Thomas Dreher

Zusammenfassung: Hintergrund: Eine Vielzahl unterschiedlicher Erkrankungen in allen Altersgruppen, von Kleinkindern bis zu Erwachsenen, erfordert operative Eingriffe an Hüfte und Becken. Gut etablierte Techniken sind in Planung und Durchführung komplex und basieren derzeit größtenteils auf zweidimensionaler prä- und intraoperativer Bildgebung. Dies kann zu potenzieller Ungenauigkeit und hoher Outcome-Variabilität führen. Unzureichende Korrekturen bergen ein erhebliches Risiko für Rezidivbeschwerden, welche möglicherweise eine Re-Operation erforderlich machen. Fallbeispiele: In dieser Fallserie demonstrieren wir anhand von drei eindrucksvollen Beispielen die Chancen des Einsatzes dreidimensionaler Bildgebung und derer Anwendungsmöglichkeiten in der Diagnostik, präoperativen Planung und zur intraoperativen Orientierung durch Navigation oder Guides bei Routineeingriffen sowie bei komplexen Fällen. Alle Fälle zeigten präzise Korrekturen und zufriedenstellende postoperative Verläufe. Schlussfolgerungen: Zur Minimierung von Ungenauigkeiten und zum breiteren Einsatz in der Klinik schlagen wir daher weitere Forschung vor, um standardisierte Protokolle für den Einsatz dieser unterstützenden Modalitäten zu entwickeln. Das geschieht mit der Intension, das Risiko für ein Rezidiv oder eine frühzeitige Koxarthrose zu mindern und damit die längerfristige gesundheitsbezogene Lebensqualität im Sinne einer patientenspezifischen Medizin zu verbessern. Aufgrund der bislang fehlenden jeweils spezifischen Datenlage bleibt für den breiten Einsatz in der klinischen Routine die Präzisionssteigerung und deren langfristiger Einfluss aufzuzeigen.

Background: In children with cerebral palsy, bony acetabular deficiencies are common and may be associated with progressive hip subluxation, abnormal joint loading, and ultimately hip dislocation. Hip reconstruction surgery is typically performed to prevent dislocation, and this includes acetabular reshaping using acetabuloplasty. The location of acetabular deficiency may vary among individuals; however, only radiographs are used for planning and intraoperative correction in many centers. Precise reconstruction and preop planning are necessary for the accurate correction of acetabular coverage. This study compares conventional hip reconstruction with a 3D-guided technique using individual preop 3D planning and 3D-printed guides during surgery to determine which method allows for a more accurate correction. We hypothesize that the patient-specific 3D planning leads to more precise anatomical correction of acetabular coverage compared to conventional freehand osteotomy. Methods: This study was registered in the German Clinical Trial Register (DRKS-ID: DRKS00031356) on 14 July 2023. In a randomized controlled trial, various imaging-based parameters were used to assess the bony anatomy preoperatively and postoperatively. Preoperative and 6-week postoperative computed tomography (CT) scans are part of routine clinical care. Additionally, an immediate postoperative CT scan was performed. One hip was operated on using individualized 3D preoperative planning, while the other hip was corrected using a conventional surgical approach. A standardized subtrochanteric osteotomy was performed for the varisation, derotation, and shortening of the proximal femur. This osteotomy was followed by acetabuloplasty under fluoroscopic control. For the 3D-planned operation, patient-specific cutting and repositioning guides were produced based on preoperative CT imaging. Patients with bilateral cerebral palsy (GMFCS levels I–V), aged 4–18 years, with an open triradiate growth plate and a migration index ≥ 40% in at least one hip were included. In a preliminary retrospective part, this project reproduces the existing three-dimensional acetabular index (3-DAI) and compares it with established radiographic methods to determine the utility and reliability of a reconstructed 3D CT measurement technique. A further component of the retrospective part is the creation of an age-adjusted database of typically developed hips and the development of a 3D head coverage index (3D-HCI) as a new 3D parameter to express acetabular coverage; therefore, it will be used as a secondary parameter and correlated to the 3DAI in the prospective part. Conclusions: Improved precision may have meaningful clinical implications for long-term joint congruency, load distribution, pain, and mobility outcomes.

