Linear scars can be divided in two groups:
i) Hypertrophic linear scars which are red, raised and sometimes itchy; they are confined to the borders of the original injury. These scars develop within weeks of surgery and may worsen for three to six months before improving. These scars when mature (the process of scar maturation/healing is complete) may be raised, slightly rope-like in appearance and wide. Full maturation can take up to two years.
ii) Stretched linear scars appear when the fine lines of a surgical scar become stretched and widened. These scars are typically flat, pale, soft, symptomless scars and are common after knee or shoulder surgery. Scars that healed with some wound infection or have had stitches that dehisced (burst open) also may be wide, but these scars tend to become hypertrophic. Stretch marks after pregnancy are variants of stretched scars. Unlike hypertrophic scars they are not raised or thickened, and they tend to be smooth rather than bumpy.