Slipped capital femoral epiphysis

(SCFE)

SLIPPED CAPITAL FEMORAL EPIPHYSES Introduction and definition Epidemiology and risk factors classification Pathogenesis Signs and symptoms Diagnosis Investigations Management modalities Complications

INTRODUCTION

  The capital femoral epiphysis is somewhat unique. It is one of the few epiphyses in the body that is inside the joint capsule. (The joint capsule is the tissue that surrounds the joint.)

Slipped upper femoral epiphysis" term refer to slippage of the overlying epiphysis of proximal femur posteriorly and inferiorly due to weakness of the growth plate in relation to metaphysis.

Most often, it develops during periods of accelerated growth, shortly after the onset of puberty.

The femoral epiphyses maintains its relation with acetabulum ,it’s the femoral neck and shaft upward and anterior movement on epiphyses thus epiphyses displaces relatively posterior

DEFINITION

Femoral Neck Deflection

Neck moves LATERALand VENTRAL creatingRetroversion

EPIDEMIOLOGY AND RISK FACTORS

Incidence is 2-3 per 100000 population Most common in adolescent period with rapid growth plate

(boys aged 10-16 y, girls aged 12-14 y).

Very early onset[<10yrs] and late onset[>16] should be evaluated for endocrine disorders

Males have 2.4 times the risk as females.

Obesity is a risk factor because it places more shear forces around the proximal growth plate in the hip at risk.

Bilateral slippage is common of which 2nd slip is about 12-18mths later to 1st (left hip is more common than right).

ETIOLOGY-multifactorial

1. Local trauma , obesity

2. Endocrine disorders (e.g primary or secondary hypothyroidism,

adiposogenital dystrophy(hypogonadal male),

3. Deficiency or increase of androgens.

4. Acute trauma

5. Growth hormone deficiency

6. ATYPICAL SCFE associated with renal failure,radiation therapy

Slipping of the upper femoral epiphysis occurs predominantly in obese children with underdeveloped sexual characteristics and less commonly, in tall, thin children.

MECHANICAL FACTORSImportant features of the predisposed hip that may be the primary cause of slipped epiphysis are:

1.Thinning of the perichondrial ring complex with maturation

2.Relative or absolute retroversion of the femoral neck-making it more suceptable to AP shear forces

3.A change in the inclination of the adolescent proximal femoral physis relative to the femoral neck shaft .

•Associated conditions with mechanical etiology-

1.Infantile and adolescent blount diasease

2.Patients with peroneal spastic flatfoot and Legg-Calve-Prthes disease

CLASSIFICATION Based on onset of symptoms-acute -chronic -acute on chronic FUNCTIONAL CLASSIFICATION-stable -Unstable

MORPHOLOGICAL CLASSIFICATION-mild -moderate -severe

BASED ON SYMPTOMS -

SYMPTOMS <2WKS >2WKS grdual

X-RAY displaced epiphyses remodelling and no remodelling healing notedACUTE ON CHRONIC SLIPS-Symptoms lasting longer

than 1mth and recent sudden exacerbation pain after trivial trauma

FUNCTIONAL CLASSIFICATION-It is important to determine ability of the patient to bear weight.

According to LODER-1. "Stable" SCFEs allow the patient to (walk) with or without crutches (walking aids).

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

MORPHOLOGICAL CLASSIFICATION

AP VIEW-145*LATERAL VIEW-170*

FROG LEG LATERAL POSITION--Best shows posterior slippage and subtle slipping also-Normally 10*posteriorly-Increases in slippage

MORPHOLOGICAL CLASSIFICATION-Grading Severity of SCFE according to AP and Lateral X-ray viewsPRESLIP-irregularity,widening,and indistinctness of physes

Grade-1 Grade-II Grade-III

ANTERIOR AND VALGUS SLIP the displacement is either superior and posterior (so-

called valgus slip)or, even more rarely, anterior. In valgus slips there is a restriction of adduction as

well as of flexion. In anterior slips there is a limitation of extension and

external rotation—exactly the opposite of what is found in typical slips.

