Patient Blinded Randomized Clinical Trial comparing two types of mobile bearing unicondylar knee replacement

Rationale:
In the last decades unicondylar knee arthroplasty has become widely accepted as a valid option in the treatment for unicondylar osteoarthritis. Over these decades several design options are altered and the best documented is the Oxford® unicondylar design which has a mobile bearing and single radius design. In Total knee arthroplasty the multi radius design is proven as an excellent solution. This study is designed to show the non-inferiority of the ACS® unicondylar knee arthroplasty, which is a mobile bearing with a multi radius design, compared to a Single Radius design Unicondylar knee implant (Oxford).



Objective:
To assess non inferiority of a Multi Radius design (ACS® unicondylar) compared to a Single Radius design Unicondylar knee implant (Oxford) on clinical outcome using the Oxford Knee Score.



Study population:
The study population will consist of patients with symptomatic unicondylar osteoarthritis of the knee scheduled for a medial unicondylar arthroplasty surgery in one of the participating clinics.



Study design:
The study design is a prospective patient blinded randomized controlled study comparing a Single Radius design Unicondylar knee implant (Oxford) with a Multi Radius design (ACS® unicondylar) in terms of clinical outcome, range of motion and radiological results. Inclusion will be performed ibetween 2015 and 2017, with a maximum follow up of 10 year per patient. The study will be conducted in the Orthopedium Orthopedic Clinic and Slotervaart Hospital.



Intervention:
Unicondylar knee arthroplasty with either the Oxford® unicondylar knee arthroplasty or the ACS ® unicondylar knee arthroplasty.



Main study parameters/endpoints:
Our main study endpoint is the Oxford Knee Score at two year follow up. A knee specific questionnaire specifically designed to measure outcome in knee arthroplasty patients. This score was chosen since most Partial Knee studies use this outcome, therefore our study can be compared with the other Partial Knee papers.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness:
All patients will be seen at regular follow up intervals identical to the normal unicondylar knee arthroplasty protocol. At these visits patients will be asked to fill out a questionnaire.
All patients will be treated according to standard UKA protocol, with an implant that is available on the market and has a CE marking. Bearing this in mind we judge the study as safe.

1. The ACS® unicondylar performs equal of better (non-inferior) compared to the Oxford Partial Knee ® on functional outcome (Oxford Knee Score).

2. The ACS® unicondylar performs equal of better (non-inferior) compared to the Oxford Partial Knee ® on Qol outcomes (NRS for pain, EQ5D and a KOOS-PS).

3. The revision rate of The ACS® unicondylar is equal of smaller (non-inferior) compared to the Oxford Partial Knee ®.

Baseline, direct postoperative, 6 months, 1 year, 2 years, 5 years, 10 years

Placement of an unicondylar knee arthroplasty with either the Oxford® unicondylar knee arthroplasty or the ACS ® unicondylar knee arthroplasty.