A new study in BMJ , the British medical journal, has revived interest in the issue of the kind of materials best used for hip replacements.

Problems have long been reported from many quarters when metal is used to refashion both sides of the ball-and-socket hip joint. We wrote about one manufacturer’s defective product last year.

The trouble comes when the metal parts abrade each other, releasing tiny bits of metal into the surrounding tissue. Essentially, it’s metal poisoning, called metallosis, characterized by pain and inflammation that impedes the ability to walk.