View source for Bunion

{{short description|Deformity characterized by lateral deviation of the big toe}}
{{Infobox medical condition (new)
| name            = Bunion
| synonyms        = Hallux abducto valgus, hallux valgus<ref name=Day2017/>
| image           = Hallux Valgus-Aspect pré op décharge.JPG
| caption         = 
| field           = [[Orthopedics]], [[podiatry]]
| symptoms        = Prominent, red, and painful joint at the base of the big toe<ref name=AO2016/>
| complications   = [[Bursitis]], [[arthritis]]<ref name=AO2016/>
| onset           = Gradual<ref name=AO2016/>
| duration        = 
| types           = 
| causes          = Unclear<ref name=Day2017/>
| risks           = Wearing overly tight shoes, [[high-heeled shoe]]s, family history, [[rheumatoid arthritis]]<ref name=AO2016/><ref name=Highheel2016/>
| diagnosis       = Based on symptoms, [[radiographs|X-rays]]<ref name=AO2016/>
| differential    = [[Osteoarthritis]], [[Freiberg's disease]], [[hallux rigidus]], [[Morton's neuroma]]<ref>{{cite book|last1=Ferri|first1=Fred F.|title=Ferri's Differential Diagnosis E-Book: A Practical Guide to the Differential Diagnosis of Symptoms, Signs, and Clinical Disorders|date=2010|publisher=Elsevier Health Sciences|isbn=978-0-323-08163-4|page=323|url=https://books.google.com/books?id=-WD_tbHZEFoC&pg=PA323|language=en}}</ref>
| prevention      = 
| treatment       = Proper [[shoes]], [[orthotics]], [[NSAIDs]], surgery<ref name=AO2016/>
| medication      = 
| prognosis       = 
| frequency       = ~23% of adults<ref name=Day2017/>
| deaths          = 
}}
<!-- Definition and symptoms -->

{{see also|Tailor's bunion}}

A '''bunion''', also known as '''hallux valgus''', is an outward deformity of the foot's [[metatarsophalangeal (MTP) joint]] which connects the [[big toe]] to the [[foot]].<ref name=AO2016>{{cite web|title=Bunions|url=http://orthoinfo.aaos.org/topic.cfm?topic=a00155|website=OrthoInfo - AAOS|access-date=8 November 2017|date=February 2016}}</ref> The rear tarsametatarsal joint that holds the metatarsal bone in a straight-ahead position weakens, and the metatarsal moves outward and rotates 90 degrees, bringing the sesamoids up against the adjacent toe. This results in the head of the metatarsal bulging outward while the big toe bends inward toward the other toes. The joint often becomes red and painful due to rubbing in a cramped shoe.<ref name=AO2016/> The onset of bunions is typically gradual.<ref name=AO2016/> Joint complications may include [[bursitis]] or [[arthritis]].<ref name=AO2016/> A similar condition of the little toe is referred to as a [[bunionette]].<ref name=AO2016/>

<!-- Treatment and epidemiology -->[[File:X-rays showing effect of bunion splints on angle of Hallux valgus in patients.jpg|thumb]]
Treatment may include proper shoes, [[orthotics]], or [[NSAIDs]].<ref name=AO2016/> If this is not effective for improving symptoms, surgery may be performed.<ref name=AO2016/> Since 2020, many new and highly effective surgical techniques for bunion correction have been developed. Bunions exist in about 23% of adults.<ref name=Day2017/> Females are affected more often than males.<ref name=AO2016/> Usual age of onset is between 20 and 50 years old.<ref name=Day2017/> The condition also becomes more common with age.<ref name=Day2017/> It was first clearly described in 1870.<ref name=Day2017/> Archaeologists have identified a high incidence of bunions in skeletons from 14th- and 15th-century England, coinciding with a fashion for pointy shoes.<ref>{{Cite web|last1=Dittmar|first1=Jenna|last2=Mitchell|first2=Piers|title=Fashion for pointy shoes unleashed a wave of bunions in medieval England|url=http://theconversation.com/fashion-for-pointy-shoes-unleashed-a-wave-of-bunions-in-medieval-england-162570|access-date=2021-06-28|website=The Conversation|date=11 June 2021 |language=en}}</ref><ref>{{Cite journal|date=2021-06-11|title=Fancy shoes and painful feet: Hallux valgus and fracture risk in medieval Cambridge, England|journal=International Journal of Paleopathology|language=en|doi=10.1016/j.ijpp.2021.04.012|issn=1879-9817|doi-access=free|last1=Dittmar|first1=Jenna M.|last2=Mitchell|first2=Piers D.|last3=Cessford|first3=Craig|last4=Inskip|first4=Sarah A.|last5=Robb|first5=John E.|volume=35 |pages=90–100 |pmid=34120868|pmc=8631459 }}</ref>

