Managing Unstable Musculoskeletal Injuries

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  • Review the anatomy of the musculoskeletal system
  • Describe the physics of fractures
  • Review consequences of improper splinting
  • Discuss management of musculoskeletal injuries

Musculoskeletal injuries are one of the most common injuries EMS providers manage. Nearly 85% of all patients suffering blunt force trauma experience some sort of musculoskeletal injury.1 In addition, musculoskeletal injuries affect one in four Americans annually, and their symptoms are the number two reason for physician visits.2 EMS providers encounter musculoskeletal injuries in a wide variety of incidents including motor vehicle collisions, sporting accidents, falls and physical assaults.

Musculoskeletal injuries are a significant source of pain,1 and their proper management not only reduces this pain but also reduces further injury to surrounding tissues and prevents long-term damage.

Isolated musculoskeletal injuries, as well as those occurring during multi-system trauma, all deserve the same proper management to provide the patient optimal care.

Musculoskeletal System

The musculoskeletal system is a living organ system comprised of connective tissues, ligaments, tendons, muscles and bones that work together to provide the body with stability, form, support, protection and the ability to move. Bones are living organs that serve many additional functions. They are a major storage area for calcium and phosphorus and the bone marrow produces red blood cells. When the body has a surplus of calcium and phosphorus, it has the ability to deposit the surplus of these minerals in the bones. Conversely, when the body experiences a shortage of either mineral it will pull the mineral from the bone.

There are 206 bones in the adult human body. These bones are broken down into five bone types: long bones (e.g., femur), short bones (e.g., patella), flat bones (e.g., scapula), irregular bones (e.g., vertebrae), and sesamoid bones. Sesamoid bones are bones that have a tendon embedded in them, and include the patella, the first metacarpals, the first metatarsals and in the great toe.

All bones have the same essential structures (Figure 1). The outer lining of each bone, termed the periosteum, is a fibrous skin-like layer of connective tissue that can be torn. The periosteum is also heavily innervated with nociceptor nerve endings, making injury to the periosteum highly painful. Directly beneath this is the compact bone, which makes up the majority of the bone mass and gives it its white and smooth appearance, and also provides the bone with its strength and ability to provide support and structure. The spongy bone, also called the trabecular bone, is a porous structure that allows nerves and blood vessels to pass through it. Bone marrow can also be found in the spongy bone. At the center of each bone is bone marrow, which is highly vascularized with arteries and veins. Yellow bone marrow, often found at the center of long bones, is primarily fatty cells. Red bone marrow is found in the flat bones and is responsible for the development of red blood cells, platelets and most white blood cells.

When a bone is fractured the blood vessels and nerves in all layers of the bone are interrupted. Additionally, yellow (fatty) bone marrow, if also broken loose, can enter into a bloodstream, and become an embolism.

Physics of Fractures

Not all bones are created alike or have identical strength. As a general rule, small bones such as the metacarpals require a smaller amount of force to sustain injury in compared to large bones such as the femur or pelvis. An injury to the musculoskeletal system proximal to the ankle or wrist is an indication that a significant force impacted the body.1 The larger the injured bone, and the greater the force, the more suspicion EMS providers need to have for other injuries. Of particular importance, simultaneous limb injuries above and below the diaphragm significantly increase the likelihood of internal torso injury.1

Conditions such as osteoporosis, calcium deficiencies, myeloma and malnourishment result in decreased bone strength. As a result patients with these conditions can experience bone fractures when lesser forces are involved.

Fracturing a bone interrupts the integrity of a living organ. Patients experience pain any time an organ is injured—including the bones. Bone fractures also result in bleeding for two reasons. First, they can tear or sever vessels near the bone. Second, when the bone marrow tears during a fracture it can bleed into the body’s cavities, rather than delivering red blood cells directly into the bloodstream. In particular, unstable pelvis fractures and open femur fractures have an extremely high risk of major bleeding that is significant enough to cause class III shock.1 Table I summarizes the estimated blood loss in various bone injuries while Table II highlights vital sign changes seen in the different hemorrhagic shock classes.

