Assessing the safety and performance of a hip resurfacing
prosthesis compared with a conventional total hip prosthesis in
relatively young males with primary arthritis; a prospective,
controlled clinical study.

Since the beginning in the 1960s, total hip arthroplasty is being seen as one
of the most reliable procedures and has changed the quality of life of patients
with disabling osteoarthritis. In older patients the ten-year survival rate
ranges from 90%-96% (Corbett, 2010). However, young, active and high-demanding
patients (<60 years) have relatively disappointing results after a conventional
THA (ten year survival rates from 72%-86%). For this reason, research for
better solutions for this younger and active patient category has always
continued (Corbett, 2010) (Smolders J. , 2013).

The Birmingham Hip Resurfacing (BHR) prosthesis (Smith & Nephew Inc) is such a
solution. The BHR is a so-called Metal-on-Metal (MoM) resurfacing prosthesis
that was released in the market 15 years ago and is successfully implanted
worldwide ever since. A prosthesis such as the BHR is characterized by low wear
and a more accurate restoration of the anatomical situation and therefore ideal
for the relative young, active patients with an end stadium of primary
arthritis of the hip.

Because of the success of the BHR hip prosthesis, many orthopaedic
manufacturers have developed and marketed similar prostheses. Unfortunately
these prostheses appeared to be of incorrect design. Also in the Netherlands
these erroneous prostheses have been implanted, including the ASR (Johnson &
Johnson) and MoM total hip prosthesis (THP, Biomet) and have been implanted in
high numbers. Due to the failure of these prostheses the MoM technology has
received a lot of negative publicity in the Netherlands. The Dutch Orthopaedic
Association (NOV) has reacted to this publicity by issuing a guideline to her
members regarding the use of MoM prostheses. The advice of the NOV of January
17 2012 indicates that there is still a possibility to use MoM-prostheses,
provided that they are implanted within the setting of a clinical trial that
complies with GCP (see attachment I).

However, many publications and national registries, including those from
England & Wales and Australia, show that the BHR is a safe and good hip
prosthesis, provided that it is correctly implanted (see 2.6) with the correct
indication (Murray, 2012) (Holland, 2012) (Treacy, 2011) (Matharu, 2013 ) .
Looking at the group of demanding patients, who currently receive a traditional
total hip, the BHR would perform even better (Baker, 2011). Also, the BHR is
compliant with the benchmark of the National Institute for Health and Clinical
Excellence (NICE); a revision level of less than ten percent after ten years
for primary THP (Weegen, 2011). In a recent review (Haddad, 2011) of MoM hip
implants, the BHR shows the lowest failure rates compared with other MoM
implants.

In this paper (Haddad, 2011) the authors also emphasizes that the result of MoM
hip resurfacing largely depends on an appropriate surgical technique and
patient selection. Also, current data suggests that the correct surgical
technique in an appropriate selected cohort of patients is associated with a
low incidence of adverse soft-tissue reactions. High-risk factors for
developing complications include small component (implant) sizes, female gender
and significant anatomical variations due to for example, dysplasia, where
correct positioning may be difficult. Therefore, only patients with a primary
diagnosis of arthritis of the hip will be included and female patients and
males with a small femoral head size will be excluded. Besides that, the
performing orthopaedic surgeon and investigator has extensive experience in
resurfacing procedures with the BHR system (see 2.6). Combined with the
extensive safety measures in this protocol we provide a safe and beneficial
environment for the selected study patients.

With this study we compare the BHR and a conventional THP in a young and active
patient group, to confirm that for this specific patient group and under
favorable implantation circumstances, the BHR is a better solution regarding
the post-op activity score with comparable safety.

With this study we compare the BHR and a conventional THP in a young and active
patient group, to confirm that for this specific patient group and under
favorable implantation circumstances, the BHR is a better solution regarding
the post-op activity score with comparable safety.

This is a non-randomized, interventional controlled study with CE marked
medical devices.
In the study 2 groups are compared; one group is treated with the BHR
prosthesis, the other group with a conventional uncemented THP. The groups will
be followed for 10 years.
Both groups will complete 4 questionnaires pre-operatively and annualy post-up
(UCLA activity score, HOOS, EQ-5D en OHS) and physical examination will be
done. The incidence of any device related adverse events will be assessed.
Patients in both groups will have will have annual xrays and MARS-MRI and
ultrasound imaging at 1, 5 and 10 year FU to check for any device related
adverse events.
De BHR group will be followed according to the current MoM guidelines;
If a patient has any complaints which could be related to the hip or if there
are any findings on the xray images further examinations will be done
(Mars-MRI, utrasound) to identify any device related adverse events and to
provide treatment when necessary.

The selected patient group in this study is already qualfied for a hip
replacement.
The intervention in this trail is the implantation of the BHR resrurfacing
implant instead of the standard total hip replament implant.
The control group will have no interventions.

Burden:
Since only patienst are included who are in need of a hip replacement only the
study specific burden is lised below:
Both groups;
- Pre-operatively and annually post-operatively patients are requested to
complete 4 questionnaires.
- During the 1, 5 and 10 year post-operative visits an MRI scan and ultrasound
imaging will be done to identify any
incipient adverse device effects.
BHR group:
- During the annual visits blood is drawn for determination of cobalt levels.
It is anticipated that the annual visits will take about 0,5-1 hour more than
usual.
Risks (BHR group)
The related risks can be categorized into 3 categories: general surgery
related, general hip replacement related and
specifically device related.
Since all patients will undergo a hip replacement anyway, only the specific
device related risks are listed below:
- Adverse reactions to metal debris (ARMD)
- Peri-prosthetic aseptic lymphocyte dominated vasculitis associated lesions
(ALVAL)
- Soft tisue masses (pseudotumoren)
- Avascular necrosis
- Femoral neck fractures
In the group of patients included in this study the above mentioned adverse
events are rare. This specific patient group is
relatively young and are still very active and therefore have high demands on a
prosthesis. The BHR prosthesis is very
wear resistant and in case a future revision is needed (due to the relatively
young age a lot of patients outlive their
prosthesis) it will be much easier compared to a initial total hip prothesis
(because the femoral head is left in place and no
femoral shaft is used).

No study specific risks are expected for the control group.