Final answer:
The appropriate gait for a second-day post-op patient of a left hip replacement, who is non-weight bearing, is the three-point gait using crutches or a walker, where the patient avoids putting weight on the affected limb.
Step-by-step explanation:
The appropriate gait for a patient with a left hip replacement in the second day post-operative period who is non-weight bearing would be the three-point gait using crutches or a walker. In this gait, the patient supports weight on both crutches or the walker while lifting the affected limb, in this case, the left limb, to move forward. Then the right, weight-bearing, leg is brought forward. It's essential to ensure that the patient does not put weight on the left hip to facilitate proper healing. Physical therapy usually guides patients through the correct usage of assistive devices during their recovery period.