X-RAY of valgus slip show -superior or lateral displacement of the capital

epiphysis on the femoral neck on the AP projection -posterior displacement on the lateral projection.

Anterior slips may appear little different from typical slips on the AP projection, but the anterior displacement of the capital epiphysis is identified on the lateral projection.

Pathology

Grossly , with gradual slipping of the capital epiphysis in the typical posterior position

Periostium is stripped from the anterior and inferior surface of the femoral neck

So the area between the original femoral neck and the posterior periostium fills with callus which ossifies and become progresively more dense

The anterior and superior portion of the neck forms a hump or ridge that can impinge on the rim of acetabulum

Normally ,this ridge will remodel with anterior portion of the neck contouring into smoother surface

In case of acute slipping the periostium is torn anteriorly and haemarthrosis will be present.

PATHOLOGY Microscopically Characteristc changes in PROLIFERATIVE and HYPERTROPHIC ZONES of epiphyses chondrocytes -number decrease and -irregularly arranged collagen fibres and Matrix are increased

SYMPTOMS

1. Pain : in the groin and around the knee.

2. Antalgic Limp (intermittent). 3. Shortening of the affected limb (1-2 cm).

4. The limb is in external rotation.[frog leg position]

5. Flexion, abduction, medial rotation are limited

6. External rotation, adduction are increased.

7.The presence of hip flexion contracture points towards the possibility of chondrolysis.

8.Axis deviation – pathognomonic – when hip is flexed, the

limb goes into external rotation

DIAGNOSIS

The diagnosis is a combination of clinical suspicion plus radiological investigation.

20-50% of SCFE are missed or misdiagnosed on their first presentation to a medical facility.

This is because the common symptom is knee pain. This is referred pain from the hip. The knee is investigated and found to be normal

In acute cases it is essential to differentiate between SCFE and type 1 epiphseal#as most of time both come with history injury/trauma

SCFE pt has prodromal pain in groin,thigh or knee.insidious onset whereas in type 1 epiphyseal # pt is normal acute pain associated with high energy trauma

it is neccesary to try to differentiate SCFE from PERTHE’S-

SCFE PERTHE’S DISEASE

Usually occurs in 10-14yrs age late onset in 14-16yrs

Usually in 4-7yrs age late onset in 7-10yrs age

Thin and tall adolescents or short and obese individuals

Occurs in normal child

Presents as pain with slippage and limping noted at later stage

Initially the child limps and then at later stages complaints of pain

Limb never has fixed flexion deformityIt may be in hyperextension state

Fixed flexion deformity is usually noted

X-RAYS-AP VIEW-thretowan’s sign[kleins line] -steel metaphysel blanch

sign -sham’s sign -capner’s sign -widening of growth plate -decrease of epiphyseal

height X-RAY -frog-leg [lowenstein]lateral view CT-SCAN MRI SCAN

INVESTIGATIONS

A.P. VIEW-Posterior ,inferior,And medial translation of epiphyses

LATERAL VIIEW-to measure lateral epiphyseal shaft angle

TRETHOWAN’S SIGN- In normal hip a line drawn tangential to

superior femoral neck[klein’s line] intersects small portion of lateral capital epiphyseal.

In posterior displacement of epiphyses the line doesn’t intersect.

METAPHYSEAL BLANCH SIGN-

In AP VIEW-crescent-shaped area of increased density overlying the

metaphysis adjacent to the physis This increased density is due to the overlapping of the femoral neck and the posteriorly displaced capital epiphysis

SHAM’S SIGN- In the normal hip the inferiomedial femoral neck

overlaps the posterior wall of the acetabulum producing triangular radiographic density

With displacement of capital epiphysis this dense triangle is lost because this portion of the femoral neck is located lateral to the acetabulum.