There are a few other complications that can occur during bone fracture. When blood vessels are interrupted, pieces of bone, fat and other tissues can enter the bloodstream causing an embolism. Fat is the most common foreign debris entering the bloodstream during fracture, particularly when fatty marrow is broken free from the bone marrow during the injury. Injuries resulting from crushing forces can cause bone fracture and also injure large amounts of muscle mass. Injured muscles release myoglobin, which when enough muscle mass is injured can result in rhabdomyalosis.

Consequences of Improper Splinting

Remember it is important to limit on-scene time, particularly in major trauma. However, interventions such as splinting should still be performed while en route to the hospital to improve patient comfort and reduce soft tissue injury.

The American College of Surgeons Committee on Trauma believes musculoskeletal injuries cannot be ignored for treatment at a later time.1 Foregoing splint application causes patients to experience increased pain because the loose bone ends continue to move freely against soft tissues, which increases the damage to these tissues. This can cause increased blood loss, damage to the neurovascular bundles and trigger a fatty embolism.3 Improperly applied splints tend to either be too large or too small, too loose or too tight. Applying too large of a splint, or one that is not adequately secured, provides ineffective splinting and has the same effect as no splint at all and the bone ends continue to move relatively freely as no support or protection is provided. Splints that are too small or too tight can cause ischemia distal to the splint which increases the patient’s pain and can cause a buildup of acids in ischemic tissues.


Evaluating a musculoskeletal injury is important. Any life-threatening hemorrhage present should have been managed in a primary assessment; severe hemorrhages are best controlled with well-aimed direct pressure and take priority over injury stabilization. Begin assessing a musculoskeletal injury visually, looking for debris such as dirt, stick fragments, broken glass or stones that may have become embedded in the skin at the time of impact. Brush off these objects prior to applying a splint so they aren’t ground deeper into the body from the splint’s compressive effects. During this time also remove any clothing or jewelry on the injured extremity; folds and seams in clothing can rub against the skin if left inside of a splint, causing tissue breakdown and increasing opportunities for infection. Take note of any angulation or deformity. Table III identifies common deformities seen in joint injuries.

Next palpate the injury site for crepitus. Crepitus is the sensation felt when bone ends grind together. Many clinicians do avoid palpating obviously fractured bones to avoid additional discomfort, and only touch the limb to realign it and apply a splint. Document any swelling that is observed as well. Rapidly progressing swelling is typically associated with capillary or small vessel bleeding while swelling that develops over the course of several hours is generally caused by the build-up of edema. Also evaluate the portion of the extremity distal from the injury for circulation, sensation and motion. A temperature difference or weaker pulse in comparison to the non-injured extremity suggests vascular compromise, while loss of sensation or muted pain sensation suggests nerve injury. Decreased motion may suggest nerve injury, but is also common with angulation and deformity as ligaments and muscles are already stretched around the injury. Be sure to document any deficits that are present prior to splint application.


When a musculoskeletal injury is identified, the treatment goal is to restore and maintain bone and joint alignment to control pain, reduce motion, prevent further soft tissue injury and promote the tamponade effect of muscles on any injured vessels. This is best achieved by realigning extremities into an anatomical position as early as possible, then applying a properly sized splint to maintain the alignment and protect the site from further injury. These management goals can only be met by performing an accurate injury assessment.


Traditionally, EMS classrooms teach students to splint musculoskeletal injuries in the position found unless there is poor distal circulation, in which case there is one attempt to reposition the extremity. However, splinting an angulated extremity is technically difficult and it is well known that the longer deformity persists, the more difficult it becomes to realign the extremity because muscles begin to spasm. Additionally, while splint application does reduce pain, the most significant pain relief often results from the realignment of fractured bone ends, as well as the administration of analgesia. The goal of prehospital musculoskeletal injury straightening is not to perfectly realign the bone ends. Rather, it is to significantly reduce pain, protect distal circulation and nerve function, and allow splinting to become easier and more effective. Straightening an angulated or long bone is fairly straight forward. Follow these simple steps:

  • Check and document distal CSM
  • Stabilize above and below the injury site
  • Apply gentle traction to the distal extremity in the direction it is facing
  • While maintaining traction, move the distal extremity back towards its anatomical position
  • STOP repositioning when there is resistance, significant increase in pain, or when the anatomical position is reached
  • Re-check and document CSM
  • Apply an effective splint.

