Classification of Injuries

Sports Injury Classification

Acute / Traumatic

•  extrinsic causes: direct blow, collision, impact •  intrinsic causes: muscle forces, joint loadings

Acute vs Overuse Injuries v  increasing frequency

of overuse injuries

v  acute injuries: high velocity uncontrolled impacts macro-trauma

v among most common sporting injuries

v muscle fibres fail under imposed demands

v  recurrent (particularly hamstrings)

Muscle Strains

Muscle Strains Grade I small # fibres ruptured, pain localised, no strength loss Grade II large # fibres ruptured, reduced strength, swelling & pain limited movement Grade III complete tear of muscle, muscle-tendon junction, significant strength loss, obvious visual defect

v  sudden acceleration or deceleration

v neural innervation

Biomechanical & Anatomical Factors in Muscle Strains

v  eccentric action mode ² force velocity curve

v  biarticular muscles pre-disposed ² hamstrings ² rectus femoris ² medial gastrocnemius

Biomechanical & Anatomical Factors in Muscle Strains

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

0 eccentric concentric

100%

200%

Contraction Velocity

Contraction Force

Sarcomeres lengthening under load

Sarcomeres shortening under 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

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” v mild - severe bruising v local fibre damage & bleeding

v edema & hematoma

v ICE not HARM v  myositis ossificans

Tendon Rupture

v Partial Rupture Small to large # ruptured fibres, pain and limited function (equivalent to Grade I / II sprain)

v Complete Rupture Total rupture of tendon, pain and non-function of specific muscle-tendon unit (Grade III equivalent)

Biomechanics & Anatomy in Tendon Rupture

v sudden acceleration v jumping / landing v unexpected loading v stretch-shortening action

Biomechanics & Anatomy in Tendon Rupture

v in vivo loading pattern v excessive stiffness v muscle-tendon “imbalance” (e.g., Achilles tendon)

Tendon “Avulsions”

v detachment of tendon v mallet finger (extensor mechanism)

v jersey finger (flex digit profundus)

Ligament Sprains Grade I pain on stressing ligament no increased joint laxity

Grade II pain increased joint laxity with definite end point

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

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

v  Grade I - III “overstretching” fibre model ² mild, moderate, severe

Ligament Sprains

Stress - Strain Curve

Classic Ankle Inversion Sprain

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

v AC Injuries: Type I - VI (Rockwood classification)

v joint capsule v acromioclavicular lig’s v coracoclavicular lig’s trapezoid conoid

v  single, debilitating episode ² e.g., Knee ² ACL ² ACL + L/MCL ² ACL + L/MCL + Meniscus ² ACL + PCL

Ligament Sprains

v  multiple, debilitating episodes (chronic on acute)

² e.g., Ankle ² ATFL ² ATFL+CFL+PTFL ² Syndesmosis ² ATFL+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 Score Elbow extension > 10° 1 1 Knee extension >10° 1 1 Thumb apposition to ant forearm 1 1 5th finger ext >90° 1 1 Forward 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

Biomechanics & Anatomy in Joint Injuries

v  direct impacts v  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., acromion process) and recurrent injury

Biomechanics & Anatomy in Joint Injuries

v  “unstable” joints / structures more likely to dislocate ² shoulder (anterior) ² acromioclavicular joint ² fingers (PIP joints) ² patella (lateral)

v  “stable” joints however do dislocate ² hip ² elbow

Acute Meniscus Injuries

v  Joint line pain v  +ve McMurray’s test v  Joint effusion / swelling v  Popping or clicking within joint v  Giving way sensation / locking v  Arthroscopic surgery

Acute Joint Injuries – Joint Effusion

v increased intra-articular fluid

v traumatic ligament, bone or meniscal injuries

Acute Joint Injuries – Joint Effusion

v synovial fluid v bloody effusion:

hemarthrosis

Acute Articular Cartilage Injuries

v  fragments sheared from articular surfaces (luxations)

v  chondral & osteochondral fractures common

v  osteoarthritis link v  typical changes seen on X-ray

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

v  better detection (MRI, CT) v  arthroscopic surgery

Bone Fractures v common sporting injury v direct trauma

² blow / collision v indirect trauma

² twisting v splint / stabilize v medical referral

Bone Fractures v closed fractures v open fractures

² (compound)

v nerve damage v vessel damage v bleeding / shock v infection

Simple & Complex Fractures

Peak Fracture Prevalence in Adolescence

Collés Fracture

Biomechanics & Anatomy in Fractures Avulsion fractures l internal forces l younger athletes

Stress fractures l repetitive forces l pars interarticularis

Greenstick fractures l incomplete break l younger athletes

Bone Bruising

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

•  MRI shows bone marrow oedema •  Evident for 12 - 14 weeks •  Subperiosteal hematoma - bleeding beneath

periosteum. •  Interosseous bruise - bleeding inside bone

marrow is located. •  Subchondral bruise – between cartilage and bone

beneath, causing cartilage to separate from bone.

