT mean soft tissue position) – PROXIMAL joint vs DISTAL joint comparison
- Normal version is present when the angular difference is within 2 standard deviations of the mean
Torsion
- Torsion: present when the version is excessive (abnormal) or greater than 2 standard deviations outside of the mean
Femoral torsion
- Femoral torsion (abnormal) = increase in femoral version (normal)
- ANTEtorsion: medial femoral or internal femoral torsion = abnormal increase in femoral anteversion
- RETROtorsion: lateral femoral or external femoral torsion = abnormal increase in femoral retroversion
Femoral version
- Femoral version: NORMAL angular difference between the transcondylar axis of the knee and the neck of the femur
Tibial version
- Tibial version: NORMAL angular difference between the transcondylar axis of the knee and the transmalleolar axis of the ankle
Femoral anteversion
- Femoral anteversion: the NORMAL angle of femoral version
made when the axis of the neck is directed forward or
anterior from the femoral shaft - When looking at our diagram, the axis of the neck makes
a larger angle with the transcondylar axis of the knee
Femoral anteversion image
- NOTE: as the anteverted hip articulates with the normal acetabulum,
the knee will be internally rotated when femoral anteversion is present - In infants, the knee position is internally rotated, in adults, the patella
is pointed forward so that the knee is pointed forward on the shaft
Femoral retroversion
- Femoral retroversion: the angle of femoral version made when the axis of the neck is directed backward or posterior from the femoral shaft
- When looking at our diagram, the axis of the neck makes a
smaller angle with the transcondylar axis of the knee
- A femur which exhibits an internal rotation less than 2 standard deviations from normal is called o Femoral retroversion o Femoral retrotorsion o Femoral anteversion o Femoral antetorsion
- Answer: 3 – less than 2 standard deviations means NORMAL, so we say “version” and if it is internal rotation, it is “anteversion”
Femoral torsion
- Femoral torsion: ABNORMAL increase in femoral version
Antetorsion
- Antetorsion: medial or internal femoral torsion-ABNORMAL increase in femoral anteversion
Retrotorsion
- Retrotorsion: lateral or external femoral torsion-abnormal increase in femoral retroversion
Clinical vs classic biomechanics
- In classic biomechanics, torsion means a force tending to rotate an object about its long axis
- CLINICALLY, it implies deformity or abnormality – WE ARE USING THE CLINICAL DEFINITION***
Femur at birth
- At birth the femur is rotated internally to about 30°
- At the same time, the soft tissue of the hip externally rotates the thigh to about 50°
Development of femur
- The angle of declination decreases from 30° internal to about 10° internal (or femur externally rotates 20°)
- Subsequently, the soft tissue changes around the hip, internally rotate thigh from 50° external to 10° external (or internally rotates thigh 40°)
- The 8 to 12° of femoral anteversion is balanced by the external rotation of about 10° caused by normal soft tissue contraction at the hip
Summary of rotational changes
- The end result is that the knee is eventually pointed straight ahead in gait
Normal hip rotational development
- Infants: 60-90° external; 0-30° internal (3:1)
- Up to 1 year: 50-60° external; 30° internal (2:1)
- 4 years to adult: 45° external; 45° internal (1:1)
- ***NOTE: KNOW THE RATIOS ** - This is how much the hip moves total (can’t tell how much of it is from a boney cause unless you take a CT scan)
Problems with normal hip rotational development
- When this normal hip rotational development does not occur, we will have either an externally rotated or internally rotated leg and foot
- Here we are talking about how much the hip joint moves - incorporates soft tissue and bone
Result of abnormal hip rotational development – BONEY problem
- Antetorsion will cause an in-toe gait, retrotorsion an out-toe gait*
- We are talking about torsion in the BONE – twist in the BONE
Calculation of Neutral Femoral Position (NFP) = MAIN POINT
- This compares the amount of internal and external rotation sitting and then laying
- If values for internal/external rotation are the SAME in both positions, BONEY problem (torsion)
- If they are DIFFERENT, it is likely a SOFT TISSUE problem
- NEED to understand how we determine if the problem is due to soft tissue or bone
In-toe gait due to SOFT tissue
- An in-toe gait can also be caused by tightness of the internal rotators of the hip or a tight iliofemoral, pubofemoral, or ligamentum teres ligament
Out-toe gait due to SOFT tissue
- An out-toe gait can be caused by tightness of the external rotators of the hip or a tight ischiofemoral ligament
External hip rotators
External hip rotators (Notre Dame theme song: “Go Out And Get Some Quality Players”) o Gluteus maximus o Obdurators o Adductors o Gemelli o Sartorius o Quadratus femoris o Piriformis
Internal hip rotators
- Gluteus medius
- Gluteus minimus
How do we determine if the rotational deformity is due to femoral torsion or a soft tissue contracture (or laxity)?
