What is a bunion or hallux valgus?

Hallux valgus is a deformity that causes a bunion on the foot. But what is a bunion exactly and what does hallux valgus mean? How does it progress over time? EPITACT^® helps you know this foot deformity better: definition, stages, symptoms, consequences and foot care solutions.

What is hallux valgus deformity? What does hallux valgus mean?

The medical term for a bunion is hallux valgus. This word is derived from Latin. ‘Hallux’ means ‘big toe’ and ‘valgus‘ indicates an outward direction. Literally, this condition is a deviation of the big toe outwards (towards the other toes). It is combined with the deviation of the 1st metatarsal inwards (towards the other foot).

What is a bunion?

Hallux valgus is a deformity that causes a bump at the lateral base of the big toe⁽¹⁾, usually called 'bunion'. Indeed, this bony protrusion that juts out on the side of the big toe corresponds to the first metatarsal head. As the big toe drifts outwards and the first metatarsal drifts inwards, the joint between these two bones forms an angle. This angle can give more information about the stage of the deformity.

The different stages of a bunion

allux valgus is permanent and the deformity continues to worsen if it is not treated. The progression of the hallux valgus deformity is classified in 4 stages, according to the angle between the first metatarsal bone and the big toe.

How is it diagnosed?

An x-ray imaging or a simple visual assessment during the clinical exam can confirm what is the bunion stage. The radiographic diagnosis is based on two images:

• a front image showing the middle metatarsal bones;
• a side image showing the foot section on its inner side.

Visual assessment allows to measure the angle of the deviation using the “Manchester scale”. This scale draws four levels: zero level, lower level, middle level or severe level^{(3, 4)}. These four distinctions have an indicative value and may vary according to the authors of the science papers^{(1, 2)}. Note that two measures are needed:

• the angle between the big toe and the first metatarsal;
• the angle between the first and second metatarsals.

What is a bunion at a zero level?

The level zero corresponds to a ‘normal foot’. The angle between the 1st metatarsal and the big toe as well as between the 1st and 2nd metatarsals is maximum 10 degrees.

What is a mild hallux valgus deformity (lower level)?

The lower level of a bunion shows an angle of deviation between the 1st metatarsal and the 1st phalanx (MTP1) of 11 to 20 degrees and an angle of 12 degrees between the 1st and the 2nd metatarsal (M1M2). At this stage, the shoes put pressure and create rubbing against the bunion. Inflammation may occur (reddened skin).

Wearing a foot bunion corrector* during the day can contribute to reducing pain while it corrects the deviation. Moreover, there is no or little weight transfer onto the second toe at this level. The pain is not precise and the bump is still quite invisible. Compression of the medial cutaneous nerve against the shoe can also lead to pain.

What is the middle level or moderate bunion meaning?

Moderate hallux valgus presents an angle MTP1 between 20 and 40 degrees and an angle M1M2 of 15 to 18 degrees. The phalanx does not articulate correctly against the metatarsal, it is blocked by the deviation. The lateral weight transfer brings pain under the second metatarsal head, as it is hindered in its usual supporting function.

It is the deformity of the joint that causes pain in the sole of the foot. The bunion grows and brings painful friction with shoes. Few possibilities exist to reduce this already large protrusion and osteoarthritis symptoms may appear next to the joint when walking.

What is a severe bunion or hallux valgus?

Hallux valgus is defined as severe when the MTP1 angle is larger than 40 degrees and the M1M2 angle is over 20 degrees. As a consequence of its very severe deviation, the big toe is deviated under the second toe. The joint is completely flattened, leading to its entire luxation in most critical situations.

The deviation of the second toe is so large that the foot sole is now deformed. At this stage, the subluxation or even the complete luxation of the first phalanx from the second phalanx can be easily identified through manual testing when one can notice a deformity similar to a small step.

What other problems can cause hallux valgus or bunions?

People who develop bunions can have additional deformities and problems.

Claw toes and hammer toes

The most commonly known are called claw toes and usually affect the second toe. This kind of deformity more often appears at an advanced stage of hallux valgus.

