Final answer:
The ICD-10-CM code for a bruised left knee during the initial encounter is S80.02XA. It denotes a contusion of the left knee and that it is the first time the patient is being seen for this injury.
Step-by-step explanation:
The correct ICD-10-CM code for a bruised left knee during the initial encounter is B. S80.02XA. The ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification) is a system used by healthcare providers to classify and code all diagnoses, symptoms, and procedures recorded in conjunction with hospital care in the United States.
For a bruised left knee, 'S80' indicates the injury is to the knee or lower leg, '0' specifies that it is a contusion (bruise), '2' specifies the injury is to the left knee, and 'XA' indicates that it is the initial encounter for the injury.