Sigma CR150 Versus Sigma CR Knee RCT
Condition: Osteoarthritis
MeSH terms: Osteoarthritis
Intervention: Sigma CR150; Sigma CR
Intervention description: Sigma CR150 femoral component used in combination with the Highly Polished Cobalt Chrome fixed bearing tibial tray and the Curved (XLK) polyethylene bearing (cemented, no patellar resurfacing).; Sigma CR femoral component used in combination with the Highly Polished Cobalt Chrome fixed bearing tibial tray and the Curved (XLK) polyethylene bearing (cemented, no patellar resurfacing).
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Enrollment: 191.0
Sex: All
Minimum age: 50 Years
Maximum age: 75 Years
Healthy volunteers: No
Keywords: Sigma; cruciate; retaining; fixed; primary; total; knee; arthroplasty; cemented; osteoarthritis

Summary:

      This study will compare two very similar designs of knee replacement device. One device
      (Sigma CR150) is a slightly modified version of the original (Sigma CR) and has been modified
      to enhance/accommodate higher flexion. The original device has been in widespread clinical
      use with excellent results since 1996 and this study will determine whether the design
      modifications of the newer device add further value. The newer device has been in clinical
      use with good short-term(unpublished) outcomes since becoming commercially available in
      January 2009.

      Achieving higher knee flexion may be required for cultural reasons or by the increasingly
      younger, more active patient population undergoing knee replacement today. In addition to
      promoting flexion, it is also possible that this design change may help the knee replacement
      to last longer than traditional implants in patients who achieve higher flexion. Therefore,
      the study will compare the two devices in terms of survivorship, flexion and other measures
      of the success of a total knee replacement (range of motion, knee-related quality of life,
      activity and generic quality of life) over the short-term.

      A minimum of one hundred and forty subjects (minimum 70 per group) with osteoarthritis and
      aged 50-75 years will be included at UK/international hospitals.

      Study duration is 2 years and patients will complete standard knee outcome scores plus
      radiological evaluation.

      Subjects would receive one of the study devices regardless of their involvement in the study,
      and apart from (possible)additional visits, x-rays and/or questionnaires, treatment and
      follow-up care will be as per the care they would receive outside of the study.
    

Eligibility criteria:

        Inclusion Criteria:

        i)Male or female subjects, aged between 50 and 75 years inclusive.

        ii)Subjects who are able to give voluntary, written informed consent to participate in this
        clinical investigation and from whom consent has been obtained.

        iii) Subjects who, in the opinion of the Clinical Investigator, are able to understand this
        clinical investigation, co-operate with the investigational procedures and are willing to
        return to the hospital for all the required post-operative follow-ups.

        iv) Subjects defined by the Investigator as ASA Grade I or II.

        v) Subjects with a primary diagnosis of osteoarthritis.

        vi) Subjects who require a primary total knee arthroplasty.

        vii) Subjects who can achieve active flexion of 90 degrees.

        Exclusion Criteria:

        i) Subjects who, in the opinion of the Clinical Investigator, have an existing condition
        that would compromise their participation and follow-up in this clinical investigation.

        ii) Subjects who are known drug or alcohol abusers or with psychological disorders that
        could affect follow-up care or treatment outcomes.

        iii) Subjects who have participated in a clinical investigation with an investigational
        product in the last month.

        iv) Subjects who are currently involved in any injury litigation claims.

        v) Subjects with an anatomical limb alignment of above 20 degrees varus or valgus.

        vi) Subjects with a fixed flexion deformity of over 20 degrees.

        vii) Subjects with recurvatum (definition: hyperextension ≥ 5 degrees).

        viii) Subjects who cannot flex their hip to 90 degrees.

        ix) Subjects with a BMI of 35 or above.

        x) Subjects defined by the Investigator as ASA Grade III-V.

        xi) Subjects who are identified pre-operatively as having bone defects which require
        augmentation.

        xii) Subjects who have previously undergone total or unicondylar knee arthroplasty, high
        tibial osteotomy, ligament reconstruction, ORIF or with previous fracture in the knee
        joint.

        xiii) Subjects with primary or secondary diagnosis of inflammatory or traumatic arthritis.

        xiv) Subjects who have undergone contralateral total knee arthroplasty during the previous
        6 months.

        xv) Subjects who in the opinion of the Investigator require patellar resurfacing.

        Intra-operative exclusion criteria:

        i) Subjects who have uncontained bone defects or defects bigger than 8 mm3 and/or require
        augmentation.

        ii) Subjects who are not suitable to receive both the study and comparator devices.

        iii) Subjects who require patellar resurfacing