Joint injuries are more complicated. It is nearly impossible in the prehospital setting to distinguish between simple dislocations and those complicated by fractures as well. Thus, injured joints with intact distal CSM are best protected and splinted in the position found, unless their position prohibits safe transport or is not possible to splint. When there is impaired CSM, or when the joint cannot be safely stabilized in its present position, consider repositioning the joint toward its midrange anatomical position. Repositioning joints follows these simple steps:

  • Check and document CSM
  • Stabilize above and below the injured joint
  • Apply traction along the distal long bone in the direction it is pointing
  • While maintaining traction move the joint toward its midrange anatomical position
  • STOP repositioning if there is resistance, significant increase in pain, when the midrange position is reached, or when CSM returns
  • Recheck and document CSM
  • Apply an effective splint.

Remember, when repositioning a joint, the goal is not reducing any dislocation, it is to return CSM and to have the extremity in a position where the joint can be effectively stabilized. Circulation through a joint is maximized when joints are in a neutral position. In the lower extremities, knees are optimized with a roughly 10 degree bend, ankles at 90 degrees and the hips straight. In the upper extremities, elbows should have a 90 degree bend, shoulders directed parallel to the chest, wrists straight and the fingers should have a natural bend, as if they were holding a ball.

Pain management for patients with traumatic injuries, particularly musculoskeletal injuries, is important. While realignment is uncomfortable for the patient, it often is associated with an immediate significant reduction in pain and decrease in anxiety. EMTs without rapid access to ALS providers capable of administering analgesia should not delay realignment. However, when capable, analgesia should be administered prior to realigning an extremity.

Unfortunately, pediatric patients with traumatic injuries have been found to be undertreated with analgesia in the prehospital environment even though they often receive analgesia in the emergency department.4 This study found that only 21.9% of injured pediatric patients (and 26.3% of adult patients) received prehospital analgesia even though 79.4% of the patients ultimately received analgesics. Interestingly, the same study also found that among patients who did receive prehospital analgesia, additional emergency department doses were often administered after the drug’s half-life had passed. The authors concluded that prehospital analgesia is important and underutilized.4 This research is also supported by a study released at the 2012 NAEMSP assembly, which identifies that paramedics see too many barriers toward administering analgesia to pediatric patients and encourages a cultural shift in promotion toward pediatric analgesia.5 Introducing intra-nasal atomized fentanyl has been shown to decrease paramedic discomfort with pediatric analgesia and leads to increased analgesic administration.6

Both morphine and fentanyl are accepted and commonly utilized for prehospital analgesia. Both drugs provide similar degrees of pain relief, though fentanyl requires a higher comparative dose than morphine.7 Fentanyl has been shown to be relatively free of side effects, and not cause hypotension, respiratory depression, hypoxemia or sedation when administered with an initial dose of 1–2 micrograms per kilogram.8

Drs. Caroline Lee and Keith Porter published in the Journal of Emergency Medicine3 that in some cases, such as with entrapped patients, mangled extremities and complicated open fractures, a peripheral nerve block may be the analgesic of choice during prehospital care. They did acknowledge that this skill requires additional training and close monitoring; however, particularly for programs with extended transport times, it may be worth discussing introducing this safe and proven practice with a medical director.3

Whenever patients present with angulated or deformed musculoskeletal injuries, consider the administration of narcotic analgesia early during their patient care. While the routine administration of benzodiazepines for musculoskeletal injury care is not recommended, advanced life support providers can consider sedation when there is a need to straighten an extremely angulated fracture or dislocation.1 Sedation during extremity manipulation can provide the patient amnesia as some benzodiazepines, such as midazolam, have amnesic properties. Benzodiazepines also help to relax spasming muscles so that straightening the extremity is easier.

Splint Construction

Applying an effective splint is an essential component of musculoskeletal injury management. Effective splints follow the principle of complete, compact and comfortable. These three Cs are taught by Wilderness Medical Associates to first responders who will not have access to any pre-made splints when they need to manage patients with musculoskeletal injuries. Following the 3 Cs, splints can be made of nearly any materials available, and can effectively immobilize an injury as well as any commercially made device.

