A spica cast is a hard covering over the waist, hips, and legs that prevents movement of the hips. A bar between the legs strengthens the cast. An opening in the genital area allows normal urine and bowel elimination. A spica cast may be used to keep the hip joint of a child with developmental dysplasia of the hip (DDH) in the position for normal growth. Spica casts are usually worn for 2 to 3 months. They can't be removed during this time.