Rotational & angular deformities of lower limb

Classification
Rotational

Toeing in

      internal femoral torsion

      internal tibial torsion

      metatarsus adductus

Toeing out

      physiological

      external tibial torsion

      pronation/abduction of the feet

Angular

Varus

      physiological genu varum

      tibia vara (infantile/adolescent Blountís disease)

      rickets

      anterolateral bowing of tibia (pseudarthrosis)

Valgus

      physiological genu valgum

      post traumatic genu valgum

      congenital posteromedial bowing

      anteromedial bowing (fibular hemimelia)

Rotational deformities

definitions

      version

      normal rotation

      femoral version

      angular difference between transcervical and the transcondylar axes

      tibial version

      angular difference between axis of knee and the transmalleolar axis

      torsion

      values 2 standard deviations above or below the mean

normal development

      lower limb bud develops during 4th wk

      great toe points laterally

      during 7th wk limb bud rotates medially to bring the hallux into the midline

      for remainder of intrauterine period and childhood limb rotates laterally

      femoral anteversion decreases from ~40o at birth to ~15o at maturity

      tibia increases its lateral rotation from ~5o at birth to ~15o at maturity

Assessment
Presentation

      initiator of referral

      reason for consultation

History

      age of onset

      severity

      disability

      previous management

      age first walked

      if delayed consider CP

      family history of in/out toeing

Examination

General screening

      assess height percentile

      check spine

      check hips

      examine feet

      consider

      CP (in-toeing)

      CDH (limb asymmetry)

      SUFE (out-toeing)

      genu varum (in-toeing)

Staheli's torsional profile

Foot progression angle (FPA)

      assessed on gait

      is usually 10o (0o-30o) out

Internal hip rotation (HIR)

      assessed with child prone

      usually 40o (20o-60o)

External hip rotation (HER)

      usually 40o (20-60o)

      greater in young child

Thigh - foot angle (TFA)

      assessed with child prone and knees flexed

      usually 15o (0o-30o) out

Transmalleolar axis (TMA)

      assessed with child prone and knees flexed

      usually 0-30o out

Foot

      shape of foot

      metatarsus adductus or everted foot affects FPA

Investigations

      required if

      problem complex

      surgical intervention planned

AP x-ray of pelvis

      acetabular version

      hip dysplasia

AP and lateral x-ray of hip

      allows calculation of version using tables

      Magilligan technique

      uses standard AP and lateral views

      then uses a table to convert these measurements of neck length into an angle of anteversion

CT scan

      direct measurement of femoral and tibial version.

MRI or ultrasound

      may replace existing techniques

treatment
General principles

      trying to control the sleeping, walking, or sitting of infants and children is impossible

      operative correction effective but carries significant risk

      surgery only justified in the child with severe deformity that has failed to resolve with time

      daytime splints (twister cables, modified shoes) and nighttime splints (Dennis-Brown shoes) of no benefit and interfere with child

      observational management indicated for most children with rotational deformity

      1% will come to surgery

      operative correction usually only appropriate after 8 years of age

toeing in

      incidence of 15%

      most common identifiable causes are

      internal femoral torsion

      internal tibial torsion

      metatarsus adductus

      talar neck deviation

      first year of life

      usually due to metatarsus adductus

      second year of life

      usually caused by internal tibial torsion

      third and later years

      usually due to internal femoral torsion

Metatarsus adductus

      commonest cause of intoeing in first year of life

      may be associated with CDH (10-15%)

