Authors of section

Authors

Philip Henman, Mamoun Kremli, Dorien Schneidmüller

Executive Editor

James Hunter

General Editor

Fergal Monsell

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Below-knee cast

1. General considerations

Indications

Most tibial shaft fractures require initial management with a long leg cast.

A below-knee cast (or short leg splint or brace) may provide sufficient support for stable diaphyseal tibial and fibular injuries.

Tibial fractures managed with a short leg cast require close radiological follow-up.

A short leg cast can also be used following surgical fixation in the early postoperative period.

Pediatric fracture healing below knee cast

Complications

  • Pressure sores
  • Skin irritation
  • Loss of reduction
  • Compartment syndrome
  • Thermal burns (avoid using hot water)

2. Preparation

Read the additional material on preoperative preparation.

Material

  • Tubular bandage (stockinette) of appropriate size
  • Cast padding
  • Felt
  • Casting material: synthetic, plaster of Paris, or a combination of both
  • Water

The water temperature should ideally be between 22° and 25° C.

Material for cast application

3. Casting

Patient and leg positioning

Place the patient in a supine position with a bolster under the knee to keep it flexed.

An assistant also supports the leg to maintain knee flexion.

Patient and leg positioning for application of a short leg cast

Dressing

The cast extends from just below the knee to the base of the toes.

Apply a tubular bandage and cut it slightly longer than the length of the final cast.

The assistant holds the toes, not the stockinette, with the ankle in a neutral position.

Dressing for short leg cast

Padding

Add thick felt or additional padding at the free edges of the cast and prominent areas (eg, tibial crest, malleoli, and heel) to prevent pressure sores.

Apply cast padding without creases, overlapping each layer by 50%.

It should be appreciated that, when more padding is applied, there will be less support at the injury site.

Padding for short leg cast

Cast application

Apply the first layer of cast material and overlap each layer by 50%.

Avoid sharp edges at the ends of the cast.

Apply further layers of cast material to produce sufficient stability.

Cast application for short leg cast

Avoid pressure over the fibular head and neck by adding sufficient padding and shortening the cast to prevent injury to the peroneal nerve.

Avoiding pressure over the fibular head and neck with application of a short leg cast

Fold the tubular bandage and padding over the edges of the cast before applying the final layer of casting material.

Ensure that all toes are visible for vascular assessment.

Folding bandage and padding over the edges of a short leg cast

4. Final assessment

After cast application, check the fracture configuration with x-rays in both planes.

Confirm normal toe color and capillary refill at the end of cast application.

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