How effective are kenalog (triamcinolone) injections for keloids?

Very. The use of corticosteroids is well establish for the treatment of keloids. Multiple injections may be needed over time.
First line treatment. Kenalog (triamcinolone) is an injectable steroid that is in a Depo-Provera form. It, and other injectable steroids, are used to reduce the inflamation in a keloid, and can sometimes stop or even reverse keloid growth. Recurrence is common, and repeat injection may be needed. There are downsides to kenalog (triamcinolone) injections too, so be certain to discuss this option with your doctor.