Time‐dependent changes in bone healing capacity of scaphoid fractures and non‐unions

Abstract

The scaphoid is the most frequently fractured carpal bone and prone to non‐union due to mechanical and biological factors. Whereas the importance of stability is well documented, the evaluation of biological activity is mostly limited to the assessment of vascularity. The purpose of this study was to select histological and immunocytochemical parameters that could be used to assess healing potential after scaphoid fractures and to correlate these findings with time intervals after fracture for the three parts of the scaphoid (distal, gap and proximal). Samples were taken during operative intervention in 33 patients with delayed or non‐union of the scaphoid. Haematoxylin and Eosin (HE), Azan, Toluidine, von Kossa and Tartrate‐resistant acid phosphatase (TRAP) staining were used to characterise the samples histologically. We determined distribution of collagen 1 and 2 by immunocytochemistry, and scanning electron microscopy (SEM) was used to investigate the ultrastructure. To analyse the samples, parameters for biological healing status were defined and grouped according to healing capacity in parameters with high, partial and little biological activity. These findings allowed scoring of biological healing capacity, and the ensuing results were correlated with different time intervals after fracture. The results showed reduced healing capacity over time, but not all parts of the scaphoid were affected in the same way. For the distal fragment, regression analysis showed a statistically significant correlation between summarised healing activity scores and time from initial fracture (r = −0.427, P = 0.026) and decreasing healing activity for the gap region (r = −0.339, P = 0.090). In contrast, the analyses of the proximal parts for all patients did not show a correlation (r = 0.008, P = 0.969) or a decrease in healing capacity, with reduced healing capacity already at early stages. The histological and immunocytochemical characterisation of scaphoid non‐unions (SNUs) and the scoring of healing parameters make it possible to analyse the healing capacity of SNUs at certain time points. This information is important as it can assist the surgeon in the selection of the most appropriate SNU treatment.

Comparison of Shape Memory Staple and Gelled Platelet-Rich Plasma versus Shape Memory Staple alone for the Treatment of Waist Scaphoid Nonunion: A Single-Center Experience

“…24,25 SNUs are not healed fractures, but living bone alongside the nonunion site preserves its healing capacity. 26 They have a lower healing potential compared with simple fractures. 27,28 Schmidle et al found that the healing capacity depends on the time passed out from trauma concerning the distal pole and gap region; conversely, there is limited healing capacity of the proximal pole already at early stages, with few alterations over time.…”

“…27,28 Schmidle et al found that the healing capacity depends on the time passed out from trauma concerning the distal pole and gap region; conversely, there is limited healing capacity of the proximal pole already at early stages, with few alterations over time. 26 Trusting in potential healing, some authors have reported positive results of fixed SNUs without bone grafting. [29][30][31] However, these studies are heterogeneous considering the population, techniques, and assessment of results, even if they reported promising results.…”

Kahnbeinpseudarthrose: Erfahrungen aus mehr als 280 Rekonstruktionen mit einem vaskularisierten Knochenblock aus der medialen Femurkondyle

“…Hinsichtlich der gegenwärtig aufflammenden Diskussion über die Notwendigkeit vaskularisierter Knochentransplantate [1,2,32,33] ist eine objektive Klärung einerseits dringend erforderlich, andererseits methodisch nach unserem Dafürhalten wegen mangelnder Vergleichbarkeit unterschiedlicher Patientengruppen nahezu unmöglich. Dies wird auch nicht besser durch immer umfassendere Metaanalysen, da dieses Aufblähen von Fallzahlen die eigentliche Datengrundlage in der Realität verwässert und eine Pseudogenauigkeit generiert.…”

3D-Bildgebung in der Analyse von Frakturen und Pseudarthrosen des Kahnbeins

“…In einer histologischen Studie konnten wir zeigen, dass im proximalen Fragment unabhängig von der Zeitdauer des Bestehens der verzögerten Knochenheilung resp. Pseudarthrose das Knochenheilungspotential reduziert ist [29]. Mit zunehmendem Fraktur-/Pseudarthrosenalter nahm die biologische Aktivität allerdings auch im distalen Fragment ab.…”