· disorder of proximal femoral epiphysis in puberty with slip through physis
· incidence 2 per 100 000
· occurs in 2 yr period around puberty
· 11-13 in girls
· 13-15 in boys
· av. 18 months before closure of epiphysis
· more common in
· boys (3:1)
· blacks (2:1)
· left hip
· most patients have
· obesity
· delayed skeletal maturation
· delayed sexual maturation
· associated with
· hypothyroidism
· pituitary dysfunction
· advanced renal disease
· bilateral in 50% (25-75%)
· may be imbalance between sex hormones and growth hormone
· growth hormone shown to weaken growth plate
· sex hormones shown to strengthen growth plate
· slip in growing child with deficient sex hormones
· supported by many facts
· occurs during period of hormonal change
· sometimes associated with abnormality in hormonal function
· patient are sexually immature
· slip due to forces of
· gravity
· weight-bearing
· muscle activity
· probably physiological forces acting on pathologically weak physis rather than pathological forces acting on normal physis
· weakness of perichondrial ring
· slip occurs through hypertrophic zone
· near junction with proliferative zone
· cf. Salter Harris fractures which occur near junction with zone of provisional calcification
· physis shows disruption
· thickening
· distortion of columnar arrangement
· synovium becomes oedematous and vascular
· head remains in acetabulum
· attached by ligamentum teres
· head slips posteriorly on neck
· neck externally rotates
· new bone laid down on back of femoral neck
· slip usually proceeds slowly
· symptoms usually start some time after slip
· progressive slipping usually occurs
· remodelling of neck occurs simultaneously
· remodelling usually significantly corrects deformity
· esp. if triradiate cartilage still open
· shown to lead to premature osteoarthritis
· characteristic pistol-grip deformity of femoral neck 2o to SUFE common in arthritic hips
· severity of OA related to severity of slip
· treatment to prevent further slip can decrease OA
· poor results accelerated by
· chondrolysis
· avascular necrosis
· usually insidious onset of pain
· groin and thigh
· knee (may be only site)
· may sometimes be sudden pain afer minor trauma
· externally rotated leg
· antalgic gait
· abductor lurch
· positive Trendelenburg sign
· may be shortening
· wasting of thigh in chronic slip
· decreased ROM
· esp. IR in flexion
· leg usually externally rotates when flexed
· associated synovitis causes pain and mild restriction in other ranges
· AP and lateral (true or frog-leg)
· if severe, slip easily visualised
· if mild, subtle signs on AP
· reduced epiphyseal height
· widening of physis
· blurring of metaphysis
· Trethowan’s line (line along superior neck) does not intersect any of epiphysis
· femoral head appears to be in varus
· Shenton’s line may be broken
· classified on duration of symptoms
Acute
· symptoms < 3 wks
· new slip on x-ray
Chronic
· symptoms > 3 wks
Acute on chronic
· symptoms < 3 wks
· old slip on x-ray
· classified on degree of slip on x-ray
Grade 1
· slip of < 1/3 of width of physis
Grade 2
· slip of 1/3 to 1/2 of width of physis
Grade 3
· slip of > 1/2 of width of physis
· prevent further slip
· promote premature fusion of epiphysis
· avoid iatrogenic complications
· chondrolysis
· avascular necrosis
Primary treatment
· to prevent further slip
Pinning in situ
· most common technique
· associated with
· chondrolysis
· avascular necrosis
Epiphyseodesis
· open procedure with bone graft
· advocated to avoid complications of pinning
· more difficult procedure
· limited experience
Secondary treatment
· to reduce slip that is present
Manipulation
· most often used for acute SUFE
· successful in only 50%
· may predispose to avascular necrosis
· not advocated
Osteotomy
· performed to
· prevent onset of OA
· alter arch of motion
Tertiary treatment
· salvage procedures
· for patients with
· avascular necrosis
· chondrolysis
Osteotomy
· may be indicated for limited segmental AVN
Arthroplasty
· not usually advocated because of poor longevity in young patients
· may be indicated in bilateral disease
· esp. on one side
Arthrodesis
· procedure of choice for unilateral hip joint desruction
Principles
· pin must not penetrate joint
· two radiographic images at right angles
· pin must be in central axis of femoral head