Complete splints are properly sized to immobilize the joints above and below fractured long bones and the long bone above and below injured joints. Most organizations accept the joint above and below an injured long bone require immobilization. However, exactly what determines complete joint-injury immobilization is debated in some circles. One position states that splinting the long bone above and below the injured joint is acceptable and provides adequate stabilization. This position states it is reasonable, for example, when an elbow is injured, to allow wrist movement. However, the other position to this argument is not only do the long bones above and below the injured joint require immobilization, but that the next closest joints require immobilization as well. Thus this position would state when an elbow is injured, the wrist and shoulder require immobilization as well. The rationale for this position is that the associated joints (wrist/shoulder to the elbow) share a muscle with the injured joint, and moving those muscles would allow some joint movement. To add evidence to this ambiguity, the NREMT EMT testing station requires that injured joint management requires both long bones to be immobilized, and then to “secure the entire injured extremity.” It does not actually specify whether this means the additional joints do or do not require immobilization.

When sizing splints, there are a variety of preformed splints available. Cardboard splints are one option; however, they are designed for standard arm/leg sizes, and although they can be cut to shape around joints, they cannot be made wider when an extremity’s width is greater than the splint. Rigid padded board splints may be reasonable in some situations, but they require additional padding and support to ensure that the extremity is properly splinted. In addition, in the authors’ experience neither cardboard splints nor padded board splints can consistently and reliably provide effective joint immobilization. Vacuum splints have the potential to provide some of the best support and protection compared to other splints; use caution though around broken glass and other sharp objects, as the splint loses its rigidity and strength when punctured. Complete splints also can be secured above and below the injury, and will not fall apart from the vibrations during transport.

Compact splints are appropriately sized, shaped and proportioned to the part of the body being immobilized. They are not excessively bulky. Bulky splints have the potential to press down on the injury, increasing pain. Splints that are not compact may be too large and not effectively stabilize the injured bones, or may extend too far beyond the end of the extremity, causing difficulty when trying to move and/or transport the patient. Preformed commercial splints offer the potential to be compact for some injuries, but are designed with the assumption that an injury is realigned prior to application. When an injury cannot be realigned, these preformed splints may be too cumbersome to effectively utilize. The SAM Splint is one example of a flexible and adjustable splint that is rigid yet can be conformed to nearly any injury.

Comfortable splints are well padded. Most commercial splints require some additional padding be applied. When beginning to apply padding, visualize the size difference between the splint you will use and the extremity. Approximate where there may be voids between the extremity and the splint—this is where extra padding is needed. Cover any open wounds with a sterile dressing. Following this, use bulky gauze, towels or any other soft cloth available to pad around the injury, as well as the entire length of the extremity being splinted. Pay particular attention to add additional padding to bony prominences such as the medial and lateral malleolus of the elbow and ankle. Circumferential cotton padding can be applied but must be loose to minimize the potential for compartment syndrome.9

Femur Fractures

Femur fractures are a unique injury associated with significant blunt forces. The presence of a femur fracture raises the index of suspicion for internal injuries. Femur fractures can be described as distal, mid-shaft and proximal fractures. Distal and proximal femur fractures may be difficult to distinguish from knee and hip injuries respectively and are often best treated without traction. One reason for this is that femur fractures are often associated with femur neck fracture as well as posterior hip dislocations.1 Mid-shaft femur fractures, whether open or closed, are treated by the application of traction splints.

Applying a traction splint is particularly complicated because they are designed for patients with an isolated injury, yet the mechanisms for injuring the femur are more consistent with multi-systems trauma; it takes 250 newtons to fracture the femur.10 One study that evaluated traction splint utilization during multi-system trauma identified a 38% complication rate, which was defined as simultaneous injuries to the pelvis, knee, patella or tibia/fibula.10 The authors of this acknowledged that paramedics applying the traction splints placed them on patients with femur fractures in 97.5% of cases, but urged caution in their utilization due to the high complication rate. They supported this caution by also identifying that traction splint application results in an average additional 5–6 minutes on scene and requires two providers for proper application.10

Regardless of the device used, the theory of the traction splint remains the same. Controlled forces are applied proximally in a ring-like fashion against the buttocks, perineum, groin and hip, and also distally through the ankle. Used appropriately, the splint separates the femur’s fractured bone ends to limit soft tissue injury, control bleeding and reduce pain, and can return the extremity to a nearly reduced position.3 Excessive amounts of traction can damage the skin and also cause neurovascular compromise.