== Signs and symptoms ==
[[File:Bunion (cropped).png|thumb|left|Drawing of a bunion]]

Symptoms may include irritation of the skin around the bunion, and blisters may form more easily at the site. Pain may be worse when walking.

Bunions can lead to difficulties finding properly fitting footwear and may force a person to buy a larger size shoe to accommodate the width of the bunion. If the bunion deformity becomes severe enough, the foot can hurt in different places even without the constriction of shoes. It is then considered as being a mechanical function problem of the forefoot.

==Cause==
[[File:VerbildeteFusseNormaleFusse.gif|thumb|High heels are associated with developing bunions.<ref name=Highheel2016/>]]

The exact cause is unclear.<ref name=Day2017>{{cite book|last1=Dayton|first1=Paul D.|title=Evidence-Based Bunion Surgery: A Critical Examination of Current and Emerging Concepts and Techniques|date=2017|publisher=Springer|isbn=978-3-319-60315-5|pages=1–2|url=https://books.google.com/books?id=NK80DwAAQBAJ&pg=PA1|language=en}}</ref> It can be due to a combination of internal and external causes.<ref name=Bru2010/> Proposed factors include wearing overly tight [[shoes]], [[high-heeled shoe]]s, family history, and [[rheumatoid arthritis]].<ref name=AO2016/><ref name=Highheel2016>{{cite journal |last1=Barnish |first1=MS |last2=Barnish |first2=J |title=High-heeled shoes and musculoskeletal injuries: a narrative systematic review. |journal=BMJ Open |date=13 January 2016 |volume=6 |issue=1 |article-number=e010053 |doi=10.1136/bmjopen-2015-010053 |pmid=26769789|pmc=4735171 }}</ref> The American College of Foot and Ankle Surgeons states that footwear only worsens a problem caused by [[genetics]].<ref name=footphysicians>{{cite web |url=http://www.footphysicians.com/footankleinfo/bunions.htm |title=Bunions (Hallux Abducto Valgus) |publisher=Footphysicians.com |date=2009-12-18 |access-date=2011-03-20 |archive-date=2011-12-08 |archive-url=https://web.archive.org/web/20111208042651/http://www.footphysicians.com/footankleinfo/bunions.htm }}</ref> Diagnosis is based upon simple viewing of the foot, symptoms of pain, and by [[radiographs|X-rays]].<ref name=AO2016/> Excessive low arch to a flat foot inward ankle [[pronation of the foot]] also can cause increased pressure on the inside of the big toe that can result in a [[Deformity|deformation]] of the medial capsular structures of the joint subsequently increasing the risk of developing a bunion.<ref name=Bru2010>{{cite book |last1=Brukner |first1=Peter |title=Clinical sports medicine. |date=2010 |publisher=McGraw-Hill |isbn=978-0-07-027899-8 |page=667 |edition=3}}</ref><ref>{{cite journal |last1=Chou |first1=Loretta B. |title=Disorders of the First Metatarsophalangeal Joint |journal=The Physician and Sportsmedicine |date=19 June 2015 |volume=28 |issue=7 |pages=32–45 |doi=10.3810/psm.2000.07.1075|pmid=20086649|s2cid=21529142 }}</ref>

== Pathophysiology ==
The bump itself is due to the head of the metatarsal partly due to the swollen [[Synovial bursa|bursal sac]] or an osseous (bony) anomaly on the metatarsophalangeal joint. The larger part of the bump is a normal part of the head of the first metatarsal bone that has tilted sideways to stick out at its distal (far) end (metatarsus primus varus).

