Robotic Arthroplasty: a Clinical and cost Effectiveness Randomised controlled trial for Hips (RACER-HIP)

Many people who have conventional hip replacements continue to have some pain and limited function due to poor component position. More precise robotic assisted hip replacement surgery may improve component position and hence improve outcomes. This promise of improved outcomes has led to a rapid growth in the use of this technology within the NHS and around the world.

However, it is unclear whether more precise but expensive robotic assisted hip replacement surgery offers any meaningful benefit to patients or represents good value for money to the NHS.

This proposal addresses two of the top ten research priorities within the James Lind Alliance, which are intra-operative factors that can be modified to influence outcome and techniques to control longer term pain and improve function in hip replacement surgery.

We propose a multi-centre assessor and participant blinded prospective randomised superiority trial of robotic assisted hip replacement surgery versus conventional hip replacement in adults with end stage arthritis of the hip. The primary objectives wil be to:

i. Compare Forgotten Joint Score (primary outcome) at 12 months after randomisation between robotic assisted hip replacement and conventional hip replacement surgery.

ii. Determine the cost-effectiveness of robotic assisted hip replacement in the UK, compared to conventional hip replacement.

The study will begin with an internal pilot to help confirm the expected rate of recruitment and will take place at a minimum of five centres over eight months. We will seek to recruit >5 participants/ month/ centre, and we have clear stop/go criteria. The main trial will continue to recruit from these centres.

A research associate will collect baseline demographic data, FJS, pain intensity, estimated blood loss, opioid use, time to hospital discharge, EQ-5D-5L, Oxford Hip Score, satisfaction and adverse events related to the operation. We will also capture resource use from participants and NHS records.

Randomisation will be performed with minimisation with a random factor to help ensure balance for the following factors: age, hospital site, body mass index and type of hip replacement construct. Patients will be allocated (1:1) to interventions.

Participant and assessor blinding will be achieved using drapes and headphones with music if regional anaesthesia is used, thee small sham incisions in the control group and trial specific operation notes.

Follow-up will occur for the first three post-operative days and then at six weeks, three months, six months, one year (primary outcome time point) and then at two, five, and 10-years. Consent will be sought from participants to allow future follow up through efficient means using linkage to routine healthcare databases including hospital episode statistics, National Joint Registry of England and Wales and joint registries in Scotland.

The results of the trial will establish whether robotic assisted hip replacement surgery is truly worthwhile for patients and the NHS and will be disseminated to patients and their carers, surgeons, commissioners of healthcare and all other key stakeholders.