Slipped Capital Femoral Epiphysis

Vinod Naneria

Girish Yeotikar

Arjun Wadhwani

Choithram Hospital & Research Centre, India

Incidence

• SCFE occurs between the ages of 10 & 16 yrs.

• 20% bilateral involvement at the time of presentation.

• 20-40% will subsequently progress to bilateral slips.

• When the presentation is sequential, the second hip usually presents within 18 months of the first SCFE.

Risk factors

• Pre puberty / puberty / growth spurt• obesity, • Hypothyroidism, • low growth hormone level, • Pituitary tumors, • Craniopharyngioma,• Down syndrome,• Renal osteodystrophy,• Adiposogenital syndrome.

Theory

• Biomechanical events versus biochemical events having impact at the time of puberty.

• The zone of slipping always occurs primarily through the zone of hypertrophy in a corrugated undulating fashion.

• The growth plate at the time of puberty is weakened in SCFE, leads to a mechanical failure of the growth plate.

Theory

• The prepubertal obesity + an increasingly oblique physis + degree of retroversion creates a mechanical environment that, coupled with alterations in the hormonal balance of thyroid hormone, growth hormone, testosterone, and estrogen, render the plate intrinsically suspectible to slip by innocuous forces occurring in a shear plane.

SCFE results from a Salter-Harris type 1 epiphyseal fracture.

The growth plate is unusually widened, primarily due to expansion of the zone of hypertrophy.

The hypertrophic zone, which constitutes 15-30% of the normal epiphysis, can account for up to 80% of the width of the epiphyseal plate in affected patients.

Pathophysiology

• The position of the proximal physis normally changes from horizontal to oblique during preadolescence and adolescence, redirecting hip forces from compression forces to shear forces. There is an association between femoral neck retroversion and a reduced neck-shaft angle with SCFE. These changes can increase the shear forces across the hip, leading to SCFE

Investigations

• Clinical history – pain hip / thigh / knee

• Hip movements – flexion / abd / int rotation

• X-rays – both hips, frog leg lateral

• CT scan – 3D for quantification – screw placement

• MRI – non specific marrow edema

• Ultrasonography

• Bone scan – for AVN in severe slip

Investigations

• Endocrine profile

• Routine hormonal screening of children with slipped capital femoral epiphysis (SCFE) is not indicated.

• Age below 10 and above 16 years needs endocrine profile

classification

• "Stable" SCFEs allow the patient to ambulate with or without crutches.

• "Unstable" SCFEs do not allow the patient to ambulate at all; these cases carry a higher rate of complication, particularly of AVN.

Acute: < 3wks, Chronic: > 3wks, Mild – Moderate – Severe

Radiological classification

• Type I slippage is less than 33% displacement.

• Type II slippage is between 33% and 50% displacement.

• Type III slippage is greater than 50% displacement.

The blurring of physis (Blanch sign)

Plain Radiology

• In the pre-slip phase, there widening of the growth plate with irregularity and blurring of the physealedges.

• The slip that occurs is posterior and to a lesser extent, medial and therefore is more easily seen on the frog-leg lateral view rather than the AP hip view.

• A line drawn up the lateral edge of the femoral neck (line of Klein) fails to intersect the epiphysis during the acute phase

• Additionally, because the epiphysis moves posteriorly, it appears smaller because of projectional factors.

Southwick angle

Southwick angle

• Radiographic angle used to measure the severity of a slipped capital femoral epiphysis (SCFE) on a radiograph.

• The angle is measured on a frog lateral view of the bilateral hips. It is measured by drawing a line perpendicular to a line connecting two points at the posterior and anterior tips of the epiphysis at the physis. A third line is drawn down the axis of femur. The angle between the perpendicular line and the femoral shaft line is the angle.

Southwick angle

• The angle is measured bilaterally. The slipped side is then subtracted from the normal side. The number calculated determines the severity. Mild is classified by < 30°. Moderate is 30°-50°. Severe is >50°. 12° is the normal control value and can be used in the case of bilateral involvement.

http://radiopaedia.org/articles/slipped-upper-femoral-epiphysis

A Klein line is a line drawn along the superior border of the femoral neck that would normally pass through a portion of the femoral head

Frog leg radiograph

• Frog leg radiograph: A straight line through the center of the femoral neck proximally should be at the center of the epiphysis. If not, and the line is anterior in the epiphysis, it is likely an SCFE.

http://radiopaedia.org/articles/slipped-upper-femoral-epiphysis

CT Scan

• Is a sensitive and an accurate method of measuring the degree of upper femoral epiphyseal tilt and detecting the disease in its early stage.

• 3 D images - the relationship of femoral head to the metaphysis in three planes.

• A metaphyseal blanch sign is an increase in density in the proximal metaphysis. It represents an attempt of healing process that occurs before the visible displacement of the epiphysis.

Treatment

• Surgical emergency

• Fixation in situ

• Avoid joint penetration

• Corrective osteotomy

• Safe surgical dislocation

• Sub-trochanteric osteotomy

20/10/2014

Case two

Open Epiphyseal plate Closed Epiphyseal plate

Lateral view in frog leg position

13/3/04

7/11/2004

7/11/2004

21/4/2005

Epiphyseal closure complete

Case three

28/4/2004

28/4/2004

2/6/2004

2/6/2004

Old SCFE

Severe slipped capital femoral epiphysis: The Dunn's operation

• After extra-digital trochanterotomy, subperiosteal detachment was achieved by disinserting first the vastus lateralis muscle, then the entire trochanteric region; after anterosuperior capsulotomy, detachment continued right around the neck of the femur. The epiphysis was then detached from the neck by a spatula gently introduced into the physis, so as to remain in contact with the vessel-bearing periosteal lamina. The metaphyseal region, and the postero-inferior beak in particular, was then regularized. This completely separated the epiphysis and metaphysis. The reduction was maintained by backward and forward pinning previously implemented in the neck of the femur, with a compression screw when the diameter was sufficient. Postoperative traction was systematically maintained for between 15 and 21 days.

http://www.boneandjoint.org.uk/highwire/filestream/5328/field_highwire_article_pdf/0/833.full-text.pdf

Potential complications include

• AVN of the femoral head: 10-15%.

• Chondrolysis (7-10%): acute cartilage necrosis deformity

• Degenerative osteoarthritis: 90%

• Acetabular impingement.

• limb length discrepancy

Follow up

• Both osteonecrosis and chondrolysis usually appear, clinically or radiographically, during the first year after the operation.

• Osteonecrosis and chondrolysis develop between three and eight months after surgical treatment.

• Follow-up interval of at least one year should have been sufficient to identify most such complications.

DISCLAIMER

Information contained and transmitted by this presentation is based on personal experience and collection of cases at Choithram Hospital & Research centre, Indore, India. It is intended for use only by the students of orthopaedic surgery. Views and opinion expressed in this presentation are personal. Depending upon the x-rays and clinical presentations viewers can make their own opinion. For any confusion please contact the sole author for clarification. Every body is allowed to copy or download and use the material best suited to him. I am not responsible for any controversies arise out of this presentation. For any correction or suggestion please contact naneria@yahoo.com