What is a Bunion?
By Laurence Schubert APAM
Hallux valgus, more commonly known as a bunion, is a progressive condition in which your first metatarsophalangeal (MTP) joint becomes subluxated over time. The MTP is located at the ball of the foot. As the condition progresses, this joint begins to deviate causing the phalanges to adduct and the metatarsals to abduct. This leads to a bony prominence on the lateral aspect of your foot and associated soft tissue deformities. The angle that your bunion creates is known as the Hallux valgus angle. Anything less than 15° is considered normal, greater than 20° is considered abnormal and greater than 45° is considered severe.
Is it Common to have a Bunion?
Overall, 23% of adults aged 18-65 years and 35% of adults over 65 years. There is a higher prevalence in women compared to men, as well as in the elderly population. So yes, almost one quarter of middle aged people have some degree of a bunion.
What Causes a Bunion?
The exact cause of a bunion is unknown; however it is likely to be a result of biomechanical changes that occur in your feet. It is clear that type of footwear plays a significant role in the cause of bunions. Bunions are approximately 10 times more prevalent in Western countries compared to Eastern countries. Therefore, it is thought that due to cultural differences such as style of shoe, increase the prevalence of bunions. For example, narrow fitting shoes that push the big toe into adduction (inwards) causes damage to the MTP (joint at ball of the foot). Additionally, high heels increase the amount of weight through the front of your foot; as a result your body tries to increase the width of surface area to support this change. After prolonged use of constraining footwear, your foot begins to adapt and compensate for this change, leading to the development of a bunion. Other factors are also thought to contribute to the cause of a bunion.
Footwear (tight fitting shoes).
Congenital deformity or predisposition.
Chronic Achilles tightness.
Hyper mobility of the first metatarsocunieform joint.
Gender (x10 more prevalent in women), likely to be caused by cultural factors.
Signs and Symptoms of a Bunion
You will notice a bump forming on the medial aspect of your big toe (MTP) joint. As the bunion/bump begins to appear, it will lead to irritation and inflammation of the MCL ligament and MTP joint. Local tenderness of the bunion and hardened skin will also be present.
These factors lead to a change in gait pattern, often with increased weight bearing through the lateral aspect of the foot. Furthermore, there will be swelling, pain and weakness of the muscles surrounding the big toe and foot.
How do you manage a Bunion?
Obviously, prevention is the goal in the ideal world, this would include modifying footwear that fit and ensuring you have an appropriate gait pattern. However, I’m sure you wouldn’t be here if you wanted prevention! Once a bunion is beginning to form there are several strategies you should explore before seeking a surgical opinion.
Non-operative management of a bunion
- Adjustment of footwear – ensure there is enough space and width for your foot, particularly your toes.
- Strengthening of foot and ankle muscles – strengthening your peroneus longus muscle is crucial in order to maintain stability and appropriate gait pattern. The peroneals run on the lateral aspect of the shin but attaches underneath the medial foot on the first metatarsal (just below the big toe).
- Gait re-training – as part of strengthening program it may be necessary to address any abnormalities that have developed due to the bunion. This will assist in reducing the stress on the bunion and decreasing the likelihood of the injury worsening.
- Addressing pes planus (flat foot) – this can be improved through strengthening and control exercises as described above, however in some cases the use of orthoses are used.
- Physiotherapy manual therapy techniques – this includes graded mobilisation of the sesamoid bones, release of soft tissue structures, trigger point therapy and taping.
Your physiotherapist will work with you in determining the most important factors for you to focus on during your treatment. Initially the main aim will be to relieve your pain and minimise your swelling. Following this, a period of rehabilitation will address any biomechanical deficiencies that are present.
Surgical management of a bunion
There are numerous different surgical procedures that can address a bunion. This should only be considered after at least 3 months of conservative management has been attempted and shown little to no improvement. Majority of these surgeries will include the use of surgical metal wear in order to fixate the new position of the joint.
To get you started:
- Towel toe curls – stand with one foot on a towel and scrunch the towel towards you by using your foot muscles. Complete 10 sets twice daily.
- Single leg balance – stand on leg balancing, aim for 30 seconds, close your eyes if too easy. Aim 30 sec x 5, twice daily.
- Ice therapy – place a cold pack on your bunion once daily for 20 minutes.