Department of Orthopedic Surgery, Hospital de l'Esperança-Parc de Salut MAR, Universitat Autonoma de Barcelona, Barcelona, Spain.
Foot Ankle Int. 2013 Apr;34(4):504-11. doi: 10.1177/1071100713477386. Epub 2013 Feb 8.
The correlation between angle of fusion of the first metatarsophalangeal (1MTTP) joint and pressures under metatarsal heads and hallux has not been well characterized. The main purpose was to investigate the correlation between fusion dorsiflexion angle of the 1MTTP joint and plantar pressures under the first metatarsal head and hallux during gait.
Patients who underwent arthrodesis of the 1MTTP joint from 2005 to 2010 were seen for a follow-up examination. Of 27 patients, 15 (22 feet) with a mean follow-up of 26.2 months were evaluated in the study. Main outcomes included the fusion clinical and radiological dorsiflexion angles and the mean and maximum dynamic plantar pressures under all 5 metatarsal heads and under the hallux. Plantar pressures were measured through an in-shoe system while patients walked normally along a corridor.
The dorsiflexion angle was positively correlated with mean dynamic plantar pressures under the first metatarsal head: P = .02 (r = 0.5) for clinical angle, and P = .01 (r = 0.58) for radiological angle. Patients with 15 degrees or more of clinical dorsiflexion angle demonstrated higher mean dynamic plantar pressure under the first metatarsal head (P = .05) and higher maximum dynamic plantar pressure under the second metatarsal head (P = .04) compared with patients with less than 15 degrees. In contrast, the latter patients demonstrated higher mean dynamic plantar pressure beneath the hallux (P = .04). Patients with 30 degrees or more of radiological dorsiflexion angle demonstrated significantly higher mean dynamic plantar pressure under the first metatarsal head (P = .04) compared with patients with less than 30 degrees.
Higher dorsiflexion angles correlate with higher plantar pressures under the first metatarsal head. Lower dorsiflexion angles increase plantar pressures beneath the hallux during gait.
Significant increase in plantar pressure under the first metatarsal head may be avoided by performing the arthrodesis of the 1MTTP joint below 30° and 15° for the radiological and clinical dorsiflexion angles, respectively.
第一跖趾关节（1MTTP）融合角度与跖骨和大脚趾下压力之间的相关性尚未得到很好的描述。主要目的是研究步态时 1MTTP 关节融合背屈角度与第一跖骨和大脚趾下的足底压力之间的相关性。
对 2005 年至 2010 年间接受 1MTTP 关节融合术的患者进行随访检查。在 27 例患者中，有 15 例（22 只脚）进行了研究，平均随访 26.2 个月。主要结果包括融合临床和放射学背屈角度以及所有 5 个跖骨和大脚趾下的平均和最大动态足底压力。通过鞋内系统测量足底压力，患者在走廊正常行走时。
背屈角度与第一跖骨下的平均动态足底压力呈正相关：临床角度 P =.02（r = 0.5），放射学角度 P =.01（r = 0.58）。临床背屈角度为 15 度或以上的患者，第一跖骨下的平均动态足底压力较高（P =.05），第二跖骨下的最大动态足底压力较高（P =.04），而背屈角度小于 15 度的患者则较低。相比之下，后者患者的大脚趾下的平均动态足底压力较高（P =.04）。放射学背屈角度为 30 度或以上的患者，第一跖骨下的平均动态足底压力显著高于背屈角度小于 30 度的患者（P =.04）。
较高的背屈角度与第一跖骨下的较高足底压力相关。较低的背屈角度在步态时会增加大脚趾下的足底压力。
分别将 1MTTP 关节融合的放射学和临床背屈角度设定为 30°和 15°以下，可以避免第一跖骨下的足底压力显著增加。