· both on AP and lateral
· entry point in anterior neck
· because head displaced posteriorly
· single cannulated screw
· increased complication risk with multiple screws
· must be strong enough
· cannulation allows percutaneous techniqe
Technique
· image intensifier
· traction table
· percutaneous approach
· starting point on anterior neck
· guide wire positioned and checked
· 6.5 mm cannulated screw inserted
· advanced to no more than 5 mm of subchondral surface
· screw checked in two planes with rotation technique
· arthrogram performed through screw
Postoperative
· mobilise with crutches next day
· home when safe
· protected wt bearing for 6 weeks
· followup with x-ray at 4 month intervals until physis closed
· usually closed with 12 months
Removal
· advocated because of increased likelihood of need for THR in future
· may be difficult to remove because of bone overgrowth
· probably can be left in
· if removal desired, should be done
· early
· with II, guide wire and semi-percutaneous technique
Complications
General
· in form of
· chondrolysis
· avascular necrosis
· occurs in 20%
· related to
· severity of slip
· number of pins used
· persistent pin penetration
Pin-related
· loss of fixation
· back out
· breakage
· subtrochanteric fracture
· infection
Prophylactic
· advocated because of high incidence of bilaterality
· may cause complications
· not usually indicated
· may have place in patients with
· unreliable carers
· geographic isolation
· metabolic or endocrine cause
Indications
· prophylactic
· correction of deformity may decrease incidence of OA
· no clear evidence
· remodelling usually significantly corrects deformity
· probably not indicated
· symptomatic alteration of arch of motion
· loss of internal rotation, flexion and abduction may be severe
· disability may be functional rather than just cosmetic
· should wait at least 12 months as significant improvement likely
· symptomatic collapse of avascular segment
· valgus osteotomy may shift more normal articular cartilage to superior weight-bearing area
· most cases do not remain symptomatic
Principles
· safest procedure is away from blood supply of femoral head
· needs to offer sufficient correction
Technique
· Southwick intertrochanteric osteotomy
· wedge of bone removed from anterolateral proximal femur near lesser trochanter
· wedge closed and distal fragment internally rotated
· head brought into more normal relationship with acetabulum and femoral shaft
· secondary deformity produced in intertrochanteric region
Complications
· avascular necrosis
· significantly decreased with intertrochanteric cf. head or neck osteotomy
· chondrolysis
· reason for increased incidence unclear
· pin all in situ on presentation
· delayed intertrochanteric osteotomy with significant symptomatic deformity
Definition
· destruction of articular cartilage with secondary loss of joint space and stiffness
Aetiology
· most cases occur after treatment of SUFE
· may also occur with
· prolonged immobilisation
· trauma
· severe burns
· idiopathic
SUFE-associated
· incidence of 20%
· increased incidence with
· severe slip
· blacks and girls
· persistent pin penetration (50%)
Pathogenesis
· theories are
· lack of production of synovial fluid
· immune process
Pathology
· first stage is synovitis
· next stage is cartilage destruction
· final stage is synovial and capsular fibrosis and exposed articular bone covered with granulation tissue
Clinical
· pain
· decreased ROM
· contracture
· flexion and adduction contracture in SUFE
· abduction contracture in idiopathic
Radiology
· loss of joint space
· osteoporosis
· premature closeure of physes
Differential diagnosis
· septic arthritis
Natural history
· varies from
· transient pain and stiffness with joint narrowing
· fulminating course with ankylosis in few months
Treatment
Acute
· NSAIDs
· traction
· CPM
Salvage
· arthrodesis
· does not occur in untreated SUFE
· occurs with treatment
· manipulation
· pinning
· osteotomy
· occurs most frequently after acute SUFE
· incidence of 15%
· may be due to
· vascular interruption with forced manipulation
· vascular disruption by screw
· may lead to chondrolysis
· necrosis may lead to collapse with subsequent pin penetration
· related to
· severity of slip
· associated chondrolysis or avascular necrosis