Radiostereometric Analysis (RSA) and DEXA to Evaluate Fixation and Wear of the Restoration ADM Acetabular System
Condition: Osteoarthritis
MeSH terms: Osteoarthritis
Study type: Observational

Summary: 
      The dual mobility design concept for acetabular liners, as is used in the Restoration ADM
      Acetabular System, has been applied in various implants since its introduction by Gilles
      Bousquet in France in 1976. Dual mobility cups have shown good clinical results and have been
      particularly lauded for low incidence of dislocations. However, the wear performance of this
      design concept has not been proven to date. As wear particles are a possible contributing
      factor in aseptic loosening, the assessment of wear and fixation is an important step in
      proving this implant design.

      The proposed study will combine RSA and peri-prosthetic bone mineral density as well as
      outcome questionnaires to provide a complete in vivo evaluation of prosthesis fixation,
      polyethylene wear, and objective and subjective outcomes for the Restoration ADM Acetabular
      System.
    

Detailed description: 
      Question 1: a) Do the implant components of the Restoration ADM Acetabular System achieve
      adequate fixation to the underlying bone? Null Hypothesis: There is no significant increase
      in micromotion of the implant components after 1 year indicating adequate long-term fixation
      at the implant - bone interface. Alternative Hypothesis: There is a significant increase in
      micromotion of of the implant components after 1 year indicating inadequate fixation at the
      implant - bone interface. b) What are the migration patterns (translations and rotations) of
      the Restoration ADM Acetabular System components during the first three years
      postoperatively? c) For what proportion of implants does migration continue to increase
      during the three year follow-up? d) Are inducible displacements, measured during
      weight-bearing follow-up exams, consistent over time and do they indicate that adequate
      fixation has been achieved? e) Are there significant differences in migration patterns
      (translations and rotations) between the Restoration ADM Acetabular System components and
      other implants previously studied with RSA and reported in the literature? Question 2: a) How
      much does the femoral head wear into the polyethylene liner?b)How much backside wear occurs
      on the polyethylene liner? c)How does the total wear compare to that with other implants
      previously reported in the literature? Question 3: Does the polyethylene liner demonstrate
      mobile bearing properties? Question 4: a) Are there changes over time in bone mineral density
      of peri-prosthetic bone with the Restoration ADM Acetabular System components? b) Where do
      changes in bone mineral density occur? Question 5: Does total hip arthroplasty using the
      Restoration ADM Acetabular System result in significant improvement in health status and
      functional outcome?
    

Intervention name(s): ADM Cup
Intervention type(s): Device
Intervention description(s): ADM Cup
Other intervention name(s): Styrker ADM Acetabular Cup
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Osteoarthritis of the hip
      
Keywords: Osteoarthritis