      treatment

      observe

      splint if does not correct

      operation not indicated

Internal tibial torsion

Epidemiology

      commonest cause of intoeing in the second year of life

Natural history

      10% of children under 2 yrs have at least 1 leg in internal tibial torsion

      TMA increases from 0o to 5o in between age 1 to 2 yrs

      external tibial rotation usually continues throughout childhood

      most cases of internal tibial torsion resolve by 18 to 24 mths

      some resolution may occur beyond this

      correction should not be expected after age 8 yrs

      resolution not universal

      positive family history may be an indicator of poor prognosis

      consider neuromuscular cause if

      unilateral

      asymmetrical

      progressive

Aetiology

      believed to be due to fetal position

      prone sleeping with limbs internally rotated may delay spontaneous recovery

Clinical

      TFA usually medial

      usually little functional deficit

      may be compensatory pronation and abduction of foot

Treatment

      no treatment in toddler who is stable or improving

      surgery rarely indicated

      supramalleolar osteotomy considered

      if TMA > 3 standard deviations from the mean (< -10o or > 35o)

      should be delayed until age 10 - 12 years

Internal femoral torsion

Definition

      transverse plane rotation of the femoral neck axis anteriorly relative to the transcondylar axis

Aetiology

      cause for persistence of fetal anteversion in an otherwise normal child unknown

Natural history

      resolves with time in 95%

      compensatory lateral tibial torsion may develop after age 4 -5 yrs

      little functional disability

      >50% of patients with persistent femoral antetorsion achieve normal gait

      does not predispose to osteoarthritis

Presentation

      intoeing in early childhood

      apparent age 3 yrs

      most severe age 4-6 yrs

Findings

      squinting patellae

      typically sit in W position

      degree may be estimated by noting the position of the patella with the greater trochanter in the direct lateral position

      increased IR with concomitant decreased ER

      abnormal if internal rotation > 70o

      may be no external rotation possible in severe cases

      total arc of motion should > 90o

      if unilateral or progressive in toeing

      must rule out neglected hip dysplasia or cerebral palsy

Treatment

Nonoperative

      no evidence to support the use of orthoses

      may produce

      ligamentous problems at the knee and ankle

      valgus deformity at the knee

      severe external tibial torsion

Indications for surgery

      unusually severe gait disturbance

      rotational criteria

      IR >85o AND

      ER <10o AND

      measured anteversion > 50o

      cosmesis

Principles

      surgery in form of derotation osteotomy

      should not be performed before age 8 yrs

      better delayed until age 10 - 12 yrs

      may be performed at any level

      proximal intertrochanteric osteotomy preferred

      avoids knee stiffness

      better cosmesis for scar

      wide surface of cancellous bone for better union and fixation

      any loss of position producing a malunion is less obvious

      approximately equal amounts of ER and IR should be produced at surgery

Toeing Out

      during first year of life

      normal

      due to external rotation contractures of hip

      during childhood

      due to external tibial torsion

External tibial torsion

Aetiology

      generally occurs

      in compensation for medial femoral torsion

      secondary to neuromuscular disease.

      njudicious use of orthoses for medial femoral torsion may result in excessive external tibial torsion

Presentation

      often worsens with time

      natural tendency is for leg to externally rotate with growth

Treatment

      rarely indicated on functional grounds

      lever action of the foot is not lost until the FPA angle > 50o - 60o

      osteotomy indicated

      if TFA > 35o

      certain cases of CTEV and neuromuscular disorders

presentations by age
1st year of life

Feet turn in

      metatarsus adductus

One foot turns out

      metatarsus adductus on other side

Both feet turn out

      lateral rotation pattern of infantsí hips

2nd year of life

Feet turn in

      internal tibial torsion

After 3rd year of life

Feet turn in

      internal femoral torsion

Foot turns in

      internal tibial torsion

Foot turns out

      external tibial torsion

Teens

Malalignment of patella

      internal femoral torsion plus external tibial torsion

management

      generally observation only

      most deformities show

      lack of disability

      lack of long-term problems

      ineffectiveness of nonoperative management

      disability-producing deformities persist in 1 in 1000 children

Angular deformities

normal development

      progression of bow legs to knock knees to physiological valgus

      birth

      15o varus (range 1o to 30o varus)

      age 2

      neutral (range 16o varus to 16o valgus)

