第1跖跗关节骨折脱位不同内固定方式对前足足底压力变化的影响

目的 :测量第1跖跗关节骨折脱位3种内固定对前足足底压力的变化,为选择内固定提供实验参考。方法:取8具新鲜足标本,制成第1跖跗关节骨折脱位模型,依次进行3.5 mm全螺纹皮质骨螺钉,1/4管形钢板及加压骑缝钉固定。经加载600 N后,通过F-scan足底压力分析系统,测量前足足底压力的变化。结果:第1跖跗关节骨折脱位后,第1跖骨头下的峰值压力将减小,而第2跖骨头下的峰值压力将增大,差异具有统计学意义(P<0.05)。对第1跖跗关节分别采用螺钉、钢板进行固定后,第1、2跖骨头下的峰值压力都将趋于正常状态,而进行骑缝钉固定后,虽然第1、2跖骨头下的峰值压力都有所恢复,但仍与正常状态比较,差异有统计学意义(P<0.05)。结论 :当第1跖跗关节骨折脱位后,邻近跖骨头可能存在着"负荷转移"的调节机制以代偿部分足底压力;当第1跖跗关节骨折脱位采用螺钉和钢板内固定治疗后,前足足底压力都可恢复至正常状态,而若采用骑缝钉固定,则前足足底压力仍难以恢复至正常状态。

Forefoot plantar pressure changes of the first tarsometatarsal joint fracture-dislocation fixation by different internal fixations

Objective:To measure the changes of plantar pressure of the first tarsometatarsal joint fracture and dislocation by three different implants to provide experimental reference in selecting implants. Methods:Eight fresh foot specimens were made into the models of the first tarsometatarsal joint fracture and dislocation,which were fixed with 3.5 mm cortical screw,1/4 tubular plate and compressive staple in turn. After the loading of 600 N,the changes of the plantar pressure in forefoot were measured by the method of the F-scan plantar pressure system. Results:After first tarsometatarsal joint fracture and dislocation,the peak pressure under the first metatarsal head would decrease,while the pressure under the second metatarsal head would increased,whose differences were statistically significant(P<0.05). When the first tarsometatarsal joint was fixed with screw or plate respectively; the peak pressure under the two metatarsal heads would tend to be normal. However,the staple fixation showed the statistical significant difference compared with normal state,although the peak pressure under the first and second metatarsal heads were recovered in some extent(P<0.05). Conclusion:After the first tarsometatarsal joint fracture-dislocation,the plantar pressure might be compensated partly by the adjacent metatarsal heads according to the regulation of the load transfer mechanism. While the first tarsometatarsal joint fracture-dislocation was fixated by screw or plate,the plantar pressure of the forefoot would return to the normal state. However,if the joint was fixated by the staple,it would still be difficult to return the plantar pressure to be normal.