Traumatic and mechanical disorders of musculoskeletal

system

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Ligament sprains

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• ประกอบุไปดู"วิย extracellular matrix, Proteoglycan, collagen, Fibroblast ฯล้ฯ

Classification

Ligamentous injuries of the knee

Intra-articular structures

• ACL• PCL• Medial meniscus• Lateral meniscus

Extra-articular structures

• MCL• LCL• Posterolateral corner complex : Biceps

femoris tendon, Arcuate ligament, Fabellofibular ligament, Popliteus tendon, Popliteofibular ligament, Posterior oblique collateral ligament, Plantaris longus muscle, Lateral gastrocnemius muscle(tendon part) etc.

Common injuries

• ACL injury• PCL injury• MCL injury• LCL injury• Meniscus injury

Cause of injury

• Sport injury• Motor vehicle injury

Natural history

• Ligament injury : Knee instability• Meniscus injury : pain, range of motion• Cartilage injury• Osteoarthritis

Physical examination

• Swelling• Point of tenderness• Limitation of range of motion• Special tests ***

Special tests

Stability test• Anterior drawer test • Posterior drawer test• Varus stress test• Valgus stress test• Prone external rotation test• Lachman test• Lateral pivot shift test

Lachman test

Special tests (cont.)

Meniscus test• McMurray test• Apley grind test• Squat test

McMurray test

Apley grind test

Investigation or Imaging

• Plain film X-ray • MRI (Magnetic Resonance Imaging)

Treatment

• Depend on which ligament was injuried• Non-operative treatment• Operative treatment : Repair, Reconstruction

Ligamentous injuries of the ankle

Key structures

• ATFL : Anterior Tibiofibular ligament• Deltoid ligament• Syndesmotic ligament

Mechanisms of injury

Physical examinations

• Swelling• Point of tenderness• Inability to bear weight• Special test ***

Anterior Drawer Test

Talar Tilt Test

Squeeze test External rotation test

Investigation or Imaging

• Plain film radiograph : AP ,lateral, mortise view

• For exclude bone fracture • Able to exclude ligament sprain grade by

measuring parameter

Radiographs

Treatment

• Ankle sprain grade 1 + 2 : Immobilize in slab or cast

• Ankle sprain grade 3 : Surgery Repair

Ligament healing

1. Inflammatory phase2. Reparative phase3. Remodeling phase

Strain

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• Muscle and Tendon

Anatomy

Tendon

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Collagen, Proteoglycan, Tenocyte, Tenoblast

Causes

• Improper use• Heavy lifting• Over-stretched• Occurs in Lower back, Neck, shoulder, Thigh

Treatment

• Rest • Immobilization• NSAIDs : Non Steroidal Anti Inflammatory

Drugs• Physiotherapy : Short wave, U/S

Fractures

BONE AND JOINT INJURIES

• Fracture = Disruptions of bone tissue• Osteochondral or intraarticular fractures =

Visible disruptions of articular cartilage or fractures involved both the articular cartilage and subchondral bone

• Chondral fractures = involved only the cartilage

Gross anatomy

• Spine • Upper extremity• Lower extremity• Pelvis

Bone Tissue• Its tensile strength nearly equals that of

cast iron• 3 times lighter• 10 times more flexible• Consists of mesenchymal cells embeded

within abundant extracellular matrix • Constantly changing in response to

mechanical and hormonal signals

Bone TissueThe matrix contains :1. Mineral great strength and stiffness in

compression and bending2. Collagen type 1 strength and plasticity3. Cytokine , Growth factors

Periosteum• Outer layer more fibrous layer• Inner layer more cellular and vascular

cambium layer• Participates in healing of many types of

fractures• In children , Thicker periosteum than

Adults

Types of BoneWoven bone (immature bone)

• Embryonic skeleton• More rapid rate of

deposition and resorption• Initial fracture repair• Irregular pattern of matrix

fibrils• relatively high cell content

and water concentration• 4 times the number of

osteocytes per unit volume• Less stiffness• More easily deformed

Lamellar bone (mature bone)

• Replaces woven bone during growth and development

• Replaces woven bone in remodeling phase under mechanical load

• More stiffness• Difficultly deformed

Bone formation

1. Cutting cone 2. Intramembranous formation3. Endochondral bone formation

Cutting cone

• Primarily a mechanism to remodel bone• Osteoclasts at the front• Trailing osteoblasts lay down new bone

Intramembranous formation• Long bone grows in width• Osteoblasts differentiate directly from

preosteoblasts and lay down seams of osteoid• Do not involve cartilage anlage

Endochondral bone formation

• Long bone grows in length• The chondrocytes hypertrophy, degenerate

and calcify• Vascular invasion of cartilage occurs followed

by ossification

Stages of Fracture healing• Inflammation• Repair• Remodeling

Inflammatory phase• Require high energy until remodeling• Inflammatory mediators released from

platelets, dead cells• Vasodilatation and exudate plasma

edema in the region• Macrophages and Lymphocyte migration• The inflammatory response subsides,

necrotic tissue and exudate are resorbed

Repair phase

• Fibroblasts and chondrocytes start producing a new matrix, the fracture callus

• Follows inflammatory phase rapidly• Unstable Vs Stable fracture ???

