Cemented Versus Cementless Unicompartmental Knee Arthroplasty

NHS Trust

Status: Completed

Conditions: Osteoarthritis, Knee

Treatments: Device: Cemented Oxford Unicompartmental Knee Arthroplasty; Device: Cementless Oxford Unicompartmental Knee Arthroplasty

Study type: Interventional

Funder types: Other

Identifiers

NCT05935878

PID7088

Details and patient eligibility

About

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.

Full 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.

Enrollment: 47 patients

Sex: All

Ages: 30 to 80 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Healthy Subjects with osteoarthritis of knee fulfilling the standard indications for an Oxford Unicompartmental Knee Replacement.
• American Society of Anaesthesiologists (ASA) Score of 1 to 3.

Exclusion criteria

• Subjects with severe limiting systemic illness (i.e. ASA > 3).
• Subjects who are too large for radiostereometric analysis to be carried out.
• Subjects who have had previous open surgery or anterior cruciate ligament (ACL) reconstruction on the same knee.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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47 participants in 2 patient groups

Cementless Oxford Unicompartmental Knee Arthroplasty

Experimental group

Description:

Phase III Cementless Oxford Unicompartmental Knee Replacement (Biomet)

Treatment:

Device: Cementless Oxford Unicompartmental Knee Arthroplasty

Cemented Oxford Unicompartmental Knee Arthroplasty

Active Comparator group

Description:

Phase III Cemented Oxford Unicompartmental Knee Replacement (Biomet)

Treatment:

Device: Cemented Oxford Unicompartmental Knee Arthroplasty