13.4 Musculoskeletal Trauma, Fractures, Splinting & Dislocation Reduction

13.4 Musculoskeletal Trauma, Fractures, Splinting & Dislocation Reduction

Musculoskeletal Trauma & Fracture Classification

Musculoskeletal trauma encompasses a wide spectrum of injuries ranging from minor sprains to limb-threatening open fractures and severe joint dislocations. Under the Canadian Paramedic Competence Framework (CPCF Appendix A #29 & #30), primary care paramedics must expertly assess structural bone integrity, identify limb-threatening ischemia, and apply biomechanically sound stabilization techniques.

Fracture Classification & Pathophysiological Risks

• Open (Compound) Fractures: A fracture where bone fragments breach the skin envelope, creating a direct communication between the external environment and the medullary canal. Even a tiny puncture wound adjacent to a fracture site must be treated as an open fracture. Open fractures carry an extreme risk of osteomyelitis, deep wound sepsis, and tissue necrosis. Prehospital management focuses on controlling hemorrhage, covering exposed bone ends with sterile saline-moistened dressings, and avoiding pushing contaminated bone back beneath the subcutaneous tissue.
• Closed (Simple) Fractures: The overlying skin remains intact. However, displacement of bone fragments can compress or transect adjacent neurovascular bundles or lacerate muscular tissue, leading to occult hemorrhage and compartment syndrome.
• Displacement Patterns: Fractures are described by anatomical alignment (angulation, rotation, shortening/override, or distraction) and fragmentation (comminuted fractures involve multiple bone splinters, indicating high kinetic energy transfer).

Clinical Indicators of Fracture

Paramedics identify fractures through distinct physical findings:

• Deformity & Unnatural Mobility: False motion in an area where no anatomical joint exists.
• Bony Crepitus: A dry, grating sound or palpable vibration produced by bone ends rubbing together (never deliberately elicit crepitus, as this inflicts severe pain and shreds adjacent vessels).
• Localized Point Tenderness: Exquisite focal pain directly over the bone shaft on palpation.
• Shortening & Rotational Deformity: Classic in proximal femur or hip fractures (shortened, externally rotated lower extremity).

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Mandatory Distal Neurovascular Assessment (PMS / CMS)

Neurovascular assessment is the single most critical legal and clinical requirement in musculoskeletal management. Evaluating distal Pulse, Motor function, and Sensation (PMS / CMS) must be executed and meticulously documented at two non-negotiable junctures:

1. Immediately BEFORE any manipulation, realignment, or splint application.
2. Immediately AFTER the application of any splint, bandage, traction device, or patient movement.

+-----------------------------------------------------------------------------------------+
|                        MANDATORY PMS / CMS ASSESSMENT PROTOCOL                          |
+-----------------------------------------------------------------------------------------+
|  PULSE / CIRCULATION  | Palpate distal pulses: radial (upper limb); dorsalis pedis /    |
|                       | posterior tibial (lower limb). Check capillary refill (<2 sec), |
|                       | skin temperature, color, and distal edema.                      |
+-----------------------+-----------------------------------------------------------------+
|  MOTOR FUNCTION       | Upper extremity: ask patient to make a fist, spread fingers,   |
|                       | and extend wrist (radial, median, and ulnar nerves).            |
|                       | Lower extremity: ask patient to dorsiflex foot (peroneal nerve) |
|                       | and plantarflex foot/wiggle toes (tibial nerve).                |
+-----------------------+-----------------------------------------------------------------+
|  SENSATION            | Test light touch discrimination over specific nerve zones:      |
|                       | - Radial nerve: dorsal web space between thumb and index finger. |
|                       | - Median nerve: palmar tip of the index finger.                 |
|                       | - Ulnar nerve: palmar tip of the little finger.                 |
|                       | - Peroneal nerve: dorsal web space between 1st and 2nd toes.    |
|                       | - Tibial nerve: plantar surface of the heel or sole.            |
+-----------------------------------------------------------------------------------------+

[!CAUTION] Documentation Mandate: If a patient loses a distal pulse or develops motor/sensory deficits after splinting, and the pre-splinting PMS was never documented, the paramedic cannot prove that the intervention did not cause iatrogenic nerve transection or arterial occlusion. Document PMS findings in real time.

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Biomechanical Principles of Splinting

Proper splinting stabilizes bone ends, mitigates muscle spasms, reduces hemorrhage, prevents closed fractures from becoming open, and protects adjacent neurovascular structures from laceration.

