Refracture of pediatric both-bone diaphyseal forearm fracture following intramedullary fixation with Kirschner wires is likely to occur in the presence of immature radiographic healing.

PURPOSE: Refracture of pediatric both-bone diaphyseal forearm fractures (PBDFFs) may occur, even if the fractures are treated with intramedullary nailing. The purpose of this study was to investigate the risk of refracture of PBDFFs treated with intramedullary Kirschner wires (K-wires), which are commonly used in our clinic. METHODS: The present multicenter retrospective study included 60 consecutive patients with 60 PBDFFs who were treated with intramedullary K-wires at 5 hospitals between 2007 and 2016. The age of the patients at the time of the primary fracture ranged from 2 to 15 years. The characteristics of the primary fractures and treatment course were evaluated. RESULTS: Refracture occurred in 6 patients (10.0%). Three of the patients were young girls; the other 3 were adolescent boys. Refractures were caused by falling or during sports activity. The duration from primary fracture to refracture ranged from 46 to 277 days, and in 5 of the 6 patients refractures occurred within 6 months. Although we were unable to identify factors significantly contributing to refracture (e.g. fracture type or treatment procedures), radiographs at the latest visit before refracture demonstrated findings of immature healing in five of six patients. Both K-wires and external immobilization had been removed before complete fracture healing in a large proportion of patients with refracture (80.0%). CONCLUSIONS: Refracture of PBDFF may occur several months after treatment with intramedullary K-wires if the primary fracture shows immature healing. Physicians should pay special attention when judging radiographic fracture healing, even when the fracture is deemed to have clinically healed.

Risk factors for excessive postoperative sliding of femoral trochanteric fracture in elderly patients: A retrospective multicenter study.

INTRODUCTION: The application of a load on the internal fixation of a trochanteric fracture exerts a moment along the lag screw, causing the proximal bone fragment to slide along the lag screw, allowing contact between the proximal and distal bone fragments, which promotes healing. However, excessive sliding is related to poor postoperative outcomes. We aimed to identify the risk factors for excessive sliding. MATERIALS AND METHODS: We conducted a multicenter retrospective study including 115 trochanteric fractures sustained through low-energy trauma in 19 male and 96 female patients aged 60 years or older (mean age: 82.9 years) between September 2013 and December 2014. We measured the postoperative sliding distance after osteosynthesis using a sliding hip screw or intramedullary nailing, and classified participants with ≥8 mm of sliding into the excessive sliding group (ESG) and with <8 mm into non-ESG. Finally, we investigated the risk factors of excessive postoperative sliding. RESULTS: Fifty participants were classified into the ESG and 65 participants into the non-ESG. Female sex (p = 0.0264), an A3 fracture type (p = 0.0003), greater tip-apex distance (p = 0.0250), and poor reduction in either the anteroposterior or lateral radiographic views (p = 0.0156) were identified as risk factors for excessive sliding by multivariate regression analysis. CONCLUSIONS: Female sex, an unstable fracture type, a greater tip-apex distance, and a poor reduction, in either the anteroposterior or lateral views, are associated with excessive postoperative sliding. Therefore, surgery should aim to achieve good reduction and stabilization from both radiographic views.

Gibberellin-induced formation of tension wood in angiosperm trees.

After gibberellin had been applied to the vertical stems of four species of angiosperm trees for approximately 2 months, we observed eccentric radial growth that was due to the enhanced growth rings on the sides of stems to which gibberellin had been applied. Moreover, the application of gibberellin resulted in the formation of wood fibers in which the thickness of inner layers of cell walls was enhanced. These thickened inner layers of cell walls were unlignified or only slightly lignified. In addition, cellulose microfibrils on the innermost surface of these thickened inner layers of cell walls were oriented parallel or nearly parallel to the longitudinal axis of the fibers. Such thickened inner layers of cell walls had features similar to those of gelatinous layers in the wood fibers of tension wood, which are referred to as gelatinous fibers. Our anatomical and histochemical investigations indicate that the application of gibberellin can induce the formation of tension wood on vertical stems of angiosperm trees in the absence of gravitational stimulus.