There are a variety of traction splints available today including the Hare Traction Splint, the Sager Splint, the Donway Traction Splint and the Trac-3 Splint. Each of these devices offers some benefits and drawbacks in comparison to the other. For example, a Sager Splint can potentially apply traction to both legs, while a single Hare Traction cannot. The Hare adjusts to patient sizes by sliding into length which permits its use at any length. The Sager is designed to be used for patients in the 5th to 99th percentile, but is set to adjust in 1-inch increments. It is important to practice utilizing these splints regularly. Improper application may mean failing to actually put traction on a fractured femur.

Also, it is important to be prepared to explain the splint to emergency department staff because they may not be familiar with the traction splint’s goal and inadvertently remove the splint, causing increased pain and discomfort for the patient.

Fracture Packs

Many EMS systems regularly employ the use of fracture-packs filled with pre-formed splints. The intent of these pre-formed splints is to speed the immobilization process. Proper utilization of these splints requires joints be placed into their mid-line position, which does support the need for prehospital realignment of musculoskeletal injuries. The downside to utilizing these splints is the assumption that they automatically provide adequate padding and joint immobilization. Do not fall into this trap. When selecting a pre-formed splint ensure that it is appropriately sized for the patient. Also, add supplemental padding into the splint. The limited foam and/or cloth padding provided on the splint is rarely enough to prevent the splint from shifting on the injured extremity, nor is it enough to prevent the limb from movement while inside of the splint. If a splint is too large, either cut it or select a smaller splint. Do not utilize an improperly sized splint.


Musculoskeletal injuries are commonly treated by prehospital providers. The American College of Surgeons Committee on Trauma supports the early management of musculoskeletal injuries including analgesia, repositioning and splint application. Even when patients have multiple injuries, it is important to apply splints to reduce internal bleeding, pain and the potential for fatty embolisms. Strongly consider administering analgesia to any patient with a suspected musculoskeletal injury; the majority of these patients go on to receive analgesia in the hospital while their time in the ambulance is likely the most uncomfortable period of their care. When applying a splint, remember that effective splints are complete, compact and comfortable.


1. American College of Surgeons Committee on Trauma, Advanced Trauma Life Support of Doctors, 8th ed. Chicago, IL, 2008.
2. AAOS American Academy of Orothopaedic Surgeons. Orthopaedic Fast Facts.
3. Lee C, Porter K M. Prehospital management of lower limb fractures. J Emerg Med 22:660–663, 2005.
4. Swor DO, Robert et al, Prehospital Pain Management in Children Suffering Traumatic Injury, Prehosp Emerg Care 9:40–43, 2005.
5. Williams DM, et al. Barriers and Enablers to Prehospital Analgesia for Pediatric Patients. Prehosp Emerg Care 16: 160, Jan–Mar 2012.
6. O’Donnell D, Schafer L. Does the addition of the mucosal atomizer device increase fentanyl administration in prehospital pediatric patients. Prehosp Emerg Care 16:160, Jan–Mar, 2012.
7. Fleischman MD, Ross J, et al, Effectiveness and safety of fentanyl compared with morphine for out-of-hospital analgesia. Prehosp Emerg Care 14:167–75, 2010.
8. Kanowitz MD, Arthur, et al, Safety and effectiveness of fentanyl administration for prehospital pain management, Prehosp Emerg Care 10: 1–7, 2006.
9. Do, T, Splinting,
10. Wood BS, EMT-P, Stephen, Mark Vrahas, MD, Suzanne K. Wedel, MD, Femur fracture immobilization with traction splints in multisystem trauma patients. Prehosp Emerg Care 7: 241–243, 2003.

Kevin T. Collopy, BA, FP-C, CCEMT-P, NREMT-P, WEMT, is an educator, e-learning content developer and author of numerous articles and textbook chapters. He is also the performance improvement coordinator for Vitalink/Airlink in Wilmington, NC, and a lead instructor for Wilderness Medical Associates. Contact him at

Sean M. Kivlehan, MD, MPH, NREMT-P, is an emergency medicine resident at the University of California San Francisco and a former New York City paramedic for 10 years. Contact him at

Scott R. Snyder, BS, NREMT-P, is the EMT Program Director for the San Francisco Paramedic Association in San Francisco, CA. Scott has worked on numerous publications as an editor, contributing author and author, and enjoys presenting on both clinical and EMS educator topics. Contact him at