In the present report, a case of a healthy, 38–year-old male recreational marathon runner who presented in the emergency department is discussed. He was diagnosed with a stress fracture of the femoral neck and treated surgically using a dynamic hip screw (DHS). One year after surgery, the patient was able to return to most of his previous sports activities. In the present report, the existing literature on the subject is exhibited and the points of interest in terms of incidence, risk factors, diagnosis, classification, treatment, and long-term outcome are analyzed. We suggest operative treatment of stress fractures of the femoral neck even in cases of complete undisplaced ones. This way, the risk of a displacement is counteracted, and patients can quickly return to daily activities without having to withstand long-term immobilization. Im vorliegenden Bericht wird der Fall eines gesunden 38-jährigen Marathonläufers, der sich über die Rettungsstelle vorstellte, diskutiert. Eine Stressfraktur des Femurhalses wurde diagnostiziert und mit einer dynamischen Hüftschraube (DHS) versorgt. Ein Jahr nach der Operation konnte der Patient seine vorherigen sportlichen Aktivitäten wieder aufnehmen. Im Weiteren stellt der vorliegende Bericht die aktuelle Literatur des Themas dar und analysiert die Inzidenz, Risikofaktoren, Diagnosen, Klassifikationen, Behandlung sowie das Langzeit-Outcome. Wir empfehlen die operative Versorgung von Stressfrakturen des Femurhalses auch im Falle von kompletten, nicht dislozierten Frakturen. So kann dem Risiko einer Frakturdislokation im Verlauf entgegengewirkt werden und Patienten können schnell wieder zu den täglichen Aktivitäten ohne Langzeitimmobilisation zurückkehren. Publication Date: 29 March 2021 (online) © 2021. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Aims: The aim of this study was to determine the association between knee alignment and the vertical orientation of the femoral neck in relation to the floor. This could be clinically important because changes of femoral neck orientation might alter chondral joint contact zones and joint reaction forces, potentially inducing problems like pain in pre-existing chondral degeneration. Further, the femoral neck orientation influences the ischiofemoral space and a small ischiofemoral distance can lead to impingement. We hypothesized that a valgus knee alignment is associated with a more vertical orientation of the femoral neck in standing position, compared to a varus knee. We further hypothesized that realignment surgery around the knee alters the vertical orientation of the femoral neck. Methods: Long-leg standing radiographs of patients undergoing realignment surgery around the knee were used. The hip-knee-ankle angle (HKA) and the vertical orientation of the femoral neck in relation to the floor were measured, prior to surgery and after osteotomy-site-union. Linear regression was performed to determine the influence of knee alignment on the vertical orientation of the femoral neck. Results: The cohort included 147 patients who underwent knee realignment-surgery. The mean age was 51.5 years (SD 11). Overall, 106 patients underwent a valgisation-osteotomy, while 41 underwent varisation osteotomy. There was a significant association between the orientation of the knee and the coronal neck-orientation. In the varus group, the median orientation of the femoral neck was 46.5° (interquartile range (IQR) 49.7° to 50.0°), while in the valgus group, the orientation was 52.0° (IQR 46.5° to 56.7°; p < 0.001). Linear regression analysis revealed that HKA demonstrated a direct influence on the coronal neck-orientation ( β = 0.5 (95% confidence interval (CI) 0.2 to 0.7); p = 0.002). Linear regression also showed that realignment surgery was associated with a significant influence on the change in the coronal femoral neck orientation ( β = 5.6 (95% CI 1.5 to 9.8); p = 0.008). Conclusion: Varus or valgus knee alignment is associated with either a more horizontal or a more vertical femoral neck orientation in standing position, respectively. Subsequently, osteotomies around the knee alter the vertical orientation of the femoral neck. These aspects are of importance when planning osteotomies around the knee in order to appreciate the effects on the adjacent hip joint. The concept may be of even more relevance in dysplastic hips. Cite this article: Bone Jt Open 2021;2(12):1057–1061.

(1) Background: Clinical approaches have depicted interconnectivity between the Achilles tendon and the plantar fascia. This concept has been applied in rehabilitation, prevention, and in conservative management plans, yet potential anatomical and histological connection is not fully understood. (2) Objective: To explore the possible explanation that the calcaneus acts as a hypomochlion. (3) Methods: 2 databases (Pubmed and Livivo) were searched and studies, including those that examined the relationship of the calcaneus to the Achilles tendon and plantar fascia and its biomechanical role. The included studies highlighted either the anatomical, histological, or biomechanical aspect of the lower limb. (4) Results: Seventeen studies were included. Some studies depicted an anatomical connection that slowly declines with age. Others mention a histological similarity and continuity via the paratenon, while a few papers have brought forward mechanical reasoning. (5) Conclusion: The concept of the calcaneus acting as a fulcrum in the lower limb can partially be supported by anatomical, histological, and biomechanical concepts. Despite the plethora of research, a comprehensive understanding is yet to be investigated. Further research exploring the precise interaction is necessary.