Background: Reconstructing large bone defects in pediatric patients after tumor resection is challenging, as conventional techniques are associated with high complication rates and morbidity. The Intramedullary Bone Transport Nail (IMBTN) may reduce these complications while preserving limb alignment and skeletal growth in pediatric oncologic reconstruction. Methods: A 15-year-old female with an osteofibrous dysplasia-like adamantinoma of the tibial diaphysis underwent complete en-bloc resection, leaving a 9 cm bone defect. An IMBTN (Precice, NuVasive) was implanted for distraction osteogenesis, with distraction starting eight days post-surgery at 0.25 mm twice daily. Follow-up visits monitored bone healing, alignment, and limb length. Results: The 9 cm defect was successfully reconstructed, with complete bone healing at the distraction site. Complete consolidation was confirmed at 18 months. The transport nail was removed at two years, and no further revisions were necessary. At two-year follow-up, the patient reported minimal pain on the Visual Analog Scale 1/10, and no recurrence of the tumor was noted. Conclusions: The use of IMBTN for large bone defect reconstruction following tumor resection in pediatric patients is a safe and effective technique. It enables stable bone transport while preserving alignment, maintaining limb length, and is less invasive than traditional reconstructive approaches.

Objectives: This retrospective study examines acetabular morphology and defects in children with cerebral palsy (CP). The study discovers the usefulness and reliability of a reconstructed 3D CT measurement technique and compares it to conventional radiographic measurements. Methods: 33 subjects with CP who underwent hip reconstruction, including Dega osteotomy and varus derotation femoral osteotomy, were included and compared to an age-matched group of 42 typically developing children. We reproduced a three directional acetabular index (3DAI), including anterosuperior, superolateral and posterosuperior indices in CT analysis, and compared them with established radiographic measurements for the migration percentage (MP) and the acetabular index (AI). Results: The results showed significantly higher 3DAI in every direction of wall deficiency, accentuating the methods sensitivity for acetabular dysplasia. The interrater and test–retest reliability were robust with ICC = 0.939–0.988 for the CP group. Conventional radiographic measurements demonstrated better discriminative power for identifying hip dislocation and correlated strongly with the 3DAI (p < 0.001). Conclusions: The 3DAI method showcases an important addition to the conventional radiographic measurements by enabling a quantification of the defect amount and direction for operative planning. The study supports the potential of a 3D analysis in the improvement of diagnostic precision and suggests a continuous refinement of the CT measurement technique.

Background Drawing upon the increasing burden of musculoskeletal diseases and injuries at a global scale, the authors propose Global Pediatric Orthopedics and Traumatology (GPOT) as a dedicated initiative to address the global disparities in the care of children and adolescents with orthopedic conditions. Methods Literature covering efforts in the convergence of global surgery, global trauma care, and global pediatric surgery was searched and analyzed. Results The analysis revealed a gap of dedicated efforts in pediatric orthopedic surgical care on a global scale. Subsequently, the authors propose establishing a GPOT initiative as a first step toward mobilizing resources and practitioners to contribute toward equitable pediatric orthopedic care for children and adolescents, in a manner that upholds the principles of global surgery, but also encompasses the particular features of pediatric orthopedics and traumatology. Discussion Establishing GPOT is instrumental for comprehensive pediatric orthopedic care globally. By focusing on early intervention, prevention, and the treatment of musculoskeletal conditions, GPOT has the potential to improve the quality of life for children and adolescents, reduce long-term disabilities, and support the sustainable development of healthcare systems, particularly in underserved regions.

