2.3.1 Introduction

Soft-tissue injury is perhaps the single most important aspect in orthopaedic surgery. Soft tissues are often damaged as a result of an external injury, but they may also be injured by poor surgical technique. In both trauma and elective surgery, problems with soft-tissue healing account for most complications seen in orthopaedic practice. It is therefore worth investing time and practice to learn the principles of soft-tissue handling and management to avoid their further injury and to optimize their recovery after any damage.

2.3.2 Soft-tissue anatomy

It is critical to know the anatomy of muscle, subcutaneous tissue, and skin to understand how to avoid soft-tissue complications. In general, muscle has blood supply from a named artery which passes near it. This either supplies the muscle by a single large vessel near its origin, by multiple segmental vessels arising from the named artery as it travels the length of the muscle, or by a combination of these patterns. The blood supply to a specific muscle may be found in any book which describes flaps.

Bone has two sources of blood supply, endosteal and periosteal (Fig 2.3-1). The periosteal blood supply comes through the heavy fascial attachments associated with muscle origins or insertions. It supplies the outer third of the cortex. The endosteal blood supply runs longitudinally along the medullary canal and originates from the nutrient vessels to the bone. This blood supply contributes branches which supply the inner two-thirds of the cortex. This arrangement may be reversed following a fracture, which usually disrupts the endosteal blood supply, leaving bone blood-flow dependent on the periosteal supply, which is in turn largely dependent on the overlying muscle. Fracture healing is likely to be delayed when there is poor blood supply to the bone if there is no overlying muscle (such as over the distal tibia), or if the muscle is damaged at the time of injury or subsequently, during surgery.

Skin receives its blood supply from perforating vessels which arise from the fascia overlying muscles and tendons. Figure 2.3-2 shows the typical arrangement of blood vessels from deep to superficial. This fascial plexus (1), in turn, is supplied by vessels which run through or around muscles (2). Trauma such as shear stress across the skin and poor dissection technique may destroy these vessels and cause necrosis of the skin.

There are areas of the body which are particularly sensitive to traumatic or surgical shear injury. These areas include the ankle, calcaneus, tibial plateau, and elbow that are vulnerable to degloving and skin necrosis, especially when surgery is performed in the acute setting after trauma.

2.3.3 Classification of soft-tissue injury in closed fractures

There are two main classification systems for soft-tissue injury in closed fractures. The Tscherne classification (Tab 2.3-1) was an early attempt to quantify the degree of injury based on the physical appearance of the wound and fracture pattern. This classification system is still used by trauma surgeons because of its ease of use, but is limited by poor interobserver reliability. The AO soft-tissue grading system (Tab 2.3-2) is more complex and attempts to independently assess injury to the skin, muscle, subcutaneous tissue, and the neurovascular system. It is not widely used in clinical practice but is especially useful in research. Soft tissue can also be assessed by simply looking critically at the skin and subcutaneous tissue for signs of significant trauma:

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  Fracture blisters

  
  
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  Contusion in the soft tissue

  
  
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  Degloving of the skin

  
  
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  Subcutaneous hematoma