Projects / Programmes
SURVIVORSHIP OF TOTAL HIP REPLACEMENTS AS A FUNCTION OF TYPE OF BEARING SURFACES
| Code |
Science |
Field |
Subfield |
| 3.03.00 |
Medical sciences |
Neurobiology |
|
| Code |
Science |
Field |
| B600 |
Biomedical sciences |
Surgery, orthopaedics, traumatology |
orthopaedic implants, total hip replacement, biocompatibility, survivorship, wear, metal, ceramic, polyethylene, bearing surface
Researchers (13)
Organisations (2)
Abstract
The main goal of the proposed project is to establish the dependence of the survivorship of the total hip replacement (THR) as a function of type of bearing surfaces and to reveal the in vivo changes and biological impact of particular type of prostheses. Within the proposed project we will study the hypothesis that the survivorship of total hip replacements is dependent on the combination of materials of the bearing surfaces, i.e., of combination of materials of femoral hand and acetabular cup.
Four groups of patients will be selected, all of them having the same type of femoral stem and acetabular components (SL-Plus stems and Bicon-Plus cups) and differing only in the type of bearing surface. Traditional THRs with the metal femoral head and polyethylene acetabular cup, i.e., metal-on-polyethylene (M-P) THRs, show the highest volumetric wear. In order to decrease the volumetric wear, i.e., the volume of wear particles and, consequently, osteolysis, the use of alternative bearing surfaces has increased in the last decade. Ceramic-on-polyethylene (C-P) THRs show 2-times lower in vitro wear compared to M-P THRs, metal-on-metal (M-M) prostheses show 20-times lower wear, whereas the lowest wear is expected for ceramic-on-ceramic (C-C) bearings. Clinical results for the new type prostheses may or may not confirm the predictions based on in vitro studies, as was the case with M-M THRs where osteolysis was observed despite low volumetric wear in vivo.
Four groups of patients with proposed type of THRs operated at our hospital from 2000 to 2006 will be selected. We estimate that more than 760 patients will be included in the study. We will analyse demographic and clinical data of these four groups, measure the Harris Hip scores prior and following the surgery, determine the incidence of osteolysis based on radiographic analysis and calculate the Kaplan Maier survivorship curves. Besides clinical data, we will analyse the explanted prostheses and periprosthetic tissue samples taken at the revision surgeries. During the revision surgery the pH value of synovial fluid and periprosthetic tissue will be measured in order to compare the chemical environments of particular groups. Explanted components will be analysed in order to reveal the changes caused in vivo: morphological changes (measurements of roughness, SEM), chemical composition (EDS, XPS) and volumetric and linear wear (CMM). Sub-micometer sized metal, ceramic and polyethylene wear debris particles will be isolated from periprosthetic tissue and their morphology and composition will be determined. Furthermore, their biological impact on the periprosthetic tissue will be revealed based on histological analysis.
Significance for science
Proposed research has enriched the orthopaedic community with new scientific results. Interdisciplinarity of the project broadened the scientific methodology which could not be developed within individual scientific field – medicine and material science. Consequently, each of these two sciences gained and deepened the knowledge of its basic and applied research. Proposed interdisciplinary approach thus enabled more qualitative treatment of the field of total hip replacements and their impact in human body.
The results of our study are relevant for the publication in excellent scientic journals. Due to the lack of literature studies dealing with clinical results on at least three groups of patients differing in the type of bearing surface, our results have received positive review from one of the highest ranked journal in the field of orthepaedics (J. Bone Joint Surgery Am, IF =3,427; 3/26 orthopedics). We have published two papers in the high ranking journals (J. Biomed. Mater. Res. Part A, IF=2,816, 14/59, engineering biomedical) and Acta Biomaterialia (IF=3,727 (2008); 3/19: materials science, biomaterials). Further, we recieved invitations for invited lectures at international conferences (EFORT).
Combining the clinical data and results of the analysis of explanted components we have gained answers to most relevant issues concerning the choice of material of bearing surface. These answers will be of importance to the implant manufactures and to medical community.
Significance for the country
The results of the proposed project are relevant primarily to the patients having, or expecting to obtain, a total hip replacement. The results of the proposed project contribute to the better understanding of the functioning of total hip replacements and consequently to the necessary changes in the manufacture process and clinical use. Improvement of survivorship of hip prostheses consequently leads to the decrease in number of revision operations. Revision operations are not only unpleasant personal experience for the patient due to pain, limited range of motion and lastingness postoperative convalescence but also a financial burden to the health care funds and consequently to the society as a whole.
With the scientific methodology and organizational approach we follow the trends in the scientific orthopaedic community, as evidenced by published scientific papers in leading orthopaedic journals and presentation at international conferences. This process certainly strenghten the position of Slovenia as an important country at the world scientific map. Scientific work leads to the close collaboration with international partners and access to thier knowledge, resulting in cooperation in common projects and publishing of common scientific papers.
Most important scientific results
Annual report
2008,
2009,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2008,
2009,
final report,
complete report on dLib.si
