Final answer:
Malunion is a term used to describe the improper alignment of bones after a fracture, which could lead to functional impairment of the affected limb. This may require additional treatment to correct.
Step-by-step explanation:
If a client's fractured arm is healing with malunion, this indicates that the bones are healing improperly and are not aligned correctly after a fracture. This can lead to functional impairment and may require medical intervention to correct. In the case of a comminutive midshaft humeral fracture with callus formation, this suggests that there has been a break in the middle section of the upper arm bone (humerus) that has resulted in multiple bone fragments.
As the healing process begins, a callus forms around the fragments as part of the body's natural healing process. However, if these fragments do not align properly, malunion can occur. The nurse would recognize this as a concern that might necessitate further treatment, potentially including surgery, to ensure proper healing and restoration of function to the arm.