CAPENERS SIGN-

In pelvic AP view in the normal hip, the posterior acetabular margincuts across the medial corner of the upper femoral metaphysisWith slipping, the entire metaphysis is lateral to the posterioracetabular margin

LATERAL VIEW Very early slips may appear to be normal in

AP VIEW but may be clearly noted in lateral view

CHRONIC CASE OF SCFE X-RAY- Reactive bone formation along superolateral

aspect of neck Bone remodelling and broadening of neck

resulting in PISTOL GRIP like appearance[hordons hump]

USG-It has been useful in the detection of early slips -

joint effusion and a “step” between the femoral neck and the epiphysis created by slipping.

Absolute displacement of 6 mm, >2 mm is diagnostic of a slipped epiphysis.

CT-useful in documenting presence of decreased upper femoral neck anteversion or true retroversion.

it’s more accurate measure head–neck angle. CT is useful in the management of slips. First, CT of the hip can be very helpful in

demonstrating whether penetration of the hip joint by fixation devices has occurred (Fig. 18-9).

CT is also used to confirm closure of the proximal femoral physis and also when reconstructive osteotomy is being considered.

MRI-useful to assess AVN

COMPLICATIONS

1. Avascular necrosis.

2. Chondrolysis.

3. Osteoarthritis.

4. Coxa vara (is a deformity of the hip, whereby the angle between the ball and the shaft of the femur is reduced to less than 120 degrees).

5. Slipping of the opposite hip ≈ 20% to 805 of cases

NATURAL HISTORY

•30-40% second slip asymptomatic (slow)

•Premature OA (pistol grip deformity 40% primary OA)

•Onset of OA directly related to severity of slip

IDEAL TREATMENT

•Prevent further slippage•Stimulate early physeal closure•Reduction of epiphyseal displacement•Avoid complications like osteonecrosis , chondrolysis and osteoarthritis

•Any child with SCFE and open epiphyses needs treatment ,without stabilisation it progresses.

•In a patient with closed physes, the only surgical treatment in the absence of severe degenerative changes is proximal femoral osteotomy. Indications are functional limitations, unacceptable gait, or cosmetic deformity

MANAGEMENT- Conservative management-rest and traction Closed manipulative reduction Operative management -In situ pinning -ORIF -BONE PEG Epiphysiodesis -Osteotomy -reconstruction by-Arthroplasty -Arthrodesis -Cheilectomy

Conservative Treatment

Rest for atleast 12wks and traction can be an alternative to surgical treatment

Indicated in – temporary measure before operative ℞

- slip due to hypothyroidism Rest in spica cast - ⇧ incidence of

complications like chondrolysis

Operative treatment1.Percutaneous and open in situ pinning• Percutaneous pinning is done for mild, moderate and some

severe acute or chronic SCFE

• Open pinning is used for more severe acute or acute on chronic slipping and when closed reduction pinning fail

• Generally 2 cannulated screws for acute (unstable) slips 1 screw for chronic stable slips. •Entry point is anterior rather than lateral aspect of femoral neck.

• With increasing severity of the slip, the entry point will be found progressively more superior on the femoral neck. •After in situ pinning –early wt bearing in stable slips• -after 6-8wks in unstable slips•Sports activities only after physeal closure.

Pinning in situPinning in situ

NOT HERE

HERE

-Screw should enter head perpendicular to its physeal surface and in its centre.-If two screws are to be inserted, first screw should lie in central axis of head and second screw below it avoiding superolateral quadrant.

-pin tip be advanced to 8 mm or one third of the femoral head radius from subchondral bone, whichever projection is the closest. This places the actual tip 7 to 18 mm from the subchondral bone, leaving a safe margin.

