Patellar Resurfacing Versus Patellar Retention in Total Knee Arthroplasty - A Randomized Clinical Trial
Condition: Total Knee Replacement
Intervention: Patellar Replacement Prosthesis; Profix TKR with Patellar Retention
Intervention description: The Profix™ Total Knee System, a posterior cruciate retaining prosthesis manufactured by Smith and Nephew, Inc. was utilized in all subjects. Subjects randomized to the Resurfaced group received an all polyethylene patellar implant; All subjects received a Profix TKR. Subjects in the Patellar Retention group retained their native patellar surface.
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Enrollment: 38.0
Sex: All
Minimum age: 40 Years
Maximum age: 75 Years
Healthy volunteers: No
Keywords: Total Knee Replacement; Patellar Resurfacing; Health Related Quality of Life

Summary:

      Background:

      Despite the excellent results of total knee replacement, also known as total knee
      arthroplasty (TKA) there is persistent controversy over whether or not to replace the surface
      of the kneecap. Anterior knee pain, which occurs with variable and unpredictable frequency,
      continues to be a problem in a subset of TKA patients. Some clinicians replace the surface of
      all kneecaps during TKA to avoid repeat surgery, which occurs in approximately 10% of cases.
      However, others cite the complications attributed to replacing the surface of kneecap as
      reasons to avoid this procedure.

      This study prospectively randomized patients receiving TKA into two groups, those receiving
      replacement of the kneecap surface and those left without replacement of the kneecap surface
      to determine clinical outcomes and revisions over the first 5-10 postoperative years.

      Objectives:

      The primary objective of this work was to compare pain, stiffness and function between groups
      at five years postoperatively. Secondarily, we compared pain, stiffness and function at one
      and 10 years postoperatively. Finally, we examined the number of reoperations following TKR
      over 10 years in the 2 groups of subjects. The investigators hypothesized that there would be
      no difference between the two groups of subjects in the measured outcomes.

      Methods:

      Patients receiving TKA were prospectively enrolled before surgery and randomized
      intraoperatively to either receive a replacement of the kneecap surface or have no kneecap
      intervention. The Smith and Nephew Profix TKA system was implanted in all cases; the
      post-operative regimen was standardized. Subjects were assessed pre-operatively and at 1 and
      5 years postoperatively for pain, function, and stiffness using a disease-specific (Western
      Ontario and MacMaster Osteoarthritis Index [WOMAC]) and generic health status (Short Form 36
      [SF-36]) questionnaire. At the end of the five year follow-up, the study was extended to a
      10-year followup and the same outcomes were assessed. The revision rate was also compared
      between the two groups at the end of the 10-year follow-up.
    

Eligibility criteria:

        Inclusion Criteria:

          -  scheduled for primary TKA to treat non-inflammatory arthritis

          -  age 40- 75 years of age

        Exclusion Criteria:

          -  history of knee sepsis

          -  previous patellectomy

          -  previous high tibial osteotomy

          -  knee flexion contracture of >20 degrees

          -  varus or valgus deformity of > 20 degrees

          -  < 90 degrees of knee flexion

          -  tibial or femoral bone deficiency requiring augmentation