Schiff Adam, Havey Robery, Carandang Gerard, Wickman Amy, Angelico John, Patwardhan Avinash, Pinzur Michael
Department of Orthopaedic Surgery, Loyola University Health System, Maywood, Illinois, USA.
Biomechanics Laboratory, Hines Veterans Administration Medical Center, Hines, Illinois, USA.
Foot Ankle Int. 2014 Aug;35(8):779-782. doi: 10.1177/1071100714535201. Epub 2014 May 21.
There is a paucity of objectively recorded data delineating the pattern of weightbearing distribution within the prosthetic socket of patients with transtibial amputation. Our current knowledge is based primarily on information obtained from finite element analysis computer models.
Four high-functioning transtibial amputees were fit with similar custom prosthetic sockets. Three load cells were incorporated into each socket at high stress contact areas predicted by computer modeling. Dynamic recording of prosthetic socket loading was accomplished during rising from a sitting position, stepping from a 2-leg stance to a 1-leg stance, and during the initiation of walking. By comparing the loads measured at each of the 3 critical locations, anterior/posterior shear, superior/inferior shear, and end weightbearing were recorded.
The same load pattern in all 4 subjects was found during each of the 3 functional activities. The load transmission at the distal end of the amputation residual limbs was negligible. Consistent forces were observed in both the anterior/posterior and superior/inferior planes. Correlation coefficients were used to compare the loads measured in each of the 4 subjects, which ranged from a low of .82 to a high of .98, where a value approaching 1.0 implies a linear relationship amongst subjects.
This experimental model appears to have accurately recorded loading within a transtibial prosthetic socket consistent with previously reported finite element analysis computer models.
This clinical model will allow objective measurement of weightbearing within the prosthetic socket of transtibial amputees and allow objective comparison of weightbearing distribution within the prosthetic sockets of patients who have undergone creation of different versions of a transtibial amputation residual limb and prosthetic socket designs.
关于经胫骨截肢患者假肢接受腔内负重分布模式的客观记录数据匮乏。我们目前的认知主要基于从有限元分析计算机模型获得的信息。
为四名功能良好的经胫骨截肢者装配了类似的定制假肢接受腔。根据计算机建模预测，在每个接受腔的高应力接触区域内置入了三个载荷传感器。在从坐姿起身、从双腿站立转换为单腿站立以及开始行走过程中，对假肢接受腔的负荷进行动态记录。通过比较在三个关键位置测得的负荷，记录前后剪切力、上下剪切力和最终负重情况。
在三项功能活动中的每一项活动期间，所有四名受试者的负荷模式均相同。截肢残肢远端的负荷传递可忽略不计。在前后平面和上下平面均观察到一致的力。使用相关系数比较四名受试者各自测得的负荷，范围从低至0.82到高至0.98，其中接近1.0的值意味着受试者之间存在线性关系。
该实验模型似乎准确记录了经胫骨假肢接受腔内的负荷情况，与先前报道的有限元分析计算机模型一致。
该临床模型将允许对经胫骨截肢者假肢接受腔内的负重进行客观测量，并允许对接受不同版本经胫骨截肢残肢和假肢接受腔设计的患者的假肢接受腔内负重分布进行客观比较。