Serious disadvantage is Persistent pin penitration

Adverse affects attributed to unrecognized pin penitration :

•Joint sepsis

•Localised acetabular erosions

•Synovitis

•Post operative hip pain

•Chondrolysis

•Late degenerative osteoarthritis

Prophylactic pinning of the contralateral hip

•Follow Up till skeletal maturity

•Pin if symptoms are present

•Pin if there is known metabolic/endocrine disorders

•Pin if Follow up is unreliable

Manipulative Reduction

Only for acute and acute on chronic severe slips

Within 24 hours of slip High risk of ischemic necrosis of head. So, manipulate only acute severe slips that

may be technically difficult or impossible to pin in situ.

Alternatively gradual reduction by skin traction and internal rotation over 3 – 4 days.

OPEN REDUCTION

•Biomechanical disturbances caused by the tilt of the epiphysis may cause early degenerative joint changes,

•So open reduction, limited osteotomy, and internal fixation, if necessary, have been recommended if a severe acute or chronic slip which cannot be reduced by closed methods

•Dunn emphasized the need to shorten the femoral neck to prevent tension on the posterior vessels when the epiphysis is reduced, making the procedure a closing wedge osteotomy, rather than a simple open reduction.

• The Heyman-Herndon procedure gave consistently good results for moderate slips,• Dunn's procedure gave better results for severe slips

Bone peg epiphysiodesis is not done now a days because of associated postoperative complications:

•Osteonecrosis

•Chondrolysis

•Infection

•Thigh hypesthesias

•Heterotopic ossification

•After bone peg epiphysiodesis of acute slips, spica cast immobilization may be necessary for 6 weeks or more to prevent further slipping

OSTEOTOMY:Because moderately or severely displaced chronic slips produce permanent irregularities in the femoral head and acetabulum, some form of realignment procedure often is indicated to restore the normal relationship of the femoral head and neck and possibly delay the onset of degenerative joint disease

Two basic types of osteotomies:

•Closing wedge osteotomy through the femoral neck, usually near the physis to correct the deformity.

•Compensatory osteotomy through the trochanteric region to produce a deformity in the opposite direction

Four femoral neck osteotomies are described:

(1)the technique of Fish,

(2) the technique of Dunn just distal to the slip,

(3) the base of the neck technique of Kramer et al., and

(4) the technique of Abraham et al.

(5)Compensatory osteotomies in the trochanteric region and partial cheilectomy to reduce deformity also are described

(6)1 and 2 in open epiphyses

OSTEOTOMY SITES

Fish technique: just distal to the the physisDunn technique: just distal to the slipKramer technique: base of the neckAbraham technique: at the trochanteric region

• The advantage of osteotomy through the femoral neck [DUNN and FISH type]is that the deformity itself is corrected, but incidences of osteonecrosis ranging from 2% to 100% and of chondrolysis from 3% to 37% have been associated

• ABRAHAM and KRAMMER are osteotomies done adjusting according to deformity

CUNEIFORM OSTEOTOMY OF FEMORAL NECK[FISH]

•Make the wedge anterior and superior to correct epiphyseal position-subcapitally•The more severe the slip the more is wedge superiorly•Reduce the epiphysis by flexion, abduction, and internal rotation of the limb•After wedging, diameter of femoral head is greater than femoral neck.

•Indication-severe chronic or acute on chronic slips

intent of this procedure is to reduce the capital femoral epiphysis on the femoral neck by resecting a portion of superior femoral neck,carefully preserving the posterior periosteum of femoral neck and preventing tension on it during reduction. The a lateral approach allows stripping of the periosteum and its contained vessels under direct vision to avoid damaging the blood supply to the femoral head. In the lateral view, the head should appear to sit squarely on neck, In the anteroposterior view, the head should be tilted into about 20 degrees of valgus 2WKS later walking with crutches 3-4mths later partial wt bearing

CUNEIFORM OSTEOTOMY FEMORAL NECK[DUNN]

Its basal femoral neck osteotomy that corrects the varus and retroversion components of moderate or severe chronic SCFE.

