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Was your life was just interrupted by a foot or ankle fracture?
Are you wondering what the next several weeks are going to be like?
Are you now leaving the Emergency room with a splint and a pair of crutches?
As many of my patients sustain fractures, I thought it would be helpful to explain what using a fracture cast is all about. I will, of courses, concentrate on the casts for foot and ankle fractures.
What are the benefits and risks of fracture cast and splint ?
While fracture casts and splints allow for stabilization of injured body part, pain reduction, and healing rate increase, they can also cause injury when applied and used incorrectly. Long term use of casts and splints can result in stiffness and atrophy. Let’s learn all about it to help you make and educated decision on how to get the best outcome after sustaining a fracture!
Once you have been evaluated by a doctor, a decision will have to be made on how the fracture is going to be treated. Sometimes, when the fracture is significantly displaced or bone is impinging or pocking through the skin, surgery is required to restore proper alignment. After surgery, splints of various types can be used as they allow for variable swelling, which is expected after injury and surgery.
Other times, when the fracture is stable, well aligned, or if the patient is too sick for surgery otherwise, casts are used to stabilize the broken fragments and to allow for healing.
Can a fracture heal without a cast?
The short answer is Yes! However, it may not provide for optimal healing. This is particularly true if the fracture is misaligned, which may result in deformity and limb shortening.
What are cast alternatives?
Fracture boots, splints, knee scooters, wheelchair use, etc provide a degree of stability but frequently lack comprehensive stability allowed by the cast. These modalities also tend to be heavier than casts. Their benefit is that they are removable and thus allow for breaks, showering and, of course, lack complications associated with cast formation.
Bone stabilization with a cast is not a new phenomenon. In fact, surgery for broken bones was only started in late 1700s and was refined thereafter. Death rate and limb loss after surgery was significant in those early times because antibiotics and sterile technique was not discovered/invented yet. Thus, most fractures were treated with various wooden, metal, or composite material splints.
How does a cast support a broken bone?
In our modern times, cast immobilization and stabilization is frequently used after surgery to support internal fixation or instead of surgery to reinforce and sustain fragile bone alignment. Stability is required for broken bone ends to communicate via chemical signals to start bridge building process. This is called bone callus formation. This stability also provides for adequate blood supply which brings in the repair molecules, oxygen and nutrients to the healing site.
Can broken bone move in a cast?
Once the swelling has subsided and sutures, likely, have been removed, casting can be initiated for a period of time expected for a particular bone fragment to heal. For lower extremities, this period generally lasts from 6-10 weeks, depending on the type of surgery, injury and the type of stabilizing internal hardware used. Cast is usually changed on regular bases to ensure that it does not become too loose or too constrictive. If properly designed, a broken bone should not move in a cast. However, it is important to remember that the cast only stabilized the bone in one plane and, at least in lower extremities, only prevents bending forces. So, if you apply a loading force or twisting force, the bone may move.
What about stiffness after the cast is removed?
Prolonged immobilization will result in some degree of stiffness due to tissue remodeling. This occurs primarily due to muscle belly atrophy (length and width decrease) and tendon shortening which pulls the bone/joint into a contracted position.
Elasticity of tissue is decreases and adhesions develop. Then fibrosis, hardening of tissues, ensues (trigger points and scar tissue) with prolonged immobilization. The process starts as early as 2 weeks after the onset of splinting/casting. Research shows that these changes are reversible in early stages but may become permanent with longer immobilization periods. These changes may not always result in disability or compromise function. Permanent and extensive changes may result in need for surgical deformity correction.
This could be of help if such a contracture is the desired outcome (trying to achieve tendon shortening after a tear/over-lengthening) or could be detrimental (applying the cast plantarflexed resulting in ankle equines deformity).
Whenever possible, passive open kinetic chain stretching of at least 30 minutes per day should be employed to reduce the contracture risk. It is important to remember that one must stretch the contracting muscle and its antagonist during the rehabilitation process. In the case of the Achilles tendon and gastrocnemius muscle, the antagonist muscle is tibialis anterior. This is essential when using prolonged splinting. Passive stretching should prevent muscle shortening and will promote joint range of motion preservation and cartilage health.
Can I walk on the cast?
As healing progresses, your doctor may recommend that you start walking on your cast. Usually a rubber rocker is applied to the bottom of the cast or a cast shoe is supplied. This allows for rocking through the midfoot area during gait. Of course, this is not normal walking but it’s better than not using the limb at all. Adding a rocker allows for rolling through the motion on that limb instead of constantly having to march on the cast because the bottom of a standard cast is flat. Walking with a flat cast would force you to constantly pick up your knee to go through gait cycle.
What are risks and complications of cast and splint use?
