ISRCTN - ISRCTN54967983: Periprosthetic bone mineral density (BMD) around two different stems in total hip arthroplasty

Plain English Summary

Not provided at time of registration

Trial website

Contact information

Type

Scientific

Primary contact

Prof Christina Stukenborg-Colsman

ORCID ID

Contact details

Orthopädische Klinik Medizinische Hochschule Hannover im Annastift
Anna-von-Borries-Str. 1-7
Hannover
30625
Germany
christina.stukenborg@ddh-gruppe.de

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

Scientific title

Periprosthetic bone mineral density (BMD) around two different stems in total hip arthroplasty: an observational longitudinal study

Acronym

Study hypothesis

To monitor the bone mineral density (BMD) around a well known approved femoral implant and a new short stem design femoral implant. The data is used to validate a finite element model of both implants.

Ethics approval

Local ethics committee approved on the 23rd May 2006 (ref: 4226)

Study design

Observational longitudinal study

Primary study design

Observational

Secondary study design

Cohort study

Trial setting

Hospitals

Trial type

Screening

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Osteoarthritis of the hip

Intervention

In all patients the Metha short stem (monoblock with 130° CCD angle and 0° ante-, retrotorsion) or the Bicontact stem (AESCULAP AG, Tuttlingen, Germany) was implanted by three experienced senior surgeons over a standard lateral approach in supine position. The cementless short stem implant is made of a titanium forged alloy and has a proximal rough titanium micro-porous coating. An additional 20 µm dicalciumphosphate layer is applied electrochemically. The stem is anchored metaphyseally within the closed ring of the femoral neck. The Bicontact stem is designed for proximal fixation and load transfer to bone. According to the implant design and the Plasmapore-coated proximal part the secondary implant stability is achieved by proximal anchoring and cancellous bone ingrowth. Pre-operatively, 1 week after surgery, 6 month and 12 month after implantation the patients were examined clinically (Harris Hip Score) and underwent DXA examinations.

All patients underwent full weight bearing post-operatively. DXA scans were performed using a HOLOGIC Discovery A S/N 80600 device (Hologic Inc., Waltham, MA). The BMD (g/cm2) of the operated hip was measured using the "metal-removal hip" scanning mode. Conventional Gruen's zones were adapted to the short stem design. Each patients individual ROIs were saved on the Hologic system and were used for all following measurements to reduce bias. The images were analyzed using the dedicated Windows analysis software (version 11.2). The patients were placed in supine position with the affected leg in 20° internal rotation. The foot was secured in the Hologic foot positioning device in order to obtain reproducible rotation in all patients to limit measurement errors, since it has been demonstrated that rotation influences the BMD.

DXA precision was assessed on all subjects. The patients underwent sequential DXA examinations of the contralateral unoperated hip and the proximal femur - taken preoperatively and one week later. Additional quality controls were done every morning for the DXA equipment according to the manufacturer's guidelines, to verify the stability of the system, and did not show any shift or drift during the entire study period. The device used in our study was therefore chaacterised as stable. The same observer (ML) analysed all DXA examinations. A Student's t-test was used to test the hypothesis of a difference between the means at the different measurement time points in the Harris hip Score as a normal distribution was ascertained. The Shapiro-Wilk-tests did not show a normal distribution in the DXA measurements, the Wilcoxon signed-ranks test was used to statistically compare the density changes over one year. A p<0.005 was considered significant. Data analysis was performed with SPSS (11.05 SPSS Inc. Chicago, Illinois). After two years the Bicontact branch was ended, but the Metha branch will continue for additional two years.

Intervention type

Other

Phase

Not Applicable

Drug names

Primary outcome measure

BMD (g/cm^2) in Gruen Zones 1 - 7 per DEXA, measured 1 day pre-operatively, and 1 week, 6 months, 1 year, 2 years, 3 years and 4 years post-operatively.

Secondary outcome measures

Harris Hip Score per questionaire and clinical examination, measured 1 day pre-operatively, and 1 week, 6 months, 1 year, 2 years, 3 years and 4 years post-operatively.

Overall trial start date

01/06/2008

Overall trial end date

31/12/2014

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

1. Indication for unilateral implantation of the Bicontact stem or the Metha short stem due to osteoarthritis of the hip
2. Patients' ages between 35 and 70 years of either sex
3. Written informed consent

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

25 per implant, 50 in total

Participant exclusion criteria

1. Manifestly overweight (body mass index [BMI] greater than 35 kg/m^2)
2. History of previous surgeries on the same hip
3. Femoral fractures
4. Metabolic bone diseases
5. Use of steroids or other drugs affecting bone metabolism
6. Intraoperative cracks
7. Severe osteoarthritis of the contralateral hip
8. Received total hip arthroplasty (THA) on the contralateral hip during the study period
9. Patients in whom an event leading to restricted weight bearing on the ipsi- or contralateral hip occurred

Recruitment start date

01/06/2008

Recruitment end date

31/12/2014

Locations

Countries of recruitment

Germany

Trial participating centre

Orthopädische Klinik Medizinische Hochschule Hannover im Annastift
Hannover
30625
Germany

Sponsor information

Organisation

German Research Council (Deutsche Forschungsgemeinschaft [DFG]) (Germany)

Sponsor details

Kennedyallee 40
Bonn
53170
Germany
+49 (0)228 885 1
postmaster@dfg.de

Sponsor type

Research council

Website

http://www.dfg.de

Funders

Funder type