Ankle Splinting

Anatomy and Physiology

Ankle splinting is anatomically and physiologically justified based on the complex structure of the ankle joint and the biomechanical principles of ligamentous stability. Understanding the anatomy helps explain why specific splinting approaches are used for different injuries. The ankle functions as a complex 3-part articulating structure consisting of the tibiotalar, subtalar, and inferior tibiofibular joints.[6][7] The tibiotalar joint is the primary site of dorsiflexion and plantarflexion, while the subtalar joint allows inversion-eversion movements that enable the foot to adapt to uneven ground surfaces.[8][9] The ankle is more stable in dorsiflexion and less stable in plantarflexion due to the conical shape of the talus and the tightening of ligaments in dorsiflexion.[8][10] Forces on the ankle joint can reach 4 times body weight during walking, and are primarily determined by muscle activity.

The distal tibia has 3 distinct portions: the plafond, the lateral distal tibia, and the medial malleolus. The plafond is the actual weight-bearing portion that articulates with the talus below. The distal tibia is concave and congruent with the talar body/dome. The lateral distal tibia serves as an important attachment site for 2 of the syndesmotic ligaments, the anterior-inferior tibiofibular ligament and posterior-inferior tibiofibular ligament. The anterior-inferior tibiofibular ligament attaches to the Tillaux-Chaput tubercle, and the posterior-inferior tibiofibular ligament attaches to the posterior malleolus.[11] The lateral distal tibia also contains a groove for the fibula called the incisura. The medial malleolus serves as the attachment site for the deltoid ligament, which is composed of a superficial and deep portion. In addition to this, the medial malleolus serves as a bony restraint to the medial translation of the talus within the tibiotalar joint.

The distal fibula is commonly referred to as the lateral malleolus of the ankle joint. As previously mentioned, it serves as an important attachment site for the 2 syndesmotic ligaments: the anterior-inferior and posterior-inferior tibiofibular ligaments. The distal fibula also serves as an attachment site for the anterior talofibular ligament, the posterior talofibular ligament, and the calcaneofibular ligament. Avulsion fractures are common due to the multiple ligamentous attachments to the lateral malleolus. The lateral malleolus serves to resist lateral translation of the talus within the tibiotalar joint and is important in the stability of the ankle joint.

The lateral and medial ligament complexes are key contributors to ankle joint stability. The lateral ligament complex consists of the anterior talofibular ligament, calcaneofibular ligament, and posterior talofibular ligament.[4] The anterior talofibular ligament is the most commonly injured ligament, providing 70% to 80% of anterior stability in the unloaded ankle.[10] Mechanical loading on a plantarflexed and inverted foot particularly increases its vulnerability.[4] 

The calcaneofibular ligament restrains inversion, external rotation, and dorsiflexion, while the posterior talofibular ligament limits dorsiflexion and external rotation.[12] Medially, the deltoid ligament complex provides 50% to 80% of posterior stability and consists of the posterior tibiotalar ligament, anterior tibiotalar ligament, and tibiocalcaneal ligament.[12] At the subtalar joint, the interosseous talocalcaneal ligament and cervical ligament provide critical stability.

The nervous structures surrounding the ankle joint include the saphenous, tibial, sural, superficial peroneal, and deep peroneal nerves. The saphenous nerve, the terminal branch of the femoral nerve, descends in the superficial medial leg and anterior to the medial malleolus, providing sensation to the medial aspect of the ankle with no motor function. The tibial nerve originates from the anterior division of the sacral plexus and descends posterior to the medial malleolus into the tarsal tunnel, where it provides sensation to the medial heel and motor innervation to the superficial and deep posterior compartment muscles.

The sural nerve is formed from the medial sural cutaneous nerve, a branch of the tibial nerve, and the lateral sural cutaneous nerve, a branch of the peroneal nerve; this nerve runs subcutaneously in the posterolateral leg and supplies sensation to the posterolateral distal leg without motor function. The superficial peroneal nerve, a branch of the common peroneal nerve, runs in the lateral compartment of the leg and crosses anteriorly approximately 10 cm above the lateral malleolus, providing sensation to the anterolateral leg and ankle and motor innervation to the lateral compartment muscles. The deep peroneal nerve, which branches from the common peroneal nerve, travels in the anterior compartment of the leg alongside the anterior tibial artery, supplying motor function to the anterior compartment muscles, providing minimal cutaneous sensation, primarily to the first dorsal web space.

