Total knee arthroplasty with comparison of inset versus onlay patella replacement: investigation of anterior knee pain and function.

In patients with knee osteoarthritis requiring total knee arthroplasty, does patella replacement with an inset design prosthesis, compared with an onlay design prosthesis, improve anterior knee pain and function?

Status

Completed

Phases

Unknown

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12615000550505

Enrollment

100

Registered

2015-05-29

Start date

2017-02-06

Completion date

2023-12-30

Last updated

2025-09-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

The aim of this trial is to compare current patella component designs (inset vs onlay), with the hope of finding significant improvement in anterior knee pain or knee function for one design over the other. Subsequently, future patients can benefit from surgery using the superior design. This trial will recruit suitable and consenting participants from the private rooms of Prof. D Wood at the Perth Orthopaedic Institute, HPH. Consenting participants would undergo a total knee arthroplasty (which they otherwise would undergo, whether they were enrolled in this study or not, as part of their clinical care). The patella component of their total knee arthroplasty (TKA) will be randomised to either an inset design or onlay design. All surgeries will be carried out by Prof. D Wood using his routine surgical technique and peri-operative care. Participants are not placed at increased risk or offered inferior treatment in this study based on current knowledge. Participants will have standard postoperative weekly physiotherapy sessions as part of the standard care following total knee arthroplasty, and will be followed up by Prof Wood at 3, 6, 12, 24 and 60 months, also as part of usual care. During this interval follow up, participants will also complete a series of validated scoring questionnaires and functional tests, administered by a trained assessor. These functional data will be compared across the two study groups (inset patella component, onlay patella component) and hazard ratios and confidence intervals generated using statistical software. Anonymous results will be submitted for publication in a leading orthopaedic journal to inform other surgeons and medical professionals of the results.

Interventions

Zimmer NexGen(Registered Trademark) Posterior Stabilised Total Knee Arthroplasty System. Either Inset or Onlay design NexGen(Registered Trademark) patella components.

Study design

Allocation

Randomised controlled trial

Intervention model

Parallel

Primary purpose

Treatment

Masking

Blinded (masking used) (Subject, Outcomes Assessor)

Eligibility

Sex/Gender

All

Age

45 Years to 80 Years

Healthy volunteers

Inclusion criteria

45-80 years; planning to undergo primary total knee arthroplasty for knee osteoarthritis with at posterior stabilised prostheses; willing to participate in the trial and follow up; under the care of Prof Wood at Hollywood Private Hospital, Western Australia.

Exclusion criteria

Revision total knee arthroplasty; previous high tibial osteotomy; total knee arthroplasty for non-osteoarthritic pathology; Age <45years or >80years; participant refusal to participate or sign informed consent; participant incapable or unable to participate with the clinical questionnaires or knee function assessments.

Outcome results