Complex sentence: Elkins made his UFC debut on the preliminary card of, where he defeated Duane Ludwig via TKO after Ludwig suffered a serious ankle injury after being taken down by Elkins in the first round.
Split into simpler sentences: Elkins made his UFC debut on the preliminary card of, where he defeated Duane Ludwig. Elkins defeated Ludwig via TKO after Ludwig suffered a serious ankle injury after a takedown from Elkins in the first round.