Wound contraction is the movement of the edges of a wound towards the center to close it. This process precedes the maturation stage of healing, and generally occurs between five and 15 days after the original injury is sustained. It should not be confused with contracture, which is the formation of dense bands of scar tissue that limit range of motion. Skin and tissues tighten around a contracture, and may freeze a limb in a painful position.
Healing follows a precise set of stages, starting with an inflammatory response to the initial injury, following with a proliferative phase where new tissue rapidly grows in to start filling the wound, and ending with a maturation phase. In wound contraction, the boundaries of the injury shorten and tighten as fibrous tissue starts to form inside and pull together. This closes the injury, protecting underlying tissues and laying the groundwork for maturation. During the final stage, the wound fills in, and the skin has a chance to recover its normal color and texture, depending on the size and nature of the injury.
Shrinkage is an important part of the healing process. During contraction, the wound may feel slightly tight, and can itch as the tissues heal. Patients may notice the size of the wound going down as it contracts from end to end and side to side. Square wounds in particular tend to tighten considerably during wound contraction, while irregular and round injuries can develop a distorted shape as the edges pull together and start to fill in.
One concern with wound contraction is the risk of developing a contracture. The wound shouldn’t tighten too much, or it might create heavy scarring that limits range of motion. This can be a particular concern with full thickness burn wounds over a large extent of the body. These injuries are so large that as they tighten, they may pull against the skin in the region. Patients may need to use physical therapy during healing to retain flexibility and keep the skin supple so it doesn’t tighten too much.
During this phase of healing, it’s important to keep the wound clean and dry. Severe injuries may be treated in a hospital environment where nurses can monitor the site. Contraction is considered a good sign, as it indicates the injury is ready to start maturing, and the patient may be able to go home soon. Complications during wound contraction could include underlying infection, contracture, and a failure to fully close.