I have a lytic lesion on my proximal femur. If surgery is necessary, will they pin it? Is traction necessary?

Diagnosis first . You need a diagnosis of the type of lesion growing first.. This then determines treatment. Once you know the cell type growing there, a team approach to help you is made. Sometimes this requires local removal of the lesion, sometimes wide removal, and then based on what is needed to be removed, how it is managed next is determined. Then an oncologist may be involved to further treatment.
Unlikely & possible. The leg is unlikely to be pinned. The decision to use traction will depend upon how much residual bone is left around the margin of the lesion after it is removed.