Original Editors - Bradley Svoboda
- 1 Definition
- 2 Clinically Relevant Anatomy
- 3 Epidemiology
- 4 Clinical Presentation
- 5 Diagnostic Procedures
- 6 Management / Interventions
- 7 Physical Therapy Management
- 8 Differential Diagnosis
- 9 References
Hallux valgus is a progressive foot deformity in which the first metatarsophalangeal (MTP) joint is affected and is often accompanied by significant functional disability and foot pain,. This joint is gradually subluxed (lateral deviation of the MTP joint) resulting in an resulting in an abduction of the first metatarsal while the phalanges adduct.,. This often leads to development of soft tissue and bony prominence on the medial side of what is called a bunion  (exostosis on the dorsomedial aspect of the first metatarsal head).  At a late stage, these changes lead to pain and functional deficit: i.e. impaired gait (lateral and posterior weight shift, late heel rise, decreased single-limb balance, pronation deformity) . There is a high prevalence of hallux valgus in the overall population (23% of adults aged 18-65 years and 35.7% of adults over 65 years of age). There is a higher prevalence in women (females 30% - males 13%) and the elderly (35.7%)
Clinically Relevant Anatomy
The Hallux or first toe, is the medio-distal part of the foot. It is formed by the first metatarsal (articulates with two sesamoid bones), the first proximal phalanx and the first distal phalanx. So the hallux is formed by three bones instead of four, unlike the other toes who have an extra bone called the intermediate phalanx.
The first toe has three synovial joints. The first joint is the art. tarsometatarsae and is situated between the medial cuneïforme bone and the first metatarsal, it does not allow a lot of movement. The second joint, art. metatarsophalangae, connects the first metatarsal and the first proximal phalanx. The joint allows flexion and extension of the first toe and a small ab- and adduction towards the centre of the second toe. It is also reinforced by ligaments (lig. metatarsophalangae collateralia and lig. Metatarsophalangae plantaria). The last joint, art. Interphalangae, is the connection between the two phalanges of the first toe. This joint only allows flexion and extension and it is also reinforced by ligaments (lig. Interphalangae collateralia and lig. Interphalangae plantaris).
As mentioned earlier, there are two sesamoid bones that articulate with the first metatarsal bone. These sesamoid bones protect the tendons of the muscles that are attached to them but their main function is helping those muscles generate more force by extending their levers.
Other structures: M. tibialis anterior, M. extensor hallucis longus, M. peroneus longus, M. flexor hallucis longus, M.extensor hallucis brevis, M. abductor hallucis, M. flexor hallucis brevis, M. adductor hallucis, M. interossei dorsales I, aponeurosis plantaris. 
The angle created between the lines that longitudinally bisect the proximal phalanx and the first metatarsal is known as the hallux valgus angle. Less than 15° is considered normal. Angles of 20° and greater are considered abnormal. An angle of 45-50° is considered severe.
The exact etiology is not well established. However, certain factors have been considered to play a role in the development of hallux valgus;
- gender (10x more frequent in women)
- footwear (tight pointed shoes)
- congenital deformity or predisposition
- chronic achilles tightness
- severe flatfoot
- hypermobility of the first metatarsocunieform joint
- systemic disease
Wearing tight shoes and/or heeled shoes between 20 and 39 years of age can be crucial in the development of hallux valgus in later years. It is also possible that abnormal muscle insertions are partly responsible for hallux valgus. Hallux valgus is also associated with hip and knee OA and is inversely associated with a higher BMI. 
In this foot deformity, the medial eminence becomes prominent as the distal end of the first metatarsal drifts medially and the proximal phalanx deviates laterally. The first MTP becomes subluxed, leading to a lateral deviation of the hallux, medial displacement of the distal end of the first metatarsal and bony enlargement of the first metatarsal head .
The mechanism behind this hallux valgus formation starts with the stretching of the abductor hallucis muscle (for example as a result of wearing tight shoes). The base of the first proximal phalanx starts to lateralise and abducts. During gait the forefoot is turned into pronation, which stretches the medial collateral ligament and the capsular structures of the first MTP joint. As the first MTP joint consists of multiple bones, ligaments, sesamoid bones and has muscles nearby, structures influence other structures as they move or stretch. That way, once a threshold degree of valgus of the first PP is reached, the first metatarsal bone starts his way into a varus position. This way, the hallux is pushed into a valgus position. The capsule gets weaker and the abductor hallucis tendon turns into a flexor of the hallux. As it turns worse, multiple muscles tend to worsen the situation as their axis of pull is lateralized.
As a bunion appears, friction is raised when shoes are worn. There may be an irritation of the MCL ligament of the first MTP joint, which leads to inflammation and calcification of the joint. This worsens the pain and bunion size. In an early stage, this leads to tenderness of the bunion due to footwear. The skin over the bunion is hard, warm and red. Later on the patient may have other complaints due to osteoarthritis. The bunion keeps moving medially and the pain gets worse.  
