PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Synonyms: hallux abductovalgus, bunion
The problem is lateral deviation of the great toe so as to put a valgus deformity on the first metatarsophalangeal (MTP) joint. A deviation of 15-20° is considered abnormal. This deviation upsets the biomechanics of the foot. It may cause subluxation of the first MTP joint and the great toe may even overlap the second toe.
Lateral subluxation produces a prominence on the metatarsal head (bunion) often followed by the development of a fluid-filled bursa. This becomes painful as it rubs against the shoe.
It is helpful to consider this, as correction of the biomechanical factors may prevent excessive pronation and progression of the deformity:
- When walking, the hallux and digits stay parallel to the long axis of the foot. This is true generally regardless of how pronated or abducted the forefoot is.
- The pull of the conjoined adductor tendon, extensor hallucis longus, and flexor hallucis longus tendons ensures that the hallux and digits remain parallel.
- Displacement of the joint gives the tendons mechanical advantage and this displaces the joint further. As this occurs, tension is created on the medial aspect of the joint (with compression laterally).
- Medial tension causes ligaments to pull and cause the bone to proliferate on the dorsomedial aspect of the first metatarsal head.
- Lateral tension causes the sesamoid apparatus to stick in a dislocated position laterally.
- Remodelling occurs laterally and medially and this affects joint cartilage.
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- Bunions are common but the exact prevalence of bunions is unknown.
- There is often a significant family history.
- Women are more often affected than men.
- The incidence and prevalence is lower in children and increases with age.
Because the risk factors affect both feet, the condition is usually bilateral, although it may be more marked on one side than the other.
- Footwear affects the incidence of hallux valgus:
- The incidence is lower in adults who do not wear shoes. However, this does not mean that the footwear causes the condition.
- Tight shoes can cause pain and nerve entrapment in association with hallux valgus. Fashionable shoes can be too tight and too narrow, to 'flatter the foot'.
- High heels force the foot down into the shoe and this further aggravates the problem. However, it is worth noting that footwear problems are not limited to the dedicated followers of fashion.
- A study from Australia found that old people often wear tight and inappropriate footwear, especially older women.
- There is higher incidence of hallux valgus in women. Footwear may account for this.
- Dancers put a great deal of stress through the first MTP joint but it is unlikely that dancing causes bunions.
- There is also a higher incidence recorded in rock climbers.
There are specific causes of biomechanical instability, including neuromuscular conditions. It may be associated with arthritis of various forms. These associated diseases include:
- Rheumatoid arthritis.
- Psoriatic arthropathy.
- Joint hypermobility with conditions such as Ehlers-Danlos syndrome, Marfan's syndrome, Down's syndrome and ligamentous laxity.
- Multiple sclerosis.
- Charcot-Marie-Tooth syndrome.
- Cerebral palsy.
Presentation is usually as a result of pain, although the condition is also unsightly. Pain is usually progressive and may have been present for many years. The frequency or duration of pain may have recently started to increase, and activity may exacerbate the pain.
- A patient may present with a deep or sharp pain in the hallux MTP joint on walking, and exacerbation during particular activities. This suggests degeneration of the intra-articular cartilage.
- There may be an aching pain in the metatarsal head due to irritation by shoes. There may be a recent increase in the size of the deformity or medial bump.
- Ask about limitation of physical or daily living activities to understand the severity of the pain. Ask what relieves the pain. It may be simply removing shoes.
- There may be a history of trauma or inflammatory arthritis.
- A rarer presentation is burning pain or tingling in the dorsal aspect of the bunion, which indicates entrapment neuritis of the medial dorsal cutaneous nerve.
- The patient may also describe symptoms caused by the deformity, such as a painful overlapping second toe, interdigital keratosis, or ulceration to the medial metatarsal head, without complaint of the bunion deformity.
Examine the foot whilst bearing weight, although much of the examination will have to be performed whilst not weight bearing. Watch the patient walk. This will indicate the degree of pain and difficulty that the problem causes and abnormal gait may point to a contributory factor or be the result of the condition.
- Note the position of the hallux relative to the other toes. It may be overriding, under-riding or abutting the next toe. Distortion of the joint may occur in more than one plane.
- Note the medial prominence of the joint. Erythema or bursa indicates pressure from shoes and irritation.
- Note the range of movement of the hallux MTP joint. Normal dorsiflexion is 65-75° with plantar flexion less than 15°. Note if pain, crepitation, or both are present. Pain without crepitation suggests synovitis.
- Note any keratosis that suggests abnormal friction from abnormal gait.
- Associated deformities may include second digit hammertoes and flexible or rigid flat foot. Instability of the second digit may allow a more rapid progression of hallux valgus, as it is unable to act as an adequate lateral buttress.
- With the patient standing note any:
- Increase of hallux abduction in the transverse and frontal planes.
- Increase in medial prominence.
- Change in dorsiflexion of the joint.
Also, note the general condition of skin and peripheral pulses. If surgery it to be contemplated it is imperative that peripheral blood flow be adequate for healing.
X-ray will show the degree of deformity and may indicate subluxation of the joint.
