Posterior Ankle Splint Kit — Ankle Soft Cast & Fracture Treatment
The professional-grade posterior ankle splint — also called an ankle soft cast — used by emergency departments and orthopedic clinics. If you've been searching for a plaster posterior ankle splint, ankle soft cast, plaster ankle splint, or plaster leg splint — this is the upgraded fiberglass version that clinicians now use instead. Same posterior immobilization with the ankle set at 90°. Lighter weight. Faster setting. More durable than plaster.
This complete professional-grade kit includes pre-padded synthetic fiberglass splint material, self-adhesive bandages, and synthetic padding for quick, effective treatment of severe ankle sprains, fractures — including posterior malleolus fractures — and post-operative care, with no additional materials needed. Sets in just 5–7 minutes.
Medical Uses & Indications
- Severe Ankle Sprains — Grade II and III ligament injuries
- Posterior Malleolus Fractures — Fractures of the back of the ankle requiring posterior immobilization
- Malleolar Fractures — Medial, lateral, and trimalleolar ankle fractures
- Distal Tibia Fractures — Lower leg fractures near the ankle
- Fibula Fractures — Lateral ankle bone fractures
- Achilles Tendon Injuries — Partial tears and post-repair immobilization
- Post-operative Immobilization — After ankle surgery or procedures
Key Features
- Pre-Padded Design: Padding already built into splint material — no extra layers or stockinette needed
- Quick-Setting: Hardens in just 5–7 minutes for fast patient care
- Ankle Set at 90°: Optimal neutral position for healing and patient comfort
- Complete Kit: Includes splint, self-adhesive bandages, cast padding, and gloves
- Professional Quality: Same materials used by orthopedic specialists and emergency departments
- Posterior Design: Applied to the back of the leg — the correct position for posterior malleolus and ankle fracture immobilization
- Radiolucent: Compatible with X-ray imaging without removal
- Color Options: White, Black, and Hot Pink bandage colors available
What Is a Posterior Ankle Splint (Ankle Soft Cast)?
A posterior ankle splint — sometimes called an ankle soft cast — is a fiberglass slab applied to the back of the lower leg and foot, holding the ankle in a neutral 90° position. Unlike a full circumferential cast, the posterior design allows room for swelling in the acute phase of injury, making it the preferred immobilization method in emergency settings.
This splint is the standard of care for posterior malleolus fractures, bimalleolar and trimalleolar ankle fractures, severe ankle sprains, and Achilles tendon injuries. Historically made from plaster of Paris, modern clinical practice has shifted to fiberglass — which sets faster, weighs significantly less, and is far more durable.
Kit Contents by Size
| Size | Splint Dimensions* | Self-Adhesive Bandage | Synthetic Padding |
|---|---|---|---|
| Child 6–12 | 3" × 35" | 2 Rolls 3" | 1 Roll 2" |
| Teen 13–17 | 4" × 30" | 2 Rolls 3" | 1 Roll 3" |
| Adult 18+ | 5" × 30" | 2 Rolls 3" | 1 Roll 4" |
* Trim the splint to the correct length for the individual patient.
How to Apply a Posterior Ankle Splint
Why Buy Direct Instead of at Your Doctor's Office?
Purchasing your posterior ankle splint kit directly from OrthoTape offers significant advantages over getting it at your doctor's office or emergency room. Emergency room splint applications can cost $300–600 or more when billed through insurance, while our complete kit costs a fraction of that. Our splint materials are the same professional-grade products — if not better — than what your doctor or ER uses, meeting or exceeding all industry standards.
Many medical offices have limited inventory and may only stock basic white bandages, while we offer multiple color options. By ordering from us, you get exactly what you need at a fraction of the cost, with fast shipping directly to your door.
Frequently Asked Questions — Posterior Ankle Splint & Ankle Soft Cast
What is a posterior ankle splint and when is it used?
