About the Exactech Connexion GXL Liner
Total hip arthroplasty, or THA, is a surgery that requires the implantation of four main components: shell, femoral head, stem, and liner. The shell (see image below) is a metal cup placed into the patient’s hip socket. The femoral head and stem fit into the shell in the hip socket. The liner is placed into the cup-shaped shell to provide a ball-and-socket joint that allows for movement similar to a natural hip.
The liner used in THA implants must last as long as the other components to avoid implant failure.
Exactech’s Connexion GXL Liner is a “moderately cross-linked” liner made from polyethylene, the plastic most commonly used in liners for THA. Cross-linking is intended to prevent wear and increase the lifespan of the liner, benefits that Exactech highlighted to market the product. These liners were designed for use in the Exactech Novation, Acumatch, and MCS hip implant systems and have been used in hip replacement surgery nationwide.
The Problems with the Connexion GXL Liner
March 2020 Study: “Unusual Early Excessive Wear”
In March 2020, researchers published a study in Arthroplasty Today, in which they reviewed 204 THA procedures performed by a New York surgeon using the Exactech Connexion GXL Liner. They identified five cases of severe polyethylene wear and osteolysis within five years of the THA surgery. The Exactech liner exhibited “unusual early excessive polyethylene wear,” despite the ordinarily “excellent long-term wear properties” of modern THA polyethylene components.
The faster rate of wear on Exactech liners causes patients to suffer implant failure during the first five years, which represents a stark deviation from the expected lifespan of modern hip implants.
The study confirmed all devices were implanted properly and found no patient risk factors for early implant failure (other than high activity level). Having ruled out these external possible causes, the authors noted their belief that “there may have been a variation in the processing of at least a batch of Exactech GXL liners that created a predisposition for early wear.” These findings demonstrated a “concerning trend with the use of the Exactech Connexion GXL Liner” and were reported to Exactech.
May 2020 Study: “Severe Secondary Osteolysis”
In the May 2020 issue of The Journal of Arthroplasty, researchers reviewed the University of Florida College of Medicine’s database for all cases of patients who presented osteolysis after surgery with Exactech’s Connexion GXL Liner. The case review, spanning January 2009 to June 2019, identified 12 patients presenting significant osteolysis, nine of whom had undergone revision surgery. The study also noted 22 reported cases of wear-related implant failure from 2009 to 2019 on the FDA Manufacturer and User Facility Device Experience (MAUDE) database.
The case review identified 12 patients presenting significant osteolysis, nine of which had undergone revision surgery . . . the study concluded that the Exactech Connexion GXL liner may be prone to a “high rate of early failure from wear and severe secondary osteolysis.”
Of the patients with significant osteolysis, the average time it took to diagnose implant failure was approximately 4.5 years. Consistent with the New York study, the Florida study identified no “risk factors related to patient demographics or implant position.” Given the absence of notable external causes, the study concluded that the Exactech Connexion GXL liner may be prone to a “high rate of early failure from wear and severe secondary osteolysis.” The authors recommended “close surveillance” of patients with these liners.