Urena

Lenny Urena appeals his jury conviction for assault with a dangerous weapon in violation of 18 U.S.C. § 113 (a)(3) and pos session of contraband in prison (a prison knife or “shank”) in violation of 18 U.S.C. § 1791 (a)(2), (b)(3). First, Urena argues that the district court abused its discretion by refusing to instruct the jury on his theory that he acted in self-defense. Second, Urena claims that the district court violated his Confrontation Clause rights by refusing to allow him to cross-examine the treating physician about the cause of the victim’s injuries, and that the district court erred by refusing to let him designate the treating physician as his expert witness on causation during the trial. Finally, Urena further claims that his sentence is substantively unreasonable because his guidelines range sentence included “recency points,” which were removed from the guidelines after he was sentenced. We have jurisdiction under 28 U.S.C. § 1291 , and we affirm.

I

On the morning of April 11th, 2006, federal prisoner Gary Dennis grabbed fellow inmate Lenny Urena and called him a “bitch.” Urena returned the insult and the two separated. Hours later, Urena attacked…