Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Zinggl, C.
Does a constitutional varus affect the postoperative leg axis after total knee replacement by using the extension-first-technique?
Humanmedizin; [ Diplomarbeit ] Medizinische Universität Graz; 2021. pp. 62
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Hörlesberger Nina
- Lohberger Birgit
- Altmetrics:
- Abstract:
- In the context of Total Knee Arthroplasty (TKA), the alignment of the leg axis is an essential factor. 3 % of the population present a varus alignment of the leg axis of 3° varus or more. As a result, a neutral alignment of the leg axis cannot be considered physiological for everyone. Therefore, some surgeons favour a 3° varus alignment in TKA. The aim of the study was to evaluate whether a varus position results postoperatively for preoperatively varus-aligned leg axes even if this 3° Concept is not considered and the Extension First Technique is used in TKA. For this purpose, 224 whole-leg radiographs (preoperative and postoperative) of 112 randomly selected patients were measured by hand. Femoral and tibial angles (lateral, medial, proximal, distal), as well as the femorotibial angle, the hip-knee-ankle angle, and the deviation of the Mikulicz Line from the center of the knee joint were measured. Patients were divided into three groups, varus (n=63), valgus (n=33), or orthograde (n=16), according to their preoperative leg axis. After calculating the differences between pre- and postoperative for each angle, statistical analysis was performed using analysis of variance (ANOVA) and, in case of significant differences, additional Post-Hoc t-Tests. In 83 % (N=52) of the patients with preoperative varus alignment, an orthograde leg axis could be found postoperatively. This indicates that using the Extension First Technique without considering the 3° Concept for preoperative varus aligned knee joints does not lead to a postoperative varus alignment in most cases. However, considering the results of the varus group compared to the non-varus group (valgus and orthograde), a postoperative orthograde leg axis can be achieved in only 61 % (N=30) of patients in the non-varus group. In contrast to knee joints with a preoperative varus position, almost half of the knee joints with preoperative valgus alignment are also valgus aligned postoperatively. The tendency of increased postoperative valgus alignment in preoperatively valgus aligned knee joints is interesting for further investigations, also, in order to reveal the primary influencing factor (among others surgical techniques, measurement techniques, patient population). Overall, this study showed that the TKA by using the Extension First Technique mostly results in a postoperative orthograde leg axis, regardless of the phenotype.