The toe looks like a claw as it is bent over itself. As a result, the joint rubs against the shoe and corns appear upon the proximal interphalangeal joint. This makes it really hard to wear tight shoes and create sharp pain. Hard corns on the end of the toes can also appear.

Metatarsalgia and calluses

The role of the joint between the big toe and the head of the first metatarsal is to give support to the first ray of the foot (big toe + first metatarsal). As it is no longer aligned, it does not operate its function properly and the big toe can’t bear its part of the body weight. As a consequence, this load is transferred to the other toes and leads to metatarsalgia.

Metatarsalgia slowly develops at the middle toes and causes ball of the foot pain. This is coming in addition to the pain caused by frictions between the bunion and the shoes. According to the stage of hallux valgus deformity, the recurrent pressure over the head of the four other metatarsals may cause calluses⁽²⁾.

Joint problems

The progression of a bunion forces the joints to offset the defect pressure holding points in order to maintain an approximate stability. In practical terms, painful repercussions may be felt in the knees or in the lumbar belt. The hallux valgus deformity may be relieved from pain as another joint would start aching. Then it becomes necessary to examine the whole body to analyse the personal locomotion biomechanical process. As feet make the connection between the body and the ground, its biomechanical function has effects on the other biomechanical chains of the body.

What are the bunion symptoms?

The first symptom of hallux valgus is a throbbing ache in the first metatarsophalangeal joint. This is often due to the first distortions of the joint coming into friction with the shoe (reddened and wounded skin). A compression of the medial nerve against a bone, the soft parts of the foot and shoes, could even generate additional pain.

Later, a metatarsalgia combined with the transfer of weight creates additional specific pain areas. As the second toe is forced to a 'claw' position, it will be hardly bearable in normal shoes and the regular friction causes hard corns on the proximal interphalangeal joint⁽⁵⁾. These uncomfortable symptoms encourage the patient to see a medical specialist in search of pain relief, improvement of his locomotion function or even just to erase cosmetic inconvenience.

The EPITACT^® solutions for relieving hallux valgus and bunions

EPITACT^®, specialist for foot care, has designed various medical devices for hallux valgus*:

• A bunion splint for night use* that corrects the deformity and limits its progression. It is heat-moldable so that it adapts to your own foot shape for optimal comfort.
• A bunion corrector for day use* you can wear in your shoes that realign your big toe while relieving you.
• A bunion protector* that is very thin that fits any type of shoes. It is usually recommended for advanced bunions to protect it from the shoe.

The earlier the condition is managed, the less invasive and radical are the treatments. Preventive solutions contribute to defer the emergence of the hallux valgus and to slow down its development. Now you know everything about the most frequent foot deformity: what is a bunion, what is hallux valgus and how to recognise their stage. EPITACT^® suggests further articles about how to choose shoes that fit well and about bunion surgery.

*These solutions are class I medical devices that bear the CE marking under this regulation. Carefully read the instructions before use. Manufacturer: Millet Innovation. 01/2021

For more details about this general and simplified approach, here are further sources:

⁽¹⁾Vanore JV, Christensen JC, Kravitz SR, Schuberth JM, Thomas JL, Weil LS, et al. Diagnosis and treatment of First Metatarsophalangeal Joint Disorders. Section 1: Hallux valgus . The Journal of Foot and Ankle Surgery. Mai 2003; 42(3):112‑23.

⁽²⁾Baudet B. "Traitement de l'hallux valgus " in Thibaut Leemrijse, Jean-Luc Besse, Bernhard Devos Bevernage, Bernard Valtin "Pathologie du pied et de la cheville", Paris, Elsevier Masson. Vol. 1. 2009, p 102-106.

⁽³⁾Garrow AP, Papageorgiou A, Silman AJ, Thomas E, Jayson MIV, Macfarlane GJ. The Grading of Hallux Valgus: The Manchester Scale. Journal of the American Podiatric Medical Association. févr 2001; 91(2):74

⁽⁴⁾Menz HB, Munteanu SE. Radiographic validation of the Manchester scale for the classification of hallux valgus deformity. Rheumatology. 1 août 2005;44(8):1061

⁽⁵⁾Curvale G, Rocheweger A, Piclet-Legre B. Hallux valgus . Podologie. 1999; 27-080-A-30: p 6.