Classification of Injuries

Sports Injury Classification

Acute / Traumatic

• extrinsic causes: direct blow, collision, impact

• intrinsic causes: muscle forces, joint loadings

Acute vs Overuse Injuriesv increasing frequency of

overuse injuries

v acute injuries:high velocityuncontrolled impacts macro-trauma

Classic Ankle Inversion Sprain

Ligament SprainsGrade Ipain on stressing ligament no increased joint laxity

Grade IIpainincreased joint laxity with definite end point

Grade IIIpain + / -gross joint laxity without a firm end point

v Clinical continuum based on ligament stress-strain curve ²Stress-Strain curve

v Grade I - III “overstretching” fibre model²mild, moderate, severe

Ligament Sprains

Stress - Strain Curve

Rupture of Joint Capsule / Ligaments(AC Injury Examination under Anesthesia)

vAC Injuries: Type I - VI(Rockwood classification)

v joint capsulevacromioclavicular lig’svcoracoclavicular lig’s

trapezoidconoid

v single, debilitating episode ²e.g., Knee²ACL²ACL + L/MCL²ACL + L/MCL + Meniscus²ACL + PCL

Ligament Sprains

v multiple, debilitating episodes(chronic on acute)

²e.g., Ankle²ATFL²ATFL+CFL+PTFL²Syndesmosis²ATFL+CFL+PTFL+Deltoid

Ligament Sprains

v Clinical premise -“hypermobility”, assessed by multi-joint “laxity”, predisposes to subluxation / dislocation injuries

Joint Dislocations & Subluxations

Joint Action ROM ScoreElbow extension > 10° 1 1Knee extension >10° 1 1Thumb apposition to ant forearm 1 15th finger ext >90° 1 1Forward flexion Palms flat on floor 1

/ knees straight

Total maximum possible score 9

Beighton Score

Joint Dislocations & Subluxations

v dislocation: complete dissociation of the articulating joint surfaces

v subluxation: articulating surfaces remain partially in contact

Tendon Subluxation – Acute / Chronic

Diastasis - Tibiofibular Syndesmosis

AP Xray>6mm overlap

v Distal separation of the tibia & fibula due to tear / rupture of syndesmosis

v “high” ankle sprain

Biomechanics & Anatomy in Joint Injuries

v direct impactsv distracting forces

Biomechanics & Anatomy in Joint Injuries

v injury to surrounding joint capsule and structures with luxations

v luxation / laxity predispose to impingement (e.g., acromionprocess) and recurrent injury

Meniscal Injuries – Knee Joint

Acute tears shear stress with knee in flexion & compression with femoral rotation (twisting with planted foot)

medial meniscus at greater risk of injury (less mobile) than lateral meniscus

Acute Meniscus Injuries

v Joint line painv +ve McMurray’s testv Joint effusion / swellingv Popping or clicking within joint v Giving way sensation / lockingv Arthroscopic surgery

Acute Joint Injuries – Joint Effusion

vincreased intra-articularfluid

vtraumatic ligament, bone or meniscalinjuries

Acute Joint Injuries – Joint Effusion

vsynovial fluidvbloody effusion: hemarthrosis

Acute Articular Cartilage Injuriesv fragments sheared from articular

surfaces (luxations) v chondral & osteochondral

fractures common v osteoarthritis linkv typical changes seen on X-ray

include: joint space narrowing, subchondral sclerosis, subchondralcyst formation, and osteophytes

v better detection (MRI, CT) v arthroscopic surgery

Chondral Injuries

acute chondral / osteochondralinjuries from high compressive / shearing forces“poor healing” – limited regenerative / repair capacityrange of injury severity

v among most common sporting injuries

v muscle fibres fail under imposed demands

v recurrent (particularly hamstrings)

Muscle Strains

“Classic” Muscle Strain Classification

Grade Ismall # fibres ruptured, pain localised, no strength lossGrade IIlarge # fibres ruptured, reduced strength, swelling & pain limited movementGrade IIIcomplete tear of muscle, muscle-tendon junction, significant strength loss, obvious visual defect