A common problem in people with hallux valgus (pre-operative), is one or more disorders in their gait pattern due to the deformity of the first metatarsophalangeal joint. Dysfunctions that may be present:
- Gait deviations in the midstance (middle stage) and the propulsion phase (late stance). As the body weight moves forward on a foot on the ground, the patient will tend to keep his weight on the lateral border of the foot. This leads to a lateral and posterior weight shift
- Patient has also a pronation deformity
- Patient is unable to supinate his / her foot and will tend to keep his body weight on the lateral border of the foot which results in a late heel rise
- The period of single-limb support will be diminished 
When a physical examination is executed, the following indications could be present:
- Lateral deviation of the MTP joint
- Swelling of first MTP joint
- Shortening of flexor hallucis brevis muscle
- Tenderness of hallux
- Weakness of hallux abductor muscles 
- Pain (primary symptom) 
Radiographs are used to determine the presence of hallux valgus by looking at the angle formed between the longitudinal bisections of the first metatarsal and the proximal phalanx. If the angle is greater than 15°, hallux valgus is diagnosed. An angle of 45-50° is considered serious. The degree of displacement of the sesamoids and the level of osteoarthritic change within the first MTP joint should be considered as well.
It is not always possible or necessary to take radiographs to determine the severity of hallux valgus. Therefore, the Manchester scale was developed .The Manchester scale consists of standardized photographs of four types of hallux valgus: none, mild, moderate and severe. Research has shown that this scale is reliable in terms of both re-test and inter-tester reliability (kappa values of 0.77 and 0.86).In the study by Roddy et al (2007) , the authors developed a tool that consists of five photographs instead of four. Each photograph had a hallux valgus angle increased with 15°. This tool had a good retest reliability (kappa = 0.82) and is also a good tool to use to determine hallux valgus severity . Both scales (the four-level classification or dichotomised scale) can be used to determine the severity of hallux valgus.
Physical examination should be performed with the patient both seated and standing. During weight bearing, the deformity is generally accentuated. During examination, the presence of pes planus and contracture of the Achilles tendon should be evaluated. The height of the longitudinal arch and hallux, with its relation to the lesser toes, are also examined .
Management / Interventions
A hereditary factor or predisposition (for example as a result of a generalized ligamentous laxity) is not preventable but other things are. For example, wearing shoes that fit properly (not too tight) and avoiding high heels can be important factors in preventing hallux valgus. (level of evidence: 2B)
The first treatment option is non-operative care:
- Adjustment of footwear to help in eliminating friction at the level of the medial eminence (bunion) e.g., patients should be provided of a shoe with a wider and deeper toe box
- The condition of pes planus may be helped by an orthosis. Severe pes planus can lead to a recurrence of hallux valgus following surgery.
- Achilles tendon contracture may require stretching or even lengthening  (level of evidence: 4)
This type of treatment can be applied in the early stage when the secondary contractures of the soft tissues and the alterations of the articular surfaces have not become permanent . (level of evidence: 5)
If non-operative treatment fails, surgery could be considered . (Level of evidence: 4) Before an operation is chosen, the severity of the hallux valgus has to be determined. In order to do that, a weight bearing plain film radiography is used.
There are several surgical procedures that we can apply depending on the severity of the injury:
- Austin/Chevron Procedure
This procedure is frequently used for mild deformities. The osteotomy is in a "V" shape, a sagittal saw is used in a medial to lateral direction inside the first metatarsal head. The loose fragment is then placed differently to correct the first metatarsal angle. The fragment is fixated with pins or screws.
- Reverdin Procedure
A wedge is removed from the head of the first metatarsal head in order to get a better organisation of the articular cartilage. The wedge is situated on the dorsal side and medially based. In some cases, the surgeon decides that is necessary to rotate the articular cartilage. A screw or K-wire is used for fixation.
- Scarf Procedure
When the deformity is moderate to sever, the scarf procedure is a frequently used option. The osteotomy is longitudinal, in a medial to lateral direction, inside the shaft. The capital piece is moved more to the lateral side and stabilized with two screws.
- Closing Base Wedge Procedure
Base procedures are mostly used for severe deformities, so is this one. A wedge is made in the proximal metatarsal, on lateral side. When the wedge is removed, the distal part is translated to the lateral side causing the gap to close and the first metatarsal to align with the second. The minimum fixation is a bicortical screw.
- Lapidus Arthrodesis
This is another option when a severe deformity is observed. By removing a piece of the articular cartilage of the medial cuneiform and the base of the first metatarsal, a fusion between the two is created. The fixation can be external, by the use of a plate or screws.
- Akin Procedure
An extra correction can be constructed when a wedge is made on the medial side of the first proximal phalanx. The gap is closed by pushing the distal part to the medial side and fixating it. The similarities with the closing base wedge procedure stand out.
- First Metatarsal-Phalangeal Joint Arthrodesis
The permanent elimination of motion is the reason that this procedure is one of the last options to treat a significant deformity. Most of the time, there is another component that motivates the choice of this joint destructive procedure: degenerative arthrose or an unstable joint. The proximal phalanx is correctly positioned towards the first metatarsal and is then fixated through the joint with screws, plates or crossing K-wires.  
