May 30, 2024

Adolescence coxa vara

Epiphyseal coxa vara

Epiphyseoslisthesis

During adolescent rapid growth, epiphyseal growth plate is weakened and capital epiphysis is displaced downward and backward

Name is a misnomer as femoral neck-shaft is displaced upward and anteriorly while femoral epiphysis remains in the acetabulum

Early effects: disabling external rotation deformity–> later AVN femoral head, Chondrolysis –> Degenerative arthritis

Etiology: Unknown

Predisposing factors:

Age: Period of rapid growth (10-17 years)

Sex: M > F

Body type:

  • Obesity with underdeveloped genitalia
  • long, slender, rapidly growing people

Location:

  • L>R
  • B/L: 25%

Trauma:

  • Usually trival or not at al
  • Rarely severe trauma: Acute Slip

Hormonal therapy:

  • Line of detachment passes through area of hypertrophic cartilage cells
  • Growth hormone=> Increase area of hypertrophic layer
  • Sex hormone: Inhibits secretion of growth hormone.So,

Increase growth hormone=> Increase risk

Decrease sex hormone ( Esp. Estrogen)

Mechanical factors:

Theory of periosteal thinning:-

During childhood, periosteum spanning the epiphyseal plate –> Thick and strong

During adolescent, periosteum become progressively thinner as adulthood is approached

Periosteal covering is stretched and unable to withstand shearing force

Pathology

Epiphysis slowly displaced “inferiorly and posteriorly with femoral neck shifting upward and rotating anteriorly to anteversion position.”

Results is varus deformity, adduction and ER of femur

Displacement takes place through layer of hypertrophic layer

Normal width of epiphysis = 2-6 mm

In SCFE= 12 mm

Interval produced by separation become filled with fibrous tissue, embryonic cartilage callus, particularly at posteroinferior angle

At all time , Head is attached to neck by soft tissue, particularly posterior periosteum (retinaculum) through which major vessels passes to reach epiphysis

Early stage synovial membrane is swollen, edematous, hyperemic and villous later become less vascular and more fibrotic

After several month epiphyseal junction heals and exposed portion of neck (Superior and anterior), covered with fibrocartilages

Capital epiphysis fixed (Posterior and inferiorly)

Limits ABDUCTION AND INTERNAL ROTATION

Clinical Features:

  • Insidious onset
  • Displacement- slight to extreme

Pre-slippage Stage

  • Early symptoms arise ( when little or no displacement occurs)
  • Slight discomfort in groin, Usually after activity and subside with rest
  • Slight stiffness + occasional limb
  • Radiate along anterior and medial aspect of thigh

Acute SCFE

  • Vague symptoms for 2-3 weeks
  • Acute slip due to dramatic fracture like episode occurring after trivial trauma
  • Differentiated true salter harris I epiphyseal fractures=> As SCFE occurs with trivial trauma, prodromal symptoms or Vit D deficiency child

Chronic Slipping Stage

  • Pain increases in intensity, some times acutely

Antalgic limb ” Pronounced and persistence”

Objective finding:

  • Tenderness about hip
  • Limitation of movement-> Abduction, Flexion and IR
  • With further flexion thigh goes in ER and knee moves to ipsilateral axilla

Drehmann’s sign

  • Limb gradually develops ADDUCTION and EXTRENAL ROTATION deformity
  • Real Shortening due to upward displacement of femur
  • Apparent shortening is due to adduction
  • Further flexion : ER deformity is accentuated
  • Gluteal medius: Inadequate
  • B/L severe slipping: WADDLING GAIT

Acute on chronic slip

Prodromal symptoms more than 3 weeks with sudden increase in pain

X- Ray would show some signs of remodelling with further acute slip

Stage of fixed deformity

Pain and muscle spasm disappear

Limp

ER + ADD + Shortening persist

Classification

Lateral slip grade

Change in opposition

Slip angle

Epiphyseal shaft angle

Southwick angle:

Southwick angle

X-ray findings:

Above mentioned

Earliest findings:

  • Globular swelling
  • Irregular widening of epiphyseal line
  • Decalcification of epiphyseal border of the metaphysis

As displacement occurs head slips inferiorly and posteriorly

Shenton line continuity is broken

Later epiphysis slips further exposing upper portion of neck and head

Form callus which fills the inferior angle between head and neck, fills exposed upper portion of head and neck

Kliens line

Line on AP radiograph along superior border of neck

In normal hip the line should intersect the epiphysis

Failure to do so results in Trethowan sign

Klien’s line

Steel’s sign

Double density or metaphyseal blanch is seen on AP radiograph caused by overlapping of posteriorly displaced physis over metaphysis

Carpener’s Sign

Reduction in the double density cresent created by the overlap of the posterior acetabulum triangle proximal metaphysis as metaphysis is displaced laterally by worsening slip-on AP radiograph

Treatment

Conservative

  • Abstinence from weight-bearing by bed rest, crutches, sling, cast or brace in an effort to prevent further displacement is required
  • Absolute bed rest

Longitudinal traction

  • Helpful to relieve muscle spasm and medial rotation
  • Reduce displacement of acute slip
  • Followed by Internal fixation

Forceful abduction with traction is avoided which may leads to AVN of femoral head

Usually after 6 weeks of traction

  • Pain is relieved= Improvement in hip range of motion
  • If pain is persistent / ROM is further restricted=Most probable chondrolysis

Surgical Principles

  1. Immobilize to prevent further slip
  2. Reduce displacement
  3. Early closure of epiphysis

Slight displacement

Internal fixation insitu by pins with/ without entering joint cavity

Insitu pinning +/- CR

by

  • Knowles pin
  • Threaded steinman pin
  • Hip compression screw
  • CC screw

2-3 pins were used with good outcome, but now recommended to use large diameter single pin/ screw (cannulated (6.5-7.3 mm)

Screw trajectory should be in centre of epiphysis and perpendicular to physis

Complications

  • Screw perforation
  • Failure to physeal fusion
  • Progression of slip
  • Loss of fixation
  • Implant failure
  • AVN

Displacement

Options:

  • Cuneiform osteotomy through fracture callus or femoral neck (Dunn’s Procedure)
  • Close wedge osteotomy at the base of neck
    • Intracapsular ( Kramer)
    • Extracapsular (Barmada and co-worker)
  • Intertrochanteric osteotomy (Southwick)

Cuneiform subcapital osteotomy

Watson Jones Incision

Capsule incise anteriorly and parallel to the femoral neck

Transverse incision at acetabular margin widens the capsular opening

{Epiphysis is free= Elevated with towel clip}

Epiphysis is fixed

Widened while epiphyseal line and prominence of the proximal portion of the neck will present anteriorly

Wedge shape section of bone removed with its base directed anteriorly and superiorly with apex posterior and inferiorly

Osteotome should not penetrate intact posterior periosteum

Then epiphysis should not be elevated forward

Should be angulated (anteriorly and superiorly)with undue force

Several drill holes were made through the epiphyseal plate

Several threaded small pins are inserted retrograde through the neck and made to emerge below the base of GT the epiphysis is opposed to the neck while the leg is rotated internally

Epiphysis is opposed to the neck while the leg is rotated internally

Pin drove forward

Depth of pin checked in fluoroscopy

Capsule closed

Wound closed in layers

Postoperatively:

Active motion is started but weight-bearing is forbidden for several months until the AVN is ruled out.