What is the most poorly tolerated complication of a 1st MTP joint arthrodesis?

• A. Malposition
• B. Infection
• C. Nonunion
• D. Hardware irritation

Answer: (A)

The most important factor in a first metatarsophalangeal joint fusion is achieving correct alignment. During walking, the first MTP joint acts as a critical lever for push-off; the windlass mechanism and forefoot loading rely on the joint being in proper sagittal and transverse positions. If the fusion is malpositioned, the toe cannot function as a solid, efficient lever, leading to abnormal weight distribution, persistent pain, and difficulty with shoe wear. This usually causes troublesome gait disturbances and often requires revision to restore function, making malposition the most poorly tolerated complication.

Infection, nonunion, and hardware irritation are serious and can require intervention, but they do not inherently derail push-off mechanics to the same extent. Those issues can sometimes be addressed without fundamentally compromising the overall gait pattern if corrected appropriately, whereas malalignment directly undermines the primary purpose of the fusion.