The Complications With Shoulder Joint Replacement Implants

Shoulder replacement, like any form of joint replacement, is often the only option left when a patient can no longer handle the pain and loss of motion due to a deteriorating joint. Injury or arthritis may require such measures, and patients hope that going through the difficult surgery and recovery will mean a better quality of life in the long run. Unfortunately, for many patients the exact opposite happens, and it happens more often than it should.

This can be due to the imperfect nature of joint replacement surgery, which has only been available since the 1940s. However, poor joint design plays a major role as well, and companies like Wright and Tournier are examples of device manufacturers that seem to have taken too many risks with their products.

Prior to surgery, a patient must undergo an extensive battery of tests, including hematology, urine and ECG testing, along with several X-ray sessions. The goal is to ensure the patient is not contraindicated for the procedure and to help develop an implant design that will serve the patient’s particular needs. This latter process is known as templating, and is essential to ensuring a proper fit.

During surgery, the deteriorated joint is removed from the body and the surgical area is prepped for the artificial joint. The new joint is then installed in the body and secured to healthy bone near the joint area. The entire process can take several hours, and often takes a major toll on the patient. Successful implanting also requires a completely clean operating room, as any pathogens or toxins in the surgical space may infiltrate deeply into tissues that are exposed for long periods of time. For this reason, infections near the surgical site are fairly common.

Usually within a few days following surgery, patients are encouraged to begin moving the effected joint. This is to prevent severe, even fatal complications like an embolism, but it does subject the patient to a great deal of discomfort and pain. For weeks, patients will be under close observation as they transition back to a normal life, and it may be several months before the patient fully recovers from the pain and loss of motion caused by the new joint.

In addition to the aforementioned deep tissue infections, shoulder joint replacements can produce some severe complications, particularly when those joints are designed with a metal-on-metal composition.

Metal-on-metal joint designs have a tendency to produce microscopic metallic debris if the two joint segments rub against each other excessively. Excessive friction may result from poor implant design or poor placement, but in either case, the result is similar. Over time, the joint erodes further and further, releasing a steady supply of metal particles into surrounding tissue. When the particles cause damage to this surrounding tissue, it is known as metallosis.

Metallosis is a serious condition that emerges in about 5% of patients that receive a metal-on-metal replacement joint, according to the Journal of Orthopedics. Metallosis can be caused by any kind of metallic debris, though some metals are more biologically active than others. For example, cobalt is an especially dangerous metal in the body, even though some implants are still made with the material. If cobalt leeches into the blood, it can cause a range of symptoms, including blindness and deafness.

The primary symptom of metallosis is tissue death near the implant site, which presents as a mass of dark necrotic tissue near the affected area. This tissue death and continued infiltration of metallic debris can produce a variety of secondary complications, including:

  • Chronic pain, which can become debilitating.
  • Loss of supporting bone tissue, which may lead to joint failure and fractures.
  • Infection, as necrotic tissue loses the ability to defend itself from bacterial and viral invaders.
  • Heart problems, including heart failure.
  • Cognitive impairment, including psychological and behavioral disturbance.
  • Damaged hearing, and even total deafness if not corrected quickly.
  • Thyroid and skin damage.

The only way to treat metallosis is to remove the damaged tissue and the underlying cause of the metal debris, which in this case is the implant. Of course, doing so means subjecting the patient to additional surgeries, which come with their own risks and extended recovery times, not to mention additional financial costs.

With these risks in mind, the FDA has maintained a safety communication that it has updated for several years. The FDA’s safety communication is intended to keep medical practitioners up-to-date on the latest research regarding metal-on-metal implants, and it has little positive to say about such implants. In fact, the FDA believes doctors should look at all other implant options before choosing a metal-on-metal implant. And even then, the FDA wants doctors to exercise maximum thoroughness when screening patients to ensure they are not at a higher risk of developing complications.

Some patients that are considered to occupy a higher risk profile include:

  • Female patients.
  • Patients with small femoral heads. The femoral heads are the uppermost part of the femur bones, and small femoral heads make it more difficult to properly fit the implant.
  • Patients receiving bilateral implants, or implants that are placed on both sides of the body.
  • Patients that are significantly overweight.
  • Patients that regularly engage in heavy physical activity.
  • Patients with a history of renal problems.
  • Patients with a suppressed immune system.
  • Patients with a noted allergy to metals, particularly nickel or cobalt.

In short, there are a lot of people that are at greater risk of developing metallosis, and this is something that doctors must keep in mind before sending a patient to surgery. In some instances, metallosis may also form pseudotumors, which may appear similar to cancerous tumors, but are actually due to fluids building up around the affected area. Fibrosis can also occur, and fibrous masses can spontaneously become cancerous.

Though there is no established link between metallosis and cancer, the FDA considers cobalt and trivalent (a form of chromium) to be possible carcinogens, so the likelihood is that metallosis does increase the risk of cancer in some way.

WRIGHT AND TOURNIER FACING SCRUTINY

In 2015, Wright and Tournier joined forces through a corporate merger, creating a powerhouse in the medical device industry. When the news was announced, it was met with a lot of praise, as the two companies have complementary strengths, ensuring they could diversify their product offerings significantly. It also gives the companies a chance to dominate certain elements of the industry. For instance, together Wright and Tournier now control close to 50% of the global ankle replacement market.

The merger was also met with some skepticism by regulators and industry observers because it involves a heavy tax inversion scheme as well. During tax inversion, a company shifts its tax burden to countries that demand less taxes, while maintaining operational facilities and headquarters stateside. Currently, federal regulators are attempting to get a handle on tax inversion, including determining to what extent it should be prohibited. Specifically for Wright and Tournier, the merger will involve moving the new company’s legal address to the Netherlands, where Tournier has maintained its headquarters for eight years. The new company’s U.S. headquarters will be housed at Wright’s Kentucky facilities.

While tax inversion doesn’t necessarily indicate company malfeasance, it does suggest Wright and Tournier are willing to skirt regulations to maximize their profits. And there are examples of Wright implants causing problems in the past. Specifically, its hip replacement joints have also been responsible for many instances of metallosis. In one case, a ski instructor named Robyn Christansen received a Wright hip implant in 2006. After reviewing information provided directly by Wright, Christansen determined the company’s metal-on-metal implants was the best choice, as it was advertised to last longer. Six years later, in 2012, Christansen began suffering from severe pain, which she believed was due to the replacement joint shifting out of place. She underwent corrective surgery, and during surgery the medical team discovered extensive tissue death due to metallosis.

In 2013, Christansen filed a lawsuit against Wright, stating that the company did not properly represent the safety of its implants. A couple years later, a jury found Wright responsible for Christansen’s injuries, leveling an $11 million judgment against Wright, of which $10 million was punitive. In other words, the jury agreed that Wright’s negligence was especially egregious and warranted additional recompense.

In fact, some see the merger between Wright and Tournier to be an attempt on Wright’s part to remain fiscally solvent as it sustains additional financial damage and scrutiny from regulators.

That financial damage will likely continue into the foreseeable future, as its metal-on-metal shoulder replacement joints are already attracting negative attention. Industry experts expect Wright, and now Tournier, to be subjected to another round of legal action.