Kinematic Analysis of a PS, FB Primary Total Knee Arthroplasty (ATTUNE Knee System) Using Dynamic RSA
Condition: Osteoarthritis
MeSH terms: Osteoarthritis
Study type: Interventional

Summary: 
      Background: Across the European Union there are 535,000 Total Knee Arthroplasty (TKA)per
      year. Statistics indicate that for patients over 60 year old approximately one out of 20 will
      require corrective reoperations within 10 years after surgery. However, for patients younger
      than 60 years, approximately one out of 10 will require revision total knee arthroplasty
      within 10 years of surgery. As the number of younger patients is increasing, there has been a
      shift in focus in total Knee Replacement (TKR) outcome, with post-operative function and
      implant longevity being the important issues for quality of patient care. Furthermore, it has
      been reported that up to 25% of patients are not satisfied with the functional results of
      their TKA. In vivo the gold standard for obtaining reliable 3D measurements is RSA. However
      these are often static, because of even most advanced x-ray film exchanger limit the number
      of pictures taken to less than 10 per second. Our dynamic RSA technique allows producing real
      time x-ray video of TKA in weight-bearing (WB) conditions with active muscle contraction.

      The purpose of this study is to investigate the effect of a new implant design on the
      post-operative active knee kinematics, focusing on mid-flexion instability of the joint. A
      prospective randomized study will be performed on a new implant: the DePuy ATTUNETM
      fixed-bearing (FB) posterior-stabilized (PS) knee prosthesis.
    

Detailed description: 
      The main goal of this study is to investigate the effect of a new implant design on the
      postoperative active knee kinematics on mid-flexion instability of the joint. Data will be
      collected during the surgery with a Computer Assisted Surgery system and in the post
      operative follow up phase using the dynamic RSA focusing. A prospective study will be
      performed on a new implant: the DePuy ATTUNETM fixed-bearing (FB) posterior-stabilized (PS)
      knee prosthesis.

      Kinematic tests will be performed to analyze femoral rotation patterns and translation
      patterns of the medial and femoral condyle respect to the tibial plateau during different
      daily life motor tasks.

      Despite reportedly good implant survival rates, not all patients are fully satisfied after
      total knee arthroplasty (TKA). One of the most debated topics in TKA is the effectiveness of
      the prosthesis to reproduce physiological kinematics at the replaced knee, usually expressed
      in terms of patterns of joint rotation in the three anatomical planes, of the functional
      axis, and of the tibio-femoral contact points on the medial and lateral condyles, that is,
      femoral roll-back.

      Implant design can influence final kinematic results. The mid-flexion instability may be the
      cause of joint instability, paradoxical femoral rollback, surgical variation.

      Recently an improved implant design of fixed bearing PS DePuy implant has been anticipated to
      early users. This implant has been claimed to reduce midflexion instability and improve joint
      kinematics, because of a particular multiradius shape of the condylar surface.

      For intra-operative kinematic acquisition, a commercial navigation system (BLUIGS, Orthokey
      Italia srl, Firenze, Italy) with a dedicated software for kinematic tests will be used.

      In the present study, the investigators will use a postoperative bi-planar imaging method in
      weight-bearing motor tasks with active muscle contraction , to determine the in vivo contact
      areas on the tibial articulating surface of a PS TKA during flexion of the knee.

      The objective of the present study is to determine the contact areas and their movement
      through a 0-140° arc of motion in both the anteroposterior (AP) and ML directions. The cohort
      will also be compared with data of normal knee kinematics, as reported in current literature.

      At 6 months follow-up, dynamic fluoroscopy will be used to analyze implant kinematics (i.e.
      stair descent, level-walking and non weight-bearing maximum knee flexion) and a simultaneous,
      real-time collection of ground reaction forces with a force platform will be performed.
      Clinical scores will be collected at that time and compared with all the data registered
      before surgery and during the follow up routinely made at 1 and 3 months after surgery.

      A specifically developed device installed at the Rizzoli Orthopaedic Institute will be used
      to assess the kinematic of the knee at 9 months after surgery. This equipment is unique
      worldwide: it was specifically designed, built and certified for dynamic and static RSA
      evaluation of TKA. The purpose of this study is to investigate the effect of a new implant
      design on the post-operative active knee kinematics, focusing on mid-flexion instability of
      the joint. A prospective randomized study will be performed on a new implant: the DePuy
      ATTUNETM fixed-bearing (FB) posterior-stabilized (PS) knee prosthesis.
    

Intervention name(s): Primary Total Knee Arthroplasty (ATTUNE Knee System)
Intervention type(s): Device
Intervention description(s): The patient will undergo primary Total Knee ArthroplastY use ATTUNE Knee System. During surgery a navigation system will be used to record preoperative joint kinematics under different tests. During the test the 6 degrees of freedom (DOF) of the joint will be computed and shown to the surgeon; these are the femoral rotation and translation pattern against flexion ranges. Navigation system will be also used to monitor the implant positioning and possible surgical bias. Dynamic RSA will be used to analyze the in vivo kinematics of the prosthesis at 6 months follow-up.
The above mentioned motion tests will be performed 3 times. The first 2 will be executed to gain comfort with the experimental set-up with no X-ray exposure. During the last data is collected.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Dynamic RSA; Knee; Total Knee Arthroplasty; Kinematic Analysis