The main vascular structures surrounding the ankle include the anterior and posterior tibial arteries. The anterior tibial artery branches off the popliteal artery and courses beneath the tibialis anterior and extensor hallucis longus tendons anterior to the ankle joint, where it continues as the dorsalis pedis artery in the foot. The posterior tibial artery, also a branch of the popliteal artery, travels with the tibial nerve in the deep posterior compartment and passes between the flexor digitorum longus and flexor hallucis longus tendons posterior to the medial malleolus, where its pulse is palpable.

Indications

Ankle splinting is indicated for acute fractures, severe sprains, and initial stabilization of ankle injuries where immobilization is needed to reduce pain, prevent further injury, and facilitate healing. In general, the ankle should be immobilized for fractures and dislocations. Rigid splinting is indicated for confirmed or suspected ankle fractures identified through the Ottawa Ankle Rules.[13] The Ottawa Ankle Rules recommend obtaining radiographs in patients with any of the following findings, with splinting indicated if a fracture is confirmed: inability to bear weight for at least 4 steps, both immediately after the injury and at the time of evaluation, point tenderness along the posterior edge or tip of the medial or lateral malleolus, or localized bony tenderness involving the talus or calcaneus.[13] Splinting may also be used for pain control and joint protection during the acute phase (up to 3 days) of any ankle injury, while awaiting a definitive diagnosis.[4]

Ankle fractures include those involving the lateral, medial, or posterior malleolus, as well as combined malleolar fractures and fractures of the talus. Dislocation of the tibiotalar joint is common with malleoli fractures, as the malleoli serve as bony restraints to keep the talus centered within the ankle mortise. After reduction of a tibiotalar dislocation or subluxation, the splint maintains joint alignment and helps prevent redislocation or recurrent subluxation until definitive treatment is provided.[14][15][16] Indications for ankle splinting include fractures of the lateral, medial, and posterior malleoli, as well as combined injury patterns such as bimalleolar and trimalleolar fractures. Splinting is also indicated for tibiotalar dislocation or subluxation, as well as ankle fracture-dislocations, to maintain joint alignment and stability until definitive management is provided.

Contraindications

Ankle splinting has few absolute contraindications, but several relative contraindications and situations requiring caution exist. The primary concerns relate to vascular compromise, compartment syndrome risk, prolonged immobilization, and high-risk patient populations. 

Absolute Contraindications

• Vascular compromise is the most critical contraindication. Blue, purple, or pale extremities indicate poor perfusion and represent a limb-threatening injury requiring immediate medical care rather than splinting alone.[17] Splinting should not delay emergent vascular evaluation and intervention in these cases.
• Suspected or evolving compartment syndrome is another critical contraindication. Compartment syndrome can result in irreversible tissue damage within 6 hours of impaired perfusion. Warning signs include pain disproportionate to the injury, pain with passive stretch, and paresthesia. In patients at risk, constrictive dressings should be removed and the limb elevated, rather than additional immobilization.[18]

Relative Contraindications

• Prolonged rigid immobilization (>10 days) should be avoided for ankle sprains, as it can lead to muscle atrophy, proprioceptive deficits, and delayed return to function.[4] A 4-week period in a lower-leg cast results in a longer time to return to work and sport compared with functional treatment. For ankle fracture-dislocations requiring delayed surgery, temporary external fixation may be preferred over splinting due to high rates of loss of reduction (50%) and skin necrosis (17.6%) with splinting alone.[5][19]
• High-risk populations require extra caution, including those who are obtunded or comatose, patients under anesthesia, very young individuals, developmentally delayed patients, and those with spasticity, all of whom have higher complication rates with immobilization.[20]

Equipment

Equipment required for ankle splinting includes stockinette, cast padding, fiberglass or plaster splinting material, water, elastic bandages, and abdominal pads for postoperative use. Cold water extends molding time, while warmer water accelerates hardening. The most commonly used plaster material is plaster of Paris, a soft, malleable substance that hardens as it dries. This material is supplied as rolls of crinoline, a stiff fabric composed of cotton, nylon, or polyester and impregnated with plaster. In postoperative immobilization, using 8 to 10 abdominal pads provides effective cushioning and accommodates swelling without significantly increasing compartment pressure.

