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Background: In-vivo high-resolution peripheral quantitative computed tomography (HR-pQCT) has high potential in scaphoid bone pathologies' scientific and clinical fields. The manufacturer's visual grading scale (VGS) classifies motion artifacts and divides scans into five quality grades ranging from grade 1 (good quality) to grade 5 (poor quality). This prospective study aimed to investigate the feasibility of the VGS and the influence of image quality on bone density and microarchitecture parameters for the scaphoid bone.Methods: Within one year, twenty-two patients with scaphoid fractures received up to six scans of their fractured and contralateral wrist (each consisting of three stacks) using second-generation HR-pQCT (total 256 scans). Three experienced observers graded each stack following the visual grading system, and interand intraobserver variability were assessed. The contralateral uninjured scaphoids were then compared pairwise within each patient to high-quality grade 1 scans to determine the influence of image quality on density and microarchitecture parameters.Results: Inter-and intraobserver variability among the three observers significantly revealed fair to moderate agreement, P<0.001 and P<0.05, respectively. Bone volume (BV) fraction tended to increase with poorer image quality but did not exceed four percent. Trabecular bone mineral density (Tb.BMD) decreased with poorer image quality but did not exceed five percent. Trabecular number and trabecular thickness significantly increased by 15.5% and 6.8% at grade five (P<0.001), respectively, and trabecular separation significantly decreased by 13.7% at grade five (P<0.001).Conclusions: This study revealed a considerable influence of motion on bone morphometry parameters of the scaphoid. Therefore, high image quality must be a central point in studies focusing on the histomorphometry of small objects. The high inter-and intraobserver variability limit the VGS. Future research may focus on other grading systems or automated techniques leading to more consistent and reproducible results. Currently, the use of microarchitectural analysis should be limited to cases without motion artefacts or, at most low graded motion artefacts.

ZusammenfassungDie Behandlung von Kahnbeinpseudarthrosen ist nach wie vor eine Herausforderung für den behandelnden Handchirurgen – im Speziellen bei avaskulären, proximalen Kahnbeinpseudarthrosen oder vorangegangenen fehlgeschlagenen Operationen. Unterschiedliche operative Verfahren wurden etabliert und basieren auf der Rekonstruktion der korrekten Anatomie des Kahnbeins, welche einerseits Stabilität bietet und andererseits eine ausreichende Durchblutung wiederherstellt. Das Behandlungsspektrum reicht von avaskulären bis hin zu freien, gefäßgestielten Spaninterponaten. Die beiden am häufigsten verwendeten freien vaskularisierten Knochenspäne stammen vom Beckenkamm und vom medialen Femurkondyl. Der Femurkondylenspan zeigt eine konstantere Gefäßanatomie, geringere Hebemorbidität und höherer Heilungsrate im Vergleich zum Beckenkammspan. Zudem ist der Span technisch einfacher zu heben und kann sowohl als kortikospongiöser, wie auch osteochondraler Span gehoben werden. In Summe der Vorteile kommen wir zu dem Schluss, dass die Versorgung der Kahnbeinpseudarthrose bei avaskulärem proximalen Pol mittels gefäßgestieltem Femurkondylenspan die Methode unserer Wahl ist.

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