Decrease
Fracture
· due to
· angulation
· overlap
· due to
· genetic abnormality
· damage to physis
· alteration of forces
Inhibition
Congenital shortening
· growth slowed
· because of abnormal programming of genetic mechanism
Trauma
· injury to physis
· due to
· direct injury to cells responsible for growth
· formation of bony bridge
· SH I and II fractures
· occur through zone of hypertrophy (weakest)
· do not involve area primarily responsible for growth
· unlikely to interfere with growth
· SH III and IV
· cross growth zone
· likely to result in growth arrest or bony bridge
· SH V
· involve whole physis
· interfere with growth
Infection
· may result in destruction of physeal cells
· results in formation of large bony bridge
Paralysis
· mechanism for growth inhibition unclear
· may be due to
· decreased blood flow from decreased muscle activity or abnormal vasomotor control
· decreased compression across physis from reduced muscle activity
Tumour
· due to
· destruction of physis by tumour invasion
· damage to physis by irradiation
· origination of tumour from physis (enchondroma, osteochondroma)
Avascular necrosis
· blood supply of physis from epiphyseal vessels
· interference with epiphyseal blood supply also affects physis
Stimulation
· probably due to increased circulation
Tumour
· vascular malformations
· haemangiomatosis
· Klippel-Trenaunay-Weber
· nonvascular tumours
· neurofibromatosis
· fibrous dysplasia
Inflammation
· may be seen in
· chronic osteomyelitis
· juvenile rheumatoid arthritis
Fracture
· of diaphysis
· due to increased blood flow
· most common in femoral shaft fractures
Congenital / developmental
· terminal limb deficiencies
· paraxial hemimelias
· PFFD
· hemiatrophy or hemihypertrophy
· congenital pseudarthrosis of tibia
· Ollier’s disease
· CDH
Paralytic
· polio
· cerebral palsy
· myelopathy
Infections
· with growth retardation
· with growth stimulation
Trauma
· malunion
· physeal damage
· overgrowth
Tumours
· overgrowth
· fibrous dysplasia
· osteoid osteoma
· haemangioma
· neurofibromatosis
· retardation
· enchondroma
· bone cyst
· neurofibromatosis
Apparent
· pelvic obliquity
· scoliosis
· joint contracture
Child
· usually compensates well
· walks on toes of short leg
· results in smooth gait
· only abnormality is lack of heel strike on short side
· another possible compensation is flexion of knee of long leg
· never done because too much effort required
Adult
· compensates less well
· walks with bilateral heel-toe gait
· vaults over long leg
· produces excessive up and and down motion of pelvis and trunk
· results in increased energy expenditure
· asymmetry of gait may persist with correction of leg length
· knees at different levels
· alters cadence of each leg
· effect of two-legged stance is uncovering of hip of long leg
· theoretical risk of development of degenerative arthritis
· no evidence that this occurs
· probably because little time spent in two-legged stance
· one study showed increased knee pain in athletes
· similar to hip
· theoretical risk of developing scoliosis but no evidence
· four physes contribute consistent proportions of growth
· proximal femoral physis 1/8” / yr
· distal femoral physis 3/8” / yr
· proximal tibial physis 2/8” / yr
· distal tibial physis 1/8” / yr
· relationship between
· maturity (skeletal age)
· stature (leg length)
· aging (years of age)
Stature and age
· steady growth occurs
· growth spurt in early adolescence
· cessation at 14-15 (girls) and 16-17 (boys)
Maturity and age
· maturation can occur at different rates
· if early, are tall early and stop growing early
· can have spurt where mature more than age
· pass through skeletal ages more quickly
Stature and maturity
· reflected by Green and Anderson curves
· growth vs skeletal age
· shows no growth spurt
· because growth spurt and maturation spurt occur together
· determine cause
· determine deformity
Leg length
· apparent length
· from umbilicus
· real length
· from ASIS
· functional length
· blocks
Other factors
· pelvic obliquity
· spine deformity
· hip contractures
· ankle contractures
· knee deformities
· joint stability
· muscle power
Leg length
Teleroentgenogram
· single exposure of both legs
· on long film with radiopaque ruler
· advantages
· single exposure
· shows all of bones
· disadvantages
· inconvenient to handle
· parallax errors
Orthoroentgengram
· similar film
· separate exposures of hip, knee and ankle
· advantages
· eliminates parallax error
· disadvantages
· multiple exposures (problem with movement)
Scanogram
· similar separate exposures
· film moved between exposures
· advantages
· smaller film
· disadvantages
· multiple exposures
CT scan
· cuts taken through points of interest
· distances between points measured
· advantages
· accurate
· comparable cost
Skeletal age
· comparison of x-rays with atlases
Greulich-Pyle atlas
· x-rays of left hand and wrist
· advantages
· correlated with leg length (Green-Anderson)
· disadvantages
· large gaps in atlas
· some children do not follow orderly progression