Personnel

Effective ankle splinting requires a coordinated effort among trained healthcare professionals to ensure safe and accurate immobilization. Primary care clinicians are typically responsible for evaluating the injury, determining the indication for splinting, and selecting the appropriate technique. Nurses and orthopedic technicians play a key role in preparing materials, assisting with positioning, and applying the splint under supervision or per protocol.

All personnel must be familiar with proper padding, molding, and securing techniques to avoid complications such as pressure injury or neurovascular compromise. Additionally, team members are responsible for performing and documenting pre- and post-application neurovascular assessments. Clear communication among team members ensures efficient workflow, patient comfort, and optimal clinical outcomes.

Preparation

Three main splinting options are available for the ankle. The most stable splint is the combined stirrup (U) and posterior slab splint. This is the ideal splint for bimalleolar, trimalleolar, or ankle fracture-dislocations. The other options include a stirrup splint or a posterior slab splint. These 2 splints are generally insufficient for injuries beyond isolated medial, lateral, or posterior malleolar fractures. The posterior slab provides anteroposterior stability and prevents dorsiflexion and plantarflexion of the ankle. The stirrup wraps around the medial and lateral malleoli, providing medial-lateral stability.

The required length of plaster or fiberglass should be determined before beginning. For patient comfort, the uninjured leg may be used as a substitute to measure length. The length of the posterior slab should begin just proximal to the metatarsal heads and end below the popliteal fossa.

The posterior slab must not be too long, as this can cause skin irritation and breakdown in the popliteal fossa, especially when the knee is flexed. The stirrup portion wraps from the medial aspect of the leg, around the heel, and up the lateral aspect of the leg. The stirrup should begin around the proximal third of the tibia medially and below the fibular head laterally. Plaster needs to be at least 8 sheets thick to provide adequate strength, but no more than 12 sheets thick to avoid thermal injury. Plaster produces heat as it hardens, and care must be taken to prevent thermal injury.

Before splint application, any fracture-dislocation should be reduced. Stockinette is cut to cover the leg, leaving extra past the toes and knee. The extra stockinette is folded down over the plaster, creating padded cuffs at the ends of the splint for patient comfort.

Cast padding is used to wrap directly over the stockinette, beginning from the metatarsal heads and continuing all the way up to the tibial tubercle. Care must be taken to adequately pad the medial and lateral malleoli and the heel to prevent pressure ulcers from developing within the splint. The fiberglass or plaster splinting material for the posterior mold is wet, wrung, bonded, and placed on the plantar aspect of the foot, extending up to below the popliteal fossa.

Cast padding may be used to wrap over the splint material to secure it during application. The splinting material for the stirrup is wet, wrung, bonded, and placed starting on the medial aspect of the leg, wrapping around the plantar aspect of the heel and up the lateral aspect of the leg. Cast padding may be used to wrap over the splinting material once more, and the excess stockinette at the splint ends may be folded down to form a cuff.

An elastic bandage is used to wrap over the splint. Once wrapped with the elastic bandage, molding may begin. Molding is necessary for ankle dislocations or subluxations to provide a buttress that keeps the ankle joint reduced. Ensuring that the ankle joint is positioned in neutral dorsiflexion is also important. Splinting the ankle in a plantarflexed position results in an equinus contracture of the Achilles tendon.

