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Objectives: The idea to aim for an "individualized" alignment, whereby the constitutional alignment is restored, has gained much interest among knee surgeons. This requires insight into the prediseased, natural alignment of our patients' knees. The aim of this study is (1) to determine how the hip-knee-ankle (HKA) angle is influenced during the arthritic process and (2) to investigate the correlation between joint line changes and the progression of osteoarthritis (OA). It is our hypothesis that the most pronounced coronal parameter changes appear at the proximal tibia and at the joint line., Methods: One hundred sequential full-length X-rays with a minimum follow-up of 1 year were retrospectively reviewed from a radiographic joint database. Patients had to be at least 50 years of age needed to have an HKA angle of more than 1.3° varus to be included. Patients with ipsilateral total hip arthroplasty, femoral or tibial fracture, osteotomy, or ligamentous repair were excluded. Fifteen alignment parameters were investigated on the sequential full-length X-rays. Moreover, the relationship between the alignment parameters and the Kellgren-Lawrence grade (KL grade) was determined by using linear mixed models., Results: A progressive KL grade is associated with an increase of the HKA (p < 0.001). Mostly, HKA differs due to decrease of the medial tibial plateau (MPTA) angle (0.93°) and an increase of the joint line angle (JLCA) (0.86°). The mLDFA demonstrated the most pronounced changes in the beginning of OA (KL grade 1-2) (p = 0.049). In particular, the MPTA becomes considerably smaller (p = 0.004) in the later stage of OA (KL grade 3). Also, a progressive increase of the JLCA (p < 0.001) is observed upwards of KL grade 3., Conclusion: By comparing consecutive full-length X-rays in the same patients, it is possible to define the coronal alignment changes during the arthritic process. The HKA angle increases according the arthritic progression, whereby the most pronounced changes appear at the proximal tibia (MPTA) and at the joint line (JLCA).The alignment changes in varus OA knees can be divided in three stadia: (1) erosion of the distal medial femoral condyle, (2) erosion of the medial tibial plateau, and (3) a progressive increase of the joint line angle., Level of Evidence: Therapeutic Study, Level III., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Purpose: The influence of type and intensity of sports during growth on knee alignment was investigated. The second aim was to ascertain whether the distal femur or proximal tibia contribute most to knee alignment. Also, the influence of field position and leg dominancy on knee alignment in soccer players was audited., Methods: Standardized full-leg standing digital radiographs were obtained from 100 males and 100 females on which 8 different alignment parameters were measured. Participants were questioned on their sports activities during different stages of growth. Sports activities were graded according to the Tegner score., Results: The mean (±SD) hip-knee-ankle angle (HKA) was significantly lower (p < 0.001) in high-activity male athletes (-2.8° ± 2.4°) than in low-activity male athletes (-0.9° ± 1.9°). No differences in HKA were observed between different activity levels in females. Males who practiced soccer between 10-12 years and 15-17 years had, in turn, a lower HKA than athletes practicing other high-activity sports in these age categories (mean difference ≥1.2°, p ≤ 0.046). The most contributing factor for the varus alignment in male soccer players was a lower medial proximal tibial angle (MPTA)., Conclusion: High-activity sports participation during youth is associated with varus alignment at the end of growth in males. The most pronounced bowlegs were observed in male soccer players, and this was primarily determined by the proximal tibia. Adjustments in loads applied to the knees during skeletal growth in males might prevent the development of varus alignment and associated pathology, but further studies are required., Level of Evidence: Diagnostic study, Level III.

Purpose: In this study, the value of the adductor tubercle as landmark for joint line reconstruction in revision total knee arthroplasty (TKA) was investigated., Methods: On 100 calibrated full-leg standing radiographs obtained from healthy volunteers, distances from the medial epicondyle, the lateral epicondyle, the adductor tubercle, the fibular head and the centre of the knee to the joint line were determined., Results: The average distance to the joint line from the medial epicondyle, the lateral epicondyle, the adductor tubercle and the fibular head was found to be 27.7 mm (SD 3.0), 27.1 mm (SD 2.7), 44.6 mm (SD 4.3) and 15.1 mm (SD 3.7), respectively. The distance from the adductor tubercle (R = 0.82) and the centre of the knee (R = 0.86) to the joint line showed a strong and linear correlation with the femoral width. The medial epicondyle, the lateral epicondyle and the fibular head showed less strong correlations. There was no significant correlation with the limb alignment. The adductor ratio was defined as the distance from adductor tubercle to the joint line divided by the femoral width and was found to be 0.52 (SD 0.027) with only small inter-individual variation. The adductor ratio was the most accurate ratio and reconstructed the joint line within 4 mm of its original level in 92% of the cases., Conclusion: The adductor ratio is a reliable and accurate tool for joint line reconstruction in revision TKA. It was found to be more accurate then the use of absolute distances and the epicondylar ratios. This study supports the use of the adductor tubercle for joint line reconstruction in revision TKA., Level of Evidence: II.

Background: Most knee surgeons have believed during TKA neutral mechanical alignment should be restored. A number of patients may exist, however, for whom neutral mechanical alignment is abnormal. Patients with so-called "constitutional varus" knees have had varus alignment since they reached skeletal maturity. Restoring neutral alignment in these cases may in fact be abnormal and undesirable and would likely require some degree of medial soft tissue release to achieve neutral alignment., Questions/purposes: We investigated what percentage of the normal population has constitutional varus knees and what are the contributing factors., Subjects and Methods: We recruited a cohort of 250 asymptomatic adult volunteers between 20 and 27 years old for this cross-sectional study. All volunteers had full-leg standing digital radiographs on which 19 alignment parameters were analyzed. The incidence of constitutional varus alignment was determined and contributing factors were analyzed using multivariate prediction models., Results: Thirty-two percent of men and 17% of women had constitutional varus knees with a natural mechanical alignment of 3° varus or more. Constitutional varus was associated with increased sports activity during growth, increased femoral varus bowing, an increased varus femoral neck-shaft angle, and an increased femoral anatomic mechanical angle., Conclusions: An important fraction of the normal population has a natural alignment at the end of growth of 3° varus or more. This might be a consequence of Hueter-Volkmann's law. Restoration of mechanical alignment to neutral in these cases may not be desirable and would be unnatural for them.