Sports Injuries Mikey Bengzon, MD, MBAH 30 November 2010

Sports Injuries

Mikey Bengzon, MD, MBAH

30 November 2010

Specific Learning Objectives:

• Enumerate and define common acute and chronic orthopedic Sports injuries.

• Describe the anatomy and physiology of musculoskeletal structures.

• Review the ligamentous anatomy of the knee.• Analyze the pathology of Orthopedic sports

injuries.• Enumerate the methods of treatment of

Orthopedic sports injuries.

Sports Injuries

Acute injuries• Ankle sprain• Muscle Strain• Contusion• rupture/dislocations

Chronic injuries• Tendinitis• Stress Fractures• Osgood Schlatter

Disease• Sever’s disease

Orthopedic Sports Injuries

• S - Onset: Acute vs. Chronic;– MOI: Direct vs. Failure

• O - Location: Long bone vs. Periarticular; Structure: Osseous vs. Soft tissue

• A – Osseous or non osseous, Location

• P - ?

Contusion

• Blunt injuries• Intra: Within the

compartment; more painful; swelling lasts longer; no obvious hematoma

• Inter muscular: less painful; swelling resolves sooner; obvious hematoma

• Grade 1 – 3 (tightness)

Stress(?) Fracture

• Incomplete fracture• Overuse -> Fatigue• Force transfer from

muscle to bone• Rx: Rest vs IF

Osgood Schlatter Disease

Sever’s Disease

• Inflammation of the growth plate

• 8-13 year olds• Overuse injury in

running sports• Rx. Rest, control of

inflammation

Mallet finger

Rotator Cuff Tears

Supraspinatus

Infraspinatus

Teres Minor

Subscapularis

Toe RegionLinear Region

Yield/ Failure

Strain

Stress

Types of Muscle Contraction

• Concentric – Joint moves with a load and the muscle shortens (biceps contract)

• Eccentric – results in muscle lengthening while controlling a load during joint motion (biceps in elbow extension)

• Isometric – fixed load with no joint motion (quadriceps sets)

• Isokinetic – variable load with constant velocity (exercise bike)

• Isotonic contraction - tension rises and the skeletal muscle shortens

Toe RegionLinear Region

Yield/ Failure

Strain

Stress

2 types of Skeletal muscles

• Type I – Slow twitch, more for endurance and aerobic bc of the presence of mitochondria and myoglobulin

• Type II – fast twitch, for rapid generation of power but anaerobic so less able to sustain prolonged contraction – Type IIA vs Type IIB

Factors affecting muscle properties

• Strength training – High force, low repetition: leads to an increase in muscle strength; increase muscle fiber size leads to an increase in contractile proteins

• Endurance training – (low tension, high repetition): Increases capillary density & mitochondria concentration resulting in VO2 max and improved fatigue resistance– MHR = 220 – Age– Increase VO2 max, HR must increase to 65-85% of

MHR

Tendons

• Connects muscle to bone

• Collagen are more parallel and larger compared to ligaments

• Relatively avascular• 2 tendinous areas:

– Musculotendinous– Osteotendinous

Functions of Tendons

• Length of tendon allows muscle belly to be at a distance from the joint

• Transmits force between muscle and bone– Tensile stresses are high

• Conservation of muscular energy during locomotion/ energy storage capacity– Satisfies kinematical and damping

requirements

Mechanical Properties of Tendons

• Greater cross - sectional area– Larger loads can be applied prior to failure– Increased tissue strength– Increased stiffness

• Longer tissue fibers– Greater fiber elongation before failure– Decreased tissue stiffness– Unaltered tissue strength

Strain

• Pertains to muscles• Overexertion• Grade 1 strength

maintained• Grade 2 – decrease

strength• Grade 3 – loss of

strength• Treatment – Similar to

sprains

Toe RegionLinear Region

Yield/ Failure

Strain

Stress

Tendinitis

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Lateral Epicondylitis

• Tennis elbow• Tendinitis at the

common extensor origin in the elbow

• Elbow and wrist extension

Ligaments Tendons

% Collagen Less More

% Ground Substance

more less

Organization More random Organized

Orientation Weaving pattern

Long axis direction

Ligaments vs. Tendons

COMPONENT LIGAMENT TENDON

Cellular Materials:

Fibroblasts 20% 20%

Extracellular:

