What is it?
Hallux valgus is a condition affecting the big toe joint. It is associated with splaying of the first metatarsal away from the second metatarsal causing an increase in the intermetatarsal angle ((M), whilst a drift of the big toe towards the second increases the hallux valgus angle (HV).
The normal ranges for these angles are: IM angle 8-12 degrees
HV angle 0-15 degrees
Patients usually complain of increased joint pain with shoe pressure over the medial bump, which in some cases form a bursa (bunion). Although there may be some osteoarthritis within the joint, this is usually mild.
How do I examine the joint?
The first and most important thing to do is to ask the patient to stand barefoot. The foot can dramatically change shape and position on weight bearing, as contact with the ground splays the forefoot and often everts the hindfoot. This is why requesting weight bearing X-rays is so important.
With the patient non weight bearing, check the range and quality of the joint motion. Does it feel stiff? Is that stiffness associated with grating or crepitus of the joint? If so there is a good chance the joint is arthritic.
What treatment should I suggest?
NHS patients need to meet certain CCG commissioning guidelines. You will be expected to demonstrate that the patient meets the criteria.
A: Significant and persistent pain when walking AND conservative measures tried for at least 6 months
Most patients have discomfort with footwear restriction rather that acute pain, which is often seen more in osteoarthritis.
In my practice the average pain score using a validated scoring system, pre-op is 58/100 in 1754 patients audited. Most patients who request surgery therefore would score around 5-6/10 on a visual analogue scale.
There is no evidence that conservative treatments will correct the condition, however wide fitting sensible shoes along with padding or insoles may reduce symptoms.
B: Ulcer development
Ulcer development is uncommon. It may be an issue in diabetics or frail patients and requires more urgent attention.
C: Evidence of severe deformity, overlapping toes
Once the hallux valgus encroaches the second toe, structural changes occur, leading to development of hammer toe, pain in the ball of the foot and midfoot osteoarthritis. Surgery is the best option in these cases. Tip: Check for calluses between the toes or the second toe lifting off the ground, with the focus of pain within the ball of the foot.
D: Physical exam and X-ray show degenerative changes in the joint, increased intermetatarsal angle or valgus deformity greater than 15 degrees.
If the joint has degeneration it is more likely to be Hallux rigidus which is often confused with hallux valgus due to the bony exostosis that grows around the joint.
It is difficult in primary care to evaluate X-ray as usually only the report is seen. Tip: Asking the radiologist to measure the angles on X-ray when requesting the film will help you in the referral process. Alternatively stand the patient barefoot on a sheet of paper. Place a ruler along the metatarsal and draw a line, repeat along the big toe and intersect the lines. Measure with a protractor.
Remember: Private patients do not need to meet these criteria. Some patients choose surgery for more cosmetic reasons.
What can be done to treat the condition?
Surgery involves re-aligning the metatarsal and reducing both the IM angle and HV angle to normal. The vast majority of procedures are carried out under local anaesthetic. Although many different ways of correcting the deformity have been documented, the choice of operation depends on the severity. All procedures have around a six-week recovery period, although modern fixation techniques allow the patient to return to trainers at 2 weeks and shoes by 6-8 weeks.
What are the risks?
Short term risks include; infection, swelling and DVT (which is rare). Initial elevation of the limb in the first 2 weeks reduces swelling significantly. Long term risks such as joint pain/stiffness and footwear restriction are also rare and can be improved by early mobilisation of the treated joint.
How effective is the surgery?
In an audit of 1818 patients from my practice:
- 94.2% were better following surgery
- 2.6% were the same
- 2.1% a little worse
- 0.8% deteriorated
What tests should I request?
X-rays are the best imaging modality to request.
Standard views
Dorso-plantar (DP) weight bearing. This view provides the best evaluation of the deformity and is used to measure IM and HV angles.
Lateral view weightbearing. This view provides information about the alignment of the hindfoot which may be affected by the condition
Medial oblique (MO). This view provides information about the joint spaces, the lesser metatarsophalangeal and metatarso-cuneifom joints. Especially when evaluating osteoarthritis.
Useful Websites to direct patients to
Bunions https://www.nhs.uk/conditions/bunions/
Silicone pads and splints https://www.silipos.com/collections/all
Bunion splints https://www.amazon.co.uk/Best-Sellers-Health-Personal-Care-Bunion-Splints/zgbs/drugstore/2826221031
About Consultant:
Antony N Wilkinson MSc, FCPodS, Consultant Podiatric Surgeon, please click here to visit profile.