Injuries to the lower extremities can be quite common, and sometimes, applying a short leg cast becomes necessary for proper healing and support. Whether it’s for a fracture, ankle conditions, or another orthopedic issue, a well-applied cast can aid in the recovery process. On the contrary, remember that a poorly applied short-leg cast may cause discomfort, prolonged healing time, or complications, leading the patient to question the doctor’s competence and care, ultimately undermining their trust in you. In this guide, I’ll walk you through the step-by-step process of applying a short leg cast.
Podiatric training for applying a short leg cast is a crucial aspect of the education and skill development for podiatrists, who specialize in the diagnosis and treatment of foot and ankle conditions. Podiatrists undergo comprehensive training to gain proficiency in casting techniques, including the application of short-leg casts. This specialized training encompasses understanding the anatomy and biomechanics of the lower extremities, as well as the indications and contraindications for casting. Podiatrists learn to assess and manage various foot and ankle injuries that may necessitate immobilization through casting.
The training involves hands-on experience in applying short-leg casts, emphasizing proper positioning, molding, and securing the cast to manage different podiatric problems. Additionally, podiatric training places a strong emphasis on patient communication and education, ensuring that they can effectively convey post-casting care instructions and address any concerns patients may have during the immobilization period. Overall, podiatric training in casting plays a vital role in enabling podiatric physicians and surgeons to provide comprehensive and effective care for a wide range of lower extremity conditions.
Materials Needed for a Short Leg Cast:
- Fiberglass or Plaster Cast Material:
- Choose between plaster and fiberglass. If fiberglass is the selected material, you’ll need 3″ and 4″ rolls.
- Stockinette:
- A tubular stockinette helps protect the skin from irritation caused by the cast material. Often a 3″ or 4″ stockinette is appropriate.
- Cast Padding – 3” or 4″ rolls:
- Cotton or synthetic padding is essential for comfort and to prevent pressure sores and skin irritation from the fiberglass.
- Scissors:
- For cutting stockinette and cast material.
- Waterproof Cast Protector (Optional):
- Helps keep the cast dry during showers.
Step 1: Prepare the Patient
Before starting the casting process, ensure the patient is comfortable and understands the process. Position them in a relaxed position. I will typically have the patient sitting upright in an exam room chair with the leg in a dependent position and the knee flexed to 90 degrees.
Step 2: Apply the 3″ or 4″ Stockinette
- Measure and Cut:
- Measure the length of the leg and cut the stockinette accordingly.
- Extend the stockinette about 4-6 inches beyond the toes and above the knee. A mistake I often observe is individuals cutting the stockinette too short, making it difficult to fold over the fiberglass at the end of the casting process.
- Slide Over Leg:
- Gently slide the stockinette over the leg, ensuring it extends beyond the toes and proximal to the knee as stated in step 1.
Step 3: Apply the Cast Padding
- Begin at the Toes:
- Start applying padding at the distal aspect of the toes and work your way up, ensuring even coverage. The cast padding will extend distally and proximally to where the fiberglass will be placed to protect the skin from irritation from the sharp edges of the fiberglass.
- Avoid Wrinkles:
- Smooth out the padding to prevent wrinkles, which could cause discomfort.
- Extra padding should be considered along bony prominences such as the 1st and 5th metatarsal heads, the medial and lateral malleoli, as well as the tibial crest.
Step 4: Apply Fiberglass Cast Material
- Dip the fiberglass and Squeeze out excess water:
- Clean, room temperature (70-75°F/21-24°C) water should be used for application. Caution should be exercised when using warmer than 75°F (24°C) water, as this will increase the exothermic reaction while the cast is curing.
- At this temperature, it will take about 4 minutes for the fiberglass to set (a cooler water temperature will increase the time to set).
- Wrap Methodically:
- Start wrapping the cast material spirally around the leg, ensuring even coverage and a snug fit.
- Overlap the previous turn one-half to two-thirds the width of the fiberglass tape. Make care to avoid excessive tightness when rolling the fiberglass.
- Often I will use a 3″ fiberglass roll for the foot section of the cast and a 4″ roll for the leg portion, as it is easier to smoothly apply a 3″ roll to the foot.
- The cast should extend from the level just proximal to the metatarsal heads of the foot to a point that is just distal to the fibular head (usually about 2-3 finger widths) – as this avoids irritation to the common peroneal nerve.
- Before rolling the last layer of fiberglass, fold the stockinette distally and proximally at the ends of the cast, as this will protect the patient’s skin from the rough edges of the fiberglass.
- Smooth Out Edges:
- Smooth out the edges to avoid any rough surfaces that could irritate the patient’s skin.
- It has been recommended that 3-4 layers of fiberglass provide a strong non-weight-bearing cast, and 5-8 layers have been suggested for a weight-bearing short-leg cast (allow 35-45 minutes before applying any load to a weight-bearing short-leg cast).
- Patients should be instructed on cast care, including the requirement of keeping the cast dry. Wet casts may result in skin maceration/irritation and increased incidence of cast break-down.
- Evaluate the patient’s neurovascular status and motor function by assessing capillary refill time of the toes, light touch sensation, and having the patient move their toes – make sure this is documented in your progress note that you evaluated for these findings!
Step 5: Ensure Proper Positioning of the Short Leg Cast
Proper positioning of the cast is dependent on the condition being treated, but there are general guidelines to follow to ensure a proper cast application.
- Make sure the ankle joint is positioned at 90 degrees if possible.
- Ensure that the cast is not too tight, especially around the forefoot/toes.
- Be certain that the cast doesn’t extend too far proximally, which could place pressure on the common peroneal nerve and potentially induce a foot drop.
Step 6: Allow the Cast to Dry
Give the cast sufficient time to dry and harden. This process may take around 15-30 minutes, depending on the type of cast material used. It’s important to make sure the patient doesn’t rest the drying cast on the exam table/chair, as this could result in indentations on the cast causing pressure points and/or skin irritation.
Conclusion:
Applying a short leg cast requires precision and care to ensure the patient’s comfort and support during the healing process. By following these steps diligently, you contribute to a smoother and more effective recovery for the individual with the injured leg. Follow this link for instructional videos pertaining to casting techniques and this link for a step-by-step tutorial to apply a slipper cast. Finally, this link will bring you to a YouTube tutorial on the short-leg casting technique.
Leland Jaffe DPM, FACFAS
Associate Professor and Dean
Podiatric Foot and Ankle Surgeon
North Chicago, Illinois