· may be congenital anomalies of hand and wrist
Tanner-Whitehouse atlas
· similar but more refined
· 20 specific landmarks graded
· numerical score determined for each
· skeletal age determined from total score
· advantages
· more accurate
· disadvantages
· more cumbersome and time consuming
· not correlated with leg length
· White/Menelaus method
· rule-of-thumb method
· less accurate
· more convenient
· based on following statements
· girls stop growing at age 14
· boys stop growing at age 16
· distal femoral physis grows at 3/8” / yr (1 cm / yr)
· proximal tibial physis grows at 2/8” / yr (0.6 cm/yr)
· advantages
· convenient
· disadvantages
· uses chronological age cf. skeletal age (error with variations in maturity)
· uses approximation of growth curve (inaccurate in young children)
· useful to determine if time to move to more accurate method
Technique
1. determine past growth rate
· growth rate of long leg (G) = past growth / time interval
2. determine growth inhibition
· inhibition (I) = (growth of long leg - growth of short leg) / growth of long leg
3. determine future growth
· future growth (FG) = G x yrs remaining
4. determine future increase in discrepancy
· future discrepancy (FD) = FG x I
5. determine discrepancy
· discrepancy = present discrepancy + FD
6. predict effect of epiphseodesis
· effect = growth rate x yrs remaining
· based on Green and Anderson tables
· advantages
· uses skeletal age
· disadvantages
· requires availability of and familiarity with graphs
Technique
1. calculate growth inhibition as above
· I = (growth LL - growth SL) / growth LL
2. plot present length of long leg on leg-length vs age graph
3. project to maturity to determine mature length of long leg
4. calculate future growth of long leg
· future growth (FG) = projected length - present length
5. calculate future increase in discrepancy
· future discrepancy (FD) = FG x I
6. determine discrepancy as above
· D = PD + FD
7. predict effect of epiphseodesis
· use growth-remaining vs age graph
· uses Green-Anderson data
· based on principles
· growth of legs can be represented graphically by straight lines
· nomogram can be used to determine growth percentile from skeletal age and leg length
· straight line produced by altering Green-Anderson tables
· scale on X-axis manipulated
· accuracy of data preserved
· curve represented by irregularity of skeletal age lines
· plotting length of leg on graph means
· length of leg represented by vertical position
· growth rate of leg represented by slope
· discrepancy represented by vertical difference
· inhibition represented by slope difference
Technique
1. assess past growth
· plot point for long leg on sloping line marked “LONG LEG”
· draw vertical line through that point
· plot point for short leg on that vertical line
· plot point for skeletal age on vertical line
· plot successive visits
· draw straight line through short leg points
· line represents growth of short leg
2. assess future growth
· draw horizontal line of best fit through skeletal age points
· continue horizontal line to intersect line of maturity
· draw vertical line from intersection point to growth lines of long and short leg
· points of intersection indicate predicted lengths
3. predict effect of surgery
· draw lines parallel with reference lines
· intersect these with vertical line of end of growth
· points represent predicted lengths of long leg after different types of epiphyseodesis
Inhibition
· methods use previous inhibition to predict future inhibition
· assume that growth inhibition remains constant
· usually true or not different enough to alter validity of prediction
Inadequacy of data
· three possibilities
1. continuing inhibition but time of onset known
· can use straight line graph and assume equal leg lengths at time of onset
2. static discrepancy
· eg. stimulation from previous osteomyelitis or fracture, discrepancy from fracture malunion
· can assume discrepancy at maturity will be same as now
3. no assumptions reasonable
· reassess at maturity
Equal leg length
· goal with mild to moderate isolated discrepancy
Unequal leg length
· goal with paralysis
· should be 1-2 cm shorter to allow clearance
Level pelvis
· goal with deficiencies in pelvis
· should use blocks to estimate functional correction
Vertical lumbar spine
· goal with pelvic obliquity
· vertical spine more important than level pelvis
Equalisation with prosthesis
· goal with excessive discrepancy
· traditionally described as
· femur less than half length of other side
· discrepancy > 15 cm
· may require
· knee fusion
· Syme amputation
· van Ness rotationplasty
Coexistent problems
· may require correction of other problems that are prerequisites
· release of contractures
· correction of angular deformity
· correction of spinal deformity
· excision of bony bridge
· completion of partial arrest
1. correct coexisting deformities first
· deformity may adversely affect outcome
· correction may partly address discrepancy
2. choose treatment according to projected discrepancy
