7.1 Fractures, Dislocations & Cast Management

7.1 Fractures, Dislocations & Cast Management

Core Orthopedic Rule: Never primarily close an open fracture wound in the casualty department or emergency room. Every open fracture, regardless of puncture size, constitutes a contaminated surgical emergency requiring immediate sterile dressing, intravenous antibiotic prophylaxis, tetanus immunization, splint stabilization, and formal surgical irrigation and debridement in the operating theater within 6 hours of injury.

Musculoskeletal trauma represents one of the most common presentations in Kenyan county referral hospitals, sub-county hospitals, and emergency departments, driven heavily by road traffic incidents (motorcycle/boda-boda collisions, vehicular crashes) and industrial or agricultural injuries. The primary objective for the Clinical Officer is rapid clinical stabilization, systematic skeletal and neurovascular assessment, prevention of wound sepsis, and anatomically sound immobilization.

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1. Systematic Fracture Description & Biomechanical Principles

Accurate, standardized communication of fracture morphology ensures appropriate triage, splinting, and definitive surgical planning. A complete fracture description includes five mandatory components:

1. Bone & Anatomical Location: Identify the specific bone (e.g., right femur) and exact anatomical region: proximal, middle, or distal third (diaphyseal), metaphysis, epiphysis, or intra-articular extension.
2. Fracture Pattern / Geometry:
   • Transverse: Perpendicular to the long axis; caused by direct perpendicular bending forces.
   • Oblique: Angled across the bone axis (> 30°); caused by combined axial compression and bending.
   • Spiral: Twisting helical pattern; caused by rotational/torsional torque.
   • Comminuted / Multifragmentary: More than two distinct fragments; indicates high-energy trauma.
   • Segmental: Two separate fracture lines isolating a free intercalary segment of bone.
   • Incomplete (Pediatric): Torus (buckle) fracture from axial compression; Greenstick fracture with cortex disruption on the tension side and plastic deformation on the compression side.
3. Displacement Characteristics:
   • Translation (Shift): Percentage or millimeter displacement of the distal fragment relative to the proximal fragment in the coronal or sagittal plane (e.g., 50% lateral translation).
   • Angulation (Tilt): Direction of the apex of the angle formed by the fragments, or the directional tilt of the distal fragment (e.g., 15° apex medial / varus angulation).
   • Shortening (Bayonet apposition / Overlap): Longitudinal overlap measured in centimeters.
   • Rotation: Internal or external rotation of the distal limb segment relative to the proximal skeleton.
4. Skin Integrity (Closed vs. Open): Presence of any communication between the fracture hematoma and the external environment.
5. Neurovascular & Soft Tissue Status: Distal pulse presence, capillary refill time (< 2 seconds), and individual peripheral nerve motor and sensory function.

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2. Gustilo-Anderson Classification & Emergency Open Fracture Protocol

Open fractures are orthopedic emergencies due to bacterial contamination and devitalized soft tissue envelopes. The Gustilo-Anderson classification guides prognosis, antimicrobial selection, and surgical strategy.

                                [SUSPECTED OPEN FRACTURE]
                                           │
              ┌────────────────────────────┴────────────────────────────┐
              ▼                                                         ▼
    [Emergency Room Care]                                     [Operating Theater]
- Primary Survey (ATLS: ABCDE)                              - Theater within 6 hours
- Gross contamination removal                               - Extensive pulsatile irrigation:
- Photography & sterile saline soak                           * Grade I: 3 Liters saline
- Do NOT probe or close primarily                             * Grade II: 6 Liters saline
- Tetanus toxoid 0.5 mL + TIG 250 IU                          * Grade III: 9 Liters saline
- Immediate IV Antibiotics:                                 - Radical debridement of dead tissue
    * Gr I/II: Ceftriaxone 2 g IV                             ('Four Cs' of muscle viability)
    * Gr III: Ceftriaxone + Gentamicin 5 mg/kg              - Skeletal stabilization:
    * Soil/Farm: Add Benzylpenicillin 2-4 MU                  External fixator vs unreamed nail
- Splint limb in anatomical alignment                       - Wound left open / NPWT applied