Bunions are commonly associated with a deviated position of the big toe toward the second toe, and the deviation in the angle between the first and second metatarsal bones of the foot.  The small [[sesamoid]] bones found beneath the first metatarsal (which help the flexor tendon bend the big toe downwards) may also become deviated over time as the first metatarsal bone drifts away from its normal position. [[Osteoarthritis]] of the first metatarsophalangeal joint, diminished or altered range of motion, and discomfort with pressure applied to the bump or with motion of the joint, may all accompany bunion development. Atop of the first metatarsal head either medially or dorso-medially, there can also arise a bursa that when inflamed ([[bursitis]]), can be the most painful aspect of the process.

==Diagnosis==
[[File:HV and IM angles of hallux valgus.jpg|thumb|100px|X-ray showing measurements of HV and IM angles of hallux valgus.]]

Bunions can be diagnosed and analyzed with a [[projectional radiography|simple x-ray]], which should be taken with the weight on the foot.<ref>[https://books.google.com/books?id=4btAAAAAQBAJ&pg=PA533 Page 533] in: {{cite book|title=Essentials of Orthopedic Surgery|author=Sam W. Wiesel, John N. Delahay|edition=3|publisher=Springer Science & Business Media|year=2007|isbn=978-0-387-38328-6}}</ref> The ''hallux valgus angle'' (HVA) is the angle between the long axes of the [[Phalanx bone|proximal phalanx]] and the first [[metatarsal bone]] of the big toe. It is considered abnormal if greater than 15–18°.<ref name=aofas>{{cite web|url=http://www.aofas.org/PRC/conditions/Pages/Conditions/Hallux-Valgus.aspx|title=Hallux Valgus|website=American Orthopaedic Foot & Ankle Society|access-date=2016-12-30|author=Rebecca Cerrato, Nicholas Cheney|archive-url=https://web.archive.org/web/20161230230959/http://www.aofas.org/PRC/conditions/Pages/Conditions/Hallux-Valgus.aspx|archive-date=2016-12-30}} Last reviewed June 2015</ref> The following HV angles can also be used to grade the severity of hallux valgus:<ref name="Piqué-VidalVila2009">{{cite journal|last1=Piqué-Vidal|first1=Carlos|last2=Vila|first2=Joan|title=A geometric analysis of hallux valgus: correlation with clinical assessment of severity|journal=Journal of Foot and Ankle Research|volume=2|issue=1|page=15|year=2009|issn=1757-1146|doi=10.1186/1757-1146-2-15|pmid=19442286|pmc=2694774 |doi-access=free }}</ref>{{medrs|date=November 2019}}

* Mild: 15–20°
* Moderate: 21–39°
* Severe: ≥ 40°

The ''intermetatarsal angle'' (IMA) is the angle between the longitudinal axes of the first and second metatarsal bones, and is normally less than 9°.<ref name=aofas/> The IM angle can also grade the severity of hallux valgus as:<ref name="Piqué-VidalVila2009"/>

* Mild: 9–11°
* Moderate: 12–17°
* Severe: ≥ 18°

== Treatment ==
Conservative treatment for bunions include changes in footwear, the use of [[orthotics]] (accommodative padding and shielding), rest, ice, and [[analgesic|pain medications]] such as [[acetaminophen]] or [[nonsteroidal anti-inflammatory drug]]s. These treatments address symptoms but do not correct the actual deformity.<ref name="Hecht2014">{{cite journal|last1=Hecht|first1=PJ|last2=Lin|first2=TJ|title=Hallux valgus|journal=[[Medical Clinics of North America]]|date=March 2014|volume=98|issue=2|pages=227–32|doi=10.1016/j.mcna.2013.10.007|pmid=24559871|type=Review}}</ref> If the discomfort persists and is severe or when aesthetic correction of the deformity is desired, surgical correction by an [[orthopedic surgeon]] or a [[podiatric]] [[surgeon]] may be necessary.

