Ankle and Foot Splints and Casts
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Introduction
Leg, ankle, and foot injuries are very common, frequently requiring immobilization. Casting and cast splinting are most frequently used for acute injuries, while splinting and taping often take place for chronic injury during rehabilitation.
Ankle sprains may be treated with a short leg cast or sugar tong splint, and taping or bracing can be used as weight bearing improves.
Tibial or bfibular short leg fractures may be immobilized with a short leg cast. Tibial fractures may need to be immobilized for up to 10 weeks, while fibular fractures often require only 3-4 weeks of immobilization.
Splints
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Casting
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Taping
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Splinting
Estimate the length of splint. Unroll casting material into 11-13 layers.
Roll padding across foot and leg for 6-8 layers.
Apply plaster.
Finish with a single layer of padding so that the Ace bandage does not stick to the plaster.
For the sugar tong splint, measure from the fibular head to the calcaneous and double the material. Apply splint against lateral leg, beginning just distal to the fibular head. Wrap up, under the heel, and return medially. Mold the splint to support the ankle and heel. Place padding over the splint, and wrap with Ace bandage.
Posterior Splint
The posterior splint may be used for stable tibial and fbular fractures, as well as some cases of plantar fasciitis.
Measure from the metatarsal heads to just distal of the popliteal fossa. Cut plaster to size. PLace padding against patient's skin.
Wet plaster and remove excess water.
Apply splint along plantar aspect of foot and along posterior leg.Extend from metatarsal heads to the distal popliteal fossa. Mold splint to support ankle and heel. Apply layer of padding ouside splint. Wrap with Ace bandage and secure with clips and tape.
Short Leg Cast
A short leg cast may be used for fractures of the tibia, fibula, calcaneus, metatarsals, tarsals, or severe ankle sprains after swelling has receded.
The patient may be in a sitting position or prone, with knee flexed. The ankle is usually flexed to 90 degrees, using a foot stand as necessary. Only partial immobilization of the ankle is achieved, as the knee remains free.
Measure from metatarsal heads to the knee and cut stockinette to length. Allow extra room to fold over the cast when finished. Slide on stockinette and smooth away all wrinkles and folds. Trim away crease at the anterior ankle.
Wrap padding over stockinette, with 50% overlap for each wrap. Ensure padding extends from metatarsal heads to just distal of the fibular head. Ensure adequate padding around the heel, medial and lateral malleoli, metatarsal heads, proximal fibula, and anterior tibia.
Wet cast material and wrap foot and ankle over padding. Ensure 50% overlap. Use moderate tension. Mold cast to ensure 90 degree flexion of ankle. How many layers?
Fold stockinette over cast, and apply one final layer of casting material. If the cast is designed to be walked upon, add 6-8 layers of plaster from metatarsal heads to the midcalf before the final layer.
Allow 10 minutes for cast to set, and instruct against weight bearing for 24 hours.
Patient Education
Immobilize the injury for 48-72 hours to prevent swelling. Ice, in an inclosed container, may be used to reduce inflammation.
Keep splint or cast dry. If it does become wet, use a hair dryper on cool.
Do not insert anything under the cast, as injury can cause occult infection.
If the patient notices worsening pain, tightness, numbness, toe discoloration, or fever, they should be immediately assessed.
Cast Removal
Cut along the medial and lateral sides. Start at the top, and make cuts posterior to the malleoli. Use repeated plunging cuts instead of dragging the saw to prevent burns. Widen the cuts with a car spreader, and cut padding and stockinette with blunt-tipped scissors.
Complications
Informed consent is important prior to immobilization. Decreased strength and flexibility, occasionally permament, are common.
Nerve entrapment may occur with the common peroneal nerve at the fibular head, leading to foot drop. Avoid by ensuring proper placement of the proximal cast.
Compartment syndrome can occur if casting is done before swelling is maximized. If worsening pain occurs, the cast should be immediately bivalved.
Cast loosening can occur as swelling subsides, leading to inadequate stability and immobilization.
Skin necrosis can occur above bony prominences. This can be avoided by using extra padding, or by placing a window to avoid ongoing irritation.
Joint stiffness is frequent. It can be avoided by using the minimum time required for healing.
Resources and References
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