After surgery on a broken bone

Because the metal is only a splint on the inside.

The plate or rod holds the pieces in line, but it is not built to carry your full load on its own for long. If the bone is loaded too early, the metal can bend or the screws can loosen. As the bone heals it takes the load over, which is why the X-rays decide when you can do more.

Usually not.

Most plates, screws and rods are made to stay in for life and cause no trouble. We take them out only if they rub or cause pain, or for particular reasons in young patients — and only after the bone has fully healed. Wires and pins are different: they are often taken out once the bone has healed.

Small skin nerves are cut by the incision.

A patch of numbness next to the scar is common and usually shrinks over months. It is different from numbness in the fingers or toes, which needs checking the same day.

Six to twelve weeks for most bones; longer for the thigh and shin.

Bones in the arm usually knit in six to eight weeks, and most leg bones in six to twelve; the thigh and shin bones often take longer. Smoking, diabetes and infection slow it down. Strength and full movement return after the bone does, which is why the exercises continue after the X-ray looks healed.