The DePuy Synthes Radial Head Prosthesis System is a two-piece elbow-joint replacement device. It is designed to replace the arm’s natural radial head. This is the knobby end of the radius, the bone on the thumb side of the lower arm. The device consists of a stem that is inserted into the radius and a head that replaces the natural radial head.
By late 2016, DePuy had received numerous reports that the stems of these devices had loosened in several patients. The company could not determine what exactly caused the problem.
“[W]e believe the cause to be multifactorial (including possible product characteristics, operative and patient factors),” DePuy said in its global market removal letter.
The company said the head component was not involved in the loosening issue and DePuy said that component would remain available — without the stem — for revision surgeries requiring the replacement of the head component only.
The U.S. Food and Drug Administration (FDA) classified DePuy’s action as a Class 2 Device Recall, which the agency defines as “A situation where a product may cause a temporary or reversible health problem or where there is a slight chance that it will cause serious health problems or death.”
Why do People Receive DePuy’s Radial Head Prosthesis System?
The DePuy Synthes Radial Head Prosthesis System and similar devices may be used to replace the natural radial head if it becomes fractured beyond the point of repair. The American Academy of Orthopaedic Surgeons estimates radial head fractures happen in about 20 percent of all acute elbow injuries and 10 percent of elbow dislocations.
People with certain degenerative conditions such as arthritis or other conditions that have advanced to serious levels and that do not respond to other treatments may be candidates for this type of device.
The DePuy Synthes Radial Head Prosthesis System is also indicated for revision surgery to replace previous elbow implants that have to be removed and replaced due to wear or medical complications.
Complications of elbow replacement surgery can include:
- Allergic reaction to the implant
- Broken bones
- Joint instability
- Loosening of the implant
- Nerve and blood vessel injury
- Tendon weakness or failure
- Joint stiffness
Serious problems may require a second surgery to replace the original implant. Each surgery carries its own risk of complications.
Elbow Replacement Loosening Can Cause Serious Complications
Loosening of the DePuy Synthes Radial Head’s stem can result in:
- Osteolysis – a loss of bone tissue
- Poor joint mechanics
- Post-operative fractures
- Soft tissue damage
The DePuy Synthes Radial Head Prosthesis System features 10 different stem sizes that allow surgeons to customize the implant to the patient’s anatomy. During surgery, the natural radial head is removed and the stem is inserted into the end of the bone. It is designed to “press-fit” into the bone. The surface of the stem is roughened to promote the bone to grow around the stem and hold it firmly in place.
If the implant loosens, it can cause problems in the way the device works and can lead to other health problems.
If the implant loosens, the only way to correct the problem may be through revision surgery to repair or replace the device. In its product removal notice, DePuy told health care professionals of patients implanted with the devices to “continue to follow those patients in the usual manner.”
Signs of DePuy Radial Head Prosthesis System Loosening
Not all DePuy Synthes Radial Head Prosthesis System stems loosen and it can be difficult to determine if any individual implant will fail. But the first sign of a problem may be pain in the forearm.
Signs that an elbow replacement implant has loosened include:
- Impaired range of motion
The authors also pointed to forearm pain as major indication of loosening in implants similar to the DePuy design.
“The presence of proximal radial forearm pain in a patient with a radial head prosthesis is an indicator of symptomatic mechanical loosening,” the researchers wrote. “If the prosthesis has a textured surface for bone ingrowth, and was inserted without cement, we now consider this a strong indicator of loosening, even in the absence of radiographic signs.”
If a patient who has had elbow replacement surgery experiences these problems, a doctor will rely on other tests to determine if loosening is the actual cause.
To determine if a DePuy Radial Head Prosthesis has loosened, a doctor may order one or more examinations such as:
- Bone scans
- Other diagnostic imaging or clinical work-ups
DePuy Elbow Implant Approved through FDA 510(k) Process
Johnson & Johnson, DePuy’s parent company, heralded the introduction of the Synthes Radial Head Prosthesis System as a significant advancement in elbow replacement when it debuted in 2013.
“The System offers several benefits over current technologies,” the Johnson and Johnson news release read.
But the company had received FDA approval to market the device after DePuy Synthes convinced the agency its device was “substantially similar” to 12 other medical devices already on the market.
Orthopedic device maker Synthes received FDA approval to market the device on June 13, 2011. Synthes merged with Johnson & Johnson’s DePuy franchise in June 2012.
The FDA cleared the implant for sale in the U.S. through the agency’s 510(k) process on June 13, 2011. The process allows device manufacturers to skip much of the FDA’s formal approval process if they can show their device is “at least as safe and effective, that is, substantially equivalent, to a legally marketed device” that is already on the market.
In its application, the company said the device had “the same indications for use, the same fundamental technological characteristics, and similar materials” as two other radial head devices sold by competing companies. The application also said the Synthes Radial Head had similar surface characteristics as 10 devices ranging from dental implants to spinal fusion devices to two components Synthes already sold.
DePuy’s application stated that the “Synthes Radial Head Prosthesis System does not raise any new issues of safety and effectiveness in comparison to the predicate devices.”
Devices DePuy compared the Synthes Radial Head Prosthesis System to in its 510(k) application:
- Biomet ExploR Modular Radial Head
- Ascension Modular Radial Head
- Titan Endoskeleton Interbody Fusion Devices (Five different versions)
- Rhausler Plage Anterior Cervical Fusion System
- Straumann Dental Implant System (Two versions)
- Synthes Epoca Titanium Humeral Stem (Two versions)
In February 2013, DePuy recalled 417 of the devices because of a problem with its trial head. A trial head is used during surgery to determine if the actual head will function properly when implanted. DePuy reported that the trial head shipped with the implants could come lose from the stem during surgery. The company said there had been no adverse events due to the problem at the time of the earlier recall.
DePuy removed the Synthes Radial Head Prosthesis System from the market in December 2016 after reports of the stem loosening. A total of 50,311 devices were affected by the recall.
Terry Turner is an Emmy-winning, former television journalist. As a Washington-based reporter for a group of 100 local news departments across the U.S., he routinely reported on health and medical policy issues before Congress, the FDA and other federal agencies. Prior to that, he covered state and federal courts for several local television stations in the Midwest and on the East Coast.