Are metatarsalgia, hallux valgus, and hallux rigidus related?

Are Metatarsalgia, Hallux Valgus, and Hallux Rigidus Related?

Yes, these three conditions are biomechanically interconnected, with hallux valgus and hallux rigidus both serving as causative factors for metatarsalgia through first ray insufficiency and altered weight distribution across the forefoot.

Biomechanical Relationship

Hallux Valgus Leading to Metatarsalgia

The lateral deviation of the hallux in hallux valgus creates mechanical overload of the second and lesser metatarsals, directly causing transfer metatarsalgia. 1

• As hallux valgus severity increases, the first ray becomes functionally insufficient, forcing abnormal weight transfer to the central metatarsals 1
• Hallux valgus is characterized by valgus deviation of the big toe and varus deviation of the first metatarsal (metatarsus primus varus), which disrupts normal forefoot mechanics 2
• The deformity often coexists with hammertoe deformity and pes planus, both of which further contribute to abnormal plantar pressure distribution 3

Hallux Rigidus Leading to Metatarsalgia

Hallux rigidus causes metatarsalgia through loss of first metatarsophalangeal joint dorsiflexion, which prevents normal weight-bearing through the first ray during gait. 4

• The degenerative changes and stiffness in the first MTP joint limit the hallux's ability to bear weight during push-off 4
• First ray instability and hindfoot valgus increase stress on the medial side of the MTP joint, promoting both hallux rigidus development and subsequent metatarsalgia 5
• Forefoot hypermobility during propulsion phase promotes MTP joint instability and increases pain, creating a cycle of dysfunction 5

Coexistence of Conditions

A combination of hallux valgus and hallux rigidus is not uncommon, and both can simultaneously contribute to metatarsalgia. 2

• Physical examination and imaging are essential to differentiate between hallux valgus and hallux rigidus, as treatment approaches differ 2
• Hallux rigidus is the second most common cause of pain in the first MTP joint after hallux valgus 2

Critical Treatment Consideration

When treating hallux valgus or hallux rigidus surgically, it is imperative not to overshorten the first ray, as this will worsen or create transfer metatarsalgia. 1

• Excessive first ray shortening during corrective surgery eliminates the first metatarsal's weight-bearing capacity 1
• This iatrogenic first ray insufficiency forces even greater mechanical overload onto the lesser metatarsals 1

Management Implications for Diabetic Patients

For patients with diabetes who develop metatarsalgia secondary to hallux valgus or hallux rigidus, specific footwear modifications are essential:

• People with bony deformities including prominent metatarsal heads and bunions require extra-wide or depth shoes 6
• Custom-molded shoes may be necessary for extreme deformities that cannot be accommodated with commercial therapeutic footwear 6
• Well-fitted walking shoes or athletic shoes that cushion the feet and redistribute pressure are adequate for patients with evidence of increased plantar pressure 6
• Metatarsal pads placed behind the metatarsal heads can relieve focal pressure and transfer load more proximally 7

Surgical Options When Conservative Treatment Fails

For diabetic patients with neuropathic plantar metatarsal ulcers secondary to these deformities:

• Metatarsal head resection combined with an offloading device is conditionally recommended when non-surgical offloading fails 6
• Joint arthroplasty combined with a non-removable offloading device may be beneficial for hallux ulcers with limited range of motion of the first MTP joint 6
• Achilles tendon lengthening is indicated when equinus position of the foot coexists with metatarsal head ulceration 6