This abnormal positioning, known broadly as a digital deformity, is a progressive condition that changes the structural alignment of the small bones in the foot. These changes are often subtle at first, but they can make wearing shoes uncomfortable and lead to secondary issues like painful corns and calluses.
Classifying Curled Toes: Hammer, Claw, and Mallet
Curled toes are categorized based on which of the toe’s three joints is affected by the bending or contracture: the metatarsophalangeal (MTP) joint at the base, the proximal interphalangeal (PIP) joint in the middle, and the distal interphalangeal (DIP) joint closest to the toenail.
A hammer toe involves a bend at the middle joint, the PIP joint, causing the toe to buckle with the tip pointing down. This condition most frequently affects the second toe, especially if it is longer than the big toe.
In contrast, a mallet toe is characterized by a contracture solely at the DIP joint, the one nearest the tip of the toe.
The third type, a claw toe, presents as a more complex deformity involving two bends simultaneously. The MTP joint at the base bends upward, while both the PIP and DIP joints bend downward, creating a claw-like appearance. Claw toes often affect all four smaller toes and are more likely linked to nerve or systemic issues rather than just mechanical factors.
Mechanical Stressors and Poorly Fitting Footwear
External pressure and internal biomechanical imbalances are primary causes of curled toes. Footwear that is too tight, too short, or pointed in the toe box forces the toes into a cramped, bent position. Over time, this constant pressure causes the muscles, tendons, and ligaments that keep the toe straight to shorten and tighten, making the deformity permanent.
High-heeled shoes intensify this mechanical stress by forcing the foot forward and shifting the entire body weight onto the forefoot and toes. This action not only compresses the toes but also hyperextends the MTP joint, leading to a muscle imbalance where the flexor tendons overpower the extensors. The repeated constriction and unnatural positioning gradually lead to structural changes in the toe joints.
Internal biomechanical factors also play a significant role. A muscle or tendon imbalance in the foot can cause a tug-of-war effect, pulling the toes into a contracted position. Conditions such as a bunion, where the big toe shifts inward, reduce space and push adjacent toes out of alignment, often leading to a secondary hammer toe. Furthermore, structural foot issues like very high arches (pes cavus) can predispose an individual to claw toe, as the foot shape creates an inherent imbalance in the toe-controlling muscles.
Systemic Diseases and Neurological Causes
When curled toes affect multiple toes and become rigid early on, the cause often lies in an underlying systemic or neurological condition that disrupts muscle control. The primary mechanism is peripheral neuropathy, which is nerve damage that weakens the small intrinsic muscles of the foot. As these small muscles weaken, the longer, stronger muscles in the leg and foot pull the toes into a contracted position.
Diabetes is a frequent contributor, as high blood sugar levels can lead to nerve damage, or neuropathy, in the feet. This loss of nerve function results in an inability to properly flex and extend the toes, causing them to curl. The resulting claw toe deformity, combined with reduced sensation, also increases the risk of corns and skin ulcers from friction.
Inflammatory and autoimmune diseases, particularly Rheumatoid Arthritis (RA), can directly damage the toe joints and surrounding connective tissues, leading to structural instability and permanent deformities. Similarly, neurological disorders like Charcot-Marie-Tooth (CMT) disease, stroke, or cerebral palsy can disrupt the nerve signals to the foot muscles, causing severe imbalances and spasticity that result in a fixed toe contracture.
Non-Surgical and Surgical Correction Options
Treatment for curled toes depends heavily on the stage of the deformity—whether it is flexible or rigid. A flexible deformity can still be manually straightened, while a rigid one is fixed in its bent position due to permanent joint and tendon changes. For flexible toes, non-surgical approaches are the first line of defense aimed at relieving symptoms and preventing progression.
Conservative management begins with modifying footwear to eliminate pressure. Switching to shoes with a deep, wide toe box is recommended to give the toes ample room to lie flat. Other non-surgical options include using soft padding, toe crests, or custom orthotics to reposition the foot and provide support, which helps correct muscle imbalance. Physical therapy exercises, such as stretching and strengthening movements, are also employed to restore flexibility to the tightened tendons and joints.
If the deformity is rigid, severely painful, or unresponsive to conservative care, surgical correction may be necessary. Procedures often involve releasing or lengthening the tight tendons (tenotomy) to allow the toe to straighten. For more severe, fixed contractures, an orthopedic surgeon may perform a joint resection or arthroplasty, removing a small piece of bone from the affected joint to permanently straighten the toe.