Marc-Pascal Meier

Study Design: Cadaveric biomechanical analysis. Objective: To compare the biomechanical stability of plate osteosynthesis (POS), two-screw fixation (2S), single-screw fixation (1S), and headless compression screw fixation (HCS) under coupled multidirectional cyclic loading conditions. Summary of Background Data: Anterior screw fixation is an established motion-preserving treatment for type II odontoid fractures. However, the optimal fixation strategy remains controversial, and comparative biomechanical data on POS and established anterior screw fixation techniques remain limited. Materials and Methods: A total of 26 C1–C3 specimens (six POS, six headless compression screw, six 1S, and eight 2S) were included. Standardized type II odontoid fractures were created, followed by osteosynthesis according to group allocation. Specimens were subjected to cyclic loading using a custom apparatus enabling combined motion patterns. Construct stability and screw loosening were assessed by visual inspection, mechanical testing, and camera-based tracking analysis. Visual force-to-loosening data were analyzed using Kaplan-Meier methods because specimens without detectable loosening at the maximum load were treated as right-censored observations. Results: Mechanical testing and image-based analysis demonstrated significantly higher stability for 2S compared with 1S ( P =0.045 and 0.007, respectively). No additional statistically significant differences were observed between the remaining constructs. Kaplan-Meier analysis of visual screw loosening showed no significant overall difference between groups ( P =0.066). After adjustment for bone mineral density, the difference between 2S and 1S remained significant in both mechanical and camera-based analyses. Conclusion: Under coupled multidirectional cyclic loading, 2S demonstrated greater biomechanical stability than 1S and showed the highest mean stability among the investigated constructs. POS did not demonstrate superior biomechanical stability compared with established anterior screw fixation techniques. The findings support further optimization and investigation of the POS concept.

Background and Objectives: Ventral stabilization of thoracolumbar spine fractures can be achieved using different interbody reconstruction techniques, including titanium cages, vertebral body replacements (VBR), and autologous pelvic bone grafts (APBG). Although all approaches aim to restore anterior column stability and alignment, comparative data on long-term patient-reported outcomes remain limited. The objective of this study was to compare long-term patient-reported wellbeing following ventral stabilization using these three techniques. Materials and Methods: A retrospective, non-randomized single-center cohort study with prospective follow-up was analyzed. Treatment allocation was indication-based. Ninety-one patients treated between 2008 and 2018 underwent ventral stabilization using cage implantation (n = 12), vertebral body replacement (n = 45), or autologous pelvic bone grafting (n = 34). Clinical outcome was assessed at least 12 months postoperatively using a modified Visual Analog Scale Spine Score (VAS-Spine). Statistical analysis included linear and ordinal regression adjusted for age and sex. Potential baseline differences between groups were considered in the interpretation of the results. Results: Sixty-three patients (mean age 52 ± 15 years; 41% female) completed follow-up. The mean VAS-Spine score was lowest after cage implantation (2.7 ± 3.6), followed by VBR (3.9 ± 2.8) and APBG (4.9 ± 1.8; p* = 0.021). The observed difference between cage and APBG approached the minimal clinically important difference reported for VAS-based measures. Patients treated with cage implantation reported less pain during rest and activity and fewer limitations in daily life. No significant differences were observed regarding age or sex. Conclusions: In this observational cohort, cage implantation was associated with more favorable patient-reported outcomes compared with VBR and APBG. Autologous pelvic bone grafting was associated with worse patient-reported outcomes, potentially related to donor-site morbidity. Given the non-randomized design and potential confounding, these findings should be interpreted as associative and hypothesis-generating.