- Need to determine neutral femoral position of the hip with the hip extended and with the hip flexed
- A difference between NFP readings with the HF and HE suggests that there is a soft tissue cause of the rotational deformity
- The same reading for NFP with the HF and HE suggests it is solely femoral torsion
- A 2 year old child presents with an out-toe gait. You measure 60° of external hip rotation and 40° of internal hip rotation with the hip flexed and extended. This is:
o Normal
o A sign of femoral retrotorsion
o A sign of femoral retroversion
- Answer: NORMAL, 1 and 3 – KNOW THE VALUES ***
- If this was for a 6 year old, 2 would be the correct answer
Uterine position leads to…
- An increase in external rotation and flexion of the hip
- Femoral anteversion caused by femoral head and neck rotating inward against the shaft-allows maximal rotation of hip in flexed position
Anteverted hip
- The anteverted hip fits well into the acetabulum in utero while the hip is hyperflexed (walking on all fours is the true physiologic position of the hip), but as soon as the hip extension begins after birth, anterversion angle must be reduced or there will be an unstable, ANTERIOR dislocatable hip or an in-toe gait - These are the TWO THINGS that could happen – KNOW THIS***
- Anteverted position increases leverage of the gluteus maximus which allows it to better maintain the body in an upright position
- However, the upright position on an anteverted leg causes the anterio-superior portion of the femoral head to be exposed
- The anteverted position of the femur is important because:
o It is the most stable position of the hip in utero
o It allows the child to walk in-toed which is more stable
o It increases the leverage of the gluteus maximus
o It increases the leverage of gluteus medius and minimus
1 = It is the most stable position of the hip in utero
3 = It increases the leverage of the gluteus maximus
Torsion at birth
- Torsion at birth is reduced when the erect posture is assumed by pressure on the tense anterior hip capsule
3 activities occur to mold the epiphysis of the femoral head to reduce anteversion
- 1 = Upper end of femur yields under pressure to tight anterior capsule so that excessive anteversion slowly molded away
- 2 = Force also produced by contraction of internal rotator muscles and external rotators which gives rise to a shearing force acting in the AP direction on the femoral head which causes the femoral epiphysis to slip and reduce anteversion
- 3 = Pelvic movement of inward rotation on a loaded hip joint also applies a dynamic force in the AP direction on the femoral head
Walking
- Therefore, walking is the decisive factor for reducing anteversion (as well as, the angle of inclination) KNOW THIS * You NEED to walk upright to get rid of anteversion*
- However, if anterior capsule stretched, the hip dislocates anteriorly. Less force is exerted on the femur, so there is less tendency for correction of anterversion
- If the femoral head does not give way under the stress of hip extension, it must internally rotate to get inside the acetabulum, resulting in internal rotation of the entire extremity
If the anteversion of the femur is not corrected, the child is at risk for: o An out-toe gait o A dislocated hip o An in-toe gait o A Trendelenburg gait
Answer: 2, 3
- A dislocated hip
- An in-toe gait
Femoral antetorsion
- Femoral antetorsion is far more common
- Leads to an intoe gait, anterior pelvic tilt (to cover the femoral head), lumbar lordosis, apparent genu valgum (due to internal positioning of the patella), genu recurvatum, and possible flatfoot to compensate for foot adduction (causes skewfoot)
In-toeing – common cause
The most common cause of intoeing after the age of 2 or 3 is…
o Internal femoral torsion or antetorsion or
o Tight internal hip rotators and/or
o Tight iliofemoral, pubofemoral or ligamentum teres ligaments
Out-toing – common cause
The most common cause of outoeing at ANY age is…
o External femoral torsion or retrotorsion or
o Tightness of the external hip rotators and/or
o Ischiofemoral ligament
Diagnostic clue
- With the child sitting in a chair with legs in dependency, the patella and feet are pointed inward
- You will know that the child might have a hip problem, have them sit on the exam talble with the knees hanging down
- If the knees point forward, you do NOT have a problem in the hip
- If the knees point internal, it is due to hip problems in in-toeing
- If the knees point external, it is due to hip problems resulting in out-toeing