In an elderly patient in whom an operation is considered, routine investigations are required to assess suitability for operation.
Patients should be given appropriate information and advice about hallux valgus. Advice should include the following:
- Wear appropriate shoes (low, wide-fitting shoes).
- Wear shoes with laces or an adjustable strap.
- Avoid tight-fitting shoes.
- Understand that bunions are progressive and that non-surgical treatments alleviate symptoms but do not limit progression.
- The most important indication for surgery is pain, not deformity, although there will often be concern about the appearance of the deformed joint.
Analgesics, including non-steroidal anti-inflammatory drugs, may reduce pain and make the condition more bearable.
A steroid injection into the joint may give some relief of pain and inflammation.
Nondrug conservative treatment
There is no evidence of long-term benefit from physiotherapy.
Orthotics may provide some relief by tending to correct some of the other associated deformities.
The result of conservative management is so poor that surgery may be an attractive option. Surgery may be delayed without an adverse effect on the final outcome, although pain and patient satisfaction are improved with early operation.
Indications for surgery:
- A painful joint.
- Deformity of the joint complex.
- Pain or difficulty with footwear, inhibition of activity or lifestyle, and associated foot disorders that can be caused by this condition.
Associated foot disorders include:
- Neuritis or nerve entrapment.
- Overlapping or underlapping an adjacent toe.
- Hammer toes.
- Hallux metatarsocuneiform joint exostosis.
- Inflammatory conditions, such as bursitis or tendonitis of the first metatarsal head.
Contra-indications to surgery:
- Peripheral arterial disease.
- Active infection.
- Active osteoarthropathy.
- Septic arthritis.
- Lack of pain or deformity.
- Lack of compliance.
- Age alone should not be seen as a contra-indication but it is often associated with other significant medical conditions.
- Other disease, especially of the cardiovascular or respiratory system, that puts the patient at risk during the procedure.
Operative options: there are a large number of surgical options and the choice of procedure will depend upon the precise nature of the problem. It is usually a combination of bone and soft tissue surgery.
The simplest is the removal of the bony prominence (exostectomy). Alternatively, Keller's arthroplasty involves creating a flexible joint by excision of the medial eminence of the metatarsal head together with some of the proximal phalanx. Arthrodesis of the joint may be considered. Replacement of the joint for hallux valgus or hallux rigidus is a more recent option. The National Institute for Health and Care Excellence (NICE) has given the procedure a cautious welcome.
Arthroscopy is rarely indicated in this joint and less invasive arthroscopic surgery is unlikely to be helpful for hallux valgus. NICE guidance on minimal access techniques acknowledges that less invasive techniques may be attractive to patients but need further evaluation.
Complications include delayed healing of the incision, osseous malunion or non-union, nerve damage, haematoma, failure of a prosthesis, displacement of the osteotomy, delayed suture reaction, cellulitis, osteomyelitis, avascular necrosis, limitation of joint motion, hallux varus, and recurrence.
In addition to this are the risks associated with all surgery, especially if the patient is elderly. This includes venous thromboembolism.
The outlook is highly variable, as is that of the patients who are treated. Hence there is a shortage of adequate trials to compare the outcomes of the various forms of treatment. A Cochrane review found very little good evidence on which to assess either conservative or operative treatments.
Correction of the biomechanical factors may prevent excessive pronation and progression of the deformity. Judicious footwear may help prevent progression in some, but not all, cases.
Further reading & references
- Metatarsophalangeal joint replacement of the hallux; NICE Clinical Guideline (2005)
- Hallux Valgus and Bunion Surgery; Wheeless' Textbook of Orthopaedics
- Perera AM, Mason L, Stephens MM; The pathogenesis of hallux valgus. J Bone Joint Surg Am. 2011 Sep 7;93(17):1650-61. doi: 10.2106/JBJS.H.01630.
- Menz HB, Morris ME; Footwear characteristics and foot problems in older people. Gerontology. 2005 Sep-Oct;51(5):346-51.
- Kennedy JG, Collumbier JA; Bunions in dancers. Clin Sports Med. 2008 Apr;27(2):321-8. doi: 10.1016/j.csm.2007.12.004.
- Schoffl V, Kupper T; Feet injuries in rock climbers. World J Orthop. 2013 Oct 18;4(4):218-228.
- Bunions; NICE CKS, September 2012
- Torkki M, Malmivaara A, Seitsalo S, et al; Hallux valgus: immediate operation versus 1 year of waiting with or without orthoses: a randomized controlled trial of 209 patients. Acta Orthop Scand. 2003 Apr;74(2):209-15.
- Debnath UK, Hemmady MV, Hariharan K; Indications for and technique of first metatarsophalangeal joint arthroscopy. Foot Ankle Int. 2006 Dec;27(12):1049-54.
- Surgical correction of hallux valgus using minimal access techniques; NICE Interventional Procedure Guideline (February 2010)
- Ferrari J, Higgins JP, Prior TD; Interventions for treating hallux valgus (abductovalgus) and bunions. Cochrane Database Syst Rev. 2004;(1):CD000964.
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Dr Richard Draper
Dr Colin Tidy
Dr John Cox