Brodsky James W, Pollo Fabian E, Cheleuitte Domingo, Baum Brian S
Baylor University Medical Center, Orthopaedics, Dallas, TX 75246, USA.
Foot Ankle Int. 2007 Aug;28(8):880-9. doi: 10.3113/FAI.2007.0880.
Patients with neuropathic conditions may develop plantar bony deformities through neuropathic collapse, frequently placing the skin and soft tissues at risk. Orthoses have been used to accommodate and distribute plantar pressures over a large surface area, thereby minimizing peak loading pressures in small regions and reducing the risk of ulceration.
A previously described bony prominence model (Brodsky et al.) was used to test the pressure-absorbing and force-transmission properties of various orthotic material combinations used in our outpatient clinic. Six materials were tested in five combinations of materials for their compressive properties: [MS]: medium plastazote (M) + soft plastazote (S); [MN]: medium plastazote (M) + nickelplast (N); [NP] nickelplast (N) + Poron (P); [MO] medium plastazote (M) + Spenco (O); and [MC] medium plastazote (M) + P-cell (C). Materials were tested for 100,000 cycles using a materials-testing system (MTS) apparatus (MTS Systems Corporation, Cary, NC) and software. Stress-strain curves comparing the measured peak pressure to the elastic deformation, or the percentage of compression a material experiences with respect to its original thickness, were plotted for each orthotic combination.
For MS, MN, MO, and to a lesser extent, MC, a trend was noted for decreased elastic deformation with increased testing. Additionally, the peak pressures before and after testing for each 10,000 testing cycle for each of the orthotic combinations were plotted. For both MN and NP, no demonstrable difference was noted in the peak pressures in the pretesting and post-testing for the 100,000 cycles. The MO showed a trend for increased peak pressures after each testing cycle. Both the MC and MS peak pressures markedly increased with respect to pretesting value. Also, the MN, MO, and MS all showed an overall trend for increased load cell values with increasing cycles at fast loading.
These data showed that some orthotic combinations are more effective than others at reducing peak pressures during compression testing using our bony prominence model. Further studies are needed to test the orthotic combinations for shear and combined shear and compression modes.
患有神经病变的患者可能会因神经病变性塌陷而出现足底骨性畸形，这常常使皮肤和软组织处于危险之中。矫形器已被用于在较大表面积上调节和分散足底压力，从而将小区域的峰值负荷压力降至最低，并降低溃疡风险。
使用先前描述的骨性突出模型（布罗茨基等人）来测试我们门诊所使用的各种矫形材料组合的压力吸收和力传递特性。对六种材料进行了五种材料组合的压缩特性测试：[MS]：中号普拉斯塔佐特（M）+软质普拉斯塔佐特（S）；[MN]：中号普拉斯塔佐特（M）+镍质塑料（N）；[NP]镍质塑料（N）+波罗恩材料（P）；[MO]中号普拉斯塔佐特（M）+斯彭科材料（O）；以及[MC]中号普拉斯塔佐特（M）+P型细胞材料（C）。使用材料测试系统（MTS）仪器（MTS系统公司，北卡罗来纳州卡里）和软件对材料进行100,000次循环测试。针对每种矫形组合绘制应力-应变曲线，将测量的峰值压力与弹性变形进行比较，或与材料相对于其原始厚度的压缩百分比进行比较。
对于MS、MN、MO以及在较小程度上对于MC，随着测试次数增加，弹性变形有减小的趋势。此外，还绘制了每种矫形组合在每10,000次测试循环前后的峰值压力。对于MN和NP，在100,000次循环的测试前和测试后的峰值压力中未发现明显差异。MO在每个测试循环后显示出峰值压力增加的趋势。MC和MS的峰值压力相对于测试前的值均显著增加。此外，MN、MO和MS在快速加载时均显示出随着循环次数增加负荷传感器值增加的总体趋势。
这些数据表明，在使用我们的骨性突出模型进行压缩测试时，某些矫形组合在降低峰值压力方面比其他组合更有效。需要进一步研究来测试矫形组合在剪切以及剪切和压缩组合模式下的性能。
