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 Blount’s 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 infants’ 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

·      Blount’s 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

Blount’s 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