Is it permissible to combine prayers due to difficulty in movement and ablution because of a cast?

The basic principle is that prayer should be performed at its appointed time, as Allah Almighty says: "Indeed, prayer has been decreed upon the believers a book [due at] fixed times." Many scholars permit the sick to combine the Dhuhr and Asr prayers, and the Maghrib and Isha prayers, if performing each prayer at its own time causes them hardship.