Technique or Treatment

Technique for ankle splint application:

1. Measure the appropriate length of fiberglass or plaster for both the posterior slab and stirrup. The material should be 8 to 12 sheets thick, with 10 sheets as the preferred standard for each component.
2. Measure and cut the stockinette to fit the leg.
3. If a fracture-dislocation is present, perform reduction prior to splint application. The assistant should maintain the reduction throughout splinting.
4. Place the stockinette on the leg.
5. Apply cotton padding, beginning at the metatarsal heads and extending to the tibial tubercle. Use at least 2 layers with approximately 50% overlap. Ensure adequate padding over the medial and lateral malleoli and heel, avoiding wrinkles or bunching. In postoperative settings, abdominal pads may be used for additional cushioning.
6. Dip the plaster in water to thoroughly saturate it.
7. Wring the plaster and press layers together to bond them.
8. Apply the posterior slab over the padded leg, ensuring it begins at the plantar aspect of the metatarsal heads and extends to just below the popliteal fossa.
9. Apply the stirrup over the padded leg, beginning at the proximal third of the tibia medially, wrapping around the heel, and extending up the lateral aspect of the leg to just distal to the fibular head. This placement helps avoid compression of the common peroneal nerve.
10. Overwrap the plaster with a single layer of cotton padding to prevent the elastic bandage from adhering to it.
11. Fold the excess stockinette over the splint ends to create protective cuffs.
12. Loosely wrap the entire splint with an elastic bandage.
13. Apply appropriate molding while the plaster sets, ensuring the ankle remains in neutral dorsiflexion.
14. Avoid placing the splinted limb on pillows or blankets, as insulation can impair the plaster's proper hardening.
15. Once the splint has hardened, reassess the neurovascular status of the foot and toes.

Complications

Common Complications with Ankle Splinting

Pressure necrosis can begin as early as 2 hours after splint application and typically results from inadequate padding over bony prominences such as the heel and malleoli. Compartment syndrome may occur if the splint is wrapped too tightly. Thermal injury can result from excessively thick plaster or insufficient padding, while equinus contracture may develop when the ankle is immobilized in plantarflexion.

Overall, potential complications of splinting include compartment syndrome, thermal injuries, pressure sores, dermatitis, and joint stiffness.[21] Improper splint application is common. One study reported that 93% of splints were improperly placed and that 40% of patients experienced skin and soft-tissue complications.[22] Thromboembolic complications are also a concern with lower extremity immobilization, particularly in high-risk individuals.[23]

Clinical Significance

The clinical significance of ankle splinting encompasses protection from further injury, pain reduction, facilitation of healing, and prevention of chronic instability.[4][24] Ankle splinting provides effective immobilization and stabilization of the ankle joint in the acute setting of fractures or dislocations. This technique helps prevent further injury to bone, cartilage, and surrounding neurovascular structures. The noncircumferential design of splinting accommodates soft tissue swelling and allows easy removal by the clinician for evaluation of underlying wounds. Overall, splinting is a reliable method for temporizing ankle injuries until definitive treatment can be provided.[25][26][27]

After the splint is placed, patient education on proper care is essential. The splint must remain clean and dry. If it becomes wet, the plaster loses strength, and the underlying padding remains damp, increasing the risk of skin maceration and breakdown. An open wound beneath the splint increases the risk of infection. If the splint becomes wet, the patient should return to the site where it was applied. The patient should be instructed not to remove the splint, particularly when the splint is applied for a dislocation, as removal may result in redislocation or persistent joint subluxation. Most importantly, if new onset numbness or tingling develops in the foot or toes, the patient should elevate the extremity and seek reevaluation at the splinting site or the emergency department if symptoms do not resolve.

Enhancing Healthcare Team Outcomes

Acute ankle injuries require prompt immobilization to limit soft tissue damage, reduce pain, and prevent complications such as instability or neurovascular compromise. Injury patterns range from ligament sprains to fractures, with pathophysiology involving mechanical disruption of stabilizing structures and associated inflammation. Clinical presentation includes pain, swelling, limited weight bearing, and potential deformity. Evaluation requires careful history, physical examination, and neurovascular assessment, with imaging considered based on clinical findings. Appropriate splint selection and application are essential for maintaining alignment and protecting injured tissues while awaiting definitive management.

Interprofessional collaboration improves patient-centered outcomes through coordinated assessment, treatment, and follow-up. Primary care clinicians lead diagnosis, determine the need for imaging or referral, and guide management decisions. Nurses and orthopedic technicians assist with splint application, positioning, and monitoring for complications. Pharmacists support safe and effective pain management. Rehabilitation specialists contribute to recovery planning. Clear communication, shared decision making, and timely referral reduce risk, enhance safety, and promote optimal functional recovery.