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The introduction of minimally invasive bunion surgery or percutaneous bunion surgery with keyhole incisions has led to increased patient satisfaction due to reduced postoperative pain and immediate weightbearing. However, do all bunions require surgical intervention? Learn about the role of the primary care physician in the conservative management of bunions, indications for referral and new advancements in minimally invasive bunion surgery.
A bunion, also known as hallux valgus, is a common deformity in the forefoot characterised by lateral deviation and a bump over the base of the big toe.
Aetiology
Bunions form due to the abnormal balance of forces exerted on the joints and tendons across the big toe. The disruption of the balance of forces can lead to instability and over time, this abnormal motion and pressure can lead to deformity.
The exact aetiology of bunions is not well known. However, bunions can be caused and are associated with a variety of factors such as:
Genetic heredity
It is not uncommon to see a patient with bunions having the condition run across multiple generations of their family. However, it is not the bunion itself that is hereditary, but more of the foot type (shape and structure) that is passed down.
Footwear
Shoes with narrow toes can trigger a bunion as they force the big toe into deviation.
High heels can exacerbate the problem as the centre of gravity of the body is tipped forward, forcing the toes into the narrow toe box of the shoe.
Occupation
Occupations that involve a lot of standing and walking are susceptible to bunions.
Ballet dancers, whose feet suffer from repetitive stress, are also susceptible.
Neuromuscular disorders
Pes planus (flat foot) and generalised ligamentous laxity may contribute to juvenile bunions, whereby children may develop a bunion at a young age.
The symptoms of a bunion include:
Redness, pain or swelling over the first metatarsal phalangeal joint (MTPJ)
Stiffness or restricted range of motion over the big toe
Development of a callosity around the medial edge of base of the first MTPJ
Pain over the bases of the lesser toes, sometimes associated with callosity under the balls of the foot
Development of claw or hammertoe deformity over the lesser toes
20% of bunions are associated with the presence of pes planus
Non-invasive management measures include:
Non-steroidal anti-inflammatory drugs
Accommodative shoes with wide toe boxes
A wide tsoe box reduces pressure on the big toe and provides plenty of room for movement
Padding and cushioning over medial eminence
Wearing a bunion pad can keep the medial eminence from rubbing against the shoe
It serves as temporary relief and will not improve the appearance of the foot
Toe spacers and separators
Worn between the first and second toe, these act as inserts to prevent worsening lateral deviation of the big toe
Some patients experience more discomfort after wearing these toe spacers for a day as it forces the toe into a stretched position
The deformity returns once these devices are removed
Bunion braces and splints
These are usually worn at night to hold the toe straight
They do not slow down or stop the natural progression of the bunion
Orthotics – medial arch supports
These bunion treatments and remedies might help to slow the worsening and exacerbation of symptoms. However, there is no conservative treatment that will be able to correct or reverse the bunion deformity.
Referral to an orthopaedic specialist is recommended if the patient has a painful bunion and has exhausted all non-operative management.
Bunions can be progressive in nature and the deformity will not reverse itself without intervention.
However, surgery for bunions should never be done purely for cosmetic purposes. The condition should be impairing the patient's function and quality of life due to:
Pain over the bunion prominence,
Transfer metatarsalgia pain over the balls of the lesser toes, or
A wide forefoot or lesser toe deformity causing difficulty with footwear
Surgery for bunion correction is more difficult the more complex the deformity, especially if there is lesser toe involvement and deformity as well. Referral to a specialist to consider surgery can be made early once an attempt to relieve symptoms with conservative management has failed.
Surgical options for bunion surgery comprise traditional open surgery and minimally invasive surgery. The Foot and Ankle Service at Sengkang General Hospital is a strong advocate for offering 'keyhole' minimally invasive techniques, or percutaneous incisions, regarding the correction of bunion deformity.
Figure 1
In the minimally invasive method, multiple small keyhole incisions are made along the big toe, and bone-cutting or burr instruments are inserted to make an osteotomy cut to correct the deformity. Screws are inserted to maintain and stabilise the correction. (Figure 1)
A new minimal incision percutaneous method
A new minimal incision percutaneous method of minimally invasive surgery has recently been introduced. This involves making a 1.5cm to 2cm cut at the big toe. After the same distal metatarsal osteotomy cut is made with a burr or small saw, a plate is inserted to maintain the position of the newly aligned toe.
Figure 2
Figure 2 shows the clinical photos of a patient who had undergone this procedure six months post-surgery, along with the preoperative and postoperative radiographs. Lateral deviation of the great toe has been corrected with complete union at the osteotomy site.
Many patients are satisfied with this small scar which is indiscernible once it heals, as compared to multiple small incisions or the traditional 10cm to 15cm scar for open surgery.
Published local data suggests that minimally invasive bunion surgery is a safe and effective surgical option.1 Additionally, in a local study, Chong et al. showed that the percutaneous plate fixation method is a reasonable option for stabilisation in bunion correction surgery.2
Benefits of minimally invasive bunion surgery include:
Shorter recovery time
Surgery is usually done as a day surgery procedure, and patients are able to walk immediately following surgery.
The foot will be kept in a bandage for two weeks, and the patient will be walking on a cushioned shoe for the first four weeks.
The patient can then transit to normal footwear after four weeks, and return to sports after three months.
Less postoperative pain and swelling during recovery
Less postoperative analgesic requirements
Lower wound complication rate
Minimal scarring or keloid formation
Bunions are a common forefoot condition. It is progressive in nature and can result in a painful deformity at the big toe with lesser toe involvement.
Non-operative treatment largely involves analgesia, a modification of footwear, insoles and orthotics.
Early referral to an orthopaedic surgeon is appropriate once the patient has exhausted all forms of conservative management.
Pain relief and optimisation of function are the primary goals of surgery. Minimally invasive surgery or minimal incision percutaneous bunion surgery is an excellent option with proven results of a quicker recovery and return to function.
Two year outcomes of minimally invasive hallux valgus surgery. Chan et al. Foot Ankle Surg. 2019 Apr;25(2):119-126
Early radiographic outcomes of minimally invasive distal metatarsal osteotomies with the spear plate in asian patients for hallux valgus correction. Journal of foot and ankle surgery (Asia-Pacific) (2023): 10.5005/jp-journals-10040-1326
Dr Png Wenxian is a Consultant with the Department of Orthopaedic Surgery at Sengkang General Hospital. He was awarded the Health Manpower Development Plan (HMDP) Scholarship from the Ministry of Health to pursue sub-specialty training in foot and ankle deformity surgery. He also completed a fellowship in minimally invasive foot and ankle surgery at Kantonsspital St.Gallen, Switzerland where he gained proficiency in advanced techniques in minimally invasive (MIS) foot and ankle surgery.
Dr Png is also a member of MIFAS by GRECMIP, an international society focused on research, education and clinical work in MIS foot and ankle surgery. He is adept in both methods of minimally invasive bunion surgery.
GPs who would like more information about bunion surgery can contact Dr Png at [email protected].
GP Appointment Hotline: 6930 6000 GPs can visit the website for more information about the department.
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