Operative Debridement: The 'Four Cs' of Muscle Viability

In theater, the clinical team systematically excises all devitalized tissue. Skeletal muscle viability is assessed using the classic Four Cs:

1. Color: Healthy muscle is bright beefy red; non-viable muscle is pale, brown, dark gray, or black.
2. Consistency: Viable muscle is firm, resilient, and elastic; non-viable muscle is friable, soft, and shreds easily when handled.
3. Contractility: Viable muscle briskly twitches when stimulated by electrocautery or pinched with toothed forceps; non-viable muscle shows no response.
4. Capacity to Bleed: Viable muscle exhibits bright, punctate capillary bleeding when cut; non-viable muscle displays no oozing or dark venous thrombosis.

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3. Common Upper Extremity Fractures

Colles' Fracture versus Smith's Fracture

Distal radial fractures are exceptionally frequent following ground-level falls onto the outstretched hand (FOOSH) in osteoporotic elderly individuals, or high-energy falls in active youth.

   Colles' Fracture ('Dinner Fork')             Smith's Fracture ('Garden Spade')
             Dorsal Prominence                           Volar Prominence
                 ┌───┐                                         ┌───┐
                 │   │                                         │   │
          ───────┘   └─────────                       ─────────┘   └───────
          Forearm     Hand                             Forearm      Hand
      (Distal fragment tilted Dorsally)            (Distal fragment tilted Volarly)

Pediatric Supracondylar Humerus Fractures

Supracondylar fractures of the distal humerus account for over 60% of all pediatric elbow fractures, peaking between 5 and 8 years of age due to hyperextension during a fall.

• Gartland Classification:
  • Type I: Non-displaced fracture; anterior humeral line bisects the middle third of the capitellum on the lateral radiograph.
  • Type II: Displaced fracture with an intact posterior cortex (hinge); anterior humeral line passes anterior to the capitellum.
  • Type III: Completely displaced fracture with total cortical disruption; high risk of neurovascular entrapment.
  • Type IV: Multidirectional instability with circumferential periosteal stripping.
• Neurovascular Vulnerability:
  • Anterior Interosseous Nerve (AIN): Most commonly injured nerve (branch of the median nerve). Motor only; tested by asking the child to make the 'OK' sign (pinching the tips of the index finger and thumb together). In AIN palsy, the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) of the index finger are paralyzed, resulting in a flat sheet-pinch (pad-to-pad contact rather than tip-to-tip).
  • Radial Nerve: Tested via active wrist extension and sensation over the first dorsal web space.
  • Brachial Artery: Entrapped or kinked across the proximal fracture spike. Absence of radial pulse, cool pale fingers, or delayed capillary refill indicates severe ischemia. If the radial pulse is absent, urgent gentle closed reduction and percutaneous K-wire fixation under general anesthesia are required. If perfusion does not return after anatomical reduction, urgent open exploration of the brachial artery is mandatory to prevent Volkmann's ischemic contracture.

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4. Major Joint Dislocations: Shoulder and Hip Emergencies

Anterior Shoulder Dislocation

Anterior glenohumeral dislocation accounts for > 95% of shoulder dislocations, occurring from an indirect force combining forced abduction, external rotation, and extension.

• Clinical Presentation: The patient supports the injured limb with the contralateral hand, holding the arm in slight abduction and external rotation. Inspection reveals loss of the normal rounded lateral contour of the shoulder ('squared-off' shoulder), prominence of the acromion with a distinct subacromial hollow, and a palpable humeral head anteriorly in the subcoracoid fossa.
• Neurological Check: The axillary nerve wraps around the surgical neck of the humerus and is injured in 10%–15% of cases. Test sensation over the 'regimental badge' area (lateral aspect of the mid-deltoid muscle) and palpate isometric deltoid contraction prior to and following reduction.
• Reduction Techniques:
  • Kocher's Method: Patient supine; flex elbow to 90°, apply gentle axial traction, slowly externally rotate the arm 70°–80° until resistance is met, adduct the elbow across the anterior chest wall, and finally internally rotate the hand onto the opposite shoulder.
  • Stimson's Gravity Technique: Patient prone with the affected arm hanging freely over the examination table edge. A 5 to 10 kg weight is strapped to the wrist; gentle muscular relaxation allows spontaneous reduction within 15–20 minutes without trauma.
  • Hippocratic Method: Axial traction applied while placing an unbooted foot in the axilla as a counter-traction fulcrum (higher risk of brachial plexus traction; traction-countertraction using a folded bedsheet is safer).
• Post-Reduction Care: Broad arm sling or collar-and-cuff for 2 to 3 weeks, followed by pendulum exercises.