Tears of muscle at muscle-tendon junction – tendinous interfaces

“Evolving” Muscle Strain Classification

1. Small Injuries (tears)2. Moderate Injuries (tears)3. Extensive Tears4. Complete Tears

a) myofascialb) within muscle at MTJc) extends into tendon

Pollock et al. 2014

Classification by anatomical location & type/s of tissue involved

Biceps femoris strain with central tendon disruption – 72 days recoveryBiceps femoris strain without central tendon disruption – 21 days recovery

v sudden acceleration or deceleration

v neural innervation

Biomechanical & Anatomical Factors in Muscle Strains

v eccentric action mode²force velocity curve

v biarticular muscles pre-disposed²hamstrings²rectus femoris²medial gastrocnemius

vHigher proportion of fast twitch fibres

Biomechanical & Anatomical Factors in Muscle Strains

Applying Exercise Physiology KnowledgeDraw a Force-Velocity Curve on the Graph below

0eccentric concentric

100%

200%

Contraction Velocity

Contraction Force

Sarcomeres lengtheningunder load

Sarcomeres shorteningunder load

v agonist-antagonist imbalance(e.g., quad - ham ratio)

v muscle-tendon interfaces(e.g., semitendinosus)

v elasticity (cc, sec, pec)

Biomechanical & Anatomical Factors in Muscle Strains

Hamstring Strain Classification

v“Type I”

²Biceps Femoris Long Head

²High Speed Running

²Proximal Muscle Tendon Junction

v“Type II”

²Semimembranosus

²Stretching – Slow Speed

²Proximal Tendon / Ischial Tuberosity

Muscle Strains & Haematomas

vIntramuscular haematoma²More painful

²More restrictive

vIntermuscular haematoma²Generally more evident

Biceps Femoris InjuryMRI Visualization

Muscle Contusions

“Corks”v forceful impact

v localised (blunt) trauma

v “common” (superficial) sites

v vastus lateralis / biceps brachii

v “other” (medial) sites

v thigh adductors / med. gastroc

Muscle Contusions“Corks”vmild - severe bruising

vlocal fibre damage & bleeding

vedema & hematoma

vICE not HARM

v place in pain free stretched position

Myositis Ossificans Traumaticavheterotrophic ossification (bone deposition 2-4 wks)v cause - local factors (reserve of Ca++ in adjacent skeletal tissue; vascular stasis tissue hypoxia; mesenchymal cells with osteoblasticactivity) / unknown systemic factors. vmechanism - differentiation of fibroblasts into osteoblasts

Tendon Rupture

vPartial RuptureSmall to large # ruptured fibres, pain and limited function (equivalent to Grade I / II sprain)

vComplete RuptureTotal rupture of tendon, pain and non-function of specific muscle-tendon unit (Grade III equivalent)

Biomechanics & Anatomy in Tendon Rupture

vsudden accelerationv jumping / landingvunexpected loadingvstretch-shortening action

Biomechanics & Anatomy in Tendon Rupture

v in vivo loading patternvexcessive stiffnessvmuscle-tendon “imbalance”

(e.g., Achilles tendon)

Tendon “Avulsions”

vdetachment of tendonvmallet finger

(extensor mechanism)vjersey finger

(flex digit profundus)

Bone Fractures

²blow / collision

²twisting

vcommon sporting injuryvdirect trauma

²blow / collisionvindirect trauma

²twistingvsplint / stabilizevmedical referral

Bone Fracturesvclosed fracturesvopen fractures

²(compound)

vnerve damagevvessel damagevbleeding / shockvinfection

Simple & Complex Fractures

Peak Fracture Prevalence in Adolescence

Collés Fracture

Biomechanics & Anatomy in FracturesAvulsion fractureslinternal forceslyounger athletes

Stress fractureslrepetitive forceslpars interarticularis

Greenstick fractureslincomplete breaklyounger athletes

Bone “Bruising”

• Microtrabecular fracture /haemorrhage / oedema in bone following traumatic insult

• MRI shows bone marrow oedema• Evident for 12 - 14 weeks• Interosseous bruise - bleeding inside bone

marrow is located. • Subchondral bruise – between cartilage

and bone beneath, causing cartilage to separate from bone

• Subperiosteal hematoma - bleeding beneath periosteum.

Periosteal Contusion

• Sub-periosteal haematoma• Development of palpable lump• Periosteum is raised, inflammed,

irritated and painful on palpation or muscle contraction

• Maybe associated with damage to surrounding structure e.g., clunealnerve in “hip pointer”

• Protective padding e.g., shin pads, hip guards

Growth Plate Injuries

Salter & HarrisSalter & Harris

Type I - epiphysis (E) completely separated from metaphysis (M) Type II - E + growth plate (GP) separated from metaphysis MType III - Fx thru E separates part of E & GP from MType IV - Fx thru E, across GP and into MType V - GP compressed / crushed (prognosis poor)