Tibial and femoral osteotomies in varus deformities - radiological and clinical outcome

Fürmetz et al. BMC Musculoskeletal Disorders https://doi.org/10.1186/s12891-020-03232-2 (2020) 21:201 RESEARCH ARTICLE Open Access Tibial and femoral osteotomies in varus deformities - radiological and clinical outcome Julian Fürmetz1*, Sven Patzler1, Florian Wolf1, Nikolaus Degen1, Wolf Christian Prall2,3, Chris Soo4,5, Wolfgang Böcker2 and Peter Helmut Thaller1 Abstract Background: Varus deformities of the knee are frequently corrected by osteotomies, which should be performed at the level of origin. But in contrast to high tibial osteotomies (HTO), little data exists for distal femoral osteotomies (DFO). This study evaluates radiological and clinical outcomes after valgisation osteotomies in the proximal tibia and distal femur. Methods: We used an observational cohort study design and prospectively performed preoperative long standing radiographs (LSR), lateral x-rays and clinical questionnaires (SF-36, Lysholm score, VAS). Postoperative LSR and lateral x-rays were obtained on average 18 months postoperative and postoperative clinical questionnaires at final visit (mean follow up 46 months). A subgroup analysis of the different surgical techniques (oHTO vs. cDFO) was performed, with regards to radiological and clinical outcomes. Results: Finally 28 osteotomies with medial tibial opening (oHTO) or lateral femoral closing (cDFO) wedge osteotomies in 25 consecutive patients (mean age 40 years) were identified. There were 17 tibal and 11 femoral procedures. All osteotomies were performed at the origin of deformity, which was of different etiology. The average deviation of the final HKA compared to the preoperative planning was 2.4° ± 0.4°. Overall, there was a significant improvement in all clinical scores (SF-36: 61.8 to 79.4, p < 0.001; Lysholm-score: 72.7 to 90.4, p < 0.001; VAS: 3 to 1, p < 0.001). There was no significant correlation between surgical accuracy and outcome scores. Conclusion: Valgisation osteotomies lead to a significant improvement in all clinical scores with the demonstrated treatment protocol. An appreciable proportion of varus deformities are of femoral origin. Since cDFO provides comparable radiological and clinical results as oHTO, this is an important treatment option for varus deformities of femoral origin. Keywords: Osteotomies, Distal femoral osteotomy, DFO, High Tibial osteotomy, HTO, Valgisation, Realignment, Varus deformities, Medial osteoarthritis * Correspondence: 1 3D-Surgery, Department of General, Trauma and Reconstructive Surgery, University of Munich LMU, Nußbaumstraße 20, 80336 München, Germany Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Fürmetz et al. BMC Musculoskeletal Disorders (2020) 21:201 Background Varus malalignment has been identified as a risk factor for the incidence and progression of medial osteoarthritis (OA) [1]. Deformity correction with osteotomies near the knee joint is therefore an important therapeutic intervention, which may prevent or delay the need for joint replacement even in cases of severe cartilage damage independent of patient age [2]. This is especially relevant in younger patients, as lifetime risk of revision surgery after knee joint replacements increases dramatically within this patient group [3]. In varus deformities, osteotomies were usually performed in the tibia, with valgus deformities predominantly treated with femoral procedures. However, it has become common practice to perform a deformity analysis using a long standing radiograph (LSR) to determine the origin of deformity prior to surgery [4, 5], since varus deformities can be localized either in the tibia or in the femur [6–8]. In the case of femoral malalignment, a high tibial osteotomy (HTO) results in a pathological oblique knee joint line with increased shear forces and vice versa in the case of a tibial malalignment and femoral correction [9]. Clinical and biomechanical studies indicate that if the postoperative knee joint line is not physiologically aligned, this leads to a poor result [7, 10, 11]. In contrast to the HTO, very little clinical data exist on lateral distal femoral osteotomies (DFO) in cases of varus deformities. At the distal femur, a closed wedge procedure is recommended due to the frequent instability in femoral open wedge osteotomies [12]. There exist only 2 studies reporting on lateral distal closing wedge femoral osteotomies, covering a total of only 19 cases [6, 8]. For the first time, this study evaluates radiological and clinical outcomes in valgisating femoral and tibial osteotomies. Methods Patients Patients with symptomatic varus deformity treated with deformity correction (oHTO or cDFO) close to the knee joint were included in the study. Excluded were patients Page 2 of 8 requiring simultaneous multilevel osteotomies or those with incomplete follow up. In total, from 2009 to 2016, there were 28 osteotomies on 25 consecutive patients with varus deformities. The etiology was heterogenous: 9 congenital, 14 growthrelated and 5 post-traumatic deformities. The demographic characteristics of patients including the BMI are presented in Table 1. Institutional review board approval was obtained for the study (EC-Nr.: 16–008). All involved patients gave their informed consent statement prior to the study inclusion. Standardised radiological and clinical assessment Radiographic analysis of the pre- and postoperative LSR included the following parameters: mechanical axis deviation (MAD), hip knee angle (HKA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle (mLDFA), joint line convergence angle (JLCA), patella height (CatonDeschamps index), tibial slope, and posterior distal femoral angle (PDFA), according to the definitions by Paley [13]. For a better comparability to previous reports, we included the HKA. But in our daily clinical practice, joint angles, JLCA and MAD are the most i (...truncated)