Dual Mobility System Reduces Hip Dislocation Risk

A new cementless hip implant is designed to reduce the risk of dislocation, which can impact patient satisfaction and result in later revision costs.

The DePuy Synthes (West Chester, PA, USA) BI-MENTUM is a monoblock dual mobility hip system with an optimal head to shell ratio intended for patients with fracture neck of the femur (FNOF), osteoarthritis (OA), osteonecrosis of the femoral head, and for hip revision procedures where other treatments or devices have failed, and if bone reconstruction so permits. All cups in the system are composed of a metallic shell fixed in the acetabulum and a rotating polyethylene liner retained on the prosthetic femoral head. The BI-MENTUM cementless cups are made of stainless steel, coated with a double layer of titanium and hydroxyapatite plasma spray on the outer surface; the inner surface is highly polished.


Three cementless metal backs are available: the BI-MENTUM PressFit Cup; the BI-MENTUM Plus Cup, with three fixation points (two divergent pegs towards the pubis and ischium and one cortical screw through a flange towards the ilium); and the BI-MENTUM Revision Cup, with five fixation points (two divergent pegs towards the pubis and ischium, cortical screws through two flanges towards the ilium, and one foramen hook). A cemented cup is also available, with a shell made of sandblasted stainless steel to augment contact between the implant and the cement.

“With an increasing number of patients undergoing hip replacement surgery, surgeons need to address a broader range of surgical needs to help their patients stay active and get on with their lives,” said Aaron Villaruz, vice president and global platform leader for hips at DePuy Synthes. “Securing the CE Mark on BI-MENTUM enables us to better serve our customers and patients across Europe with a solution that is designed to make a continued difference in hip replacement.”

A hip replacement implant is a ball-and-socket mechanism designed to simulate a human hip joint and mimic its movement. Typical components include a stem that inserts into the femur, a ball that replaces the head of the thigh bone, and a shell that lines the hip socket. The concept of DM, which was originally developed in France in the 1970s, refers to the bearing surface of the implant; DM provide two areas of motion within the artificial socket, thus improving the range of movement and reducing the risk of dislocation.

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