Is Using a Ring External Fixator in the Treatment of Congenital Pseudarthrosis of the Tibia Associated With Better Results or Using a Locking Plate?

BACKGROUND: Congenital pseudarthrosis of the tibia (CPT) is a rare disease. CPT is often unilateral and occurs between the middle and distal third of the tibia. Concurrent involvement of the fibula is present in more than half of cases. histologic studies indicate the presence of fibrous hamartoma tissue and a sick periosteum, which leads to recalcitrant bone fracture and, eventually, pseudoarthrosis. Although there are various surgical techniques, we intend to compare the 2 methods of external fixation versus internal plating. METHODS: Demographic data were collected from 26 patients with frank pseudoarthrosis. After exclusion criteria, patients were compared in groups A (12 patients) and B (11 patients). Resection of hamartoma and sclerotic bone, intramedullary rodding and autologous bone, and periosteal grafting were performed for all patients. In group A, we used a ring external fixator for compression and rotational stability, but in group B, a locking plate was used for these purposes. RESULTS: Plating takes less time to use during surgery. In group A, the primary bony union was obtained in 67% of patients, while in group B, 82% of patients had a primary union. Meanwhile, the average time till the final union in group A was 6 months, while in group B, this time was 3.5 months. Positive union mass was obtained in 58% of the patients in group A and 82% of group B. In addition, plating prevented ankle valgus deformity in group B. CONCLUSIONS: Permanent intramedullary rodding is a surgical requirement for correction of deformity and refracture prevention, but additional stability can be achieved with the use of a ring external fixator or internal plate. Cross union and positive union mass are 2 important factors in the treatment of pseudoarthrosis; these results are achieved to a greater extent and in a shorter period of time using the plate. LEVEL OF EVIDENCE: level IV - case series.

Prognosis of Congenital Pseudarthrosis of the Tibia: Effect of Site of Tibial Pseudarthrososis and Fibular Involvement.

BACKGROUND: Congenital pseudarthrosis of the tibia is a rare condition that has long been one of the most challenging concerns in pediatric orthopedic surgery. When the fracture occurs, a recalcitrant nonunion is expected. This is why successful treatment means maintaining a long-term union. In this study, we aimed to assess the therapeutic outcomes for the middle and distal third fractures of the tibia and to explore whether the treatment of concurrent fibular pseudoarthrosis affects the outcome. METHODS: We studied 12 patients with congenital pseudarthrosis of the tibia (Crawford type 4) from 2014 to 2019. A combination approach including intramedullary rod, Ilizarov apparatus, corticocancellous bone graft, and periosteal graft was used. In the initial surgery, we did not fix the ankle and subtalar joints. RESULTS: As a result, the union was achieved in 67% of the cases after the index surgery. All of the cases with primary nonunion were related to the concurrent fibular and distal third tibial pseudarthrosis. In addition, ignoring the treatment of fibular pseudarthrosis in the index surgery led to ankle valgus deformity both in the middle and in the distal third tibial pseudarthrosis. We finally achieved a 100% union rate in all cases, with no subsequent refracture. CONCLUSIONS: Surgery at an early age was associated with favorable results and minimized deformity. In concurrent fibular and distal third tibial pseudarthrosis, it is recommended to transfix the ankle and subtalar joints to create a cross-union with fibula so that the intense union can be confidently obtained with more cross-section to prevent ankle valgus deformity. LEVEL OF EVIDENCE: Level IV-case series.

Multiple spectroscopic studies of the interaction between a quaternary ammonium-based cationic Gemini surfactant (as a carrier) and human erythropoietin.

Erythropoietin (EPO) is a hematopoietic growth factor. This substance, as a strong cell protector, can increase cell maintenance during different damages of central nervous system. Since the brain-blood barrier prevents the entrance of large proteins similar to EPO into the brain, its systemic delivery gets limited. The aim of this study was to find an alternative approach for EPO delivery into the brain to skip the blood-brain barrier prevention. So, a new quaternary ammonium-based cationic Gemini surfactant has been used to study the interaction of the cationic Gemini surfactant (as a carrier) with EPO using various spectroscopic techniques of (fluorescence and circular dichroism (CD)) and thermal denaturation. Fluorescence spectroscopy studies show the formation of Gemini-EPO complex and also static quenching of protein upon this interaction. The binding parameters of number of binding sites, binding affinity, Gibbs free energy, enthalpy, and entropy were calculated according to fluorescence quenching studies. Also, CD results have further represented that the content of regular secondary structure of EPO did not show any significant alterations by increasing the Gemini concentration. Finally, thermal denaturation behavior of EPO results indicates decreasing the thermal stability of protein in the presence of Gemini. In conclusion, the obtained results proposed that Gemini as a cationic surfactant can bind to EPO without any significant diverse effects on the structure of this drug (EPO) which can be considered as a candidate for EPO delivery in future.