Growth Plate Injuries

Salter & Harris

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

Overuse Injuries

v repetitive microtrauma exceeds tissue repair capacity

v  ⇑ prostaglandin E2 in tissues - ⇑ collagenase, ⇓ collagen synthesis

v upregulation of genes for cartilage, down-regulation of genes for tendon (rat) ⇒ tendon morphology alters to more cartilaginous.

Overuse Injuries

v important to identify / consider risk factors (RF)

v addressing intrinsic / extrinsic RF may help prevent re-injury

v often recalcitrant to treatment (months to resolve)

Overuse Risk Factors v Extrinsic Factors

² Training Errors ² Technique Errors ² Surfaces ² Shoes ² Equipment

Overuse Risk Factors v Intrinsic Factors

² Previous Injury ² Lack of Flexibility ² Leg Length Discrepancy ² Malalignment tibial torsion / vara genu valgum / varum

Overuse Risk Factors v Intrinsic Factors

² Malalignment patella alta pes planus / cavus

² Muscle Imbalance ² Muscle Weakness

In the News

Tendinopathies (Overuse)

v pathology is tendon (collagen) degeneration (tendinosis) not inflammation

v surrounding structures may

have inflammation (paratendinitis)

Multiple tendons (Supraspinatus, ECRB, Achilles) v Collagen disarray v Absent cells, prolific cells

v Abnormal vessels & nerves

v Abnormal extracellular matrix

Pathological Findings Normal → Abnormal

Dealing with Tendinopathies (Overuse Injuries)

v History (onset, nature, potential causes)

v Examination (anatomical structure, reproduce pain) Diagnosis required!

v Treatment v  Relative rest / maintain fitness v  Avoid aggravating activities v Pharmacology (NSAIDs??, GTN) v Rehab (eccentric strengthening) Try to find intrinsic / extrinsic causes!

Removing Abnormal Vessels & Nerves

Joint “Diseases” in Children / Adolescents���(Chronic??)

v Osteochondritis (apophysitis / enthesopathy) Articular Non-articular Physeal

v Osgood-Schlatter (tibia) v Sever’s (calcaneus)

Articular Cartilage Injuries / OA v  Many alternative medicines purported

to decrease pain. v  little supporting evidence for: vitamin

A, C, and E, ginger, turmeric, omega-3 fatty acids, chondroitin sulfate and glucosamine.

v  Glucosamine - 2010 meta-analysis found no better than placebo.

v  S-Adenosyl methionine may relieve pain similar to NSAIDs.

v  electrostimulation techniques - no evidence it reduces pain or disability in knee OA

Chondral Defects v  Perera et al. 2012 - isolated chondral defects of knee (>1,000

cases) Autologous chondrocyte implantation, following conclusions:

v  Smaller (<1cm2), well contained lesions may be suitable for microfracture

v  larger defects – ACI satisfactory procedure in 70–80% of cases. v  Motivated patients (15–55 yrs) with single lesion & short (<1 yr)

history and no previous procedures have best outcome. v  ACI - statistically significant improvement in objective and

patient reported clinical outcome scores with durable outcome for as long as 10years.

v  clinical results of ACI and MACI techniques comparable and percen hyaline cartilage (biopsy) appears to improve with time.

v  Lesions of the femoral condyles have superior results to those in the patellofemoral joint.

microfracture

Osteochondral autograft/allograft transfer (mosaicplasty) – cartilage plugs

ACI “tidemark” show filling

Stress Fractures (Reactions)

v Bone failure v (repetitive microtrauma) v Repetitive stresses

² Bending (muscle action) ² Compression (calcaneum) ² Tension (femoral neck)***

v Fatigued muscle ⇓ stress absorb

Stress Fracture Risk Factors

Intrinsic v Sex / Age v Menstrual irregularities v Decreased tibial bone width v Increased ext rot of the hip v Extrinsic v Training change (type, frequency, intensity) v Footwear / Training surface v Equipment

Stress Fractures

v Onset usually insidious v Initially pain during exercise v Relieved by rest v Symptoms occur one month after

change in training regime v Prolonged pain as condition worsens

Imaging of Stress Fractures Bone Scans v  excellent sensitivity / poor specificity v  50% athletes increased uptake in

asymptomatic sites v  non-visualization of fracture

CT v  visualise fracture

MRI (best performed within 3 weeks) v  differential diagnosis (e.g., infection) v  fracture lines appear as low signal

intramedullary bands

Stress Fractures v Modified rest v Avoid precipitating activity v Minimal weightbearing activity v Modify biomechanics v Orthotics v Avoid risk factors v Avoid ultrasound v Most heal ~6 weeks v Healed when

² Absence of local tenderness ² Perform precipitating activity

without pain