=== Orthotics ===
[[File:Pointe shoe toe spacers.jpg|thumb|Gel toe spacers come in a variety of sizes and shapes.]]

Orthotics are [[Splint (medicine)|splints]] or regulators while conservative measures include various footwear like toe spacers, [[Valgus deformity|valgus]] splints, and bunion shields. Toe spacers seem to be effective in reducing pain, but there is no evidence that any of these techniques reduces the physical deformity. There are a variety of available orthotics including off-the-shelf commercial products and custom-molded orthotics, which may be prescribed medical devices.<ref>{{cite journal |last1=Park |first1=CH |last2=Chang |first2=MC |title=Forefoot disorders and conservative treatment. |journal=Yeungnam University Journal of Medicine |date=May 2019 |volume=36 |issue=2 |pages=92–98 |doi=10.12701/yujm.2019.00185 |pmid=31620619|pmc=6784640 }} (see Figure Two for images of orthotics)</ref>

=== Surgery ===
Procedures are designed and chosen to correct a variety of pathologies that may be associated with the bunion.  For instance, procedures may address some combination of:

* removing the abnormal bony enlargement of the first [[metatarsal]],
* realigning the first metatarsal bone relative to the adjacent metatarsal bone,
* straightening the great toe relative to the first metatarsal and adjacent toes,
* realigning the cartilaginous surfaces of the great toe joint,
* addressing [[arthritis|arthritic]] changes associated with the great toe joint,
* repositioning the [[sesamoid bones]] beneath the first metatarsal bone,
* shortening, lengthening, raising, or lowering the first metatarsal bone,
* correcting any abnormal bowing or misalignment within the great toe,
* connecting two parallel long bones side by side by [[syndesmosis procedure]]
[[File:Bunionplasty Plastic Closure.jpg|thumb|Before and after effects of bunionplasty]]
At present there are many different bunion surgeries for different effects.  The age, health, lifestyle and activity level of the patient may also play a role in the choice of procedure.

Traditional bunion surgery can be performed under local, spinal or general [[anesthetic]].  A person who has undergone bunion surgery can expect a 6- to 8-week recovery period during which [[crutches]] are usually required to aid mobility.  An [[orthopedic cast]] is much less common today as newer, more stable procedures and better forms of fixation (stabilizing the bone with screws and other hardware) are used.  Hardware may even include absorbable pins that perform their function and are then broken down by the body over the course of months. After recovery long term stiffness or limited range of motion may occur in some patients. Visible or limited scarring may also occur for patients.

[[File:Bunionectomy.png|thumb|center|Bunionectomy]]

== References ==
{{Reflist}}

== External links ==
{{Commons category|Bunion}}
{{Wiktionary}}
* ''[https://www.kent.edu/cpm/textbook-hallux-valgus-forefoot-surgery Textbook of Hallux Valgus and Forefoot Surgery]'', links to complete text in PDF files

{{Medical resources
|   DiseasesDB     = 5604
|   ICD11          = {{ICD11|FA30.0}}, {{ICD11|LB98.20}}
|   ICD10          = {{ICD10|M|20|1|m|20}} 
|   ICD9           = {{ICD9|727.1}} 
|   ICDO           = 
|   OMIM           = 
|   MedlinePlus    = 001231
|   eMedicineSubj  = orthoped
|   eMedicineTopic = 467
|   MeshID         = D006215 
}}
{{Acquired deformities}}
{{Authority control}}

[[Category:Foot diseases]]
[[Category:Skeletal disorders]]
[[Category:Wikipedia medicine articles ready to translate]]