A hammertoe is a common foot deformity where a toe takes on an abnormal, bent shape, often leading to discomfort and difficulty wearing shoes. This condition is characterized by an imbalance in the muscles, tendons, and ligaments that typically hold the toe straight. Understanding the interplay between inherited foot mechanics and acquired stresses is necessary to determine the risk and the best approach for management.
Anatomy and Appearance of a Hammertoe
A hammertoe is defined by a bend in the middle joint of the toe, known as the proximal interphalangeal (PIP) joint. This unnatural flexion causes the toe to look like an inverted ‘V’ or a hammer. While it can affect any lesser toe, the second, third, or fourth toes are most commonly involved.
The physical manifestation of this bend creates a raised prominence on the top of the toe, which frequently rubs against the inside of footwear. This constant friction leads to the development of painful calluses or corns directly over the affected joint. In the early stages, the toe is considered a flexible hammertoe because it can still be manually straightened. Over time, the muscles and tendons tighten, causing the joint to become rigid and permanently fixed in the bent position, often accompanied by pain and swelling.
The Direct Role of Genetics
While no single “hammertoe gene” has been identified, the condition has a significant hereditary component rooted in inherited foot structure and biomechanics. The shape of a person’s foot, including the length of the toes and the height of the arch, can be passed down through families, predisposing them to the deformity. For instance, having a second toe that is noticeably longer than the big toe, a common inherited trait, means that toe is more likely to be forced into a flexed position by shoes that are too short.
Inherited structural characteristics like a high arch (pes cavus) or a flat foot (pes planus) alter the distribution of weight and stress across the forefoot. This abnormal weight bearing can lead to an intrinsic muscle imbalance in the foot, where one group of muscles overpowers the other, pulling the toe into the curled position. Estimates suggest that up to 60% of foot conditions, including hammertoes, may have some form of genetic influence through these structural factors. Therefore, if a close relative has developed a hammertoe, the risk is higher due to a shared foundational foot architecture that is more vulnerable to external pressures.
Mechanical and Lifestyle Contributors
Even with a genetic predisposition, external forces and lifestyle choices play a substantial role in the development and progression of hammertoes. The most frequently cited non-inherited cause is habitually wearing ill-fitting footwear, particularly shoes with a narrow toe box or high heels. These types of shoes force the toes into a cramped, bent position, which, over time, causes the muscles and tendons to permanently shorten and tighten in that flexed state. High-heeled shoes are especially problematic because they push the foot forward, jamming the toes against the front of the shoe and significantly increasing pressure on the toe joints.
Beyond footwear, acute trauma to the toe, such as a severe stub or a fracture, can disrupt the balance of the tendons and muscles, leading to the development of a hammertoe. The condition can arise as a secondary complication of various underlying medical issues that affect muscle control and joint integrity. Conditions like diabetes, which can cause nerve damage (peripheral neuropathy), may result in muscle weakness and imbalance that contributes to the deformity. Inflammatory joint diseases, such as rheumatoid arthritis, also cause joint destruction and instability in the foot, which can directly lead to a hammertoe deformity.
Treatment and Prevention Strategies
Addressing a hammertoe often begins with conservative management, especially when the deformity is still flexible. The most effective first step involves switching to shoes that feature a wide, deep toe box and low heels to eliminate the external pressure that aggravates the condition. Using protective padding or specialized toe crest pads can cushion the joint and reduce the painful friction against the shoe.
Custom-made orthotic inserts are frequently prescribed to correct underlying foot mechanics, such as excessive pronation or arch issues. These inserts help redistribute weight and relieve tension on the toes. Specific toe exercises, like picking up marbles or scrunching a towel, can help stretch the contracted tendons and strengthen the intrinsic foot muscles to maintain flexibility. If the hammertoe becomes rigid, or if conservative treatments fail to relieve pain, surgical correction may be necessary to restore proper alignment, involving procedures like tendon lengthening or fusing the affected joint.