Objective: This study aimed to investigate the relationship between spinopelvic parameters and radiographic foot axes and to examine whether these associations differ across age groups. Methods: This retrospective radiographic study analyzed imaging from patients treated at a university medical center for degenerative or traumatic conditions. Cases with weight-bearing, 2-view foot radiographs and standing lumbar spine radiographs, including the femoral heads, were included. Spinopelvic parameters (lumbar lordosis, pelvic tilt, sacral slope, and pelvic incidence) and radiographic foot axes (including hallux valgus angle, tibiotalar angle, and metatarsal declination angle) were measured, and correlation analyses were per formed with age-based subgroup comparisons. Results: A total of 46 Caucasian patients (33 females, 13 males) were included (mean age 55.6 ± 18.5 years). Lumbar lordosis showed a significant negative correlation with hallux valgus angle (r = −0.29, P = .015). Sacral slope was negatively correlated with the hallux valgus angle (r = −0.42, P < .001). Pelvic tilt correlated positively with tibiotalar angle (r = 0.34, P = .004) and metatarsal declination angle (r = 0.25, P = .042). Age-stratified analyses demonstrated age-related differences in correlation patterns. Conclusion: Spinopelvic alignment demonstrates measurable associations with radiographic foot alignment, supporting the concept of the spine–pelvis–lower-limb unit as a biomechanically integrated system. Clinically, these findings suggest that integrated, chain-oriented assessment and management strategies (considering both spinal and foot alignment, particularly with aging) may be relevant when evalu ating patients with coexisting spine and foot disorders. Cite this article as: Roch FE, Kletschka F, Jäckle K, et al. Age-dependent associations between spinopelvic alignment and foot axes: A retrospective radiographic study. Acta Orthop Traumatol Turc., 2025;59(6):379-386.

Zusammenfassung Hintergrund Periprothetische Frakturen am Kniegelenk gehören zu den Major-Komplikationen nach erfolgtem endoprothetischem Kniegelenkersatz. Die operative Therapie stellt eine Herausforderung dar und setzt eine gewissenhafte präoperative Analyse und Planung voraus, um die bestmögliche Versorgungsstrategie auszuwählen. Material und Methoden Der vorliegende Übersichtsartikel wurde mithilfe einer selektiven Literaturrecherche aus der Datenbank PubMed erstellt. Anhand gängiger Klassifikationssysteme und aktueller Forschungsergebnisse werden evidenzbasierte Therapieempfehlungen ausgesprochen. Ergebnisse Unabhängig von den morphologischen Merkmalen und der Lokalisation der periprothetischen Fraktur am Knie muss geklärt werden, ob die Kniegelenkendoprothese fest oder gelockert ist. Bei stabilem Implantat kann ein Prothesenerhalt mithilfe einer osteosynthetischen Versorgung erfolgen. Bei gelockertem Implantat, Prothesenfehlfunktion, Malalignment oder -positionierung, Bandinstabilitäten, Infektion sowie bei defizitärer Knochensubstanz muss der Prothesenwechsel durchgeführt werden. Zur Festlegung der operativen Strategie ist die genaue Kenntnis über den Frakturtyp sowie das einliegende Implantat unerlässlich. In diesem Beitrag werden v. a. die unterschiedlichen Strategien für den Prothesenwechsel dargestellt. Schlussfolgerung Periprothetische Frakturen am Knie sind komplexe Verletzungen, die eine spezialisierte traumatologische und endoprothetische Expertise voraussetzen, um die bestmögliche operative Versorgung durchführen zu können.

