Bone Fractures: Diagnosis and Treatment

• Bone fractures and principles of their treatment are the main topics
• Assoc. Prof. Dalia Juodžentė presents the information
• The lecture aims to cover diagnosing and describing fractures, treatment principles, complications, and prognosis

Bone Fractures

• A bone fracture is a complete or incomplete break in the bone or cartilage
• A fracture is accompanied by various degrees of injury to the surrounding soft tissues
• Causal factors for bone fractures include direct/indirect trauma, repetitive stress, and pathologies

Mechanics of Bone Fractures

• Intrisinc forces transmitted by tendons, ligaments, and joint surfaces
• Extrinsic forces originate from outside the body with no limitation in magnitude or orientation
• Basic forces: tensile, compression, shear
• Complex forces: bending and torsion

Patient Assessment

• An Accurate diagnosis is achieved via: Clinical examination + Orthopedic examination + Diagnostic imaging
• A patient assessment plan in cases of possible fractures starts with a clinical examination
• Proceed to orthopeadic examination with caution, then special tests
• Special tests are for additional pathologies and fracture diagnosis (e.g., blood tests, X-ray etc.)
• Patient and fracture stabilization are next, alongside composition of treatment plan
• Common clinical signs include localized pain, deformity, swelling, loss of function, and crepitus
• The main aim is preserving patient's life

Special Tests and Diagnostics

• Radiographic imaging is essential and should be the first choice
• Bone tissue is perfect for radiographic imaging
• If there is a long bone fracture, always include distal and proximal joints in the X-ray
• Take at least 2 views of X-rays
• General anaesthesia is required in most cases

Fracture Description

• Correct description allows accurate communication with owners and colleagues, aiding appropriate treatment planning
• Correct descriptions are possible after evaluating 2 views of X-rays
• Describe fractures using terminology or special classification
• The description includes affected limb/side, bone, whether it’s open or closed, complete or incomplete
• Other details included are if simple, multiple, or multifragmental, if there's dislocation, the direction of fracture lines, and location
• Additional information encompasses dislocations and affected articular surfaces

Open vs. Closed Fractures

• Closed fractures involve no contact between the bone and the surroundings
• Open fractures involve bone contact with the surroundings and are always contaminated
• Healing can be prolonged or harder and have a higher rate of complications
• Open fractures are divided into 3 types:
• Puncture wound in the skin with a fractured bone (bone not visible)
• Wound easily seen and caused by external trauma and injuries of soft tissue (bone visible)
• Major bone fragmentation caused by major injuries of the soft tissues (skin loss possible)

Complete vs. Incomplete Fractures

• A complete fracture involves a single circumferential disruption of the bone
• An incomplete fracture is a fracture that disrupts only one cortex
• Greenstick and avulsion fractures are examples of incomplete fractures
• Greenstick fracture: A portion of the cortex is intact, thus stabilizing the bone somewhat
• Avulsion fracture: The insertion point of a tendon or ligament is fractured and distracted from bone

Displaced vs. Nondisplaced Fractures

• Nondisplaced fractures have ends in their normal position
• Displaced fractures have ends that are rotated or displaced
• Displacement direction is described by the location of the distal segment relative to the proximal
• Most fractures are proximally displaced due to muscle contracture and swelling

Fracture Line Direction Terminology

• Describe orientation of fracture line relative to long axis
• Transverse Fracture: crosses the bone at an angle of <30° to the long axis of the bone
• Oblique Fracture: this type of fracture has an angle > 30°
• Spiral Fracture: a case of oblique fracture with a line curving diaphysis

Location of Fracture in Bone

• Fracture locations include physis(grow plate) and use the Salter-Harris classification
• Fracture is through the physis (I)
• Fracture is through the physis and a portion of the metaphysis (II)
• Fracture is through the physis and epiphysis (generally, articular fractures) (III)
• Fracture is through the epiphysis, across the physis, and through the metaphysis (also articular fractures) (IV)
• Crushing injuries of the physis are not visible radiographically but become evident after several weeks when function ceases (V)
• Partial physeal closures result from damage to a portion of the physis, causing asymmetric physeal closure (VI)

Fracture Healing and Blood Supply

• Bone tissue is highly vascularized
• Mature animal circulation is afferent supply from the principal nutrient artery, metaphyseal arteries, and periosteal arteries
• Immature animals have arteries that perforate appositional bone running longitudinally over the periosteal surface
• Metaphysis and epiphysis have separate blood supplies and generally do not communicate across the cartilaginous physis
• Fracture causes destruction of bone vascularization
• Existing components of normal vasculature are enhanced to supply the injured area

