Authors of section

Authors

Andrew Howard, James Hunter, Theddy Slongo

Executive Editor

Fergal Monsell

General Editor

Chris Colton

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Open reduction, screw fixation

1. Preliminary remarks

Avascular necrosis

These fractures involve acute failure of the physis, which is usually the result of high energy trauma. Accordingly, the risk of avascular necrosis is high and a gentle anatomical reduction with stable internal fixation is required to provide the best prognosis.

open reduction screw fixation

Hardware selection

6.5, 7.0, or 7.3 mm cannulated screws are used for adolescents.

4.0, or 4.5 mm cannulated screws may be selected for younger children. Be aware that these screws are considerably weaker and prone to breakage if used in too heavy a child.

in situ fixation with k wires or screws

Implant insertion

Typically, two screws separated vertically are inserted. This configuration may be more suitable in smaller bones.

An alternative is three screws used in an apex-distal, triangular configuration, with the lower central screw abutting the calcar.

Inserting a single central screw does not provide rotational stability and is, therefore, less applicable for fractures, even though it is a common choice for slipped capital femoral epiphysis (SCFE).

open reduction screw fixation

Pitfall: Secondary subtrochanteric fractures may occur if screws are inserted below the level of the lesser trochanter.

open reduction screw fixation

2. Patient preparation and approaches

Patient preparation

Depending on the approach, the patient may be placed either supine or lateral.

See also the additional material on preoperative preparation.

Approaches

For this procedure the following approaches may be used:

3. Reduction

A K-wire is inserted through the lateral cortex of the femur just above the level of the lesser trochanter and advanced to the fracture line.

Pitfall: Secondary subtrochanteric fractures may occur if K-wires are inserted with an entry point distal to the level of the lesser trochanter.

open reduction screw fixation

The femoral neck is manipulated gently into position, usually by traction in the line of the femoral neck using a bone hook.

open reduction k wire fixation

If necessary, manipulation of the femoral head is achieved using a small K-wire inserted into the epiphysis, as a joystick.

Gentle reduction maneuvers are emphasized in order to prevent secondary damage to the femoral head blood supply.

open reduction screw fixation

4. Fixation

Guide wire insertion

When anatomical reduction is obtained, the first wire is advanced across the fracture and into the femoral head. Penetration into the hip joint should be avoided.

open reduction screw fixation

Additional wires are inserted under image intensifier control, according to the two- or three-screw configuration chosen.

open reduction screw fixation

X-ray control

The guide wire positions are confirmed on AP and lateral x-rays.

open reduction screw fixation

If using a standard radiolucent table, the K-wire fixation is generally stable enough to allow a “frog” lateral view.

The wires are repositioned if necessary.

in situ fixation with k wires or screws

Images at multiple angles are used to confirm that the guide wires do not penetrate into the hip joint.

in situ fixation with k wires or screws

Measuring screw length

A depth gauge is used to measure screw length.

If a dedicated cannula/depth gauge set is not available, then a K-wire, of the same length as that inserted, is placed onto the lateral cortex adjacent to the inserted wire, and the difference measured to determine the screw length.

open reduction screw fixation

Drilling screw holes

The wires are overdrilled with the appropriately sized cannulated drill bit.

Adolescents in particular have very dense strong bone in the metaphysis near the growth plate and predrilling is recommended.

If cannulated screws are not available, then guide wires should be removed one at a time and an appropriate drill used.

open reduction screw fixation

Screw insertion

Two or three cannulated screws are then inserted over the guide wires.

Note: Fully-threaded cannulated screws are easier to remove later.

open reduction screw fixation

X-ray control

Image intensification is used to confirm that the screw tip does not penetrate into the cartilage or the joint.

Typically, 5 mm of epiphyseal bone/cartilage should remain between the screw tip and joint surface. Three or four threads crossing the physis provides adequate fixation.

Pitfall: Screw penetration can occur, especially with eccentrically placed screws, even if not apparent on standard AP or lateral x-rays.

Real-time, dynamic image intensification, through a full range of internal and external rotation, and at different degrees of flexion, is useful to confirm the distance between the screw tip and the joint space.

Observing an approach/withdrawal of the screw tip helps in judging its position. Some surgeons supplement this examination with 3-D image intensification for confirmation.

Arthrography is useful to confirm correct wire and screw placement in the younger patient.

open reduction screw fixation

Guide wire removal

Guide wires are removed.

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5. Hip spica

If solid fixation has been obtained with screws, and the patient/family can reliably comply with toe-touch weigh bearing, then a cast is not necessary.

For patients below 5 years of age, a hip spica cast can be used if desired.

Click here for details of hip spica application.

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6. Aftercare following hip spica application

Introduction

Hip spica is only likely to be used in the treatment of small children with proximal femoral fractures.

For larger children, internal fixation should be used even for nondisplaced fractures.

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Immediate care

After application, the spica should be trimmed to allow adequate space for bodily functions. The edges of the spica should be padded and waterproofed.


Diaper care

Generally, a hip spica should allow space for a small diaper inside the plaster and a large one outside the plaster. The diapers should be positioned to prevent soiling of the spica.

Washing

The spica is not waterproof. Bathing and showering should not be attempted. Hair washing should be done very carefully.

Skin care

No skin products should be put inside the spica. Only skin that can be seen should be moisturized.

Transport

Both the child and the spica must be lifted. A special car seat will be required. The child may be placed in a stroller or buggy.

In this circumstance, the parents/carers are advised to return to the healthcare provider.

Length of time in spica

The length of time in the spica depends on the age of the child and the healing of the fracture. A proximal femoral fracture in a child aged below 4 years should always be healed in 6 weeks.

Growth

The child will continue to grow and the tightness of the spica should be monitored.

Follow-up x-rays

Nondisplaced fractures being treated nonoperatively should have early radiological follow-up. If the spica is being used for protection of fixation, x-rays are required only when planning removal.