Background: Due to the difference in size between the humeral head and the glenoid, the shoulder joint is prone to instability. Therefore, the reconstruction of the physiological joint morphology is of great importance in shoulder joint preservation and replacement surgery. The aim of this study was to describe physiological reference parameters for the morphology of the glenoid for the first time. Material and methods: MRI images of the shoulder joints of 418 patients (mean age: 50.6 years [± 16.3]) were retrospectively analysed in a low-grade osteoarthritic population. The glenoid distance in coronal (GDc) and axial view (GDa), glenoid inclination (GI) and version (GV) as well as scapula neck length (SNL) were measured. Parameters were studied in association for age, gender, side and degeneration grade. Results: Mean GDc was 33.4 mm (± 3.6), mean GDa 26.8 mm (± 3.2), mean GI 10.5° (± 6.4), mean GV -0.4 mm (± 5.4) and mean SNL was 33.4 mm (± 4.7). GDa was significant higher in right shoulders (p < 0.001). GDc and GDa showed significant higher mean values in older patients (p < 0.001) and in shoulders with more severe degenerative changes (p < 0.05). While GDc, GDa and SNL were significant larger in male patients (p < 0.001), GI had a higher mean value in female shoulders (p = 0.021). Conclusion: Age, gender and shoulder joint degeneration influence changes in the morphological parameters of the glenoid. These findings have to be considered in shoulder diagnostics and surgery. Clinical trial number: Not applicable.

Objective: Closed reduction and dynamic hip screw (DHS) osteosynthesis are preferred as joint‐preserving therapy in case of medial femoral neck fractures (MFNFs). A change in the femoral offset (CFO) can cause gait abnormality, impingement, or greater trochanteric pain syndrome. It is unknown whether the femoral offset (FO) can be postoperatively fully restored. The aim of the study was to investigate the extent of a possible CFO in hip joints after DHS osteosynthesis in the case of an MFNF.Methods: In this retrospective study, 104 patients (mean age: 71.02 years, men: n = 50, women: n = 54) with MFNF who underwent closed reduction and DHS osteosynthesis were analyzed by postoperative x‐rays to assess CFO between the operated (OS) and nonoperated joint side (NOS). The studies covered the time period 2010–2020. A statistical comparison was performed between the mean values of FO between OS and NOS, taking into account patient age, gender, and fracture severity.Results: All operated hip joints showed a CFO. In 76.0% (79 of 104), the FO decreased (FOD), and in 24.0% (25 of 104), the FO increased (FOI). A critical CFO (>15% CFO) was detected in 52.9% (55 of 104). In hip joints with postoperative FOD, the mean FO between NOS (49.15 mm [±6.56]) and OS (39.32 mm [±7.87]) and in hip joints with postoperative FOI the mean FO between NOS (41.59 [±8.21]) and OS (47.27 [±6.68]) differed significantly (p < 0.001). Preoperative FO (r _S: −0.41; p > 0.001) and caput–collum–diaphyseal angle (CCD; r _S: 0.34; p > 0.001) correlated with postoperative CFO. FOD was found in hip joints with a preoperative FO >44 mm and CCD vice versa FOI in hip joints with a preoperative FO 134°.Conclusion: Closed reduction and DHS osteosynthesis in patients with MFNF result in a clustered significant CFO. The individual FO should be taken into account pre‐ and intraoperatively to avoid a postoperative extensive CFO.

Objective: The aim of the present study was to determine physiological reference values for the morphology of the patella and to analyse these parameters according to patella position in healthy knee joints. Material and methods: Healthy knee joints of 409 patients (mean age, 52.3 years [± 16.8]) were analysed retrospectively on MRI images for Insall-Salvati index (ISI), sagittal patella thickness (PTS) and patella length (PLS) as well as axial patella thickness (PTA) and patella width (PWA). Differences between patellar diameters were analysed depending on ISI, side, age and gender. Results: Mean PTS was 20.1 mm (± 2.4), PLS 44.0 mm (± 4.4), PTA 21.8 mm (± 2.4) and PWA 44.5 mm (± 4.7). Depending on the vertical patellar position (ISI), all patellar parameters (p < 0.01) showed significant differences between patients with a patella alta, norma and baja. In general, a smaller ISI showed higher measured values for the patellar parameters. There were no significant differences for the laterality. Only PTS showed a significant age difference (p = 0.031). All parameters were significantly larger in male compared to female knees (p < 0.001). Conclusion: Reference parameters for the patella morphology are reported. Concluding from the results, a relationship between vertical patellar position and patellar morphology seems to exist. This finding should be taken into account in diagnostics and therapy of patella disorders.