Studies Question Advantage of Zimmer’s High Flex Knees
Zimmer’s “high flexion” line of artificial knee implants are meant to provide patients with the greatest possible range of motion. Despite a 2010 Zimmer NexGen knee recall, in which the manufacturer voluntarily removed from the market certain MIS Tibial components, Zimmer continues to defend all of the products within the NexGen family of products. Several recent studies, however, have called into question whether the high flex knees really provide a significant advance over previous models.
Patients seek to gain clarity about Zimmer NexGen knee recall
Many patients have contacted a Zimmer knee lawyer to learn if serious Zimmer knee problems and knee failure are associated with the high flex devices. Patients have also reached out to a Zimmer knee lawyer to get clarity on the 2010 Zimmer NexGen knee recall, which did not target any particular prosthetic device as a whole, but only the specific MIS tibial component parts used in the surgical process of total knee arthroplasty (TKA).
In response to reports from patients and doctors that standard models of knee prostheses did not provide the ideal amount of flexibility, Zimmer launched a new line of “high flexion” knee models. These high flex devices were specifically designed to meet the demand for artificial knees that offered a greater range of motion, and which could meet the physical needs of patients looking to regain the active lifestyles they were accustomed to prior to the failure of their natural joints.
Zimmer’s market-approved high flex knees include the LPS Flex and the NexGen CR Flex, a model whose corollary MIS tibial parts were the focus of the joint maker’s voluntary 2010 Zimmer NexGen knee recall. Zimmer’s high flex knees are marketed as availing recipients of up to 155 degrees of flexion, or the bending angle required for a deep knee squat.
Studies reveal Zimmer knee problems
Recent studies seeking to discover the true extent of Zimmer knee problems, however, have called into question the marketing claim that Zimmer’s high flex knees allow patients a significantly improved range of motion. For instance, a 2009 controlled study led by orthopedic researcher Dr. I. Amed found no difference in the range of movement between standard and high flex variants of Zimmer’s NexGen devices.
Previously, a 2009 German report, known as the Wohlrab Study, compared the clinical and radiological results of 60 high flex and standard TKAs over a 5-year period. The study’s conclusion was that the advantage in range of motion offered by high flex devices was limited, if not nonexistent.
Yet another study of Zimmer knee problems, published in the Journal of Bone and Joint Surgery in the same year as the Zimmer NexGen knee recall of MIS tibial parts, confirms the findings of the previous two. Dr. W.C. Choi compared post-surgery outcomes of standard and high flex TKAs, and found no significant differences between the different models. The average maximum flexion for standard knee devices was 128 degrees, while the average maximum flexion for high flex implants was 130 degrees. A Zimmer knee lawyer would be quick to argue that a two-degree difference in flexion may not be so clinically significant as to present any practical advantage over other models.