Surgical Treatment of Subfibular Ossicle in Children: A Retrospective Study of 36 Patients with Functional Instability

BACKGROUNDS: To evaluate the surgical management of a symptomatic subfibular ossicle after severe ankle sprain with functional instability and pain sequelae in children. METHODS: We analyzed 36 patients complaining of functional instability without laxity, 1 year after an ankle inversion trauma associated with the observation of a subfibular ossicle. We systematically suggested the open excision of the residual ossicles, followed by 6 weeks of immobilization and proprioceptive physiotherapy. Seventeen of them, constituting the "resection" group accepted this surgical approach. The remaining 19 patients, the "control" group, received only rehabilitative care. The American Orthopaedic Foot and Ankle Society ankle pain and function score was evaluated in both groups. RESULTS: The mean latest follow-up was 4 years and 4 months (range, 1 y 8 mo to 14 y 7 mo). A significant improvement of the American Orthopaedic Foot and Ankle Society score was observed and was significantly higher in the resection group with a mean gain of 31 points (SD=31.8), versus 7 points (SD=7) in the control group (P<0.001). CONCLUSIONS: We conclude that in the absence of objective laxity, excision of the os subfibulare appears as a simple and effective technique in the treatment of posttraumatic functional instability and ankle pain. LEVEL OF EVIDENCE: Level IV-retrospective case-control study

Aluminum and iron can be deposited in the calcified matrix of bone exostoses.

Exostosis (or osteochondroma) is the most common benign bone tumor encountered in children and adults. Exostoses may occur as solitary or multiple tumors (in the autosomal syndromes of hereditary multiple exostoses). Exostoses are composed of cortical and medullary bone covered by an overlying hyaline cartilage cap. We have searched iron (Fe) and aluminum (Al) in the matrix of cortical and trabecular bone of 30 patients with exostosis. Al3 + and Fe3 + are two cations which can substitute calcium in the hydroxyapatite crystals of the bone matrix. The bone samples were removed surgically and were studied undecalcified. Perls\u27 Prussian blue staining (for Fe) and solochrome azurine B (for Al) were used on the histological sections of the tumors. Al3 + was detected histochemically in 21/30 patients as linear bands deposited by the osteoblasts. Fe3 + was detected in 10 out of these 21 patients as linear bands in the same locations. Fe3 + and Al3 + were not identified in the bone matrix of a control group of 20 osteoporotic patients. Energy X-ray Dispersive Spectrometry failed to identify Fe and Al in bone of these tumors due to the low sensitivity of the method. Wavelength Dispersive Spectrometry identified them but the concentrations were very low. Histochemistry appears a very sensitive method for Fe3 + and Al3 + in bone.The presence of these two metals in the exostoses advocates for a disturbed metabolism of osteoblasts which can deposit these metals into the bone matrix, similar to which is observed in case of hemochromatosis with Fe3 +

Influence of cyclic bending loading on in vivo skeletal tissue regeneration from periosteal origin

International audienceIntroduction: Periosteum osteogenic and chondrogenic properties stimulate the proliferation then differentiation of mesenchymal precursor cells originating from its deeper layers and from neighboring host tissues. The local mechanical environment plays a role in regulating this differentiation of cells into lineages involved in the skeletal regeneration process. Hypothesis: The aim of this experimental animal study is to explore the influence of cyclic high amplitude bending-loading on skeletal tissue regeneration. The hypothesis is that this mechanical loading modality can orient the skeletogenesis process towards the development of anatomical and histological articular structures. Material and methods: A vascularised periosteal flap was transferred in close proximity to each knee joint line in 17 rabbits. On one side, the tibiofemoral joint space was bridged and loading occurred when the animal bent its knee during spontaneous locomotion. On the other side, the flap was placed 12 mm distal to the joint line producing no loading during bending. Tissue regeneration was chronologically analyzed on histologic samples taken from the 4th day to the 6th month. Results: The structure and mechanical behavior of regenerating tissue evolved over time. As a result of the cyclic bending-loading regimen, cartilage tissue was maintained in specific areas of the regenerating tissue. When loading was discontinued, final osteogenic and fibrogenic differentiation occurred in the neoformed cartilage. Fissures developed in the cartilage aggregates resulting in pseudo-gaps suggesting similar processes to embryonic articular development. Ongoing mesenchymal stem cells stimulation was identified in the host tissues contiguous to the periosteal transfer. Discussion: These results suggest that the pseudarthrosis concept should be reconsidered within the context of motion induced articular histogenesis. (C) 2010 Elsevier Masson SAS. All rights reserved

Influence of cyclic bending loading on in vivo skeletal tissue regeneration from periosteal origin (vol 96, pg 833, 2010)

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Temporal evolution of skeletal regenerated tissue: what can mechanical investigation add to biological?

International audienceThe objective here was to experimentally characterize the temporal evolution of the structural and mechanical properties of large volume immature regenerated tissues. We studied these evolving tissues from their genesis in controlled mechanical conditions. We developed an animal model based on the periosteal properties leading to unloaded regenerated skeletal tissue. To characterize the temporal evolution of mechanical properties, we carried out indentation tests coupled with macroscopic examinations and histological studies. This combined methodology yielded a range of information on osteogenesis at different scales: macroscopic by simple observation, mesoscopic by indentation test and microscopic by histological study. Results allowed us to identify different periods, providing a link between biological changes and material property evolution in bone tissue regeneration. The regenerated tissue evolves from a viscous, homogeneous, soft material to a heterogeneous stiffer material endowed with a lower viscosity. From a biological point of view, cell organization progresses from a proliferated cell clot to a mature structure closer to that of the bone. During the first 7 days, mechanical and biological results revealed the same evolution: first, the regenerated tissue grew, then, differentiated into an osteochondral tissue and finally calcification began. While our biological results confirm those of other studies, our mechanical results provide the first experimental mechanical characterization by reduced Young's modulus of such tissue