MRK Poly Vs Metal

• Research type

  Research Study

• Full title

  Medial rotation knee randomised controlled trial: All-polyethylene and metal-backed tibial components

• IRAS ID

  164614

• Contact name

  Laura Richards

• Contact email

  laura.richards@matortho.com

• ISRCTN Number

  ISRCTN12532998

• Duration of Study in the UK

  3 years, 6 months, 0 days

• Research summary

  Summary of Research
  Total knee replacement has been performed for over 40 years as an end point treatment of arthritis and damaged knee joints. A knee replacement aims to reduce pain, stiffness and immobility.
  The most common measures of success in joint replacement surgery to date has been the rate at which a revision is required (further surgery to replace worn out components etc). The success of an implant can also be determined using validated patient reported outcome measures (PROMs) which are defined as validated measures to assess any aspect of health which come from the patient themselves.

  This study is a prospective, randomised study to compare two types of knee replacement implants. The Medial Rotation Knee (MRK) from MatOrtho Limited is a total knee replacement system that was CE marked in 1994. It has proven to be a very successful design of knee replacement and shows the best revision rates at only 1.83% in 7 years from the UK. The two implants to be used in this study include:

  1. MRK metal-backed tibial component
  2. MRK all polyethylene tibial component

  150 patients will be recruited in total from 3 NHS sites across the UK. 75 patients will receive metal-backed MRK implants and 75 will receive all polyethylene tibia MRK implants. Patients will be followed up over a 2 year period, during which they will be asked to complete various PROMs (both pre- and post-operatively).

  Summary of Results
  A null hypothesis was presented that the all-poly tibial implant would present an inferior range of motion at the two-year time point post total knee arthroplasty. Statistical analysis performed on the data available would indicate this hypothesis to be false. There is no statistically significant difference between the range of motions of the two cohorts at any time point of the trial, including the primary end-point at the two year time-point. Furthermore, statistical analysis of the patient reported outcome measures reported no inferiority of either implant at any of the time for which the respective PROMs were collected. Thus indicating that the all-poly tibial implant is not inferior the metal-backed implant up to the time-point of 2 years. Discrepancies in the quality of the implants may appear further down the post-operatively timeline between the two implant, further research would be needed to ascertain whether or not this is case.

• REC name

  North West - Greater Manchester South Research Ethics Committee

• REC reference

  15/NW/0005

• Date of REC Opinion

  26 Feb 2015

• REC opinion

  Further Information Favourable Opinion