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New Knee Implant Promises Longer Life

The 3DKnee™ Total Knee System is the result of over a decade of research and is the first knee implant specifically engineered to accommodate demands in contact, movement and pressure that occur in the knee joint after total knee replacement.

The discovery that ACL deficient knee motions are different to the mechanics of an ACL intact knee led to a decade long quest to accommodate these changes in total knee design. [1,2]

Using innovative fluoroscopic evaluation, tibial plateau resection, and tibial insert retrieval analysis, a revolutionary design emerged…the DJO Surgical 3DKnee. The 3DKnee is the first knee replacement developed to work in conjunction with the abnormal characteristics of the arthritic knee. Not only is the 3DKnee designed to provide a wider range of motion and greater stability than other knee prostheses, but its revolutionary design is also intended to minimize the stresses that have traditionally led to premature deterioration of most available implants. As a result the 3DKnee should have a longer life expectancy than other devices, making it a truly viable prosthesis option for younger patient populations.

The 3DKnee was conceived and developed by W. Andrew Hodge, M.D. and Scott Banks, PhD., who began working together at the Massachusetts Institute of Technology in 1989.  Scott Banks explained: “Our kinematic data showed that retaining the PCL or adding a post was not enough to ensure “normal” knee motions in TKA.”

Dr. Hodge and Dr. Banks conducted extensive research before embarking on the design phase in 2000 with the support of DJO Surgical. Their research included:
  • Analysis of hundreds of extracted tibial plateaus of knees with and without the ACL, which helped determine that wear patterns produced by knee kinematics were related to ACL integrity. [3]
  • In-vivo kinematic analysis of CR total knees that showed that the medical condyle moved significantly more anterior than the lateral condyle during flexion and more posterior during extension (the reverse pattern of a “normal” knee). [1,2,4]
  • Fluoroscopic studies showed that 72% of total knee patients reach their maximum flexion when the femur impinges on the tibial.  It was found that for every 2 mm decrease in posterior condyle offset, maximum passive flexion is reduced by 12.2 degrees.[5]
Three key discoveries influenced the development of the 3DKnee. In 1990, they found that mensical bearing total knees looked like ACL deficient knees; in 1999, they discovered a strong linear relationship existed between AP motion of the femur and weight-bearing ROM.  In 2000, through collaborative efforts with Dr Johan Bellemans, Professor of Orthopaedics at the University Hospital in Pellenberg, Belgium, Dr. Banks identified a linear relationship in CR knees between posterior condylar offset and passive knee flexion.

Joseph F. Fetto, MD, the Clinical Associate Professor at the Dept of Orthopedic Surgery at New York University School of Medicine commented: “The 3DKnee is the only device available today which is specifically designed to address the absence of the ACL created by traditional TKR surgery.” Raymond Sherman, MD, from Tri-State Orthopaedics Physicians in Sioux City, Iowa added: “Our physical therapists commented very early on that my 3D patients had a better range of motion and stopped using their walker sooner than patients with other knee designs.”

Click here to see the components of the 3DKnee and for more information.

[1] Banks, S.A., Markovichs, G.D., Hodge, W.A.: The Mechanics of Knee Replacements During Gait: In Vivo Fluoroscopic Analysis of Two Designs. American Journal of Knee Surgery, Vol. 10, No. 4, Fall 1997
[2] Harman, M.K., Banks, S.A., Hodge, W.A.: Polyethylene Damage and Knee Kinematics after Total Knee Arthroplasty. Clinical Orthopaedics and Related Research, (392): 383-93, November 2001.
[3] Harman, M.K., Markovich, G.D., Banks, S.A., Hodge, W.A.: Wear Patterns on Tibial Plateaus from Varus and Valgus Osteoarthritis Knees.  Clinical Orthopaedics and Related Research , No. 352, July 1998
[4] Banks, S.A., Hodge, W.A.: Design and Activity Dependence of Kinematics in Fixed and Mobile-Bearing Knee Arthroplasties.  The Journal of Arthroplasty, Vol. 19, No. 7, October 2004
[5] Bellemans, J., Banks, S.A., Victor, J., Vandenneucker, H. Moemans, A: Fluoroscopic Analysis of the Kinematics of Deep Flexion in Total Knee Arthroplasty: Influence of Posterior Condylear Offset.  The Journal of Bone and Joint Surgery, Vol. 84-B, No. 1, January 2002

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