There is no simple solution to a complex problem. This is true in life, and in bunion surgery.

A bunion is a complex condition resulting from either structural anomaly or biomechanical instability, and often both. Careful evaluation of the condition is required; no two bunion deformities are identical. Mistakes are made when patient expectations are unrealistic, physician capabilities are limited, there is no sound surgical plan to address every component of the deformity, or the procedure is poorly executed. The failure often occurs before the procedure is carried out.

Proper planning includes complete evaluation for causation. Removing the bump may provide short term relief, but not addressing all the causative factors will result in long term failure. That is why clinical and radiographic parameters are so critical. Along with an arsenal of procedure selection in the surgeon's pocket to choose from.

Distal osteotomy procedures are the least technically demanding and have the lowest complication rates. The good news, most patients will fall into this category. More proximal procedures are required for extremes of the deformity - rigidity, age of patient and deformity, and profound dynamic forces acting across the first ray. For the segment of patients that fall into this category, expectations should be set accordingly - the more complex the procedure, the more can go wrong. Nonunions, neuritis, hardware complications, and load transfer related issues all have a higher incidence with these procedures.

The content of this podcast is for educational and informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

The bones of the foot are arranged to not only provide stability and absorb impact, but to provide maximal efficiency in movement. Beginning with their axes of motion, which are purposefully arranged to allow motion in a specific sequence as the body's weight transfers over the foot from posterior to anterior. The ankle allows dorsiflexion, the subtlalar and mid tarsal joints allow pronation (shock absorption), which converts to supination (rigid lever), returning motion back to the ankle as plantar flexion. It is a spring-loaded structure. And stability is not just structural - it's dynamic.

It is crucial to understand that the foot and ankle are merely a system of levers and pulleys. Understanding the anatomic arrangement of the tendons around an axis describes the relative contribution of a muscle (by way of tendons) to the system. The larger the tendon, the more force it can exert. And the farther from the joint axis, the greater the lever arm, also resulting in more force. And when a tendon crosses over a joint axis, we can determine which direction the force will occur.

Tendons on the lateral side of the ankle will pull the foot into eversion, while tendons on the medial side will invert. Posterior tendons plantar flex, while anterior tendons dorsiflex. However the arrangement becomes more complex when we see tendons crossing multiple axes, and becoming maximally loaded and thus effective at specific points during the gait cycle. Pathology occurs when joint axes shift from ideal, or motion is somehow limited either by physical restriction (tight tendons or boney impingement) or by anatomic malalignment.

Such is the example with a short or elevated first ray, or a first ray with an axis moving away from the traverse plane. The result of inefficiency in the peroneal complex to sufficiently load the medial column will result in prolonged pronation, the downstream effects being hyper mobility, poor shock absorption, distal deformity such as bunions and hammertoes, and load transfer issues like metatarsalgia, stress fractures, and neuromas.

Thus you can appreciate how biomechanics is the foundation of many of the pathologies we see in foot and ankle medicine. Correcting these deficiencies is essential to surgical practice.

The content of this podcast is for educational and informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Understanding biomechanics is essential to diagnosing and treating vague symptom descriptions such as metatarsalgia.

If you remember back to our discussion on pronation and supination - the foot first must pronate when loading then convert into a supinated, rigid lever for propulsion. This occurs when the body weight moves over the center of the foot, tightening posterior structures and placing them into position for maximal effect. When this system works properly, the Achilles tendon raises the hind foot and increases pressure on the forefoot. At the same time, supination is occurring. The peroneus longus tendon begins firing, causing forefoot load to transfer from the lateral forefoot to the first ray, our most important propulsive lever in the forefoot. If an imbalance exists in this chain - for example excessively tight Achilles, poorly functional peroneal complex, or first ray insufficiency due to elevation, shortening or stiffness, then more load occurs for longer in the lesser metatarsals. This sets up a variety of pathological processes, any of which may occur or more than one may happen at the same time.

Treatment should focus on mechanics first - how did the pathology occur? Functional problems are treated with functional support such as orthotics. Structure comes second. And when a structural concern exists often surgical intervention can be helpful. However surgery just to relieve pain will often fail if it does not address mechanical causes leading to the pain.

Key takeaways for practitioners:

• Metatarsalgia is a symptom, not a diagnosis
• The first ray is critical—ignore it and you’ll fail
• Callus tells you everything about pressure distribution
• Equinus is one of the most underappreciated contributors
• Orthotics work—when done correctly
• Surgery should correct mechanics, not just relieve pain

The content of this podcast is for educational and informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.