Purpose Accurate intraoperative X-ray/CT registration is essential for surgical navigation in orthopedic procedures. However, existing methods struggle with consistently achieving sub-millimeter accuracy, robustness under broad initial pose estimates or need manual key-point annotations. This work aims to address these challenges by proposing a novel multi-view X-ray/CT registration method for intraoperative bone registration. Methods The proposed registration method consists of a multi-view, contour-based iterative closest point (ICP) optimization. Unlike previous methods, which attempt to match bone contours across the entire silhouette in both imaging modalities, we focus on matching specific subcategories of contours corresponding to bone substructures. This leads to reduced ambiguity in the ICP matches, resulting in a more robust and accurate registration solution. This approach requires only two X-ray images and operates fully automatically. Additionally, we contribute a dataset of 5 cadaveric specimens, including real X-ray images, X-ray image poses and the corresponding CT scans. Results The proposed registration method is evaluated on real X-ray images using mean reprojection error (mRPD). The method consistently achieves sub-millimeter accuracy with a mRPD 0.67 mm compared to 5.35 mm by a commercial solution requiring manual intervention. Furthermore, the method offers improved practical applicability, being fully automatic. Conclusion Our method offers a practical, accurate, and efficient solution for multi-view X-ray/CT registration in orthopedic surgeries, which can be easily combined with tracking systems. By improving registration accuracy and minimizing manual intervention, it enhances intraoperative navigation, contributing to more accurate and effective surgical outcomes in computer-assisted surgery (CAS). The source code and the dataset are publicly available at: https://github.com/rflepp/MultiviewXrayCT-Registration.

Purpose: Tendon lengthening is a common lower limb surgical procedure in paediatric orthopaedics and deformity correction. Healing of a lengthened tendon is typically supported by casting and unloading of the operated limb. Although tendon rupture or overcorrection may adversely affect surgical outcomes, few studies have examined surgical means of improving post-operative stability of the tendon. We aim to evaluate a novel method for augmenting Z-Plasty tendon lengthening as a first step to clinical translation. Methods: In this experimental ex vivo study, we employed a bovine flexor tendon model (n = 18) to examine a novel mechanical augmentation method after tendon lengthening by Z-plasty. Conventional surgical suturing of the imposed Z-plasty (n = 6) and an experimental group (n = 6), in which additional augmentation was performed by interlocking fibres of a biomaterial scaffold to the underlying tendon using a novel micro-needling technique, were compared to native tendons (n = 6). Results: The needle interlocked scaffold successfully augmented the suture repair, showing more than doubled ultimate failure force compared to controls (482 ± 107 N vs. 206 ± 37 N, p < 0.01), and more than 1.5-fold repair stiffness (41 ± 7 N/mm vs. 26 ± 9 N/mm, p < 0.01). Conclusion: We conclude that the use of an interpenetrating biomaterial scaffold represents a promising new approach for improving biomechanical tendon properties, which may have an implication on the stability of tendon suture, lengthening and tendon transfer procedures as well as on post-operative management and earlier mobilization.

Case: Triple pelvic osteotomy (TPO) is used to treat developmental dysplasia of the hip in a pediatric population. This case report highlights a new indication for this procedure. Acetabular coverage was restored in a 9-year-old patient who experienced instability following hip hemiarthroplasty and proximal femur composite allograft implantation for the treatment of Ewing sarcoma. Conclusion: TPO can be used to treat instability following prosthetic hip replacement in pediatric patients with open triradiate cartilage. It restores the acetabular bone stock and should facilitate future acetabular component implantation or revisions.

Developmental dysplasia of the hip (DDH) is a prevalent developmental condition that necessitates early detection and treatment. Follow–up, as well as therapeutic decision-making in children younger than four years, is challenging because the center–edge (CE) angle of Wiberg is not reliable in this age group. The authors propose a modification of the CE angle (MCE) to achieve comparable reliability with the CE among children younger than four and set diagnostic thresholds for the diagnosis of DDH. 952 anteroposterior pelvic radiographs were retrospectively reviewed. The MCE is defined on X-ray pelvic overview images as the angle between the line connecting the epiphyseal joint center and the outer edge of the acetabulum, and perpendicular to the Hilgenreiner line. The MCE angle exhibited high sensitivity and specificity, as well as intrarater variability comparable to the CE among children younger and older than four years. The authors recommend cut-off values for the MCE angle; for children under four years old, the angle should be equal to or greater than 15 degrees; for those under eight years old, it should be equal to or greater than 20 degrees; and for those eight years old and older, it should be equal to or greater than 25 degrees. However, the MCE angle’s reliability diminishes around the age of nine due to the curvature of the growth plate, which complicates accurate measurement. This study showed that the MCE angle can be used adequately in children under four years and could be used as a progression parameter to diagnose DDH.