The length of time that stitches should be left in depends on the location of the laceration and how much stress it receives, according to MedicineNet.com. A laceration on the knee requires that stitches stay in place longer than on the thigh because the knee stresses the skin by bending.
Stitches form a loop surrounding the laceration that causes the wound to close when pulled tight, the site notes. Scars start to form around the stitches within seven to eight days. Stitches on the face usually are removed within five days because the region has a healthy blood supply and healing occurs more quickly.
Elsewhere on the body, a doctor may wait seven to 10 days before removing stitches. This is especially true if scarring is not an issue or if there is a concern that the wound is under stress, such as on a joint.