· 0-2 cm - no treatment
· 2-6 cm - shoe lift, epiphyseodesis
· 6-15 cm - lengthening
· > 15 cm - prosthesis
Shoe lift
· excellent treatment for discrepancy 2-5 cm
· < 2 cm - not required
· > 5 cm - recurrent ankle sprains
· aim is to improve gait
Prosthetic fitting
· last resort
· often combined with amputation
· useful for
· large discrepancies
· deformed and functionally useless feet
· best for discrepancies
· > 15 cm
· > 1/2 femur
· advantages
· one hospitalisation
· good functional outcome
· optimal time
· Symes - age 1
· van Ness - age 3
Epiphyseodesis
· often treatment of choice
Advantages
· low morbidity
· usually accurate
· easy to perform
Disadvantages
· operation on normal leg
· loss of height
Indications
· anticipated discrepancy of 2-6 cm
· less well tolerated for > 6 cm discrepancy
· significant loss of height
· disproportionate appearance
Principles
· involves inducing known amount of growth inhibition
· 3/8” / yr or 38% for distal femoral physis
· 2/8” / yr or 27% for proximal tibial physis
· 5/8” / yr or 65% for both
· desired shortening achieved by operating at exactly the right time
· may choose to wait and perform femoral and tibial epiphyseodesis later
· thus may be able to achieve knee joints being at same level
· aim to produces 0.5-1 cm undercorrection
· operate a little later than calculated
· better to undershorten rather than overshorten
Technique
· creation of symmetric bony bridge
· medial and lateral approaches
· physis identified
· window removed to gain acess to physis
· circular or rectangular
· plate excised in entire thickness
· with curette
· window reorientated to act as bone graft
· circular rotated through 90o
· rectangular rotated through 180o
· fusion occurs within 8 wks
Complications
· failure of complete closure
· continued growth
· angular deformity
Femoral shortening
· similar indications to epiphyseodesis
· used in patients
· who are too old
· in whom confident prediction of discrepancy at maturity cannot be made
· diaphyseal shortening of maximum of 5 cm
· fixed with IM nail
· complications
· disadvantages quadriceps
· rotatory malalignment
· malunion or nonunion
· infection
Growth stimulation
· concept of stimulation of physis as occurs in fracture
· many methods tried
· none successful enough to be clinically useful
Leg lengthening
· uses concept of distraction osteogenesis
· osteotomy
· pins proximal and distal to osteotomy
· controlled distraction
· formation of bone in zone of distraction
Advantages
· maintains height and proportions
· avoids operation on normal side
Disadvantages
· difficult and protracted
· high rate of complications
Preoperative assessment
· patient psyche and social situation
· able to cope with psychological implications
· location of discrepancy
· general medical problems
· local orthopaedic problems
· status of adjacent joints
Indications
· discrepancy 6-15 cm
· < 6 cm - epiphyseodesis or shortening technically easy, low morbidity and acceptable result
· > 15 cm - risks outweigh benefits
Contraindications
· sensory or motor deficits
· significantly deformed or dislocated joints that cannot be stabilised
· psychological problems
Technique
· osteotomy performed
· drill-holes and closed osteoclasis in attempt to preserve periosteum
· device applied
· uniplanar device (Wagner, Orthofix)
· circumferential device (Ilizarov)
· distraction commenced
· for tibial lengthening, should first perform
· heel cord lengthening
· screw fixation of distal part of fibula
· halt or slow lengthening with
· insufficient new bone formation
· nerve parasthesias or palsies
· compartment syndrome
· equinus deformity
· joint loss of motion or subluxation
· psychological reactions
· adjust fixation with
· development of angular deformity
· once desired lengthening achieved, options are
· maintenance of external fixation device
· insertion of plate +/- bone graft
· protective brace
Concepts
· minimal disturbance of bone
· preserves intramedullary contents and blood supply
· metaphyseal lengthening
· more active osteoblasts
· greater cross-sectional area and thus strength
· two-level lengthening
· for significant discrepancy
· delay before distraction
· of 10 days
· to allow establishment of osteogenic process
· slow rate of distraction
· optimum is 1 mm/day
· rhythm of distraction
· optiumum is 4 times a day
Problems
· limitations due to biological capabilities of
· muscles
· ligaments
· neurovascular structures
· adjacent joints
· problems due to
· overstretching
· insufficient fixation
· interference with blood supply
· nontechnical problems related to
· physical and emotional stability of patient and family
· doctor-patient relationship
Complications
· of pins
· neurovascular injury
· pin tract infection
· failure
· mechanical failure of device
· fracture of bone
· joint subluxation
· knee
· hip
· delayed union
Distraction epiphyseolysis
· tibial lengthening by distraction across proximal physis
· similar amount of lengthening and complications to conventional lengthening
· continuing research