Footnotes: Hallux valgus
Welcome to the Footnotes newsletter, I hope you find it useful.
My name is Antony N Wilkinson (MSc, FCPodS, FFPM RCPS (Glasg), I am a Consultant Podiatric Surgeon and my aim is to provide you with useful information, contact details, referral options for foot and ankle problems to improve patient care.
Each newsletter will focus on a specific condition, containing information you may find useful in your clinical practice.
I have practiced in Doncaster for 22 years, treating a wide range of foot pathology. I offer treatments from orthotic management through to surgical reconstruction of the foot and ankle.
Focus on Hallux valgus
What is it?
Hallux valgus is a common 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, whilst a drift of the big toe towards the second increases the hallux valgus angle.
The normal range 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 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.
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 tool pre-op is 58/100 in 1754 patients. 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, padding may reduce symptoms.
B: Ulcer development
Ulcer development is uncommon, may be an issue in diabetics or frail patients and requires 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.
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. 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 this criteria.
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. Many different ways of doing this have been documented. The choice of operation depends on the severity of the deformity, however all procedures have around a six week recovery period. Modern fixation techniques allow a 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 is 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.
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:
Silicone Pads and Splints