A posterior ankle splint — also called an ankle soft cast — is a fiberglass slab applied to the back (posterior) of the lower leg and foot, holding the ankle in a neutral 90° position. It is the standard acute immobilization technique used in emergency departments and orthopedic offices for severe ankle sprains (Grade II–III), posterior malleolus fractures, distal tibia and fibula fractures, malleolar fractures, Achilles tendon injuries, and post-operative ankle care. The posterior design allows for swelling while maintaining immobilization — making it preferable to a circumferential cast in the acute phase.
What is a posterior malleolus fracture and how is it treated?
The posterior malleolus is the back portion of the tibia at the ankle joint. A posterior malleolus fracture occurs when this bony prominence is broken, often as part of a trimalleolar or bimalleolar ankle fracture. Non-displaced or minimally displaced posterior malleolus fractures involving less than 25% of the joint surface are typically treated conservatively with a posterior ankle splint (ankle soft cast) for 4–6 weeks, followed by a walking boot and physical therapy. Larger fragments or displaced fractures may require surgical fixation. Always follow your orthopedic surgeon's specific protocol.
What is the difference between a Grade II and Grade III ankle sprain?
A Grade II ankle sprain involves a partial tear of one or more ankle ligaments, causing moderate pain, swelling, bruising, and some instability. A Grade III sprain is a complete ligament rupture, resulting in significant instability, severe swelling, and inability to bear weight. Grade II sprains typically require 2–6 weeks of immobilization and rehabilitation. Grade III sprains may require 6–12 weeks and sometimes surgical evaluation. Both grades benefit from posterior splint immobilization in the acute phase to control swelling and protect the injured ligaments.
How long do I need to wear an ankle splint after a fracture or sprain?
Wearing duration depends on the injury type and severity. Severe ankle sprains typically require 1–3 weeks of splint immobilization followed by a walking boot and physical therapy. Distal fibula fractures may require 4–6 weeks. Posterior malleolus and bimalleolar or trimalleolar fractures may require 6–12 weeks or surgical fixation. Achilles tendon repairs typically require 6–8 weeks of immobilization. Always follow your orthopedic surgeon's specific protocol — premature weight-bearing is a leading cause of re-injury and delayed healing.
What size posterior ankle splint should I order?
Choose based on patient age and leg size: Child 6–12 (3" × 35" splint, 2 rolls 3" bandage, 1 roll 2" pad), Teen 13–17 (4" × 30" splint, 2 rolls 3" bandage, 1 roll 3" pad), or Adult 18+ (5" × 30" splint, 2 rolls 3" bandage, 1 roll 4" pad). If between sizes, size up for better posterior coverage from foot to mid-calf.
Explore Other Fiberglass Splint Kits
Looking for a different splint type? OrthoTape offers complete fiberglass splint kits for upper and lower extremities — all with the same pre-padded, ready-to-apply design:
| Splint Kit | Best For |
|---|---|
| Posterior Knee Splint Kit | Knee fractures, sprains & post-op care |
| Ankle Stirrup Splint Kit | Lateral ankle stability |
| Long Arm Splint Kit | Elbow fractures & dislocations |
| Volar Wrist Splint Kit | Wrist fractures & sprains |
| Volar/Dorsal Wrist Short Arm Splint Kit | Short arm immobilization |
| Sugar Tong / Reverse Sugar Tong Wrist Kit | Distal radius & Colles' fractures |
| Ulnar Gutter Splint Kit | Boxer fractures (4th/5th metacarpal) |
| Thumb Spica Splint Kit | Thumb fractures & sprains |
→ View All Fiberglass Splint Kits
OrthoTape is an authorized dealer of all products sold on this site. This product should be applied by a trained medical professional or for educational training. Always consult a doctor before use for proper diagnosis and treatment. Ankle injuries should be evaluated by a medical professional to rule out serious fractures or ligament damage. FSA/HSA eligible — check with your plan administrator. HCPCS: A4570.