My husband had testicular torsion when he was younger, could this be a reason why we are having trouble conceiving?

Sometimes. It might be a contributing factor, or may not be important. He should be evaluated, and if you've been trying for a year you should too.
May be... Life is a one-way street of accumulation, modification, and continuation from inception to eternity. So stated, realize many men contribute directly to 35% of infertility, even though most of them had no prior inguinal or scrotal surgery. But, studies have shown testicular damage to twisted testis carrying significant negative impact to overall sperm production. So, treat hubby's as a part o.