Is arch strain a risk factor for pes planus (flat foot)?

From the Guidelines

Arch strain is a significant risk factor for developing pes planus, commonly known as flat feet. When the arch of the foot experiences excessive strain due to factors such as prolonged standing, inappropriate footwear, obesity, or high-impact activities, the supporting structures can weaken over time. This strain affects the posterior tibial tendon, plantar fascia, and spring ligament, which are crucial for maintaining the foot's arch. As these structures become compromised, the arch gradually flattens, leading to pes planus. The condition typically develops progressively, with initial arch fatigue and discomfort eventually leading to permanent flattening. Management includes reducing strain through appropriate footwear with arch support, orthotics, weight management, activity modification, and strengthening exercises for the intrinsic foot muscles and posterior tibial tendon. Physical therapy focusing on foot and ankle exercises can help reinforce the arch structure. Early intervention when arch strain is first noticed can prevent progression to more severe flat feet, which may eventually require more intensive treatments including bracing or, in severe cases, surgical correction.

Key Points to Consider

• Arch strain can lead to pes planus due to the weakening of the posterior tibial tendon, plantar fascia, and spring ligament 1.
• Appropriate footwear with arch support and orthotics can help reduce strain on the arch and prevent the development of pes planus 1.
• Weight management, activity modification, and strengthening exercises for the intrinsic foot muscles and posterior tibial tendon are also important for preventing pes planus 1.
• Physical therapy focusing on foot and ankle exercises can help reinforce the arch structure and prevent the progression of pes planus 1.
• Early intervention is crucial in preventing the progression of pes planus and reducing the risk of more severe complications 1.

Recommendations for Management

• Use appropriate footwear with arch support and orthotics to reduce strain on the arch and prevent the development of pes planus 1.
• Modify activities to reduce high-impact stress on the arch and promote weight management 1.
• Strengthen the intrinsic foot muscles and posterior tibial tendon through exercises and physical therapy to reinforce the arch structure 1.
• Monitor and manage foot health regularly to prevent the progression of pes planus and reduce the risk of more severe complications 1.

From the Research

Arch Strain and Pes Planus

• Arch strain is not directly mentioned as a risk factor for pes planus (flat foot) in the provided studies 2, 3, 4, 5, 6.
• However, the studies suggest that factors such as posterior tibial tendon dysfunction, obesity, and ligamentous laxity can contribute to the development of pes planus 2, 5.
• Weakness of the muscular, ligamentous, or bony arch supporting structures can also lead to collapse of the arch, resulting in pes planus 5.
• The use of arch-support insoles has been shown to provide benefits for individuals with flatfoot, including shortened stance time and more evenly distributed contact areas across the midfoot 4.
• Custom foot orthoses have been found to reduce motion of the medial longitudinal arch and alter the position of the foot during weightbearing, which may be beneficial for individuals with pes planus 6.

Biomechanics and Pathophysiology

• The foot's normal structural support can be altered by an imbalance in the forces that tend to flatten the arch and those that support the arch, leading to loss of the medial longitudinal arch 5.
• The main factors that contribute to an acquired flat foot deformity are excessive tension in the triceps surae, obesity, PTT dysfunction, or ligamentous laxity in the spring ligament, plantar fascia, or other supporting plantar ligaments 5.
• Treatment of the adult acquired flat foot is often difficult, and the clinician should remember the biomechanics of the normal arch and respond with a treatment that strengthens the supporting structures of the arch or weakens the arch-flattening effects on the arch 5.