Simplex cement

• Research type

  Research Study

• Full title

  Retrospective Review of the Use of Simplex High Viscosity Bone Cement for Joint Arthroplasty

• IRAS ID

  285241

• Contact name

  Andrew Toms

• Contact email

  andrewtoms@nhs.net

• Sponsor organisation

  Stryker Orthopaedics

• Duration of Study in the UK

  2 years, 0 months, 1 days

• Research summary

  Research Summary
  Nearly 100,000 primary total knee replacement (TKR) surgeries are performed per year in the UK. There has been concern among some surgeons about the use of high viscosity (HV) cement-used to fix the joint replacement in place- as a potential cause of early loosening of the components in some patients. HV cement has advantages for surgeons- allowing more time for work with the cement at the time of surgery during the handling and setting phases than low viscosity cement. This has potential to allow for greater operational/surgical efficiency. There is a need to demonstrate the safety of HV cement used in TKR as measured by the absence of loosening (in the absence of infection) at 2 years after surgery.
  The UK arm of this study is a retrospective review of the case notes, outcome scores and radiographs of 100 consecutive TKR patients who meet the study inclusion criteria. All will have had had anti-biotic loaded HV cement (UK patients). A separate study is being conducted in the USA examining standard HV cement used in their patients. This ethics application concerns the UK study only.
  The aim is to assess the success rate of surgery defined as the absence of signs of loosening of the joint replacement. All patients will have had unilateral TKR with a minimum 2 year post-operative data set available. The surgery will have been performed at the Royal Devon+ Exeter hospital in the UK. The data will be extracted from the patients medical notes , anonymised and sent to Stryker for analysis.

  Summary of Results
  The primary objective of this retrospective study was to evaluate the success rate of cemented Triathlon Total Knee Replacement components implanted using 2 bone cements: Simplex HV and Simplex HV with the anti-biotic Gentamicin added to the cement. Simplex HV was used in the cohort of patients in the USA. Simplex gentamycin was used in the cohort of patients in the UK.
  Success was defined as the absence of a need to re-do the knee replacement due to loosening of the components in the absence of infection at 24 months (+ 2 months) after the initial surgery.
  Result: Survival rate (Success)
  Simplex HV: 100% (0/94)
  Simplex HV Gentamicin: 99% (1/100). One knee replacement needed to be re-done (revised) due to aseptic loosening (loosening in the absence of infection).

  Secondary objectives:
  1. Analysis of the Knee Society Score (KSS) results:
  Due to the retrospective nature of this study, it was not possible to collect full data sets of the pain-motion score and no data for the function score because the data were not fully available from the hospital routine. KSS was used predominantly in the cohort of patients in the USA. Results of the subgroups are as follows:

  Result: range of motion of the knee (higher scores indicate best outcome):
  Simplex HV: from 108 degree preoperative to 113 degrees up to 5 years postoperative

  Simplex HV Gentamicin: from 101 degree preoperative to 115 degrees up to 5 years postoperative

  Pain:
  Simplex HV: preoperatively, 95% (90/95) had mild or occasional, moderate continual/occasional or severe pain. At 5 year follow up, 26% (14/53) had mainly mild or occasional pain and no patient reported severe pain up to 5 years postoperatively.

  Simplex HV Gentamicin: preoperatively, 28% (18/64) had moderate continual/occasional or severe pain. At follow up, 11% (2/18) had mild or occasional pain and no patient reported severe pain up to 5 years postoperatively.

  Secondary objectives:
  2. Analysis of the Oxford Knee Score (OKS) results . The OKS is predominantly used in the UK and so results of this are only available for Simplex HV Gentamicin cases.
  The possible total score ranges from 0 to 48 points. Here, a high score (e.g. 48 points) indicates the best outcome.

  In the Simplex HV Gentamycin group, the OKS increased 20.5 points from a preoperative mean of 18.9 points to a mean of 39.4 points up to 5 years postoperatively.

  Secondary objectives:
  3. Analysis of complications:
  In the Simplex HV cohort: 3 serious complications occurred related to the operative site i.e. the knee that underwent surgery. Of these, it was considered uncertain if one complication was considered related to the knee replacement components themselves and two related to the operation.

  In the Simplex HV Gentamicin cohort: 3 serious complications occurred related to the operative site i.e. the knee that underwent surgery. Of these, it was considered uncertain if one complication was considered related to the knee replacement components themselves and two related to the operation. One complication led to a revision of the knee replacement due to aseptic loosening.

  All Adverse Events reported in this study are known complications of total knee replacement. No new information that may affect risk has been identified.

• REC name

  Wales REC 4

• REC reference

  21/WA/0028

• Date of REC Opinion

  4 Feb 2021

• REC opinion

  Favourable Opinion