Stevens Jasper, Meijer Kenneth, Bijnens Wouter, Fuchs Mathijs C H W, van Rhijn Lodewijk W, Hermus Joris P S, van Hoeve Sander, Poeze Martijn, Witlox Adhiambo M
1 Department of Orthopaedics, Maastricht University Medical Centre, The Netherlands.
2 Department of Human Movement Sciences, Maastricht University, The Netherlands.
Foot Ankle Int. 2017 Feb;38(2):181-191. doi: 10.1177/1071100716674310. Epub 2016 Oct 23.
Arthrodesis of the first metatarsophalangeal (MTP1) joint is an intervention often used in patients with severe MTP1 joint osteoarthritis and relieves pain in approximately 80% of these patients. The kinematic effects and compensatory mechanism of the foot for restoring a more normal gait pattern after this intervention are unknown. The aim of this study was to clarify this compensatory mechanism, in which it was hypothesized that the hindfoot and forefoot would be responsible for compensation after an arthrodesis of the MTP1 joint.
Gait properties were evaluated in 10 feet of 8 patients with MTP1 arthrodesis and were compared with 21 feet of 12 healthy subjects. Plantar pressures and intersegmental range of motion were measured during gait by using the multisegment Oxford Foot Model. Pre- and postoperative X-rays of the foot and ankle were also evaluated.
The MTP1 arthrodesis caused decreased eversion of the hindfoot during midstance, followed by an increased internal rotation of the hindfoot during terminal stance, and ultimately more supination and less adduction of the forefoot during preswing. In addition, MTP1 arthrodesis resulted in a lower pressure time integral beneath the hallux and higher peak pressures beneath the lesser metatarsals. A mean dorsiflexion fusion angle of 30 ± 5.4 degrees was observed in postoperative radiographs.
This study demonstrated that the hindfoot and forefoot compensated for the loss of motion of the MTP1 joint after arthrodesis in order to restore a more normal gait pattern. This resulted in a gait in which the rigid hallux was less loaded while the lesser metatarsals endured higher peak pressures. Further studies are needed to investigate whether this observed transfer of load or a preexistent decreased compensatory mechanism of the foot can possibly explain the disappointing results in the minority of the patients who experience persistent complaints after a MTP1 arthrodesis.
Level III, comparative series.
第一跖趾关节（MTP1）融合术是常用于重度MTP1关节骨关节炎患者的一种干预措施，约80%的此类患者疼痛得到缓解。该干预后足部恢复更正常步态模式的运动学效应和代偿机制尚不清楚。本研究的目的是阐明这种代偿机制，研究假设MTP1关节融合术后后足和前足将负责代偿。
对8例接受MTP1关节融合术患者的10只足的步态特征进行评估，并与12名健康受试者的21只足进行比较。使用多节段牛津足模型在步态过程中测量足底压力和节段间运动范围。还对足踝部术前和术后的X线片进行了评估。
MTP1关节融合术导致站立中期后足外翻减少，随后在终末站立期后足内旋增加，最终在摆动前期前足旋后增加、内收减少。此外，MTP1关节融合术导致拇趾下方的压力时间积分降低，而较小跖骨下方的峰值压力升高。术后X线片观察到平均背屈融合角度为30±5.4度。
本研究表明MTP1关节融合术后后足和前足对MTP1关节运动丧失进行了代偿，以恢复更正常的步态模式。这导致一种步态，其中僵硬的拇趾负荷较小，而较小跖骨承受更高峰值压力。需要进一步研究来调查这种观察到的负荷转移或足部预先存在的代偿机制降低是否可能解释少数MTP1关节融合术后仍有持续不适患者的令人失望的结果。
III级，比较系列研究。