A child over the age of 4 exhibits an in-toe gait. You find that the child has more internal rotation of the hip over external with the hip extended. Possible causes of the in-toe gait include: o Femoral retrotorsion o Femoral antetorsion o Tight gluteus minimus o Tight gluteus maximus o Tight pubocapsular ligament o Tight ischiofemoral ligament
- Answer: 2, 3, 5
- Internal means it will be ante, not retro
- Internal ligaments or muscles are in 3 and 5
3 potential hip problems in children
- ***1 = Excessive internal or external rotation of the hip (already talked about) – MOST IMPORTANT BECAUSE MOST COMMON
- 2 = Coxa vara or coxa valga (already talked about)
- 3 = Developmental hip dysplasia (DHD)-also known as dislocated (not in acetabulum) or easily dislocatable hip (comes out of acetabulum very easily) – usually detected within the 1st month
Developmental hip dysplasia
- 1-2/1000 births
- Child may not move involved extremity, but DHD is often unrecognizable except by clinical exam
- X-rays unreliable until the age of 3-5 months when the femoral head ossific center first appears, but x-rays are the most well-accepted standard after 5 months for establishing the diagnosis
- Unfortunately, the best way to diagnose is by x-ray, but it is unreliable early in life
- You want to diagnose as early as possible so you can treat it
- One of the early “tip offs” is that the child does not move the extremity – if the femur is not in the acetabulum they will not be able to move it
DHD clinical signs
- DHD includes the entities of true dislocation, as well as subluxation of the hip and refers to a syndrome where over 90% of the time, the head of the femur is positioned upward, laterally, and POSTERIORLY from its usual position in the acetabulum*** KNOW THIS
- 10% of time, hip dislocates anteriorly as we had discussed with femoral anteversion
Etiology of DHD
- DHD is generally the result of abnormal development of the soft tissues surrounding the hip joint and eventually, if not corrected, changes in the shape of the acetabulum, itself
- Usually it is NOT because of boney causes, but actually SOFT TISSUE problems, but overtime it leads to remodeling of the acetabulum and it will become a bony problem
Which factors are necessary to prevent an anterior dislocated hip?
o Walking
o Tight posterior hip capsule
o Muscle contraction of the internal and external hip rotators
o External pelvic rotation
- Answer: 1 and 3
Signs and symptoms of DHD
- Asymmetry of gluteal folds
- Limited abduction of affected hip
- Galleazzi’s or Allis’ sign
- Ortaloni’s sign
- Barlow’s test
- Telescoping sign
- Trendelenburg test is positive
- Shortening of affected leg in newborn and infant should alert one to DHD – ONE OF THE FIRST SIGNS KNOW THIS
Asymmetry of gluteal folds
o Also called “broken anchor sign”
o Results in a SHORT LEG ***
Galleazzi’s or Allis’ sign
o with child supine and hip flexed and knee flexed, there is a lower level of the knee on the affected side
Ortaloni’s sign
o More evident if hip is truly dislocated; presence of palpable click in and out as the hip is reduced by abduction and dislocated by adduction (O = hip is Out)
Barlow’s test
Barlow’s test-used with dislocatable, unstable hip – you can physically dislocate this hip by pushing posteriorly on it
o Child is supine with hips and knees flexed
o Finger placed over greater trochanter and thumb over lesser trochanter
o Hips brought into midabduction and thumb pressure is applied posteriorly over the lesser trochanter
o Dislocation of femoral head across the posterior lip of the acetabulum occurs; releasing thumb allows head to slip back into acetabulum
Telescoping sign
o When extremity is pushed in piston type fashion with hip flexed and extended, abnormal mobility or telescoping is felt
o Piston the femur up and down proximally and distally
Trendelenburg test is positive
o Due to dislocation of hip causing weak abductors, the unaffected side of the pelvis is not held level and drops down
o Only when the child is older and walking – can’t see this in the infant
4 most common criteria predictive of DDH (DDH is the same as DHD, words just switched)
- **KNOW THIS LIST **
- 1 = Ortolani/Barlow test
- 2 = Limited hip abduction
- 3 = Leg length discrepancy
- 4 = First degree family history
A dislocated hip moves: (MOST COMMON) o Superior o Lateral o Posterior o Inferior o Medial o Anterior
- Answer: 1, 2, 3
- Anterior is 10% of the time, but not most common
