Preheat your oven to 375°F (190°C).
In a large bowl, combine the ground beef, ground pork, breadcrumbs, Parmesan, onion, garlic, egg, salt, pepper, and Worcestershire sauce.
Shape the mixture into golf ball-sized meatballs and arrange them on a greased baking sheet.
Bake in the oven for 20-25 minutes, or until browned and cooked through.
While the meatballs are baking, prepare the sweet and sour sauce in a saucepan over medium heat.
Stir in the vinegar and pineapple chunks once the sauce begins to simmer.
Once the meatballs are cooked, remove them from the oven and add them to the sauce.
Let the meatballs simmer in the sauce for an additional 5-10 minutes before serving.