Histochemical assessment on the cellular interplay of vascular endothelial cells and septoclasts during endochondral ossification in mice

This study was aimed to verify the cellular interplay between vascular endothelial cells and surrounding cells in the chondro-osseous junction of murine tibiae. Many CD31-positive endothelial cells accompanied with Dolichos Biflorus Agglutinin lectin-positive septoclasts invaded into the hypertrophic zone of the tibial epiphyseal cartilage. MMP9 immunoreactive cytoplasmic processes of vascular endothelial cells extended into the transverse partitions of cartilage columns. In contrast, septoclasts included several large lysosomes which indicate the incorporation of extracellular matrices despite no immunopositivity for F4/80—a hallmark of macrophage/monocyte lineage. In addition, septoclasts were observed in c-fos-/- mice but not in Rankl-/- mice. Unlike c-fos-/- mice, Rankl-/- mice showed markedly expanded hypertrophic zone and the irregular shape of the chondro-osseous junction. Immunoreactivity of platelet-derived growth factor-bb, which involved in angiogenic roles in the bone, was detected in not only osteoclasts but also septoclasts at the chondro-osseous junction. Therefore, septoclasts appear to assist the synchronous vascular invasion of endothelial cells at the chondro-osseous junction. Vascular endothelial cells adjacent to the chondro-osseous junction possess endomucin but not EphB4, whereas those slightly distant from the chondro-osseous junction were intensely positive for both endomucin and EphB4, while being accompanied with ephrinB2-positive osteoblasts. Taken together, it is likely that vascular endothelial cells adjacent to the chondro-osseous junction would interplay with septoclasts for synchronous invasion into the epiphyseal cartilage, while those slightly distant from the chondro-osseous junction would cooperate with osteoblastic activities presumably by mediating EphB4/ephrinB2. Mini-abstract: Our original article demonstrated that vascular endothelial cells adjacent to the chondro-osseous junction would interplay with septoclasts for synchronous invasion into the epiphyseal cartilage, while those slightly distant from the chondro-osseous junction would cooperate with osteoblastic activities presumably by mediating EphB4/ephrinB2.(A figure that best represents your paper is Fig. 5c)

Infantile Blount's disease

ABSTRACT Infantile Blount's disease results in multi-planar proximal tibial deformity consisting of varus, procurvatum, internal rotation and shortening. The deformity is attributed to disordered growth of the posteromedial proximal tibial physis. The aetiology is multifactorial. It is associated with childhood obesity and African ethnicity. The ability to differentiate between infantile Blount's disease and physiological bowing depends on the findings of focused clinical examination, X-ray appearance, tibial metaphyseal-diaphyseal angle and tibial epiphyseal-metaphyseal angle. The gold standard of treatment is proximal tibial metaphyseal corrective osteotomy before the age of 4 years. The limb should be realigned to physiological valgus. The recurrence rate after realignment osteotomy is high. Recurrence is associated with age at osteotomy, obesity, higher Langenskiöld stage and medial physeal slope >60°. The surgical management of severe, recurrent or neglected infantile Blount's disease is challenging. Comprehensive clinical examination and multi-planar deformity analysis with standing long leg X-rays are essential to identify all aspects of the deformity. Distal femur coronal malalignment and significant rotational deformity should be excluded. Knee instability due to intra-articular deformity should be corrected by elevation of the medial tibial plateau. Lateral epiphysiodesis should be done at the same time as medial plateau elevation and when medial growth arrest is certain to prevent recurrence. Level of evidence: Level 5 Keywords: Blount's disease, tibia vara, genu varum, recurrence, obesity

Use of Epiphysiodesis as Treatment for a Proximal Physeal Tibial Fracture in a Dog

Objective The aim of this study was to describe the use of epiphysiodesis by the means of a screw to treat a proximal tibial Salter–Harris II fracture associated with a tibial tuberosity avulsion in a 4.5-month-old Airedale Terrier. Study design A healing proximal tibial epiphyseal fracture was observed after a 10-day period. Tibial plateau angle was 40°. The fracture was treated by the insertion of a fluoroscopy-guided 3.5-mm cancellous screw. Results Successful healing of fractures and levelling of tibia plateau were obtained. Final tibial plateau angle was 8°. At long-term follow-up (18 months), owners reported sustained and full functional recovery. Conclusion Prior to ossification of the proximal tibial physis, epiphysiodesis with a screw can be used as a treatment of sub-acute, moderately displaced, Salter–Harris I or II fractures.