Bone Healing

• Extraosseous vascular supply develops in soft tissue and nourishes the early periosteal callus
• When bone healing progresses and stability is restored, medullary blood supply is reestablished
• The healing process regenerates bone and restores function
• The first phase is inflammatory, where the hematoma signals molecules to initiate responses critical to fracture healing
• Further healing phases are repair and remodeling
• Mechanical environment impacts fracture healing, which can be either direct or indirect

Indirect Bone Healing

• Occurs in unstable mechanical environment caused by motion of the bone segments
• Characterized by the formation of fibrous connective tissue and cartilage callus at the fracture site
• The classical sequence: Hemorrhage → clot formation, and edema - proliferation of pluripotent mesenchymal cells → cartilage and bone formation → remodeling of callus
• During gap filling Stiffer tissue (granulation → connective → fibrous → fibrocartilage → mineralized cartilage → lamellar bone → cortical bone)
• During indirect bone healing, you can first see gap widening in X-rays

Direct Bone Healing

• Direct bone healing occurs when fixation devices maintain absolute fragment stability
• Characterized by direct bone formation at the fracture site without callus formation
• Direct bone healing is either contact or gap healing
• The radiographic appearance is slowly increasing density of the fracture line
• You can notice decreased density of the fracture line at X-rays

Principles of Fracture Treatment

• Principles include anatomical reduction of fracture fragments, stable fixation, preservation of blood supply
• The goal is early, active pain-free mobilization of muscles and joints adjacent to the fracture and complete return of function

Reduction

• Reduction (and fixation) of the fracture should be undertaken as soon as the patient's condition permits
• Delay in reduction happens because of spastic contraction of the muscles and increases bleeding
• Reduction can be closed (manipulation with traction and countertraction) or open
• This is usually accomplished when external skeletal fixation devices are emplyed

Open Reduction

• Open reduction cases: dislocated, unstable fractures, if occurred before more than a few days, involved articular surface and if needed
• Key principles include dividing muscles not affecting continuity, optimally revealing the fracture, and less traumatism to bone fragments

Immobilization

• Temporarly splintage is mostly used before or after surgical intervention
• Full leg casts are most useful in stable nondisplaced antebrachium or tibia fractures as a primary stabilizer
• Casts of a big variety of materials are available and are cheap, but should never be applied above the elbow/stifle

Internal Fixation

• Fixation materials include carclage wire, intramedullary pins, different plates and screws and mostly plates and screws
• Main principles: Most forces affecting the bone are counteracted and main fragments are stabilised
• There are multiple internal fixation types

Factors Effecting Internal Fixations

• Mechanical factors should be used to evaluate how strong the fixation must be for the patient
• Biological factors: An accurate biological evaluation shows how fast callus may be formed and how long the implants need to function
• Clinical factors: the factors are patient and client factors that affect healing during the postoperative period
• The principle to remember: Is the fracture reconstructable?

Factor Scoring

• Fracture assessment scores are assigned on a scale of 1 to 10
• Categorized as high (8–10), moderate (4–7), and low (1–3)
• Fractures with high scores heal successfully with few complications
• Fractures at the lower end of the scale potentially do not heal as well and have more complications

Principles of Internal Fixation

• Is based on anatomical alignment and fixation
• Main goal: early ambulation and complete return of function
• Important parts are bone/damage ratio & individual case

Internal Fixation Devices

• Used depending on Tension, Compression, Shear, Bending, and Torsion:
  • Cast, IM Pins, Tension Band, ESF, Interlocking Nail, Plates
• Specific for immature animals, physeal fractures(growth plates) are the weakest part of the bone
• Treatment is less inazive method and fastest as possible
• It is important to remember: Implants should not span the physis unless completely necessary

Open Fractures

• Are a combination of bone and soft tissue injuries
• Main principle goal: lavage, antimicrobical therapy, and soft tissue reconstruction
• Key Factors: hair clipping, wound cleaning, lavage, bacteriological sample, tissue removal, and fixation

Postoperative Treatment

• Includes pain control, antibiotics, limb immobilization, and decreasing physical activity, later increasing it alongside physiotherapy

Fracture healing evaluation

• While evaluating fracture healing in X-rays, remember the "AAAA“ mnemonic:
  • Alignment
  • Apposition
  • Apparatus
  • Activity

Key Factors in Fracture healing

• One of the main factors: animal age
• Other factors are type of the fracture, secondary diseases, gap between, right technique, and succes of postoperative treatment

Removal of Implants

• If no complications arise, implants are not removed
• Indications for removal are when nonfunctional, thermal conductor, bone changes, and cause irritation