Core Splinting Rules

1. Long-Bone Fractures: The splint must immobilize the joint above and the joint below the fracture site (e.g., a mid-shaft radius/ulna fracture mandates immobilizing both the elbow and the wrist; a tibia/fibula fracture requires immobilizing the knee and the ankle).
2. Joint Injuries / Dislocations: The splint must immobilize the bone above and the bone below the affected joint in the position found, unless neurovascular compromise dictates realignment.
3. Pad Rigid Splints: Always apply soft padding (combine pads, gauze, towels) between rigid splint structures (SAM splints, board splints) and anatomical bony prominences to prevent pressure necrosis and nerve compression.
4. Splint in Position of Function: When immobilizing hands and wrists, position the extremity in the position of function (wrist slightly extended, fingers gently curled around a rolled gauze bandage).

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Traction Splinting: Femur Fractures & Hematoma Dynamics

A fractured femur is an orthopedic emergency involving massive muscle forces. The powerful quadriceps, hamstrings, and adductor muscle groups contract violently into spasm, overriding the bone fragments, driving jagged bone ends into muscle, and ballooning the fascial compartment of the thigh. An unstable mid-shaft femur fracture can easily sequester 1,000 to 1,500 mL of blood into the thigh, precipitating severe hypovolemic shock.

Traction Splint Mechanics (Sager vs Hare Splints)

Traction splints apply mechanical longitudinal traction against the ankle hitch while providing countertraction against the ischial tuberosity or pelvis:

• Sager Splint (Unipolar): Positioned between the legs (medial) or laterally. It applies quantifiable dynamic traction: 10% of the patient's body weight per femur, up to a maximum of 15 lbs (7 kg) per injured leg.
• Hare / Thomas Splint (Bipolar): Rests against the ischial tuberosity and extends past the foot, using a ratchet windlass to draw manual traction until muscle spasm is overcome.

                  [ TRACTION SPLINT CLINICAL DECISION MATRIX ]
                                        |
                                        v
                   +------------------------------------------+
                   | Suspected Mid-Shaft Femoral Fracture?    |
                   +------------------------------------------+
                                        |
                                        v
                   +------------------------------------------+
                   | ANY CONTRAINDICATIONS PRESENT?           |
                   | 1. Pelvic fracture / ring instability    |
                   | 2. Hip fracture or femoral neck injury   |
                   | 3. Knee injury / ligamentous disruption  |
                   | 4. Lower leg (tib-fib) / ankle injury    |
                   +------------------------------------------+
                                   /          \
                                 YES           NO
                                 /              \
                                v                v
                   [ CONTRAINDICATED ]   [ TRACTION SPLINT INDICATED ]
                   (Splint with padded    (Apply Sager or Hare splint;
                    rigid board splints    pull 10% body weight up to 15 lbs;
                    or bind to good leg)   re-assess distal PMS)

Absolute Contraindications to Traction Splinting

Traction splints rely on an intact anatomical pelvis for countertraction and an intact knee, tibia, and ankle to transmit pulling force to the femur. Traction splints are STRICTLY CONTRAINDICATED if any of the following exist:

1. Pelvic Fracture: Applying traction counterpressure against the ischium/pelvis will disrupt an unstable pelvic ring, worsening internal retroperitoneal hemorrhage.
2. Hip / Femoral Neck Fracture: Traction against a proximal trochanteric or neck fracture can cause femoral head avascular necrosis.
3. Knee Injury: Traction across an unstable knee joint can tear the popliteal artery and cruciate/collateral ligaments.
4. Ipsilateral Lower Leg or Ankle Injury: The ankle hitch cannot pull against fractured tibia/fibula or ankle bones without causing catastrophic secondary displacement.

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Prehospital Dislocation Management & Realignment Protocols

Joint dislocations represent severe disruptions where articulating bone ends are completely displaced from the synovial capsule. Dislocations can stretch or compress adjacent major arteries and nerves (e.g., popliteal artery in knee dislocations; axillary nerve in shoulder dislocations; sciatic nerve in posterior hip dislocations).

Realignment Indications (The Pulseless Limb Rule)

As a universal rule, joint injuries should be splinted in the position found. However, Canadian paramedic protocols identify one critical exception:

• The Ischemic / Pulseless Extremity: If a severely angulated fracture or dislocated joint demonstrates absent distal pulses, pallor, and poor capillary refill, the paramedic must attempt gentle manual in-line traction along the long axis of the limb to restore anatomical alignment and distal perfusion.
• Procedural Rules for In-Line Traction:
  • Apply smooth, continuous, gentle manual traction in the direction of the limb's longitudinal axis.
  • Single Attempt Rule: Paramedics are permitted a maximum of ONE attempt to realign an extremity.
  • Stop Criteria: If the paramedic encounters significant mechanical resistance, or if the patient experiences an intolerable increase in pain, STOP IMMEDIATELY. Splint the limb securely in the position found, prioritize rapid transport, and request immediate ALS intercept.

