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How To Apply a Sugar-Tong Ankle Splint

(Ankle Stirrup Splint)


James Y. McCue

, MD, University of California San Francisco - Fresno

Last full review/revision Apr 2021| Content last modified Apr 2021

Sugar-tong ankle splints are rigid devices that fix and maintain stability of the ankle joint.

Sugar-tong ankle splints, also called U-shaped splints, are typically used for injuries that benefit from immobilization but do not require casting. Commercial immobilizer air-inflatable stirrups or boots may be an alternative where available. Unlike boots, sugar-tong ankle splints are generally not designed to bear weight or be removed and replaced (eg, for bathing).


  • Ankle sprain that should not bear weight and requires immobilization
  • Stable fractures of distal tibia or fibula (eg, minimally displaced fractures of the distal tibia and/or fibula)
  • Ankle dislocations (for postreduction stabilization)
  • Selected foot fractures


Absolute contraindications

  • None

Relative contraindications

  • Injuries (eg, certain mild sprains) in which immediate range of motion and/or weight-bearing is desirable
  • Injuries in which a cast is preferable*

* The indications for sugar-tong splints and casts overlap. (See also Overview of Fractures.) Even if casting is the definitive treatment, initial splinting is often recommended for some injuries until swelling subsides. A cast may be preferred when weight-bearing is permitted and when the ankle clearly must be immobilized for > 1 to 2 weeks. Conversely, immobilization boots may be preferred when continual immobilization is not required.


  • Thermal injury (caused by the exothermic reaction of plaster and fiberglass hardening)
  • Excessive pressure causing skin sores and/or ischemic injury
  • Compartment syndrome


  • Stockinette (enough to cover the area from below the fibular head to the midfoot)
  • Roll padding (eg, cotton roll) 10-cm (4-inch) width
  • Plaster or fiberglass splinting material* 10- to 15-cm (4- to 6-inch) width (wide enough to reach from the calcaneus to the metatarsal heads on the plantar surface and long enough to reach from one side below the fibular head around the calcaneus and to the other side)
  • Elastic bandage, usually 10-cm (4-inch) width
  • Lukewarm water and bucket or other container for water
  • Nonsterile gloves

* Fiberglass and plaster are usually supplied as single-layer rolls, but there are also commercially available rolls of pre-constructed splints that include multiple layers of fiberglass/plaster as well as padding.

Additional Considerations

  • Because it covers both malleoli, a sugar-tong splint may limit inversion and eversion better than a posterior splint alone.
  • A sugar-tong splint may also prevent plantar flexion more effectively than a posterior splint.
  • For unstable ankle injuries, combining an ankle stirrup and posterior ankle splint can increase the stability of immobilization.

Relevant Anatomy

  • Lateral malleolus
  • Medial malleolus
  • Calcaneus

Bones of the ankle and foot

Bones of the ankle and foot


  • The patient should lie prone with the knee flexed or sit with the lower leg dangling over the edge of the bed.
  • Maintain the ankle at 90° of flexion.

Step-by-Step Description of Procedure

  • Wear nonsterile gloves.
  • Give the patient adequate analgesia.
  • Apply stockinette, covering the area from the fibular head to the midfoot.
  • Measure the splinting material to extend from the lateral aspect of the lower leg just below the fibular head to and around the plantar surface of the foot and back up the medial aspect of the lower leg to form a U-shaped splint.
  • Wrap the padding from midfoot to mid-calf, slightly beyond the area to be covered by the splint, overlap each turn by half the width of the padding, and periodically tear the wrapping across its width to decrease the risk of tissue compression.
  • Smooth the padding as necessary.
  • Consider additional padding over bony prominences (eg, medial and lateral malleoli).
  • Lay out a length of splint material to extend from the lateral aspect of the lower leg at mid-calf to and around the plantar surface of the foot and back up the medial aspect of the lower leg to form a U-shaped splint—it should be just shorter than the area covered by the padding.
  • Unroll additional splint material, folding it back and forth along the first length until there are 6 to 8 layers (when using single-layer rolls).
  • Immerse the splinting material in lukewarm water.
  • Squeeze excess water from the splinting material (do not wring out plaster).
  • Apply the splint material to the lateral aspect of the leg at mid-calf to and around the plantar surface of the foot and back up the medial aspect of the lower leg.
  • Smooth out the splinting material using your palms rather than your fingertips to conform to the contour of the lower leg and ankle and fill in the interstices in the plaster.
  • Wrap the elastic wrap over the splinting material distally to proximally and overlap each revolution by half the width of the elastic wrap.
  • Fold the extra stockinette and cotton padding over the raw edges of the splinting material.
  • Maintain the ankle at 90° of flexion until the splinting material hardens.
  • Check for distal neurovascular status (eg, capillary refill, sensation, toe flexion and extension).


  • Provide crutches and training in their use.
  • Advise the patient to keep the splint dry.
  • Arrange or recommend appropriate follow-up.
  • Have the patient elevate the injured limb above the heart while seated or at rest.
  • Instruct the patient to seek further care if pain cannot be controlled with oral drugs at home.
  • Educate the patient about the symptoms of compartment syndrome.

Warnings and Common Errors

  • Do not wrap the padding or elastic too tightly (ie, neither should cause indentations in the skin).
  • Be sure not to let the ankle joint relax while the splint hardens so that the 90° flexion angle is lost.
  • Avoid irregular contours and potential pressure spots by using the palms of your hands rather than the fingertips to smooth out the splinting material.

Tips and Tricks

  • Warm water makes plaster set quicker, so if you are unfamiliar with applying splints use cooler water to increase your working time.

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