Cemented Versus Cementless Unicompartmental Knee Arthroplasty
Condition: Osteoarthritis, Knee
MeSH terms: Osteoarthritis, Knee
Study type: Interventional

Summary: 
      Unicompartmental knee replacement for selected cases of osteoarthritis is less invasive than
      total knee replacement. It gives better range of movement; patients stay for shorter time in
      the hospital and have a more natural feel than total knee replacement. Usually, the implant
      is fixed in the bone using bone cement. However, there are potential disadvantages of using
      bone cement. The operation takes longer; cement can get squeezed out into the surrounding
      tissues and may interfere with function. To avoid these problems, the implant can be fixed
      without cement. Cementless components have a special coating to encourage bone in-growth and
      fixation. Although the investigators believe cementless fixation will be at least as good as
      cemented fixation, there is a risk that it could be worse and might result in loosening.

      The aim of this study is therefore to compare the outcome of cemented and cementless
      unicompartmental knee replacement.
    

Detailed description: 
      Design: A prospective, randomised trial to compare the outcome of cemented and cementless
      unicompartmental knee replacement.

      Size: 40 subjects in total will be recruited with 20 in each arm.

      Methods: Patients will be recruited from the routine waiting list for unicompartmental knee
      replacement at the Nuffield Orthopaedic Centre. All subjects will have the procedure
      explained and be fully consented prior to the procedure.

      Randomisation: Patients will be randomly allocated to receive either a cemented or cementless
      Oxford Unicompartmental Knee Replacement. This will be performed using a randomisation
      program based on optimisation (Minim). Subjects will be stratified according to sex and age.

      Operation: All subjects will undergo the same surgical approach. 0.8mm Tantalum marker balls
      will be placed at standardised sites on the femur and tibia in all cases. All cemented
      components will be secured using the same cement. Cementless components have a
      hydroxy-appatite coating to facilitate bone ingrowth.

      Follow-up: All patients will be followed up at 0, 3, 6, 12, 24, 60, and 120 months with
      clinical and radiological assessment. Clinical assessment will involve documentation with the
      Oxford Knee Score. Patients will undergo radiostereometric analysis and fluoroscopy to study
      implant migration and occurence of radiolucency, respectively.
    

Intervention name(s): Cementless Oxford Unicompartmental Knee Arthroplasty; Cemented Oxford Unicompartmental Knee Arthroplasty
Intervention type(s): Device; Device
Intervention description(s): All patients will undergo the same surgical approach. 0.8mm diameter tantalum marker balls will be placed in the tibia and femur in all cases. Cementless components have a hydroxy-appatite coating to facilitate bone ingrowth. The cementless femoral component also has a smaller second peg, located anteriorly to the larger central peg that is also present of the cemented femoral component.; All patients will undergo the same surgical approach. 0.8mm diameter tantalum marker balls will be placed in the tibia and femur in all cases. All cemented components will be secured using the same cement.
Other intervention name(s): Cementless Oxford Unicompartmental Knee Replacement; Cemented Oxford Unicompartmental Knee Replacement
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Patients will be randomised to receive either a cementless or cemented Oxford Unicompartmental Knee Arthroplasty.
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Knee Arthroplasty; Unicompartmental; Fixation; Radiostereometric Analysis