Regional Dislocation Presentations

• Patella Dislocation: Typically displaces laterally. If approved under regional protocol, gentle, slow extension of the knee while applying light medial pressure over the patella frequently achieves atraumatic reduction.
• Shoulder Dislocation: Anterior dislocation is most common (>95%). The patient holds the arm in slight abduction and external rotation, with a flattened deltoid contour ('squared-off shoulder'). Splint with a sling and swathe with a small pad placed between the arm and chest wall.
• Hip Dislocation: Orthopedic emergency with high risk of femoral head avascular necrosis. Posterior dislocation (90%): limb is shortened, adducted, and internally rotated. Anterior dislocation (10%): limb is abducted and externally rotated. Splint with pillows/blankets in the position found on a vacuum mattress or stretcher.

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Cold Application, Elevation & Compartment Syndrome Awareness

• Cold Application: Cold packs wrapped in cloth (never applied directly to bare skin) reduce local blood flow, edema, and secondary enzymatic tissue injury. Cold should be applied for intervals of 15–20 minutes.
• Elevation: Elevating the injured extremity above the level of the heart facilitates venous and lymphatic drainage, minimizing post-traumatic swelling in uncomplicated closed fractures.
• The Compartment Syndrome Hazard: Compartment syndrome develops when increased tissue pressure within a closed non-yielding fascial compartment (most common in the anterior tibial compartment of the lower leg or forearm) compromises capillary perfusion.
  • The 6 P's: Pain out of proportion to injury (the earliest and most sensitive sign), Pain on passive stretch of compartment muscles, Paresthesia, Pallor, Paralysis, and Pulselessness (a very late, pre-gangrenous sign).
  • Management Warnings: If compartment syndrome is suspected, DO NOT ELEVATE the limb above heart level (elevation reduces arterial perfusion pressure, worsening ischemia) and DO NOT APPLY COLD PACKS (cold-induced vasoconstriction exacerbates microvascular hypoperfusion). Keep the limb at heart level, loosen all constricting dressings, and transport urgently for surgical fasciotomy.

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Clinical Scenario: Isolated Mid-Shaft Femur Fracture

A 26-year-old female skier crashes into a tree at high speed. Paramedics arrive to find the patient lying in the snow, screaming in agony with extreme pain localized to her left mid-thigh. Physical examination reveals obvious gross deformity, swelling, and shortening of the left mid-thigh with severe quadriceps spasm. The skin is intact.

1. Primary & Secondary Survey: The patient is alert (GCS 15). Vital signs: BP 118/76 mmHg, HR 108 bpm, RR 20/min. Physical exam confirms no pelvic tenderness, no hip pain, and no knee, lower leg, or ankle injuries bilaterally.
2. Initial Neurovascular Assessment: The left pedal pulse (dorsalis pedis) is palpable but diminished; capillary refill is 2.5 seconds. Motor exam reveals intact toe flexion/extension, and sensation is intact across all dermatomes.
3. Device Selection & Application: Recognizing an isolated, closed mid-shaft femur fracture with no contraindications, the paramedic selects a Sager traction splint. While Paramedic 1 maintains manual stabilization of the femur, Paramedic 2 applies the padded ankle hitch, positions the Sager splint along the medial thigh against the ischial ramus, and secures the thigh strap.
4. Traction Titration: The patient weighs 60 kg. Paramedic 2 extends the inner shaft until the dynamic scale displays 6 kg (13 lbs) of traction (10% of body weight). As traction is applied, the overriding bone fragments realign, the thigh contour narrows, and the patient reports an immediate, dramatic reduction in muscle spasm and pain.
5. Post-Traction Evaluation & Packaging: Elastic straps are secured around the thigh and calf to stabilize the limb against the splint. The paramedic immediately reassesses PMS: the dorsalis pedis pulse is now strong and bounding, and capillary refill improves to <2 seconds. The patient is placed on a vacuum mattress and transported comfortably to the trauma centre.

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Exam Pitfalls & Musculoskeletal Pearls

• Applying Traction Splints to Non-Femoral Fractures: Never apply a traction splint to hip fractures, pelvic fractures, knee injuries, or tibia/fibula fractures; doing so inflicts severe tissue damage and exacerbates hemorrhage.
• Omitting Post-Splinting PMS Documentation: Failing to assess and document distal Pulse, Motor, and Sensation both before and after splinting is a major clinical and regulatory violation.
• Forcing Multiple Realignments: If an ischemic, pulseless extremity fails to realign or meets resistance during the first gentle attempt at in-line traction, never make a second attempt; splint in the position found and transport immediately.
• Elevating a Limb with Suspected Compartment Syndrome: Elevating an extremity with suspected compartment syndrome reduces the hydrostatic pressure gradient driving microvascular perfusion, accelerating tissue necrosis.