Clinical Trial Details
— Status: Active, not recruiting
Administrative data
| NCT number |
NCT01326832 |
| Other study ID # |
BMETEU.CR.UK4A |
| Secondary ID |
|
| Status |
Active, not recruiting |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
September 2011 |
| Est. completion date |
December 2024 |
Study information
| Verified date |
April 2023 |
| Source |
Zimmer Biomet |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
Using the traditional and hitherto used uncemented hip prostheses achieved good clinical
results, but one of the drawbacks is the risk of fracture in the femoral shaft in indbankning
of the prosthesis (1-2%). In addition, the bone scan demonstrated that in the years after
surgery dropped almost 30% of bone mass in the femoral shaft. This bone loss increases the
risk that in the years after surgery, the increased risk of fractures around the prosthesis
and in addition to impeding the described bone replacement prosthesis later.
The newly developed prosthesis is anchored in the femoral neck and thus not involve the
femoral shaft. This ensures a more physiological or normal weight transfer to the femur bone.
This contributes to bone mass in long large extent preserved in the years after surgery, so
you have a better opportunity later to make a new prosthesis surgery with good results. The
new prosthesis should be capable of simultaneously reducing the incidence of thigh pain in
the first year after surgery.'
Description:
By insertion of artificial hip joints in young and middle aged are often used so-called
uncemented technique in which the prosthesis is fixed to the bone without the use of bone
cement. Anchoring happens when the bone cells grow into the prosthesis porous surface,
thereby creating a stable anchorage of the prosthesis, both short and long term.
A hip prosthesis consists of 3 main elements:
1. socket
2. ball
3. femoral component, which hold ball. Femoral component is anchored to the upper end of
the femur including the upper 12-15 cm of the marrow cavity.
Achieved good results with this principle. The method involves a risk of fracture at the top
end of the femur bone during and after insertion of the prosthesis, but also that there is
some bone loss in the year after surgery. Finally there is a 3-10% chance that you get thigh
pain due to different elasticity of the femur and the long shank prosthesis.
Based on the foregoing disadvantages of the femoral components, which are commonly used, has
for years been experimenting with the introduction of shorter implants, which are either
anchored in the femoral neck or femoral neck combined with the very top end of the femur bone
(metaphysis). By using such a prosthesis, it is proven to preserve the bone in the upper
femur forward and avoids the disadvantage in terms of the above described femoral pain. There
is also described problems by using these short prostheses, especially in the form of
solution, and pain secondary to anchor bolts in the upper femur forward.
In Orthopaedic Surgery, Region Nordjylland, one has in the period 1999 to 2003 33 such
prostheses implanted at clinics in Farsø and Frederikshavn and achieved good results apart
from pain similar to the above anchoring screws. At follow-up of these prostheses, using DEXA
scans, the investigators have shown that prosthesis, bone-saving, since bone mass at the
femoral neck and the very top end of the femur bone is preserved.
From our experience with the aforementioned short prosthesis, the investigators have joined
with Biomechanical Institute, Royal National Orthopaedic Hospital, Stanmore, London and firm
Biomet developed a modern design of the above. This is a short prosthesis that is anchored in
the femoral neck and the upper end of the femur (metaphysis). Prosthesis made of titanium
with a porous surface (Bonemaster ®). The prosthesis is anchored during surgery by
pressure-fit (press-fit) and in a few weeks the bone grows into the prosthesis.
Prosthesis manufactured in 5 sizes and design of the prosthesis is aligned with a series of
CT scans of the femur was carried out at Stanmore in London. Has developed instruments to
ensure a uniform instrumentation and minimizing the risk of fractures in connection with the
operation. Performed a series of laboratory tests and these tests, the prosthesis was found
to be completely stable and even full load stable and the risk of fracture related to
prosthesis insertion is minimized.
The current study intends to examine whether that can be achieved equally good clinical
results as with the conventional uncemented femoral component and bone mass in the upper end
of the femur bone is preserved. Using a specific X-ray analysis (RSA) also assessed the
stability between the prosthesis and bone. Both DEXA scan as RSA studies have routine
examinations by Orthopaedic Surgery, Region Nordjylland, Klinik Farsø.
The planned surgery 50 young men and women with primary or secondary osteoarthritis of the
hip joint. Patients fulfilling the inclusion criteria and not subject to exclusion criteria
received oral and written information about the investigation.
Accept the patient to cooperate with the investigation confirmed that the patient's signature
approx. 2 weeks after oral and written information is given.
The operation is performed after the usual principles with rear access to the hip joint,
removal of rod ends and the insertion of an uncemented socket. After preparing the femoral
neck and top of thigh to the insertion of the short femur prosthesis and make selection using
tantalumkugler for RSA analysis. When the prosthesis is inserted carried out sample-space
theorem and using a 36 mm Co-Cr-ball, which is currently the department's practices. After
surgery the patient allowed partial load the first 6 weeks. There is an ongoing clinical and
radiographic controls and registration of unforeseen events arising from the use of the
product.
If the flow after 2 years are fully comparable clinical outcomes, minimal migration as
measured by RSA and final preservation of the bone around the implant, then the use of the
implant extends to several clinics at home and abroad, as per the recommendations of the
Danish Orthopaedic Association reference program for hip replacement surgery.
When implementing any new implant designs is a lower risk of unforeseen complications in the
form of fracture encountered in denture-deployment and subsequent unexpected prosthetic
solution. If the burst occurs Intraoperative, you can convert to the deployment of
conventional hip prosthesis without involving major risks for the patient. Early prosthetic
solution is also possible deployment of conventional complete dentures without result
deteriorates. The disadvantages of the possible complications are in the worst case of
operation (revision).
In addition, the disadvantages of trial participation increased radiation dose due to 4
additional X-ray checks in the first 2 years after surgery and 4 extra bone scans (DEXA).
The described investigation will clarify whether the theoretical advantages that have
hitherto been demonstrated by clinical and biomechanical study (normal weight transfer, bone
sparing and bone-keeping in the short and long term), also obtained by applying the newly
developed prosthetic component. If so, there will then be able to especially younger patients
with osteoarthritis of the hip joints better chance of achieving good clinical outcomes and
long-term sustainability by eventual replacement surgery, typically 10-20 years after primary
surgery.
Disadvantages of the described study estimated minimal compared to the benefits that a large
group of patients could benefit.
The actual cost of conducting the survey shall be borne by the prosthesis manufacturer Biomet
UK Ltd.. and Orthopaedic Surgery, North Jutland and the amount transferred to specific
research account affiliated research unit of Orthopaedic Surgery, Region Nordjylland and paid
through the Budget and Finance, Region House, Region Nordjylland.
