Weil或V形截骨术后尸体足的足底压力与负荷

Snyder John, Owen John, Wayne Jennifer, Adelaar Robert

Orthopaedic Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia.

Foot Ankle Int. 2005 Feb;26(2):158-65. doi: 10.1177/107110070502600208.

BACKGROUND

Since metatarsal osteotomy was first used to treat metatarsalgia in the early twentieth century, many techniques have been described to accomplish the basic aim of reduction of load transmission through the operated metatarsal and reduction of localized high pressure on the plantar surface of the metatarsal. Our study examined two popular distal metatarsal neck osteotomies used for the relief of central metatarsalgia and the biomechanical changes that result from their use in a cadaver forefoot model.

METHODS

After applying 445 N (100 lbs) of axially directed force, we measured plantar pressure using the TekScan HR Mat (TekScan, Inc., South Boston, MA) in twelve paired, thawed, fresh-frozen intact cadaver legs, then after either a Weil or chevron osteotomy of the second metatarsal and finally after the addition of the same osteotomy of the third metatarsal.

RESULTS

Load in the forefoot was not significantly affected by the Weil osteotomy. A significant increase in load was produced in the first metatarsal region, and significant decreases in load were produced beneath the operated metatarsal heads after the chevron osteotomy. Average pressure in the contact area of the forefoot showed similar trends; however, load and pressure changes occurred independently, owing to the changes in contact area produced by the osteotomies. No significant changes were observed in the nonoperated metatarsal regions.

CONCLUSIONS

In this model, the chevron osteotomy more effectively reduced load and plantar pressure in the operated metatarsal regions; however, increases in load and pressure were observed in the first metatarsal region. The increase in pressure without a change in load in region 3 (third metatarsal) after a Weil osteotomy of the third metatarsal was attributed to the creation of a plantar prominence. This study did not show a reduction in load transmission as a result of the Weil osteotomy, which contradicts the proposed mechanism of clinical benefit. An intact first ray likely prevents transfer of load or pressure to adjacent lesser metatarsals with chevron osteotomy.

背景

自20世纪初首次使用跖骨截骨术治疗跖痛症以来，已有多种技术被描述用于实现减轻通过手术跖骨的负荷传递以及减轻跖骨底面局部高压这一基本目标。我们的研究考察了两种用于缓解中央型跖痛症的常用远端跖骨颈截骨术，以及在尸体前足模型中使用这些截骨术所导致的生物力学变化。

方法

在施加445牛（100磅）轴向力后，我们使用TekScan HR Mat（TekScan公司，马萨诸塞州南波士顿）在12对解冻的新鲜冷冻完整尸体腿中测量足底压力，然后在第二跖骨进行Weil截骨术或V形截骨术后，最后在第三跖骨进行相同截骨术后再次测量。

结果

Weil截骨术对前足负荷无显著影响。V形截骨术后，第一跖骨区域负荷显著增加，手术跖骨头下方负荷显著降低。前足接触区域的平均压力呈现相似趋势；然而，由于截骨术导致的接触面积变化，负荷和压力变化是独立发生的。未手术的跖骨区域未观察到显著变化。

结论

在该模型中，V形截骨术更有效地降低了手术跖骨区域的负荷和足底压力；然而，在第一跖骨区域观察到负荷和压力增加。第三跖骨进行Weil截骨术后，第三跖骨区域压力增加而负荷不变，这归因于足底隆起的形成。本研究未显示Weil截骨术可减轻负荷传递，这与所提出的临床获益机制相矛盾。完整的第一跖列可能会阻止V形截骨术将负荷或压力传递至相邻较小跖骨。