Posterior Hip Dislocation

Posterior hip dislocations comprise > 90% of hip dislocations, typically resulting from a high-energy 'dashboard injury' during motor vehicle collisions where a violent axial force impacts the flexed knee, driving the femoral head posteriorly out of the acetabulum.

                                [HIP DISLOCATION PATTERNS]
                                            │
               ┌────────────────────────────┴────────────────────────────┐
               ▼                                                         ▼
     [Posterior Hip Dislocation]                               [Anterior Hip Dislocation]
- Mechanism: Dashboard impact (flexed hip)                - Mechanism: Severe forced abduction & ER
- Position: SHORTENED, FLEXED, ADDUCTED,                  - Position: FLEXED, ABDUCTED, and
  and INTERNALLY ROTATED                                    EXTERNALLY ROTATED
- Sciatic nerve palsy (10-20%): Foot drop                 - Femoral nerve / vessel compression
- EMERGENCY: Reduce within 6 hours (AVN risk)             - Emergency reduction under general anesthesia

• Clinical Presentation: The affected lower extremity lies in marked flexion, adduction, and internal rotation, with the knee resting against the contralateral thigh. The limb is visibly shortened.
• Complications:
  • Sciatic Nerve Injury (10–20%): The peroneal division is especially prone to traction, presenting as foot drop (loss of ankle and great toe dorsiflexion) and numbness over the anterolateral leg and dorsum of the foot.
  • Avascular Necrosis (AVN) of the Femoral Head: The medial and lateral femoral circumflex vessels are kinked and stretched. Emergency closed reduction within 6 hours is mandatory; delaying reduction beyond 6 hours increases the risk of irreversible osteonecrosis from 5% to over 50%.
• Reduction Technique (Allis Maneuver): Patient supine under general anesthesia or deep muscle relaxation. An assistant stabilizes the pelvis by pushing down on both anterior superior iliac spines. The clinician flexes the hip and knee to 90°, stands over the patient, applies steady vertical in-line traction, and gently rotates the femur internally and externally until an audible, palpable 'clunk' confirms reduction.

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5. Plaster of Paris (PoP) Application Principles & Cast Safety

Plaster of Paris (hemihydrated calcium sulfate, CaSO4 · 1/2 H2O) reacts exothermically with water to form hydrated crystalline gypsum (CaSO4 · 2H2O). Proper technique prevents cast failure, neurovascular compromise, and pressure ulcers.

Core Rules of Cast Application

1. Use a Backslab First: In acute trauma, always apply a plaster backslab (slab covering only 50%–70% of limb circumference, secured with cotton bandage) rather than a full circumferential cast. Acute inflammatory swelling peaks at 48–72 hours; a rigid circular cast applied immediately carries extreme risk of iatrogenic compartment syndrome.
2. Avoid Focal Finger Indentations: Smooth the wet plaster continuously using the palms and thenar eminences, never the fingertips. Finger indentations produce internal plaster ridges that cause deep focal pressure necrosis of the skin.
3. Joint Position: Immobilize joints in their functional positions (elbow at 90°, wrist at 10°–20° dorsiflexion, ankle at neutral 90° plantigrade) unless a specific displacement pattern dictates otherwise.
4. Bivalving for Neurovascular Distress: If a patient in a cast complains of burning pain, tightness, or paresthesias, split the cast circumferentially down its entire length, and cut every layer of underlying Webril cotton padding down to bare skin. Spreading the plaster halves relieves up to 60% of intracompartmental pressure; cutting the cotton padding relieves an additional 30%–40%.