The Injury Process

The human body consists of many different types of tissue, each serving a specific purpose

Connective tissue◦ The most common type in the body◦ Ligaments, retinaculum, joint capsule, bone, cartilage,

fascia, and tendon (Cailliet, 1977) Epithelial

◦ Protection, secretion, and absorption Muscular

◦ Contraction Nervous

◦ Touch and conductivity

The Physics of Sports Injury

Connective tissue is involved in both acute and chronic injuries

50% of all injuries in some sports are acute in nature and involve either muscle or tendon tissue

Muscles and fascia are injured when excessive tension is applied while contraction is occurring

Occur during eccentric contractions◦ The simultaneous processes of muscle contraction

and stretch of the muscle-tendon unit by an extrensic force (Safran et al., 1989)

Damage to strains typically is found at the proximal musculotendinous junction (MTJ)

Mechanical Forces of InjuryThree types of forces:

Tensile ForceCompressive Force

Shear Force

Type of Tissue Connective(Tendons)

Bone Tissue Ligament Tissue

Tensile Force Resist Less effective Resist

CompressiveForce

Poorly Designed Absorb More vulnerable

Shear Force Less effective Less effective More vulnerable

Compressive force = axial loading that produces a squeezing or crushing effect

Tensile force = axial loading in the direction opposite that of compression

Shear force = acts parallel or tangent to a plane passing through the object

Each tissue type has a limit to how much force it can withstand

The limit has been referred to critical force (Nigg & Bobbert, 1990)

Factors such as age, temperature, skeletal maturity, gender, and body weight can affect the mechanical properties of ligaments

Mechanical Forces of Injury

Body’s initial response to trauma is inflammation

3 phase process◦ Inflammatory phase◦ Fibroblastic phase◦ Remodeling phase

Physiology of Sports Injury

0-6 Days Vasoconstriction promotes increased blood viscosity

(thickness), reducing blood loss through bleeding The platelet reaction initiates clotting and releases

growth factors that attract reparative cells to the site

The coagulation cascade affects clot formation The complement and kinin cascades provoke

vasodilatation and increase blood vessel wall permeability, facilitating the migration of neutrophils and macrophages in plasma exudates to cleanse the site through phagocytosis

Inflammatory Phase

3 – 21 days Connective tissues heal themselves by forming scar

tissue Fibroblasts (immature, fiber producing cells

located in connective tissue) produce a supportive network of Types I and III collagen

The platelet response and hypoxic wound environment stimulate angiogenesis (formation of capillaries, which interconnect, resulting in the formation of new vessels)

Epithelial cells migrate from the periphery toward the center of the wound to enact re-epithelialization

Proliferation Phase

Up to 1+ years Fibroblast activity decreases and habitual loading

produces increased organization of the extracellular matrix

A return to normal histochemical activity allows for reduced vascularity and water content

Types I and III collagen continue to proliferate, replacing immature collagen precursors and resulting in contracture of the wound

Scar tissue formation results in decreased size and flexibility of the involved tissues

Remodeling causes collagen fiber alignment along lines of habitual stress, with tensile strength increasing for up to 2 years post injury

Maturation Phase

How the injury process affects soft tissue and bone…

Bone injuries heal similarly to soft tissues; however, osteoclasts migrate to the region of injury and remove destroyed cells and debris

Fibroblasts (osteoblasts) migrate to the injured area

New osteoblasts are manufactured Osteoblasts develop collagen and cartilage called a callusCallus fills the space between the fractured bone ends and can be seen on an x-ray

Callus is not of sufficient strength to substitute for the original bone; however, through maturation it becomes fully functional bone

Although inflammation is the most visible aspect of an acute injury, the athlete will complain of pain as the largest problem

Pain is defined as, “the perception of an uncomfortable stimulus or the presentation or response to that stimulus by the individual,” (Thomas, 1997)

Two types of pain◦ Psychological (emotional)◦ Physiologic (tissue damage)

Result of sensory input received through the nervous system that indicates the location of damage

An athlete with high pain tolerance may underestimate the severity of the injury

An athlete with low pain tolerance may exaggerate the severity of the injury

In short, pain may not be a useful indicator of the severity of an injury

Pain and Acute Injury…

Common Modalities used to treat pain

IceHeatElectrical Stimulation (e-stim)MassageProphylactic wrapping

Suggested treatments of inflammation include the application of cyrotherapy (therapeutic use of cold),◦ Crushed ice packs, ice cups applied via massage,

ice-water baths, commercially available chemical cold packs, and aerosol coolants (ethyl chloride)

