ABSTRACT Objective: To investigate the effect of second toe-to-hand transfer on the plantar pressure distribution of the donor foot. Methods: Twelve normal fresh-frozen cadaveric foot specimens were subjected to an axial load of 600 N. An F-Scan plantar pressure analysis system was used to measure the forefoot plantar pressure. The testing was performed under the conditions of intact second toe, second toe removal with the second metatarsal head reserved, and second toe removal in combination with the distal one-third of the second metatarsal, respectively. Results: The peak pressure of the second metatarsal head was greater than other four forefoot plantar regions. There was no statistically significant change in the forefoot plantar pressure distribution after the second toe was removed (p > 0.05). When the second toe and the distal one-third of the second metatarsal were removed, the forefoot plantar pressure distribution changed significantly (p < 0.05). Conclusions: An intact second metatarsal is essential for the normal distribution of plantar pressure. Removal of the second toe with the second metatarsal head reserved had little influence on the plantar pressure distribution of the donor foot. Removal of the second toe and distal one-third of the second metatarsal resulted in abnormal plantar pressure distribution. Level of Evidence II, Experimental Study.

O processo de passivação de aço carbono durante deformação plástica em uma solução simulada de poro foi estudado usando-se testes eletroquímicos e microscopia de força atômica (AFM). Os resultados de polarização mostram que a atividade do aço carbono aumentou com o aumento do grau de deformação. Antes da ruptura dos filmes passivos, as amostras altamente deformadas apresentaram um alto potencial de circuito aberto (OCP). Por outro lado, o tempo de incubação de pite diminuiu com o aumento da deformação plástica. Os resultados de Mott-Schottky sugerem que a grande deformação tornou altamente dopados os filmes passivos. Além disso, as camadas de cargas espaciais dos filmes passivos afinaram quando a deformação plástica aumentou. As observações por AFM indicaram que os filmes passivos se tornariam menos homogêneos com aumento da deformação. Estes resultados demonstram que filmes passivos em aço carbono deformado se tornam instáveis quando a deformação plástica aumenta.

The process of passivation of carbon steel when experiencing plastic deformation in simulated pore solution has been studied using electrochemical tests and atomic force microscopy (AFM). The polarization results show that the activity of the carbon steel increased with increasing degree of deformation. Before the passive films were ruptured, the heavily deformed samples presented a high open circuit potential (OCP). On the other hand, the pitting incubation time decreased with increasing plastic deformation. The Mott-Schottky results suggested that the high deformation caused the passive films to be heavily doped. In addition, the space charge layers of passive films were thinned when the plastic deformation increased. The AFM observations indicated that the passive films become more inhomogeneous as the deformation increased. These results demonstrate that passive films on the deformed carbon steel become unstable when the plastic deformation increases.

Objective: Posterior pilon fractures are rare injuries and have not yet gained well recognition. The purpose of this study was to present the treatment outcome for patients with posterior pilon fractures treated with buttress plate. Method: In this retrospective study we identified patients with posterior pilon fractures of the distal tibia who had undergone open reduction and internal fixation at our institute. Between January 2007 and December 2009, 10 patients (mean age, 46.5 years) who had undergone buttress plating via either a posterolateral approach or a dual posterolateral-posteromedial approach, were selected. All 10 patients were available for follow-up. The clinical outcome was evaluated with the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the visual analogue scale (VAS). The radiological evaluation was performed using the osteoarthritis-score (OA-score). Results: Satisfactory reduction and stable fixation were accomplished in all patients. At a mean follow-up of 36.2 months, all patients had good radiological results and showed satisfactory clinical recovery. The mean AOFAS sore was 87.8, the mean OA-score was 0.6, and the mean VAS scores during rest, active motion, and weight-bearing walking were 0.6, 0.8, and 1.4, respectively. Conclusion: Buttress plating for posterior pilon fractures gave satisfactory clinical outcomes. It also ensured rigid fixation which in turn enabled earlier postoperative mobilization. Level of Evidence IV, Retrospective Study.

OBJETIVO: Apresentar nossas experiências no tratamento de más uniões ou não consolidações talares. MÉTODO: Entre janeiro de 2000 e setembro de 2009, 26 pacientes com má união ou não-união depois de fraturas do tálus foram submetidos a tratamento cirúrgico de acordo com os diferentes tipos de deformidade talar. Os desfechos do tratamento foram avaliados pela escala tornozelo-retropé da AOFAS, assim como por radiografias simples. RESULTADOS: 20 pacientes ficaram disponíveis para acompanhamento por 30 (24 a 60) meses. Não houve problema de cicatrização ou infecção das feridas e foram obtidas uniões sólidas em todos os pacientes. As uniões radiológicas foram atingidas em tempo médio de 14 (faixa de 12 a 18) semanas. O tempo médio para concluir o apoio de carga foi 16 (faixa de 14 a 20) semanas. O escore AOFAS médio aumentou significantemente de 36,2 (27 a 43) para 85,8 (74 a 98). CONCLUSÃO: as intervenções cirúrgicas das fraturas mal-unidas ou não consolidadas dos tálus podem produzir resultados satisfatórios e o procedimento apropriado deve ser adotado, de acordo com diferentes tipos de deformidades pós-traumáticas. Nível de Evidência: IV, Estudo retrospectivo.

OBJECTIVE: To present our experiences of treating talar malunions and nonunions. METHOD: Between January 2000 and September 2009, 26 patients with malunions or nonunions after talar fractures underwent surgical treatment according to different types of talar deformities. The treatment outcomes were evaluated using AOFAS ankle-hindfoot scale as well as plain radiographs. RESULTS: 20 patients were available for follow-up for 30 (range, 24 to 60) months. No wound healing problems or infections occurred and solid unions were achieved in all patients. Radiological unions were achieved at a mean time of 14 (range, 12 to 18) weeks. The mean time to complete weight-bearing was 16 (range, 14 to 20) weeks. The mean AOFAS score increased significantly from 36.2 (range, 27 to 43) to 85.8 (range, 74 to 98). CONCLUSION: Surgical interventions for malunions and nonunions after talar fractures can bring about satisfactory outcomes, and the appropriate procedure should be adopted according to different types of posttraumatic deformities. Level of Evidence: IV, Retrospective Study.