I say, and with God's success, the wiping over the splint is invalidated by the removal of the splint upon healing. This can happen either while in prayer or outside of it: If it is outside of prayer, one is either in a state of ritual impurity or not: If one is in a state of ritual impurity, they should perform ablution and wash the area of the splint if the wound is on the ablution parts. If one is not in a state of ritual impurity, they should wash the area of the splint only, because they are able to return to the original state, thus invalidating the ruling of the substitute, and washing is obligatory and nothing else; because the ruling of washing, which is purification in the other parts, remains valid due to the absence of what nullifies it, which is the ritual impurity, so it is not required to wash it. As for if it is during prayer: one must repeat the prayer; because they are able to return to the original state before achieving the purpose of the substitute. If one is not in a state of ritual impurity, they should wash the area of the splint only. Refer to: Maraqi al-Falah and the commentary of al-Tahawi on it, pages 136-137, and 'Umdat al-Ri'aya 1: 119, and Sharh al-Wiqaya page 120, and God knows best.