On September 27, 2016, the Department of Health Therapeutic Goods Administration (the Australian equivalent of the Food & Drug Administration) issued a hazard alert relating to LFIT Anatomic CoCr V40 femoral heads manufactured and marketed by Stryker. The LFIT V40 femoral heads are made of a cobalt and chromium alloy and utilized in a number of Stryker modular hip implant devices. The Australian safety alert notes that a higher than expected incidence of taper lock failure has occurred with LFIT Anatomic CoCr V40 femoral heads that were manufactured prior to 2011. There have been a number of published medical reports noting a failure of the taper lock, which is the place where the femoral head of the hip implant connects to the femoral neck. The Australian safety alert noted that patients and orthopedic surgeons should be concerned about the following symptoms and conditions in patients implanted with these Stryker modular hip implants: loss of mobility; pain; inflammation; adverse local tissue reaction (ALTR); dislocation; joint instability; broken bones around the hip implant; leg length discrepancy; and the need for revision surgery. The following modular hip implants were specifically noted in the Australian safety notification:
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Australian health regulators have urged patients to contact their orthopedic surgeons if they are experiencing any issues with their hip implants so that they can be evaluated for potential failure of the components used in their Stryker modular hip implant. Patients who are experiencing issues relating to corrosion and failure of the LFIT V40 femoral head can be evaluated by physical examination and various diagnostic testing, including x-rays, MARS MRI, and blood testing for elevated levels of cobalt and chromium.
Stryker has notified Australian surgeons of the potential safety concerns relating to the LFIT Anatomic CoCr V40 femoral head, which, reportedly, Stryker has attributed to a “possible taper lock interface inconsistency.” This particular defect in the modular hip implant component may be associated with a number of serious safety issues, including:
- Dissociation of the femoral head from the hip stem (where the head of the implant dislocates and separates from the rest of the hip implant device), often without warning
- Breakage of the hip stem trunnion
- Increased presence of metallic debris in the soft tissue surrounding the Stryker modular hip implant, which can lead to bone and tissue necrosis and the need for a revision surgery
- Insufficient soft tissue tension
- Noises emanating from the hip implant
- Decrease in the strength of the bone fixation
- Increased wear debris from the components of the hip implant
Australian patients and surgeons have been urged to notify their governmental safety surveillance agency to report patient injuries and medical device failures.
At the time of issuance of this safety alert in Australia, no similar notification has been issued by the Food & Drug Administration to patients in the United States. The hazard alert issued in Australia is not a product recall, but is still nevertheless an important issue that patients and their orthopedic surgeons need to take seriously, especially in light of the well-known risks of metallosis and dissociation of the modular hip implants.
In 2012, Stryker recalled its Rejuvenate and ABGII hip implant stems due to similar issues relating to metallosis and premature failure of the devices. This latest safety concern over the LFIT V40 femoral head involves corrosion and failure of the hip implant device at a different juncture in the modular implant, but has some similar characteristics with regard to the bone and tissue damage caused by the corrosive metallosis process.