For all surgical procedures, the patient is allowed to ambulate in a post-operative shoe immediately after surgery. Patients need to wear a post-op shoe and compressive dressings for 8 weeks. Long-term follow-up has shown equally positive outcomes after Chevron osteotomy for both patients both younger and older than 50 years of age.
Physical Therapy Management
As a result of the gait disturbances (see non-operative treatment), objectives for physical therapy could be:
- Adjusted footwear with wider and deeper tip
- Increase extension of MTP joint
- Relieve weight-bearing stresses (orthosis) (Level of evidence 5)
- Sesamoid Mobilization:*The physical therapist performs grade III joint mobilizations on the medial and lateral sesamoid of the affected first MPJ. One thumb is placed on the proximal aspect of the sesamoid and is used to apply a force from proximal to distal that causes the sesamoid to reach the end range of motion (distal glides). These are performed with large-amplitude rhythmic oscillations. No greater than 20° of movement of the MPJ should be allowed during the technique.( Level of evidence 2B) 
- Strengthening of peroneus longus (Level of evidence 2A)
- Gait Training:  (Level of evidence 2B)
- Stance phase: could be trained by performing a heel-strike in its physiological position at the lateral aspect of the heel.
- Stance phase could be followed by weight bearing of the first metatarsal during midstance and terminal stance, with training of active push-off by the hallux flexors, the flexor digitorum longus and brevis muscles and the lumbrical muscles (Level of evidence 1: 2B, Level of evidence 2: 2C)
During gait training, verbal cues could be provided.
These objectives should ensure that pain is reduced and function is restored.(Level of evidence 2B) 
Physiotherapists should contain an expanded program, including whirlpool, ultrasound, ice, electrical stimulation, MTJ mobilizations and exercises. This is more effective than physical therapy alone. The combination will result in a increase in ROM of the MTP joint, strength and function, and also a decrease in pain .(Level of evidence 2B)
PHASE I - Pain Relief. Minimise Swelling & Injury Protection(Level of evidence 5)
Pain is the main reason that patients seek treatment for a bunion. Inflammation is best eased using ice therapy, techniques (e.g. soft tissue massage, acupuncture, unloading taping techniques) or exercises that unload the inflamed structures. Anti-inflammatory medications may help. Orthotics can also be used to offload the bunion.
PHASE II - Restoring Normal ROM & Posture(Level of evidence 5)
As pain and inflammation settles, the focus of treatment turns to restoring normal toe and foot joint range of motion and muscle length.
Treatment may include;
- joint mobilisation (abduction and flexion) and alignment techniques (between the first and the second metatarsal)
- muscle and joint stretches
- bunion splint or orthotic
- bunion stretch and soft tissue release. (see reference for video)(Level of evidence 1 : 5) (Level of evidence 2 : 5)
PHASE III - Restore Normal Muscle Control & Strength( Level of evidence 5)
A foot posture correction Program to assist you to regain your normal foot posture.
Dorsiflexion Strengthening with Elastic Resistance Band
The ankle dorsiflexion exercise strengthens the ankle and lower leg muscles. The patient is positioned in long-sitting. The centre of the resistance band is placed on the top of the forefoot with the toes slightly pointed. The ends of the band are either held by an assistant or secured against an immovable object (e.g. a table leg). The patient then dorsiflexes the ankle, pulling "towards their nose," working against the resistance of the band.
Towel curls The patient spreads out a small towel on the floor, curling his/her toes around it and pulling the towel towards them.
Toes spread out (TSO) A possible causative factor of the hallux valgus is the muscle imbalance between the abductor hallucis and the adductor hallucis. Strengthening the abductor muscle can prevent a hallux valgus and can be helpful to correct the deformity in an early stage. The toes-spread-out (TSO) exercise is an efficient way to train abductor hallucis.  (Level of evidence 1: 5) (Level of evidence 2: 5)
PHASE IV - Restoring Full Function
The goal of this stage of rehabilitation is to return the patient to his/her desired activities. Everyone has different demands for their feet that will determine what specific treatment goals need to be achieved.
PHASE V - Preventing a Recurrence
Bunions will deform further with no attention and bunion-associated pain has a tendency to return. The main reason is biomechanical.
In addition to muscle control, the physiotherapist should assess foot biomechanics and may recommend either a temporary off-the shelf orthotic or refer for a custom-made orthotic. High heeled shoes and shoes with tight or angular toe boxes should be avoided.
|(Level of evidence 5)||(Level of evidence 5)|
Hallux valgus can be confused with other diseases or injuries during diagnosis.
In the early stages, the redness and pain can be confused with an inflammation, infection or gout of the first MTP joint. Pain related to gout suddenly appears while onset is gradual with hallux valgus. As well, semi uric acid level can be tested to differentiate between the two (since it is increased patients with gout).
Other forms of arthritis and their consequences for example hallux rigidus can be confused with hallux valgus as well as being a result of the deformity. For example, a joint affected by septic arthritis is also red and swollen.
Surgical or traumatic arthropathy
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