A dislocated hip exhibits: o A short leg on the dislocated side o A long leg on the dislocated side o Lack of spontaneous movement of the dislocated side in a newborn o Limitation of abduction o Limitation of adduction
- Answer: 1, 3, 4
Radiographic findings in DHD
- X-ray diagnosis made by studying measurement of the lateral, upward, and posterior displacement of the head of the femur
- This alters all pelvic relationships to the proximal femur
Hilgenreiner’s Line (HL)
- Hilgenreiner’s Line (HL): horizontal line connecting the two most medial
and inferior points of acetabular cavities - Normal: head of femur found below HL
- DHD: head of femur above HL
Perkin’s Line (PL)
- Perkin’s Line (PL): vertical line from most ossified lateral margin of rim
of acetabulum-crosses HL perpendicularly, forming quadrants - Normal: femoral head in lower-medial quadrant
- DHD: femoral head in upper-lateral quadrant
Acetabulum index
- Acetabular index: angle formed by HL and a line connecting it from
the most prominent medial and lateral points at rim of acetabulum - Normal: 30°
- DHD: >30°
Shenton’s or Menard’s line
- Shenton’s or Menard’s Line: arc drawn along medial border of
femoral neck and superior portion of obturator foramen - Normal: uninterrupted arc
- DHD: arc is broken
Pediatric Knee – 3 developmental changes
- Frontal plane (genu varum and valgum)
- Sagittal plane (genu recurvatum)
- Transverse plane
Frontal plane
- Genu varum (bowlegged) and genu valgum (knockneed) are usually normal developmental changes, but consider possibility of epiphyseal disease causing a non-uniform growth between the medial and lateral aspects of either the femoral or tibial epiphysis
Knee joint development in the frontal plane KNOW THIS
- Birth-2 years old: genu varum
- 2-4 years old: straight
- 4-6 years old: genu valgum
- 6-12 years old: straight
- 12-14 years old: genu valgum
- > 14 years old: straight
- NOTE: you go in and out of deformity and straight during development, which should all straighten out by older than 14 years of age
- KNOW THIS*
Sagittal plane (genu recurvatum)
- Hyperextension deformity of knee
- Can be remarkable at birth due to intrauterine position, but improves with age
- Posterior displacement of extended knee greater than 15° is pathological***
Transverse plane
- With KE, tibia rotates laterally on femur
- With KF, tibia rotates slightly medially
- Small amount of transverse plane motion in the knee (excessive motion is called pseudolack of malleolar torsion)
- A false lack of external malleolar position – This is caused by the femur twisting excessively on the tibial plateau – VERY RARE
- Patella are externally rotated 30° in newborn (due to normal increase in external hip rotation over internal)
Transverse plane motion of knee
- At birth, total range of motion is 15° with the greatest percentage internal
- At 3 years of age, it is 5°
- Anything greater than 15° is called pseudolack of malleolar torsion (the foot appears internally rotated due to an apparent lack of normal external malleolar position)
Rotational deformities below the knee
- Tibial torsion is the most common “problem” encountered
- Considerable debate if it even exists
- Most accurate definition of tibial torsion is “a change in the transverse relationship of the foot to the thigh”
- May involve rotation of knee on the leg in relation to the thigh; twisting in the leg, itself; or rotation of ankle joint on the leg
- We are measuring the distal tibiofibular axis created by the malleoli in relation to the axis of the knee
- Impossible to measure any amount of actual torsion or twisting of the tibia
- Intrauterine fetal position promotes internal leg rotation which must be corrected if proper gait is to occur
Normal at birth through development
- At birth, there is generally between 0° and 5° of external malleolar position
- At one year, it is 10°
- It increases by one degree for each year of age until 12 or 13
- Final result is 18-23° of external malleolar positioning
- Actual amount in tibial torsion is 13-18°
**Internal tibial torsion **
- Anything less than these values is called “internal tibial torsion”
- It is the most common cause of in-toe gait before the age of 2 or 3
- The term version is not used when discussing the rotational deformities below the knee
External tibiofibular torsion
- External tibiofibular torsion is necessary to counteract two natural formations of the talus:
- Flexion and extension of the talus occurs in an axis 10° internally rotated to the transmalleolar axis
- Head and neck of talus is internally rotated compared to the transmalleolar axis
