Adolescent coxa vara

ADOLESCENT COXA VARA

It is also known as Slipped Capital Femoral Epiphysis

Or Epiphysiolysis

It is displacement of the proximal femoral epiphysis

WHO?

•10 – 16 yrs•Boys•Obese or tall & thin•Blacks•Left > Right

WHY?

MOSTLY MULTIFACTORIAL

Local trauma

Obesity

Endocrine disease (hypothyroidism, hypopituitarism, chronic renal disease)

Genetic

CLINICAL FEATURES

H/O Injury

Pain in groin thigh or knee

Limp

On Examination

Leg is externally rotated

1-2cm short

Limitation of flexion, abduction and internal rotation

Classic Sign – there is increasing external rotation as the hip is flexed

INVESTIGATIONS

RADIOLOGICAL FEATURES

XRAY

In AP view-Normal head-shaft angle is 1450

In Lateral view-Normal head-shaft angle is 1700

Lateral view – most reliable sign – femoral epiphysis is tilted backwards

AP view – a line drawn on the superior surface of the neck remains superior to the

head instead of passing through it (TRETHOWAN’S SIGN)

CT SCAN

It is helpful to confirm the diagnosis in early, mild slipping

X ray-

Trethowan’s Sign positive

CLASSIFICATION

DurationA. Acute slips – sudden onset of severe

symptoms, <2 weeks, Xray shows no evidence of bone healing

B. Chronic slips – gradual onset, >2 weeks, Xray shows some bony healing and remodelling along postr. and med. femoral neck

C. Preslip – Xray finding of irregularity, widening and indistinctness of physis

D . Acute on Chronic – symptoms >1 month, recent exacerbation of pain following trivial trauma

BASED ON XRAY

MILD (GRADE I) - Neck displaced <1/3rd of diameter of femoral head, angle deviation <300

MODERATE (GRADE II) – Displacement btw 1/3rd and 1/2, angle deviation btw 300 and 600

SEVERE (GRADE III) – Displacement >1/2, angle deviation more than 600.

TWO PART CLASSIFICATION

UNSTABLE – Severe pain prevents walking even with crutches

STABLE – Walking is possible with orwithout crutches

TREATMENT

AIMS

Preserve epiphyseal blood supply

Stabilize the physis

To correct any residual deformity

NON OPERATIVE

Traction and spica cast immobilisation

Prevents further slipping

Results in premature physeal closure

More complications

MILD SLIPS Deformity is minimal

Insert one or two screws or threaded pins along the femoral neck and into the epiphysis

Now recommended – single larger diameter central pin or screw

Pins should not be removed for atleast 12 months or until epiphysis closes

MODERATE SLIPS

Fix epiphysis in situ – short threaded pins

After 1 year, if deformity present, corrective osteotomy done

Alternatively bone graft epiphyseodesis

Trim anterosuperior metaphysis to prevent impingement

SEVERE SLIPS

Open reduction by Dunn’s Method – small segment of femoral neck is removed to reposition the epiphysis, once reduced it is held by 2 or 3 pins.

Alternatively, fix epiphysis followed by compensatory intertrochanteric osteotomy

1. Tri plane osteotomy 2. Geometric flexion osteotomy

PROPHYLACTIC PINNING

It is done for contralateral slips Indicated in rare instances High risk Non compliant patients Patients with epiphysiolysis from renal failure orirradiation therapy

CLOSED REDUCTION

Done in severe acute unstable slips

Technically difficult or impossible to pin in situ

Earlier- Internal rotation alone Gradual reduction by skin traction and

internal rotation over 3-4 days

Avascular necrosis more

OPEN REDUCTION

Dunn’s in severe acute or chronic slip

Heyman – Herndon epiphysiodesis procedure in moderate slips

BONE PEG EPIPHYSIODESIS

Done by using hollow mill to create tunnel across physis, sandwiched iliac bone grafts driven across the physis

More complications than in situ pinning

Disadvantages-graft insufficiency, longer operating time,increase blood loss

OSTEOTOMY

A CLOSING WEDGE OSTEOTOMY-through femoral neck

• Cuneiform Osteotomy femoral neck (Fish)• Cuneiform Osteotomy femoral neck

(Dunn)• Compensatory Basilar Osteotomy of

femoral neck• Extracapsular Base-of-neck osteotomy

B. Compensatory osteotomy Intertrochanteric osteotomy

C. Cheilectomy resection of the part impinging

against acetabulum

COMPLICATIONS

AVACULAR NECROSIS

More common in-

Unstable (acute) slips Forceful repetitive manipulation Open reduction Osteotomy of femoral neck Superolateral placement of pins

CHONDROLYSIS

More common in- Pin penetration into joint Trochanteric osteotomy, open reduction, femoral neck osteotomy Closed reduction and pin fixation

Joint space <3mm wide and decreased range of motion of hip joint

Fibrous ankylosis follows

Treatment- intraarticular cortisone injecton

surgical manipulation

FEMORAL NECK FRACTURE

Thermal injury caused by reaming of femoral neck before screw insertion.

Prevention- avoid unnecessary drilling, pins removed after

physeal fusion

COXA VARA

Head slips backwards-femoral neck retroversion

Secondary effectsa. External rotation deformity of hipb. Shortening of femurc. Secondary osteoarthritis

CONTINUED SLIPPING

If not treated Screws not placed proximally enough Removed before complete fusion of

physis

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