A few years ago, Johnson & Johnson subsidiary DePuy found itself facing litigation over a pair of hip replacement products, the Pinnacle and the ASR Hip Implants. Both of these metal-on-metal devices were defective and prone to failure. Apparently, the company has learned nothing from being hit with a $1 billion judgment last year, because this year, another DePuy product, known as the Attune Knee System is causing patients unnecessary pain and expense – and another wave of litigation is certain to follow.

Artificial joints and implants can fail for any number of reasons, not all of which are related to product defects. In most cases, an infection sets in, or patients have other medical issues. In the case of the Attune Knee, however, it has to do with the device’s adhesion system – which is literally “coming unglued.”

When a patient undergoes either a full or partial knee replacement, the damaged or diseased joint is removed and replaced with an artificial one, which is typically made from metal or ceramic. Part of the procedure involves the use of a special adhesive, or glue, in order to attach the joint to the patient’s natural bone.

Under normal circumstances, a knee replacement is good for 12 to 20 years or longer. However, orthopedic surgeons are seeing DePuy knee replacements fail prematurely at an abnormally high rate. When they are called upon to perform revision surgery and remove the failed unit, a number of physicians report no indication that the cement had ever joined the implant to the bone. In other cases, surgeons report seeing implants that appear as if they had never been glued to the bone in the first place.

It is not entirely clear as to why the adhesive cement used in the Attune Knee System is failing, but orthopedic surgeon Dr. Mark Sanchez believes it to be a design defect. Normally, when two objects are joined together with adhesive, the surfaces must be “roughened up” in order to insure a reliable bond. However, when Dr. Sanchez removed these devices from patients, he discovered that the surfaces were “completely smooth.”

This is not the first time that DePuy has had problems with the Attune Knee System. In June of 2015, the FDA issued a Class 2 Recall for one of the system’s components, known as the Tibial Articulation Surface Instrument. This is not an actual part of the implant, but rather a special tool used during the surgery to assist in making certain the patient’s bone in is the correct position to receive the implant. That tool had a small coil that was prone to coming loose – falling into the surgical site and being left inside the patient.

So far, there has been no indication that the device will be recalled any time soon. To the contrary, DePuy continues to stand by its product, and even suggests that device failures may be due to physician error. Nonetheless, given the company’s history, it is likely that DePuy will eventually be forced to recall the Attune Knee System – and injury lawsuits will not be far behind.