How much of a chance is there for keloid to form after ear reduction surgery?

Keloid (an unusually thick and prominent scar) formation is always a possibility in any type of surgery as surgical incisions go through the healing and scar maturation process. Some of the factors involve include the patient's skin genetics including pigmentation, the tension on the wound, surgical technique, adherence to optimal postoperative care and preventive measures. The risk of prominent scar formation in otoplasty is relatively higher than some other facial surgeries such as nose job, eyelid or brow surgeries, but still low, and there are measures to lower its chance and also revise it if needed.

Keloid management must follow a protocol approach. Our office uses a
combination of Vbeam laser, Kenalog IIT, scar modulation, scar serum
therapy, and enucleation. 
Best, 
Dr. Karamanoukian
Realself100 Surgeon

Thanks for the question. As all aesthetic operations, there is a risk of bleeding and infection in the early period. After  the healing process, asymmetry, irregularities and stitching problems seen very rare. I wish you all the best.

typically behind the ear incisions heal well.  The risk of a hypertrophic scar or a keloid are never zero, but they are pretty small.

While the risk of keloid formation in the incision behind the ear is small, it's not zero.  Discuss your concerns, and personal and family history of scars with your surgeon during your preoperative consultation.  Treatment of keloids, should they form, involves scar excision, steroid injections, and low-dose radiation therapy.  Good luck!