Isvilanonda Vara, Dengler Evan, Iaquinto Joseph M, Sangeorzan Bruce J, Ledoux William R
RR&D Center of Excellence for Limb Loss Prevention and Prosthetic Engineering, Department of Veterans Affairs, Seattle, WA, USA.
Clin Biomech (Bristol). 2012 Oct;27(8):837-44. doi: 10.1016/j.clinbiomech.2012.05.005. Epub 2012 Jun 12.
Clawed hallux is defined by first metatarsophalangeal joint extension and first interphalangeal joint flexion; it can increase plantar pressures and ulceration risk. We investigated two corrective surgical techniques, the modified Jones and flexor hallucis longus tendon transfer.
A finite element foot model was modified to generate muscle overpulls, including extensor hallucis longus, flexor hallucis longus and peroneus longus. Both corrective procedures were simulated, predicting joint angle and plantar pressure changes.
The clawed hallux deformity was generated by overpulling: 1) extensor hallucis longus, 2) peroneus longus + extensor hallucis longus, 3) extensor hallucis longus + flexor hallucis longus and 4) all three together. The modified Jones reduced metatarsophalangeal joint angles, but acceptable hallux pressure was found only when there was no flexor hallucis longus overpull. The flexor hallucis longus tendon transfer reduced deformity at the metatarsophalangeal and interphalangeal joints but may extended the hallux due to the unopposed extensor hallucis longus. Additionally, metatarsal head pressure increased with overpulling of the extensor hallucis longus + flexor hallucis longus, and all three muscles together.
The modified Jones was effective in correcting clawed hallux deformity involving extensor hallucis longus overpull without flexor hallucis longus overpull. The flexor hallucis longus tendon transfer was effective in correcting clawed hallux deformity resulting from the combined overpull of both extensor and flexor hallucis longus, but not with isolated extensor hallucis longus overpull. An additional procedure to reduce the metatarsal head pressure may be required concomitant to the flexor hallucis longus tendon transfer. However this procedure avoids interphalangeal joint fusion.
爪形拇趾畸形的定义为第一跖趾关节背伸和第一趾间关节跖屈；它会增加足底压力和溃疡风险。我们研究了两种矫正手术技术，改良琼斯手术和拇长屈肌腱转移术。
对一个有限元足部模型进行修改，以产生肌肉过度牵拉的情况，包括拇长伸肌、拇长屈肌和腓骨长肌。模拟了两种矫正手术，预测关节角度和足底压力变化。
爪形拇趾畸形是由以下过度牵拉导致的：1）拇长伸肌，2）腓骨长肌+拇长伸肌，3）拇长伸肌+拇长屈肌，4）三者同时过度牵拉。改良琼斯手术可减小跖趾关节角度，但仅在没有拇长屈肌过度牵拉时才能获得可接受的拇趾压力。拇长屈肌腱转移术可减少跖趾关节和趾间关节的畸形，但由于拇长伸肌未受对抗，可能会使拇趾背伸。此外，当拇长伸肌+拇长屈肌过度牵拉以及三者同时过度牵拉时，跖骨头压力会增加。
改良琼斯手术对于矫正单纯拇长伸肌过度牵拉导致的爪形拇趾畸形有效。拇长屈肌腱转移术对于矫正拇长伸肌和拇长屈肌联合过度牵拉导致的爪形拇趾畸形有效，但对于单纯拇长伸肌过度牵拉导致的畸形无效。在进行拇长屈肌腱转移术时，可能需要额外采取措施来降低跖骨头压力。然而，该手术可避免趾间关节融合。
