Einfluß des PE-Inlay-Überstandes auf das Outcome bei der primären Knieendoprothetik: Kurzfristige Ergebnisse einer retrospektiven Studie

Die Kniegelenksendoprothetik stellt eine relative sichere und erfolgreiche Behandlungsmöglichkeit der fortgeschrittenen Gonarthrose dar. Bei den meisten, im Handel verfügbaren Prothesenmodellen richtet sich die Größe des PE-Inlays nach der Größe der tibialen Komponente. Es gibt jedoch einige Mo...

Full description

Saved in:
Bibliographic Details
Main Author: Orfanos, Georgios
Contributors: Endres, Stefan (Prof. Dr.) (Thesis advisor)
Format: Doctoral Thesis
Language:German
Published: Philipps-Universität Marburg 2021
Subjects:
Online Access:PDF Full Text
Tags: Add Tag
No Tags, Be the first to tag this record!

Knee joint endoprosthesis is a relatively safe and successful treatment option for advanced osteoarthritis of the knee. In most of the commercially available prosthesis models, the size of the PE inlay depends on the size of the tibial component. However, there are some models where the size of the inlay is based on the size of the femoral component in order to optimize the surface contact. However, it is possible that the implanted femoral component is larger than the tibial component. As a result of this mismatch, there can be a so-called polyethylene overhang over the metallic, tibial component. The overhang of the metallic components and their oversizing has been researched to a great extent in the literature. The effects of a polyethylene overhang on the functional outcome and the radiological measurements have not yet been investigated. In a retrospective study, a total of 124 patients (or 135 knee joints) were examined from August 2018 to February 2019. They all were treated surgically with a primary total knee endoprosthesis (Gemini type SL PS - fixed bearing, cemented- from Link) for symptomatic osteoarthritis of the knee. The mean follow up was 16 months. The same surgical technique, the same prosthesis model and the same follow-up treatment scheme were always used. No patient was openly operated before or after surgery (exclusion criterion). The patients were divided into two groups. A total of 68 knee joints are assigned to the first group, in which the femoral component and consequently the polyethylene inlay were the same size or smaller than the tibial component (non134 mismatch group). The second group included 67 knee joints in which the femoral component and the inlay were larger than the tibial component (mismatch group). All patients were called in, informed about the study, clinically examined personally by the author and the Knee Society Score was recorded. In addition, standardized x-rays were taken and the implant seat evaluated according to the Knee Society Roentgenographic Evaluation and Scoring System criteria. The data collected in this way were statistically evaluated. Two analyzes were carried out; the original analysis as well as a so-called sensitivity analysis, whereby all patients were excluded who had been operated on both sides in order to exclude person-specific factors. As the corresponding statistical tests showed, two groups were formed that were homogeneous in terms of age, weight and duration of the follow-up examination. The evaluation of the clinical scores showed no significant differences in the Knee Society Score total score, the Knee Society Score - knee score or the Knee Society Score - functional score in both groups. The original analysis of the radiological scores also showed no significant differences; In the sensitivity analysis, a significant difference was only found for the a.p. Femoral angle determined. Regarding retropatellar replacement, a significant difference between the two groups was also found in the original analysis alone (which, however, could no longer be found in the sensitivity analysis). The sole criterion for performing a retropatellar replacement in the patients examined was, however, the destruction of the retropatellar articular surface. A significant difference in gender distribution was found; there were significantly more women in the mismatch group than in the non-mismatch group. All of these results are well compatible with the current scientific literature. However, this study has the weaknesses of a retrospective study. Further prospective studies are necessary to confirm or refute the hypotheses presented here.