Water 60-80% 60-80%

Solids 20-40% 20-40%

Collagen 70-80% Slightly higher

Type I 90% 95-99%

Type III 10% 1-5%

Ground substance 20-30% Slightly less

Elastin Up to 2X Collagen Scarce

Dislocations/Subluxations

Toe RegionLinear Region

Yield/ Failure

Strain

Stress

Mechanical Behavior of ligaments

Sprain

• Pertains to ligaments• Ankle, knee & finger• Children vs adults• Grade 1- fxn

maintained• Grade 2 – partial

weight bearing• Grade 3 – unstable• Treatment: depends

on severity

Ligaments

• Soft connective tissue composed of densely packed collagen fibers

• Mechanical properties depend on function and location

• Fibroblasts• Extracellular matrix

Ligaments

• Functions:– Holds skeleton together– Transmit load bone to bone– Provides stability at joints– Limits freedom of movement

• Prevents excessive motion by being a static restraint• Occasionally acts as a positional bend/strain sensor• Mediate motions bw opposing fibrocartilage surfaces

Ligaments

• No molecular bonds between fascicles– Free to slide relative to

each other

• Parallel or Branching/interwoven– Collateral vs Cruciates

• Smaller diameter than tendons

Simon, SR. Orthopaedic Basic Science. Ohio: American Academy of Orthopaedic Surgeons; 1994.

Crimping: – orientation of collagen in ligaments– Allows elongation of fibers before tensile stresses are

experienced

Viscoelastic Response

• Viscous – resists strain; Elastic – returns to original state• Dependent on

– Magnitude of load – Duration of load– Prior loading

• Affected by movement of water– Resistance to compressive forces due to water trapped in

proteoglycans– Contributes to sustained or cyclic responses to stress

• Types of responses– Creep – Stress relaxation– Hysteresis

http://www.tendinosis.org/injury.htm

Creep • Time dependent elongation when subjected to a constant stress– Tendons: in an isometric

contraction, the tendon will lengthen slightly and more muscle fibers will be recruited in order to maintain the position of the limb

– Ligaments: Joints will loosen with time, decreasing the possibility of injury

• Ex. Maintaining posterior pressure of the knee in extension

http://www.orthoteers.co.uk/Nrujp~ij33lm/Orthconntiss.htm

http://ttb.eng.wayne.edu/~grimm/ME518/L5A3.html

Stress - Relaxation• Time dependent

decrease in applied stress required to maintain a constant elongation– Tendons: in an isotonic

contraction, the stress will decrease with time

– Ligaments: joints will loosen with time decreasing the possibility of injury

• Ex. Biceps curls x 2 reps

http://www.orthoteers.co.uk/Nrujp~ij33lm/Orthconntiss.htm http://ttb.eng.wayne.edu/~grimm/ME518/L5A3.html

Hysteresis

• Energy lost within the tissue between loading and unloading– Response of tissue

becomes more repeatable

– Subsequent use of the same force results in greater deformation

Knee Injuries

Knee Injuries

• Medial Collateral Ligament (MCL) strains

• Anterior Cruciate Ligament (ACL) tears

• Meniscal Tears

Examination of the Knee

• Bone

• Soft tissue

• Ligaments

Anterior Cruciate Ligament

• Located between the femur & tibia at the center of the knee– Origin: Medial Surface of the Lateral Femoral

condyle– Insertion: anterior tibial plateau– Intracapsular; extrasynovial

• 2 bundles: AM & PL*• + Lachman’s & Anterior drawer’s test

ACL

• Anterior Drawer’s test

• Lachman’s test

• Pivot Shift

KT 2000

ACL MRI

Posterior Cruciate ligament

• Origin: Medial Femoral Condyle• Insertion: Posterior Cortical

surface of the tibia in the sagittal midline

• Covered by synovium (intimately associated with the posterior capsule)

• Blood supply from the middle geniculate artery

• + sag sign, Posterior drawer’s test

Medial Collateral Ligament

• Primary stabilizer to valgus

• Origin: MFC at the adductor tubercle

• Insertion: Medial aspect of the proximal tibia

• Superficial and Deep layer

• + Valgus Stress test

Lateral Collateral Ligament

• Origin: Lateral Femoral condyle

• Insertion: fibular head

• Resists Varus stress

Meniscal tear

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Inflammation

regeneration

Fibrosis

Weeks

Stages of Healing

R.I.C.E.

• REST – avoid painful movements but use as tolerated

• Ice – 20 minutes at a time x 24-48 hours

• Compression

• Elevation

• Address main pathology

Issues in Treatment

• Temperature: – Negative Effects of Ice, Dr. Ho, University of Hawaii –

Decreases blood flow and metabolism– 1980 AOS & AJSM – nerve palsies

• Motion – immobilization affects overall health of the joint (scar tissue, cartilage necrosis, ligament weaknening)

• Medications– NSAIDS: inhibit fibroblastic growth processes

Post Surgery

• Range of Motion

• Strengthening

• Endurance