Final answer:
Bilateral shoulder films for an AC joint injury are decided upon based on a clinical assessment, including physical examination of shoulder movements such as abduction and adduction. Imaging confirms the diagnosis and informs treatment planning.
Step-by-step explanation:
The decision to obtain bilateral shoulder films in a suspected AC joint injury is based on a clinical assessment of the patient, which may include a physical examination and patient history. During the physical therapy assessment, the therapist evaluates the functionality of the shoulder joint by asking the patient to perform movements like abduction, adduction, circumduction, and flexion and extension of the arm. This examination helps to determine the shoulder's degree of function and the extent of the injury. If clinical assessment suggests an AC joint injury, diagnostic imaging such as bilateral shoulder films may be indicated to fully assess the status of the joint and confirm the diagnosis, thus informing treatment planning.