It is safer than an osteotomy made near or at the physis because the line of the osteotomy is distal to the major blood supply in the posterior retinaculum

COMPENSATORY BASILAR OSTEOTOMY OF FEMORAL NECK[KRAMER]

Widest part of wedge (at base of neck) is in line with widest part of slip, correcting varus and retroversion componentsThe osteotomy site is closed by medial rotation and abduction of the distal segment

Osteotomy done from lesser to greatertrochanter with posterior cortex intactThen fixed with cancellous screws Risk of AVN is low. Correction of varus & retroversion is less. Does not affect Limb Length Discrepency. Improves hip range of motion.

EXTRACAPSULAR –BASE OF NECK OSTEOTOMY[ABRAHAM]

Intertrochanteric Osteotomy Usually for malunited slip. If physis is still open, in situ pinning with osteotomy.

Closing wedge Trochanteric Osteotomy - to correct varus deformity with some ER.

Triple deformity – coxa vara + ER + hyperextension

- Southwick biplane wedge oseotomy - Clark’s modification of Southwick osteotomy - Ball & Socket Osteotomy

For residual deformity correction after physeal closure When a capital femoral epiphysis has chronically slipped and

has united in a poor position, a trochanteric osteotomy to produce an opposite deformity is done.

distal femoral fragment osteotomy done and flexed and medially rotated making femoral shaft parallel to epiphysis.

it restores articulotrochanteric distance (ATD), trochanter–center of head distance (TCH), and epiphyseal-shaft angle

INTERTROCHANTERIC OSTEOTOMY

Southwick biplane osteotomy

AP & lateral views taken Head shaft angle measured Difference of head shaft

angle between slipped side and normal side is taken as angle of wedge to be taken

Anterior and lateral based wedge OSTEOTOMY done

Clark’s modification of Southwick’s osteotomy

Transverse line is drawn on ant & lat surface of femur at level of lesser trochanter.

Point X is measured 15 mm proximal from tranverse line along longitudinal orientation mark.

Triangle X”XT -> Ant wedge Point X’ is measured 13mm

post to longitudinal mark at level of transverse mark.

Triangle X’XT -> lat wedge

CHEILECTOMY

When a prominence on the anterosuperior aspect of the femoral neck blocks internal rotation or abduction by impinging against the acetabulum

Simple resection of the prominence removes the obstruction and improves motion

Care to preserve the integrity of the neck of the femur and the physis because fractures of the neck of the femur and further acute slipping of the epiphysis may occur when too much is excised.

Intraarticular epiphysiodesis using bone from the crest of the ilium was recommended by Herndon.

MANAGEMENT

COMPLICATIONS

SCFE Osteonecrosis-Rare in untreated SCFE

-Results from interruption of the retrograde blood supply by:

•Original injury tamponade of the blood supply to the proximal femoral epiphysis as a result of acute hemorrhage within the capsule

•Increase with severity of slip

•increase in acute, unstable slips

•increases with forcefull repititive manipulation,

•pin placement in superior quadrant

• Osteotomy of femoral neck

DIAGNOSIS: Early postoperative bone scan has excellent sensitivity and predictive value for detection of osteonecrosis after surgical treatment of SCFE

TREATMENT• Remove metal work

• Maintain ROM

• Realignment

• Shelf acetabuloplasty

• Arthrodesis/THR

SCFE Chondrolysis

Dissolution of articular cartilage with joint stiffness and pain

Causes:

• Persistent pin penitration

• After trochantric osteotomy, open

reduction,femoral neck osteotomy

• Synovial malnutrition, ischaemia, excessive pressure

• Autoimmune

• Females>males

Bone scan in Chondrolysis

Diagnosis: Joint pace of less than 3mm wide ( normal 4 to 6 mm)

Decrease range of motion at hip joint

TREATMENT

•Bed rest

•Traction

•Salicylates

•Nsaids drugs

•Intraarticular cortisone injections

•Sugical manipulation in form of : Subtotal circumferential capsulectomy • Continuous passive motion and physical therapy

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