Patellar Resurfacing Versus Patellar Retention in Total Knee Arthroplasty - A Randomized Clinical Trial (PROFIX)

This study has been completed.
Sponsor:
Collaborator:
Smith & Nephew, Inc.
Information provided by (Responsible Party):
Lauren Beaupre, University of Alberta
ClinicalTrials.gov Identifier:
NCT01500252
First received: December 22, 2011
Last updated: April 5, 2012
Last verified: April 2012
  Purpose

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.


Condition Intervention Phase
Total Knee Replacement
Device: Patellar Replacement Prosthesis
Device: Profix TKR with Patellar Retention
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Bio-equivalence Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Randomized Clinical Trial Comparing Patellar Resurfacing Versus Patellar Retention in Total Knee Arthroplasty Using the PROFIX* Total Knee System

Resource links provided by NLM:


Further study details as provided by University of Alberta:

Primary Outcome Measures:
  • Change in Western Ontario MacMaster (WOMAC) Osteoarthritis Index Pain Score From Preoperative to 5 Years Postoperative [ Time Frame: Preoperative to 5 years postoperative ] [ Designated as safety issue: No ]

    This index assesses pain as reported by the patient. The WOMAC Pain scale has a minimum value of 0 (worst pain) to a maximum value of 100 (no pain).

    The change score was calculated by subtracting the preoperative score from the five year score.


  • Change in WOMAC Osteoarthritis Index Function Score From Preoperative to 5 Years Postoperative [ Time Frame: Preoperative to 5 years postoperative ] [ Designated as safety issue: No ]

    This measures the change in patients' reported function from preoperative to 5 years postoperative.

    The WOMAC Function scale has a minimum value of 0 (worst function) to a maximum value of 100 (no functional limitations).

    The change score was calculated by subtracting the preoperative score from the five year score.


  • Change in WOMAC Osteoarthritis Index Stiffness Score From Preoperative to 5 Years Postoperative [ Time Frame: Preoperative to 5 years postoperative ] [ Designated as safety issue: No ]

    This is the change in the patients' perceived pain between preoperative and 5 years postoperative.

    The WOMAC stiffness scale has a minimum value of 0 (maximal stiffness) to a maximum value of 100 (no stiffness).

    The change score was calculated by subtracting the preoperative score from the five year score.



Secondary Outcome Measures:
  • Change in WOMAC Osteoarthritis Index Pain Score From Preoperative to 1 Year Postoperative [ Time Frame: Preoperative to 1 year postoperative ] [ Designated as safety issue: No ]

    This index assesses pain as reported by the patient. The WOMAC Pain scale has a minimum value of 0 (worst pain) to a maximum value of 100 (no pain).

    The change score was calculated by subtracting the preoperative score from the one year score.


  • Change in WOMAC Osteoarthritis Index Function Score From Preoperative to 1-year Postoperative [ Time Frame: Preoperative to 1 year postoperative ] [ Designated as safety issue: No ]

    This index assesses function as reported by the patient. The WOMAC function scale has a minimum value of 0 (worst function) to a maximum value of 100 (no functional limitations).

    The change score was calculated by subtracting the preoperative score from the one year score.


  • Change in WOMAC Osteoarthritis Index Stiffness Score From Preoperative to 1 Year Postoperative [ Time Frame: Preoperative to 1 year postoperative ] [ Designated as safety issue: No ]

    This index assesses stiffness as reported by the patient. The WOMAC stiffness scale has a minimum value of 0 (worst stiffness) to a maximum value of 100 (no stiffness).

    The change score was calculated by subtracting the preoperative score from the one year score.


  • Change in WOMAC Osteoarthritis Index Pain Score From 5 Years Postoperative to 10 Years Postoperative [ Time Frame: 5 years postoperative to 10 years postoperative ] [ Designated as safety issue: No ]

    This index assesses pain as reported by the patient. The WOMAC Pain scale has a minimum value of 0 (worst pain) to a maximum value of 100 (no pain).

    The change score was calculated by subtracting the five year score from the 10 year score.


  • Change in WOMAC Osteoarthritis Index Function Score From 5 Years Postoperative to 10 Years Postoperative [ Time Frame: 5 years postoperative to 10 years postoperative ] [ Designated as safety issue: No ]

    This index assesses function as reported by the patient. The WOMAC function scale has a minimum value of 0 (worst pain) to a maximum value of 100 (no pain).

    The change score was calculated by subtracting the five year score from the 10 year score.


  • Change in WOMAC Osteoarthritis Index Stiffness Score From 5 Years Postoperative to 10 Years Postoperative [ Time Frame: 5 years postoperative to 10 years postoperative ] [ Designated as safety issue: No ]

    This index assesses stiffness as reported by the patient. The WOMAC stiffness scale has a minimum value of 0 (worst stiffness) to a maximum value of 100 (no stiffness).

    The change score was calculated by subtracting the five-year score from the 10 year score.


  • Number of Revision Surgeries [ Time Frame: 10 years ] [ Designated as safety issue: No ]
    This measure examined the number of reoperation in the two groups of subjects


Enrollment: 38
Study Start Date: September 1996
Study Completion Date: December 2009
Primary Completion Date: June 2004 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Patellar Resurfacing
These subjects received a Profix TKR including an all polyethylene patellar implant.
Device: Patellar Replacement Prosthesis
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
Active Comparator: Patellar Retention
This group received a Profix TKR, but retained their native patella
Device: Profix TKR with Patellar Retention
All subjects received a Profix TKR. Subjects in the Patellar Retention group retained their native patellar surface.

  Eligibility

Ages Eligible for Study:   40 Years to 75 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01500252

Locations
Canada, Alberta
University of Alberta Hospital
Edmonton, Alberta, Canada, T6G 2B7
Sponsors and Collaborators
University of Alberta
Smith & Nephew, Inc.
  More Information

No publications provided by University of Alberta

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Lauren Beaupre, PT, PhD, Associate Professor, University of Alberta, University of Alberta
ClinicalTrials.gov Identifier: NCT01500252     History of Changes
Other Study ID Numbers: Pro00002794
Study First Received: December 22, 2011
Results First Received: January 3, 2012
Last Updated: April 5, 2012
Health Authority: Canada: Ethics Review Committee

Keywords provided by University of Alberta:
Total Knee Replacement
Patellar Resurfacing
Health Related Quality of Life

ClinicalTrials.gov processed this record on July 24, 2014