Wounds and Soft Tissue Injuries

Definition, Pathophysiology and Classification

·         Wound: An injury to living tissue (especially an injury involving a cut or break in the skin).

Pathophysiology of a Wound Infection

·         Most wounds are contaminated except for surgical wounds made under aseptic conditions.

·         Wound infection follows contamination by dirt, damaged tissue, and foreign bodies.

·         The bacteria invade tissues and cause more damage while tissues which have not been damaged resist infection by a process called inflammation.

·         When a wound is inflamed, blood vessels dilate to bring more blood to the injured part.

·         The capillary walls change so that antibodies and white cells can pass through more easily.

·         The result is the part becomes warmer and redder because there is more blood in it, and swollen because there are more white cells and fluid.

·         Pain is partially due to increased swelling in the part, and partially due to the effects of the inflammation process.

Signs of Acute Inflammation (Cardinal Signs of Inflammation)

·         Heat (Calor )

·         Redness (Rubor )

·         Pain (Dolor )

·         Swelling (Tumor )

·         Loss of function (Functio laesa )

Figure 1: An Open Wound and the Balances of Force

Source: Bewes P, 1984, AMREF

Figure 2: The Effect of a Stitch

Source: Bewes P, 1984, AMREF

Classification of Wounds

·         There are several classifications of wounds.

·         Each classification can direct treatment modality.

·         Classification by degree of contamination:

• Clean wounds are mostly those made in the operating rooms in hospitals.
• They have clear sharp edges, not contaminated and have minimal tissue damage.
• Contaminated wounds occur outside the operation rooms, they are potentially contaminated thus liable to develop infection.
• Tissue damage may be extensive.
• Infected wounds show obvious signs of infection like pus and necrotic tissue.

Management of Wounds

Wound Assessment

·         History

•  How long ago was the wound sustained?
•  How was the wound sustained?
• What is the status of active immunization against tetanus?

·         Examination of the wound; look for:

o    Active bleeding

o   Contamination

o   Depth and describe tissues involved

o   Edges

o    Site

Cleansing the Wound (Social Toilet)

·         Clean the wound and surrounding skin with soap and water.

·         Do not use hard brush, sponge should suffice.

Figure 3: Social Toilet

Source: Bewes, 1984

Surgical Toilet

·         All contaminated wounds need to undergo surgical toilet.

·         Clean the wound by debridement (remove dead and damaged tissues using a knife and apply antiseptic solution).

Figure 5: Trimming the Skin Edge

Source: Bewes, 1984

Classes and Indications for Wound Closures

·         Primary wound closure

• Clean post operative wounds
• Surgically clean wounds after surgical toilet

·         Delayed primary closure

• Done for contaminated wounds after surgical toilet
• Wound is observed for three to four days observing for onset of infection
• If there is no infection then wound closure is performed

·         Secondary closure

• Indicated for obviously infected wounds
• Closure is deferred until infection is under control

Complications of Wounds and their Management

·         Cellulitis

• Non suppurative invasive infection of surrounding tissues by organisms such as ß-haemolytic streptococci, staphylococci and Clostridium perfringens.
• Cellutitis is managed by application of local antiseptic and systemic antibiotics.

·         Septicemia

• Multiplication of bacteria in the blood with the production of severe systemic symptoms such as fever and hypotension.
• It has an extremely high mortality and demands immediate and appropriate attention.
• It is managed by adequate rehydration, systemic antibiotics and antipyretics.

Management of Soft Tissue Injuries

·         Soft tissue injuries are those injuries excluding fractures, affecting the joints and muscles of the limbs.

·         Sprains and strains are considered soft tissue injuries.

·         Sprains: Ligamentous injuries associated with the overextension of a joint.

• Ligaments connect bone to bone
• Damage to ligaments can range from microscopic to complete disruption

·         Strains: Injuries to the musculotendonous unit (tendons connect muscle to bone)

• May range from microscopic to complete disruption. 

·         The treatment of soft tissue injuries is based on resting the injured part, applying ice packs to limit swelling and reduce pain by prescribing analgesics or local analgesic cream or gel.

·         RICE: The application of a firm compression bandage as support, and elevation of the limb.

·         The acronym ‘RICE’ can be remembered as follows:

o   R= Rest        I= Ice        C= Compression       E= Elevation

·         The application of ice and compression causes vasoconstriction and tamponades the blood vessels and elevation of the limb improves venous drainage.

Complications of Soft Tissue Injuries and Their Management

Compartment Syndrome

·         Increased tissue pressure within a muscle compartment compromising the blood supply and the function of structures within that space.

·          Causes

o   Tight casts or dressings

o   External limb compression

o   Burn eschar

o   Fractures

o   Soft tissue crush injuries

o   Excessive exertion

·         Clinical presentation

• Pain out of proportion to the injury
• Puffy/tense muscle compartments to palpation
• Parasthesia (decreased sensation)
• Paralysis (weakness of the involved muscle groups)
• Pallor
• Pulselessness (decreased capillary refill, late finding)

·         Management

• Split the cast and remove dressings, if present
• Place limb in neutral position; elevation may be harmful
• Support circulation with IV fluids or blood where indicated
• Observe carefully for improvement i.e. colour, pulse and pain
• If signs and symptoms persist, refer for immediate surgical decompression (fasciotomy)
• Fasciotomy must be performed early, ideally within six hours of the onset of symptoms

Myositis Ossificans 

·         Myositis ossificans is an unusual condition that often occurs in athletes who sustain a blunt injury that causes deep tissue bleeding.

·         Severe bleeding into the muscle creates a hematoma, which may trigger a healing pathway that leads to formation of ectopic bone in the muscle.

·         Treatment of myositis ossificans consists of:

• Rest
• Immobilization in a stretched position
• Pain relief with acetaminophen; NSAIDS are avoided in order to limit bleeding