Repair and Remodeling of Unstable Fractures (Secondary bone healing

• Organization of hematoma first step in fracture repair

• Initiate fracture healing• The intact fracture hematoma provides a

fibrin scaffold that facilitates migration of repair cells

• Platelets and cells in hematoma release GFs and other proteins cell migration, proliferation, matrix synthesis

• Blood supply, medullary system and periosteum are important for fracture healing

• The mesenchymal cells proliferate, differentiate, and produce the fracture callus consisting of fibrous tissue, cartilage, and woven bone

Osteoclast

• Derived from circulating monocytes in the blood and monocytic precursor cells from the bone marrow

• Do not appear to form repair tissue

Osteoblast• Develop from the

undifferentiated mesenchymal cells that migrate into the fracture site

• Participate in bone formation

• Hard (bony) callus “The bone formed initially at the periphery of the callus by intramembranous bone formation”• Soft (fibrous and cartilaginous) callus“forms in the central regions with low oxygen tension and consists primarily of cartilage and fibrous tissue”• Endochondral ossificationenlarging the hard callus and increasing the stability of the fracture fragments

Callus

• At these stages, the healing is not complete

• The immature fracture callus is weaker than normal bone

• Gaining full strength during remodeling phase

• During final stage of Repair, Remodeling of the repair tissue begins with replacement of woven bone by lamellar bone and resorption of unneeded callus

• By radioisotope studies, the remodeling process continues for year after clinical and radiographic union

• Decrease bone density and remains changes for years

Repair and Remodeling of Stabilized Fractures (Primary Bone Healing)

The fracture surfaces are rigidly held in contact

Fracture healing can occur without grossly visible callus in either cancellous or cortical bone

Called “ Primary bone healing”Small bone gaps Vs bone contact??

• Lamellar bone can form directly across the fracture line by extension of osteons

• A cluster of osteoclasts cuts across the fracture line, osteoblasts following the osteoclasts deposit new bone, and blood vessels follow the osteoblasts

• The new bone matrix, enclosed osteocytes, and blood vessels form new haversian systems.

Joint tissue (synovial joint)

• Congruent articulating cartilaginous surfaces• Subchondral bone• Metaphyseal bone• Joint capsule• Ligaments• Synovial membrane• **fibrous tissue meniscus** (labrum)

Articular cartilage

• Sparsely distributed chondrocytes• Surrounded by an elaborate, highly organized

macromolecular framework filled with water• Collagens, Proteoglycans and Non-

collagenous proteins form the macromolecular framework

Physical examination

• Pain• Swelling• Tenderness• Limitation of Range of motion• Neurological status• Vascular status

Imaging

• Plain film X-ray• Computerized Tomography

Treatment

• Non-operative• OperativeDecision making depend on • Site of injury, • Severity of injury• Fracture configuration• Surrounding structures injury• Other organ system injury• Patient’s underlying disease

Non-operative treatments

• Splint• Slab• Casting• Bracing• Traction

Operative treatments

Internal fixation• Dynamic compression plate and screw • Locking plate and screw • Intramedullary nailing system• WiringExternal fixation• External fixator• Ilizarov system

Principles of treatment

• Displacement• Intra-articular involvement• Soft tissue injury• Nerve and Vascular injury• Diaphysis of Lower extremity : Nailing

Bone Healing

• Dynamic compression plate : Primary• Locking plate : Secondary• Nailing : Secondary• Wiring : Primary• External fixator : Secondary• Ilizarov : Distraction osteogenesis

“Clinical union”• Stability of the fracture fragments

progressively increases because of the internal and external callus formation

• The fracture site becomes stable and pain-free

“Radiographic union”

• Plain radiographs show bone trabeculae or cortical bone crossing the fracture site

• Often occurs later than clinical union

Failure of Fracture Healing

Delay union

• Fracture line remains clearly visible radiographically• There is no undue separation of the

fragments, no cavitation of the surfaces, no calcification, and no sclerosis• Related to the severity of the injury, poor

blood supply, the age and nutritional status of the patient, or other factors

Nonunion

• An arrest of the healing process• With a large volume of callus called “Hypertrophic

nonunion”• With some callus but less than normal

“Oligotrophic nonunion”• Without callus or less called “Atrophic nonunion”• With cartilagenous tissue and clear fluid filled in

cavity called “Pseudarthrosis”• “A Fibrous Union”

HypertrophicNon-union

Oligotrophic non-union

AtrophicNonunion

Synovial pseudarthrosis

Dislocation

• Joint dislocation• Low velocity Shoulder, Elbow, wrist, finger• High velocity Hip, Knee, Ankle

Common direction

• Shoulder : anterior• Elbow : posterior• Wrist : Lunate volar dislocation• Finger : Posterior• Hip : posterior• Knee : all direction• Ankle : all direction

Physical examination

• Mark swelling• Mark deformity• Limitation of motion• Neurological status• Vascular status

Imaging

• Plain film X-ray

Treatment

• Emergency closed reduction• Under sedation• Under General anesthesia• Open reduction

Acute compartment syndrome

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