After the acute inflammatory phase has passed, usually 48 to 120 hours following thermotherapy (therapeutic use of heat) may be appropriate◦ Hydrocollator packs, warm and moist towels, and

ultrasound diathermy

Intervention Procedures…

Cyrotherapy and Thermotherapy

Ice helps reduce recovery time

Tissue cooling reduces the metabolic activity of the cells with reduces need for O2

During first few minutes of the inflammatory phase, direct application of cold may reduce vasodilation, there by reducing the swelling

RICES should then be applied which stand for◦ Rest◦ Ice◦ Compression◦ Elevation◦ Support

Standard first aid procedure for sprains, strains, dislocations, contusions and fractures

Thermotherapeutic agents may also have a beneficial effect on soft tissue injury

Research is unanimous that such treatments should never be applied during the acute inflammatory phase

If we heat the tissue during the early phases of the injury, the metabolic activity of the inflammatory agents increases, resulting in an increase in inflammation (Wilkerson, 1985)

May be useful during the final phases of injury◦ Increasing available oxygen and stimulating vasodilation ◦ Heat increases local metabolic activities

In addition to cold and heat therapy, pharmacologic agents – drugs designed to prevent swelling (anti-inflammatories) or drugs designed to prevent pain (analgesics) are often used to treat inflammation

Majority prescribed by a medical doctor Some are available over the counter OTC Should consult with parents prior to

recommending any sort of pharmacologic agent, including OTC medications

Classified into two groups: steroidal and nonsteroidal anti-inflammatory drugs (NSAIDS)

Steroidal Anti-inflammatory Drugs◦ Best known is cortisone◦ Others commonly used include hydrocortisone,

rednisone, prenisolone, trimcinolone, and dexamethasone

◦ Even introduced through the skin via phonophoresis (using ultrasound energy) or iontophoresis (using electrical current)

Pharmacologic Agents

NSAID’s block specific reactions in the inflammatory process◦ Do not negatively affect collagen formation

Block the breakdown of arachindonic acid to prostaglandin, which in turn decreases the inflammatory response to injury

Done by decreasing the healing time or by increasing the strength of the new tissue

Commonly used NSAID on the treatment of acute ankle sprains

Nonsteroidal Anti-Inflammatory Drugs

Best approach to treating the majority of soft-tissue injuries involves the application of RICES during the acute inflammatory phase

Followed by a combination of RICES, prescribed pharmacologic agent and prescribed and properly supervised rehabilitative exercises

The coach or other nonmedical personnel should provide only initial first aid to any soft-tissue injury then refer to appropriate medical authority

Most effective treatment for any sports injury, especially those involving soft tissue is physical activity

Need to have a properly constructed and supervised exercise regime

Research indicates that rehabilitative exercise can exert a variety of positive effects on collagen formation (AAOS, 1991)

The Role of Exercise Rehabilitation

According to knight (1995), exercise is essential during the healing process for two reasons◦ 1. Exercise results in increased circulation with a

concomitant increase in oxygen supply to the healing tissue

◦ 2. Exercise stresses the healing tissue and in essence “guides” the proper structuring of collagen

The process of collagen formation and tissue regeneration requires 2 to 3 weeks

Have the area properly protected with adhesive taping, wrapping, or bracing

Return to participation by a medical professional with experience in sports injury

An injury severe enough to warrant a medical diagnosis should be treated with a comprehensive program of exercise rehabilitation

Rehabilitative exercise, often called therapeutic exercise, is a four-phase process consisting of categories of exercise based on a continuum of severity and recovery

First, if the athletes injury is severe, the initial exercise involves the therapist moving the injured extremity through a series of passive exercises◦ Reestablishment of a normal range of motion (ROM)◦ Reduction of swelling and muscle spasm

Second, as injury improves the next phase becomes active assisted◦ Athlete becomes a working partner in the exercise

process, making a voluntary effort to move the injured joint while being assisted by a therapist Improved ROM and increased muscle strength

4 Phase Process

Thirdly, rehabilitation process is active exercise◦ Athlete continues moving the joint through a full ROM,

using gravity as resistance to stimulate development of muscle strength

◦ PT supervises activity, no physical assistance Fourth, the final phase is resistive

◦ External resistance is applied to the joint movements◦ Manual resistance, resistive exercise machine, free

weights Primary objective is to improve the strength of the

muscles surrounding the injured area to protect the injured area from future injury

Must incorporate functional activities

4 Phase Process