The Polarstem Versus Corail; a Comparison of Micromotion and Periprosthetic Bone Remodelling of Two Femoral Stems. A Randomised Trial of 60 Patients Using Radiostereometric Analysis, Dual Energy X-ray Absorptiometry and Computer Tomography
试验速览
- 阶段
- 不适用
- 状态
- 进行中（未招募）
- 入组人数
- 60
- 试验地点
- 2
- 主要终点
- Periprosthetic femoral bone mineral density (BMD); Change from baseline (postoperative) to the prescribed time
研究概览
简要总结
A randomised controlled trial comparing a recently introduced femoral stem with an established stem for total hip arthroplasty (THA). 60 patients will be randomised into one of the two groups
- Polarstem uncemented femoral stem (Smith & Nephew)
- Corail uncemented femoral stem (De Puy) All patients will receive a 32mm cobalt-chromium (CoCr) femoral head and an R3 acetabular cup with a 10 Mrad highly cross-linked polyethylene (XLPE) liner (Smith & Nephew).
Radiostereometric analysis (RSA) will be used to measure stem migration. Dual-energy x-ray absorptiometry (DXA) measurements will be used to measure bone mineral density. Clinical outcome will be assessed at different time point to evaluate satisfaction and function. Data from the Norwegian Arthroplasty Register will be used to investigate the risk of revision.
详细描述
The gold standard in THA the last 45 years has been the all-cemented metal-on polyethylene prostheses such as the Charnley low-frictional arthroplasty. From 1980 and onwards however, uncemented THA have been increasingly popular worldwide, especially for the younger patients. The reasons for this were reports on poor results of the Charnley cemented THA in young patients, and the belief that the cement itself was the cause of periprosthetic osteolysis and loosening of the prostheses. Uncemented THA have good results in some reports and poor results in others. The modern uncemented femoral stems have proven good or even excellent results at medium to long term follow-up in the register and in other clinical studies. The Corail uncemented femoral stem (DePuy) has dominated the Norwegian market on uncemented stems since the mid 1980'ies. Its clinical performance is well documented with good results in terms of implant survival5. The Polarstem (Smith & Nephew) was introduced in 2002 by a group of surgeons that believed the Corail stem had certain limitations, and the Polarstem is a Corail-like stem with some modifications. The basic design philosophy of a straight tapered design is the same for both stems.
Unlike drugs, medical devices such as orthopaedic implants can be launched on the market without any proof of clinical efficacy. In some cases, inferior implants have been used in thousands of patients before the inferior results were discovered. Some authors propose a stepwise introduction of new implants in order to avoid compromising large numbers of patients. The present study is a step in the introduction of a relatively new femoral stem. High accuracy measuring tools will be used to measure critical factors such as implant migration and bone remodelling at short-term follow-up. The findings will give information on the expected clinical outcome at longer term.
The aims of the study are
- To compare the migration of the Polarstem and the Corail stem with RSA. The null hypothesis is that there is no difference in the early (2 years postoperative) migration of these implants. Early migration has earlier proved to be a surrogate for implant performance at medium and long term.
- To compare any remodeling of periprosthetic femoral bone from direct postoperative measures to later time points. Periprosthetic bone loss, especially in the proximal femur, can compromise the longevity of a prosthetic joint. This bone loss vary and will be compared between the two designs.
- To assess and compare clinical outcome measures and radiological outcomes such as signs of loosening and osteolysis.
Components
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Triple (Participant, Care Provider, Outcomes Assessor)
盲法说明
Computer generated block randomization for each participating surgeon. The envelopes are sequentially numbered, opaque and sealed. The surgeon is not blinded, but the patient and the physiotherapist that do the clinical follow-ups are.
入排标准
- 年龄范围
- — 至 75 Years（Child, Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •primary arthritis
- •secondary arthritis
- •aseptic necrosis of the femoral head
- •acute hip fracture
- •sequelae after hip fracture
- •can use standard implants
排除标准
- •active malignant disease
- •rheumatoid arthritis or other generalised auto-immune arthritic disease
- •insulin dependent diabetes mellitus
- •chronic or recurrent infection
- •liver disease
- •Pagets disease
- •dementia or lack of compliance for other reasons
- •uncompensated cardiac- or pulmonary disease (ASA class 3 or 4)
结局指标
主要结局
Periprosthetic femoral bone mineral density (BMD); Change from baseline (postoperative) to the prescribed time
时间窗: Baseline (1, 2 or 3 days after operation; post-operative), 24 months and 60 months after surgery.
Periprosthetic femoral bone mineral density (BMD) will be measured within 1, 2 or 3 days after operation (post-operative) to have a baseline and at the prescribed intervals using Dual x-ray absorptiometry (DXA). A DXA-machine (Lunar Prodigy, GE) located at the Department of Rheumatology at Haukeland University Hospital will be used with customized software.
Migration of femoral component into the bone; Change from baseline to the prescribed time
时间窗: Baseline (1, 2 or 3 days after operation; post-operative), 3 months, 12 months, 24 months, 60 months, and 10 years postoperatively.
Radiostereometric pictures will be taken within 1, 2 or 3 days after operation (post-operative) to have a baseline and at the prescribed intervals. Migration will be measure with radiostereometric analysis (RSA) at the described intervals. Implant migration the first few years after implantation can correspond to loosening at long term.
次要结局
- Position of the stem: Varus/valgus(Baseline (1, 2 or 3 days after operation; post-operative))
- EQ-5D-3L; Change from pre-operative to the prescribed time(Pre-operative, 3 months, 12 months , 24 months, 60 months, and 10 years after surgery.)
- Position of the stem: Cup inclination(Baseline (1, 2 or 3 days after operation; post-operative))
- Hip pain; Change from pre-operative to the prescribed time(Pre-operative, 3 months, 12 months , 24 months, 60 months, and 10 years after surgery.)
- Osteolysis in Acetabulum; Change from baseline to the prescribed time(Baseline (1, 2 or 3 days after operation; post-operative), 12 months, 24 months, 60 months, and 10 years postoperatively.)
- Harris Hip Score (HHS); Change from pre-operative to the prescribed time(Pre-operative, 3 months, 12 months , 24 months, 60 months, and 10 years after surgery.)
- Hip Disability and Osteoarthritis Outcome Score (HOOS); Change from pre-operative to the prescribed time(Pre-operative, 3 months, 12 months , 24 months, 60 months, and 10 years after surgery.)
- EQ VAS; Change from pre-operative to the prescribed time(Pre-operative, 3 months, 12 months , 24 months, 60 months, and 10 years after surgery.)
- Satisfaction with the Hip; Change from pre-operative to the prescribed time(Pre-operative, 3 months, 12 months , 24 months, 60 months, and 10 years after surgery.)
- Position of the stem; Change from baseline to the prescribed time(Baseline (1, 2 or 3 days after operation; post-operative), 12 months, 24 months, 60 months, and 10 years postoperatively.)
- Osteolysis in Femur; Change from baseline to the prescribed time(Baseline (1, 2 or 3 days after operation; post-operative), 12 months, 24 months, 60 months, and 10 years postoperatively.)
研究者
Geir Hallan
Clinical Professor
Helse-Bergen HF