      age 3

      10o valgus (range 5o varus to 30o valgus)

      age 6

      6o valgus (range 8o varus to 24o valgus)

      persistence of physiologic variations may occur

      esp. in some families and racial groups

general evaluation
History

      family history

Examination

General

      height and weight

      rotational profile

      joint laxity

Angular profile

      femorotibial angle

      intramalleolar distance

X-rays

      AP film

      weight-bearing

      patellae directed forward

      femur and tibia on same film

      peform if pathological form suspected

      positive family history

      ††††††††††† asymmetry

      ††††††††††† other musculoskeletal abnormalities

      ††††††††††† inconsistent with normal sequence of development

      below 5th percentile

      ††††††††††† severe deformity

differential diagnosis
Physiological

Early infancy

      lateral tibial bowing

Late infancy

      common bowing

Early childhood

      common knock-knees

Pathological

Varus

      Blountís disease

      unresolved physiological varus

Valgus

      post-tibial metaphyseal fracture

      lateral condylar hypoplasia

      unresolved physiological valgus

Either

      trauma

      malunion

      partial physeal arrest

      metabolic

      rickets

      renal disease

      osteopaenia

      osteogenesis imperfecta

      rheumatoid arthritis

management

      avoid dogmatic predictions

      clinical course variable

      not all cases resolve

      shoe wedges and other bracing ineffective

prognosis

      uncertain

      genu valgum may cause

      chondromalacia

      patellar dislocations

      genu varum may cause

      OA knee

Varus deformities
Physiologic bowlegs

Clinical

      two forms

1.   lateral tibial bowing

      occurs in 1st year of life

      nearly always resolves

2.   common bowing

      involving the femur and tibia

      seen in 2nd year

      prior to age 2 yrs, development of medial femoral condyle lags behind lateral

      resolution occurs in most children

Treatment

      bracing does not affect the natural history

      exclude pathological causes of deformity and reassure the parents

Surgery

      corrective osteotomy or epiphyseal stapling

      recommended for those chidren with persistence or worsening of physiologic varus

      stapling

      of femoral or tibial epiphysis (depending on the site of deformity)

      should be delayed until age 12 yrs

      osteotomy

      for children too old to benefit from stapling

Blountís disease

      disordered growth of proximal tibial physis

      associated with internal tibial torsion

      usually treated with osteotomy

Rickets

      causes severe genu varum (or valgum)

      associated with stunting and osteopaenia

valgus deformities
Physiological valgus

Aetiology

      may be due to wide-based gait of toddlers

Natural history

      knock knees extremely common in age 2-6 yrs

      startes at age 2 yrs

      most pronounced at age 3-4 yrs

      resolves by age 7 yrs

      may not always resolve

      correction should not be expected after age 8 yrs

Investigation

      x-ray if

      asymmetrical

      unilateral

      progressive

      leg length discrepancy

      intermallelolar distance > 10 cm

Treatment

Bracing

      thought to be useful by some

      indicated if > 10o valgus

Surgery

      indications

      cosmesis

      poor gait / function

      > 15o valgus

      age

      avoided before age 12

      technique

      hemiepiphyseodesis

      osteotomy

Post-traumatic

      usually occurs after incomplete reduction of distal femoral physeal injury

      usually SH I or II injuries

Tibial bowing

      several forms

      different consequences

      predictable by direction of bow

lateral bowing

      normal variant during 1st yr of life

      usually resolves spontaneously

anteromedial bowing

      usually associated with fibular hemimelia

      associated with short tibia

      may require leg lengthening

posteromedial bowing

      associated with

      calcaneus foot

      triceps surae weakness

      extension contracture of ankle

      anisomelia

      probably caused by intrauterine fracture or malposition

      corrects spontaneously with growth

      shortening is problem

      treated by epiphyseodesis of opposite side

anterolateral bowing

      dangerous form

      associated with pseudarthrosis of tibia

      fracture should be prevented by bracing