The use of casts and splints is not without risks and these must be understood and agreed upon before using them. It is essential to understand risks associated with all three phases of cast use: application, wear, and removal.
Different casting materials pose different risks as well, thus proper material selection for a specific patient is important.
Who is at risk?
Risk is greatest in those patients who are unable to perceive the discomfort of the cast or unable to communicate the discomfort of the cast.
This results in cast induced trauma.
1. Patients who are unable to communicate because of speech impediment, being in a coma or comatose state, those who are intoxicated, or suffering from dementia
2. Those with vision problems
3. Patients who have no feeling in the limbs like patients with spinal cord injury or those who had an anesthetic limb block prior to surgery. Patients with decreased sensation because of neuropathy (diabetic, alcoholic, viral, etc.) are at risk as well.
4. Very young patients who are not able to fully express themselves like babies and toddlers
5. Developmentally delayed individuals
6. Patients with spastic disorders are vulnerable to development of intra-cast pressure sores due to increased muscle tone and friction
7. Individuals with already poor bone health (osteoporosis, osteopenia) will experience worsening of these conditions due to prolonged immobilization.
High risk patients may be better served by application of a rigid posterior or anterior lower limb splint. These are not applied all around the limb, which allows for swelling, and also provide for excess needed to examine the injured site.
Of note, using too much padding will result in poor limb to cast support interface and may result in limb moving inside of the cast. This motion will slow down bone healing and promote formation of friction wounds. Bony prominences can be protected by extra layers of padding or by utilizing cast windows, cut outs in the cast. Windowing of the cast or cut outs are particularly helpful for wound exams and dressing changes.
What are two common cast/splint materials used and what are the risks associated with them?
Plaster of Paris
Plaster of Paris (Plaster infused cloth) has been in use since late 1800s. It is cheap and easily moldable. Its pliability affords lesser risk of pressure sore development and smaller chance of excessive compression. The downside is the need to keep the cast away from water and need to use multiple layers of material, which makes the cast relatively heavy.
Plaster comes in dry sheets which must be exposed to water to start the “setting” process. Once exposed to water, a chemical reaction starts which produces quiet a lot of heat. Increased layers of plaster result in more heat production. The faster the plaster sets, the more heat is produced as well. The speed can be increased by dipping the material into hot water. This may result in skin burn to the patient!
Fiberglass
This is a very strong water proof material. However, it must be padded and padding tends not to be water proof (think cotton rolls). Its benefits include being lighter than plaster, creating less heat when applied, and not interfering with visualizing bone healing when an x ray is taken. Fiberglass is more difficult to mold partly because it sets faster and partly because it is more rigid.
So what can go wrong?
1. Cast that is applied to tight may result in compartment syndrome
2. Pressure sore and friction sores may develop
3. Patients who do not have cast removed soon after getting water inside are at great risk of skin fragility and wound/infections
4. Osteoporosis and Osteopenia (fragile bones) may become worse
5. Joints may become stiff and contracted
6. cartilage and ligaments may weaken
7. Pressure on nerves and blood vessels may result in neuropathy (think foot drop with injury to peroneal nerve).
8. Skin cuts at edges of the cast due to insufficient padding
9. Skin pressure at edges of the cast that extends too far
10. Cast material may develop folds if the limb moves during application resulting in hard folds and again pressure points.
11. Blood clots may form in immobilized limbs.
12. Cast saw thermal and pressure injury during cast removal process
Cast use requires a partnership and clear communication of risks and benefits between the doctor and the patient to ensure the best possible outcome and to reduce risk of complications.
Doctors must do their best to use ensure proper application, mitigate risks and employ careful removal technique. On the other hand, patients must exercise good judgement in light of knowledge of risks and complications discussed to achieve optimal complication free healing.
Without clear two-way communication, success is left to chance.
Remember, prevention of injury is the best medicine.
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Until next time….happy healing!
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Halanski M, Noonan KJ. Cast and splint immobilization: complications. J Am Acad Orthop Surg. 2008 Jan;16(1):30-40. Review
Born CT, Gil JA, Goodman AD. Joint Contractures Resulting From Prolonged Immobilization: Etiology, Prevention, and Management. J Am Acad Orthop Surg. 2017 Feb;25(2):110-116
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My name is Dr. Marat Kazak. I have been working as a professional Podiatrist serving Northern California community since 2014. My extensive medical and surgical knowledge combined with an ongoing curiosity to learn about the latest trends define my success in the field of foot, ankle and leg medical and surgical care.
The goal of this website is to give you the tools to better care for yourself, to dispel medical myths, and to empower you with information to save time and money! If you are looking for an answer on foot and ankle pain, this is the place to find it. If you do not see your topic of interest covered, please send me a message and I will do my best to discuss it ng. thoroughly in my next upcoming post.
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