Many funeral homes don't showcase the service. A squeamish public might see this as taking recycling to a bizarre extreme. A British publication headlined a story "The Hip Snatchers."
But other funeral homes and crematoria proudly highlight their efforts.
Recycling is practical, after all. The joints are often made of specialty metals, such as titanium, which is also used in airplanes. It is as strong as steel, but 45 percent lighter.
Although no facility is collecting a lot of material - or, at $12 a pound for titanium, a lot of money - why waste it?
"It doesn't do anybody any good six feet under," said Mark Harris, the Bethlehem author of Grave Matters, about green burials.
"We're all dealing with a shortage of materials," Harris said, "so why source new material when we've got plenty of existing material that can be refashioned and reused?"
Bringhurst Funeral Home at West Laurel Hill Cemetery began to recycle metal joints after it started a green burial program and opened a "natural" burial ground in 2008.
"Everybody's thrilled that we do something for the environment," said Deborah Cassidy, family services director.
People are living longer and medicine is advancing, so it's becoming common for people to die with artificial joints.
In 2009, nearly 400,000 people in the United States received hip replacements, according to the American Academy of Orthopaedic Surgeons. More than 600,000 people got knee replacements.
Plus, more people are being cremated. In 1985, about 15 percent of those who died were cremated, says the Cremation Association of North America. By 2010, that figure had risen to 40 percent.
The joints survive the 1,600- to 1,800-degree cremation temperatures just fine, it turns out. Harris watched once as the door was opened after a cremation, and "that thing has got to be so purified by fire, it seemed you could almost slip that back into somebody who needed it."
Medical standards don't allow that. But the replacements are melted down at special recycling facilities, formed into ingots, and put back into the manufacturing stream.
In the past, some crematoria sent artificial joints and other noncombustible metals, such as coffin hardware, to landfills.
Others, including Harleigh Cemetery & Crematory Association in Camden and Philadelphia Crematories Inc., collected the material and buried it in a cemetery plot.
"We felt it wasn't proper to throw them away," said Philadelphia Crematories owner Bill Sucharski.orth
Now, the facility works with Implant Recycling L.L.C. in Detroit, a company owned by a fourth-generation family of metal recyclers that works with 1,200 crematoria.
The company provides bins - about the size of a curbside recycling bin - and when they're full, sends a delivery company to pick them up.
Back in Detroit, the metals are analyzed, sorted, melted down, and formed into ingots.
Donohue Funeral Homes, with a crematorium in Upper Darby, works with OrthoMetals, a Dutch firm that collects from about 25 U.S. crematoria.
Ortho founder Ruud Verberne stresses that none of the metal goes back into another human. Instead, it is used in airplanes, cars, and even wind turbines. He says people don't want metal from a beloved's joint ending up in someone else.
For others, though, that's exactly what they'd like.
Implant Recycling's managing partner, Brad Wasserman, said that its ingots have gone to job shops and that he presumed most of the metal went back into medical implants.
"Some people are comforted by this," said Joe Sehee, founder of the Green Burial Council, an advocacy and certification organization based in New Mexico. It's the idea "that a death can be somehow connected with life."
In 2010, Ray Saadeh, a California man, began a nonprofit, Alternative Solutions USA. He said his goal was to "end the commercialization" of joint recycling.
Physically, his recycling operation is similar. But the proceeds - about 40 percent of the metal's value - are given to charity, he said. In the last year and a half, he has generated $70,000 for charities.
Working with Kirk & Nice, he donated nearly $200 to Manna on Main Street, a food pantry and emergency provider in Lansdale.
The for-profit companies "were all doing a great job," he said, but an ethical problem remained. "How much [money] is being made? And do families know about it?"
Actually, other companies also encourage donations.
Wasserman said that Implant Recycling offered "compensation" for a crematoria's time and effort - roughly $70 per bin of metal. About a third of the companies refuse payment, a third designate a charity, and a third take the money but donate it themselves, customer surveys show.
"We all kind of feel it's not right for the crematory or funeral home to profit from something that belongs to a family," said Bob Arrington, a Tennessee funeral director, who is a member of the National Funeral Directors Association's executive board.
No matter how the donation comes about, crematories often choose charities with wide appeal, such as hospice programs, cancer societies, and shelters. Philadelphia Crematories has designated St. Jude Children's Research Hospital in Memphis.
In October, the funeral association's policy board decided to formulate a policy about joint recycling because the practice was becoming so pervasive.
Still, Sehee doesn't think joint recycling is on the "radar screen" for most families.
Some women lunching in Center City recently were intrigued by the idea.
Although Evy Simon, 72, has no artificial joints, she said she could support the practice as long as "they could guarantee it's not going to be used for weapons."
Susan Kellogg's artificial hip has served her well for 12 years. But the Queen Village resident, 74, wouldn't mind passing it along once she's, er, finished with it.
"It's just a piece of metal."
Ultimate recycling: What to do with what's left over
A lot of things in - or intimately linked to - our bodies outlast us.
Recycling the metal from artificial joints delves into the tricky territory of what to do with what's left over.
For years, families have been sending Poppop's eyeglasses to the Lions Club and donating Auntie's hearing aid to a clinic.
Project My Heart Your Heart at the University of Michigan Health System collects pacemakers, which have to be "explanted" before cremation because they present an explosion hazard. The goal is to reuse the devices in underserved countries.
Because of liability issues, prosthetic devices are not reused in this country, but the Amputee Coalition, based in Knoxville, Tenn., links people with organizations that send them overseas.
For example, Ability Prosthetics & Orthotics Inc. of Gettysburg has teamed up with Physicians for Peace, a nonprofit that works with "the world's most underserved populations."
The trend of reuse and recycling at some crematoria is going further still - especially in Europe.
Given the high cremation temperatures - 1,600 to 1,800 degrees - there's a lot of heat left over. Bethlehem, Pa., author Mark Harris said that some European facilities had been retrofitting crematoria with power-generating turbines. The steam generated from cooling the cremation vault can be used to make electricity.
In Britain and parts of Sweden, he said, crematoria have redirected the heat to buildings, offices, "and recently, a municipal swimming pool."
- Sandy Bauers
Contact staff writer Sandy Bauers at 215-854-5147, firstname.lastname@example.org, or @sbauers on Twitter. Visit her blog at philly.com/greenspace.