Photo by jay.tong/Flickr CC
When I was a butcher--a student job I held for less than a year in California--the cut of meat that most thrilled my knife was beef knuckle. To cut the knuckle from a quarter of cow hanging from a meat hook, you start by finding the kneecap at the top and then hacking it loose from its topmost sinews. Thus unmoored, the kneecap provides a convenient handle on which to tug down as you separate the knuckle from the rest of the leg. The knuckle falls away from the bone in a very natural way, perhaps because gravity is on your side: with a knife in your dominant hand and the kneecap in your other, you let the blade tickle the leg. The knuckle sags away, more eager than most cuts of meat to be tied up and packaged.
The pork knuckle, though, presents none of these pleasures to the butcher--nor, for that matter, to most diners. It is smaller, and is cut away intact and bone-in. Unlike beef knuckle, which is generally cut up for roasts or steaks, pork knuckle serves just one person, and at the table requires much picking around bones and fat. My local specialty butcher in Washington says that no one has asked for a pork knuckle in a year. Even good butcher shops need to special-order pork knuckle. When they do, they expect that their customers will use it for ethnic stews--generally Asian, such as certain braised pork dishes in China, or pata ("paw"), a Philippine delicacy.