Chapter 9: Mechanisms and Characteristics of Sports Trauma

Mechanical Injury

Tissue Properties

Tissue Stresses

Soft Tissue Trauma

Skin Injuries

Three types of muscle

Cardiac

Smooth

Striated

Acute Muscle Injuries

Contusions

Hematoma results from blood and lymph flow into surrounding tissue

Muscle Strain Grades

wGrade I –

wGrade II –

wGrade III-

wPathologically, strain is very similar to contusion or sprain with capillary or blood vessel hemorrhage

Tendon Injuries

Muscle Cramps and Spasms

Overexertional Muscle Problems

Two types of soreness

Acute-onset muscle soreness - accompanies fatigue, and is transient muscle pain experienced immediately after exercise

Delayed-onset muscle soreness (DOMS) - pain that occurs 24-48 hours following activity that gradually subsides (pain free 3-4 days later)

Muscle Stiffness

Muscle Cramps

Muscle Guarding

Myofascial Trigger Points

Chronic Musculoskeletal Injuries

Myositis/fascitis

Calcium at the heel

Atrophy and Contracture

Generally the result of a muscle injury which impacts the joint, resulting in accumulation of scar tissue

Synovial Joints

Joint Capsule

Bones are held together by a fibrous cuff

Consists of bundles of collagen and function to maintain relative joint position

Extremely strong and can withstand cross sectional forces

Will be slack or taut depending on joint movement

Ligaments

Synovial Membrane

Articular Cartilage

Provides firm flexible support - semifirm connective tissue with primarily ground substance

No direct blood or nerve supply

Fibrocartilage: makes up vertebral disks, symphysis pubis and menisci

Nerve Supply

Capsule, ligaments, outer aspects of synovial membrane and fat pads are well supplied

Inner structures (synovial membrane, cartilage and articular cartilage) also supplied

Myelinated mechanoreceptors provide joint position sense in fibrous capsule

Non-myelinated fibers supply blood vessels and pain receptors

Types of Synovial Joints

6 types

ball and socket –

hinge -

pivot -

ellipsoidal -

saddle -

gliding -

Functional Synovial Joints

Synovial Joint Stabilization

Articular Capsule and Ligaments

Synovial Joint Trauma

Synovial Joint Injury Classifications

Graded based on the severity of injury

Grade I - some pain, minimal loss of function, no abnormal motion, and mild point tenderness

Grade II - pain, moderate loss of function, swelling, and instability

Grade III - extremely painful, inevitable loss of function, severe instability and swelling, and may also represent subluxation

Can result in joint effusion and swelling, local temperature increase, pain and point tenderness, ecchymosis (change in skin color) and possibly an avulsion fracture

wMost vulnerable joints include ankles, knees, and shoulders

wSometimes difficult to distinguish between sprain and tendon strain

wRepeated joint twisting could result in arthritis or chronic inflammation

Acute Synovitis

Subluxations, Dislocations and Diastasis

wHigh level of incidence in fingers and shoulder

wSubluxations are partial dislocations causing incomplete separation of two bones

wLuxation presents with total disunion of bone apposition between articular surfaces

wDiastisis is the disjointing of 2 parallel bones or rupture of a solid joint (symphysis pubis)

Ankle Edema

Chronic Joint Injuries

Osteochondrosis

Bursitis

Bone Functions

wBody support

wOrgan protection

wMovement (through joints and levers)

wCalcium storage

wFormation of blood cells (hematopoiesis)

Types of Bone

wClassified according to shape

wFlat bones - skull, ribs, scapulae

wIrregular bones - vertebrae and skull

wShort bones- wrist and ankle

wLong bones - humerus, ulna, tibia, radius, fibula, femur

bones most commonly injured

Bone Trauma Classifications

wPeriostitis -

wAcute bone fractures -

Type of fractures include, depressed, greenstick, impacted, longitudinal, oblique, serrated, spiral, transverse, comminuted, blowout, and avulsion

Stress fractures- no specific cause but with a number of possible causes

Overload due to muscle contraction, altered stress distribution due to muscle fatigue, changes in surface, rhythmic repetitive stress vibrations

Major signs and symptoms include focal tenderness and pain, (early stages) pain with activity, (later stages) pain becomes constant and more intense, particularly at night, positive percussion tap test

Common sites involve tibia, fibula, metatarsal shaft, calcaneus, femur, pars interarticularis, ribs, and humerus

Management varies

More easily managed and healed if on compression side of bone vs. tension (may result in complete fx)

Running Fracture

Nerve Trauma

Nerve Injuries

wTwo main causes of injury - compression and tension

wMay be acute or chronic

Body Mechanics

Microtrauma and Overuse Syndrome

wInjuries as a result of abnormal and repetitive stress and microtraumas fall into a class with certain identifiable syndromes

wFrequently result in limitation or curtailment of sports involvement

wOften seen in running, jumping, and throwing activities

wSome of these injuries while small can be debilitating

wRepetitive overuse and stress injuries include

wAchilles tendinitis, shin splints, stress fx, Osgood-Schlaterπs disease, runnerπs and jumperπs knee, patellar chondromalacia and apophyseal avulsion

wPostural Deviations

wOften an underlying cause of injury

wMay cause unilateral muscle use as well as bony and soft tissue asymmetries

wResults in poor pathomechanics

wImbalance is manifested by postural deviations as body tries to regain balance relative to CoG

wInjury generally becomes chronic and participation must stop

wAthletic trainer should attempt to correct postural conditions

wPostural conditions can make athletes exceedingly more prone to injury