- If external torsion did not occur, in-toe gait would occur
Measurement
- Measure with child sitting in chair with KF and leg in dependency
- Normally, patella points forward and feet are also pointing straight
- With internal tibial torsion, patella points forward, but foot points inward (but there is no deformity of the foot, itself)
- Measure with the knee extended, because with the knee flexed, there is some internal rotation of the knee and the amount of external tibial torsion will be smaller
Now we will go through each step in the exam…
FYI
- Place child in sitting position with knee flexed over ledge
o Patella straight with foot internally rotated-ITT and/or MA (metatarsus adductus)
o Patella straight with foot externally rotated – ETT
o Patella internally rotated and foot internally rotated-IFT and possibly ITT and/or MA
o Patella externally rotated and foot externally rotated-EFT plus possibly ETT
o NOTE: I/ETT = internal/external tibial torsion, I/EFT = internal/external femoral torsion
- Evaluate patellar and foot position while walking
o Results should mimic sitting position findings
o Sitting in W = Femoral antetorsion
o Sitting on feet = Internal tibial torsion
- Evaluate hip range of motion with HE and HF to determine NFP
o If ROM remains the same with both maneuvers, rotational deformity is due to femoral torsion*
o If ROM changes, rotational deformity is due to soft tissue contractures*
o Can use Dennis-Browne Bar (picture on the left) for anteversion or antetorsion
- NEED to start before the child is 1 or they will not tolerate it
- You attach shoes to top of braces and sleep with them to externally rotate
feet and hope to also rotate the hip
- If child exhibits 30° external rotation and we want to get to 45°, you can
only brace them at 30° to start – can’t overdo it
- With child supine and HF, perform tests for DHD
o This infant is positioned correctly in a Pavlic harness to treat DDH (on right)
o The hips are flexed and abducted, leg is short
o Only do this if this is why they are coming in and you suspect it
- Test for medial and lateral hamstring tightness which could cause in-toe or out-toe gait respectively
No additional notes
- Measure amount of transverse plane motion at the knee with KE
o If >15°, diagnosis of pseudolack of malleolar torsion
o Don’t really do this – not very accurate
- Measure amount of knee extension beyond 180°
o If an additional 15° of extension occurs, diagnosis of genu recurvatum occurs
- With child supine and KE, measure amount of malleolar position
o 20° external, consider ETT
- Evaluate foot for MA
Metatarsus adductus
Treatment for ITT
- Wheaton brace
- Avoid sitting position on feet
- Gait plate to promote abduction – but this can cause pronation (create a new pathology)
Shoes
- Straight-last open toed shoes with ¼” felt pad along lateral side of upper at 5th metabase and medial side at 1st metahead
Match the deformity to the correct time frame…
Femoral antetorsion
o Most common cause of intoeing after the age of 2 or 3
Femoral retrotorsion
o Most common cause of outtoeing before the age of 2 or 3
o Most common cause of outtoeing after the age of 2 or 3
Internal tibial torsion
o Most common cause of intoeing before the age of 2 or 3
Match the correct knee position with the corresponding age:
o Genu varum = 0-2 years
o Genu valgum = 4-6 years and 12-14 years
o Straight = 2-4 years, 6-12 years, >14 years
- With a 10 year old child in the sitting position, the knees are pointed straight ahead, but the feet are externally rotated. A possible cause of this position is: o Femoral antetorsion o Femoral retrotorsion o Pseudolack of malleolar torsion o External tibial torsion o Tight lateral hamstring
External tibial torsion
The clinical sign of developmental hip dysplasia where there is an interruption of the normal posterior folds of the buttocks is called: o Allis’s sign o Positive Ortolani’s sign o Broken anchor sign o Negative Barlow’s sign o Telescoping sign
Broken anchor sign
A 5 year old exhibits an in-toe gait. All of the following are possible etiologies: o Internal femoral torsion o Femoral anteversion o Pseudolack of malleolar torsion o Pronation o Internal tibial torsion
- Answer: 1, 3, 4, 5
What to know
- Basic exam starts with looking at patella
- After you see what the patella looks like, check the hip, check the hamstrings, check for internal/external tibial torsion, check for metatarsus adductus
- Know the questions in lecture – they solidify what we talked about – if you know these you should do very well
