Hallux valgus

Overview

Hallux valgus is a frequent foot ailment with a multiple, complex, and unknown etiology and course. Hallux valgus has a preference for females. It is a progressive condition for which there is no known treatment to slow or stop progression. When nonoperative measures fail in healthy people, surgery is required. Infection and recurrence are also side effects of surgery. Many techniques, including soft tissue and bone restoration of the first ray, have been documented. The procedure recommended is determined by the severity of the deformity.

 

Hallux valgus definition

One of the most frequent forefoot malformations is hallux valgus (HV), often known as a bunion. The proximal phalanx deviates laterally, while the first metatarsal head deviates medially. It is usually caused by adduction of the first metatarsus, also known as metatarsus primus varus.

The precise etiology remains unknown. It is particularly common in ladies and people who wear tight shoes or heels. A physical exam is usually used to diagnose HV deformity. However, imaging is significant because it can determine whether the first metatarsophalangeal (MTP) joint is damaged.

Treatment begins with non-surgical treatments such as larger shoes, orthotics, and night splinting. If this is ineffective, surgical management is the suggested next step. Patients normally bear the procedure well, with bone union happening 6 to 7 weeks after surgery.

 

Epidemiology

HV deformity is a fairly frequent ailment. It affects around 23% of adults between the ages of 18 and 65, and up to 36% of adults over the age of 65. When it comes to adult females, HV malformation might affect up to 30% of them. When compared to the barefoot population, the prevalence is higher in individuals who wear shoes or heels. Surprisingly, when barefoot populations of men and women are compared, women are found to exhibit HV malformation twice as often as males.

 

Etiology

The actual etiology is unknown, but there are numerous potential theories. Genetics, a short first metatarsal, a dorsiflexed first metatarsal, a flexible or rigid forefoot varus, a rigid or flexible pes planovalgus, gastrocnemius equinus, improper foot mechanics, and joint hypermobility are all possible contributors to HV deformity. 

Interestingly, certain rheumatic disorders, such as gouty arthritis, psoriatic arthritis, and rheumatoid arthritis, predispose patients to HV malformation. Furthermore, HV deformity is more common in connective tissue disorders such as Marfan syndrome, Ehlers-Danlos syndrome, and Down syndrome.

An HV deformity can be caused by any muscular imbalance in the foot caused by disorders such as a stroke, cerebral palsy, or myelomeningocele.

HV deformity is widespread in persons who wear high heels and tight shoes, and this is frequently mentioned as the cause. Men who wear sensible footwear, on the other hand, frequently show noticeable HV deformity, but women who wear footwear that greatly compresses their foot have no deformity. This feature has led to the theory that footwear aggravates an underlying bone defect rather than being the primary cause.

 

Pathophysiology

The etiology of HV is complex, but the prevailing belief is that there is an imbalance between the extrinsic and intrinsic muscles of the foot, with ligament involvement as well. The strain exerted by the peroneus longus muscle laterally and the abductor hallucis muscle medially keep the first metatarsals aligned.

Collateral ligaments at the first MTP joint limit movement along the transverse plane. If the pressure at the head of the first metatarsal increases, the metatarsal will begin to shift medial-dorsally. This force raises the hallux angle, which is exacerbated further by muscle stabilization while walking.

The medial collateral ligament and the medial capsule become stressed and finally rupture as these forces drive the first metatarsal medially and the hallux laterally. The lateral structures (abductor hallucis muscle and collateral/lateral joint capsule ligaments) worsen this deformity in the absence of medial supporting structures.

 

Symptoms of HV

History

HV deformity frequently manifests as a persistent progressive onset. The proximal phalanx pronates and deviates laterally, whilst the first metatarsal head deviates medially, frequently becoming red and painful. Patients usually report with a persistent development of severe or deep pain at the MTP joint that worsens with ambulation. An aching ache at the head of the second metatarsal is occasionally described by the patient. The frequency, duration, and severity of discomfort gradually increase as the HV deformity worsens.

Patients frequently report an increase in the magnitude of the malformation. Another typical symptom is tingling or burning discomfort at the dorsal aspect of the malformation. This symptom is suggestive of a medial dorsal cutaneous nerve neuritis induced by deformity compression. These symptoms are caused mostly by three distinct processes:

• The bunion itself centers upon the medial aspect of the first metatarsal.
• Pressure against the toes that are superiorly displaced
• Increased pressure on second through fifth metatarsal bones

Blisters, ulcerations, interdigital keratosis, and itchy skin next to the deformity are some of the other symptoms that patients experience. These symptoms can cause severe morbidity and frequently impede physical activity. 

 

Physical 

A biomechanical exam will be performed as part of the physical exam to check for possible causes of HV deformity. Forefoot/rearfoot varus or valgus, subtalar joint stiffness, midtarsal joint stiffness, resting calcaneal stance position, tibial torsion, and neutral calcaneal stance posture are all common things to look for. Pathology evaluations are frequently divided into non-weight bearing and weight bearing evaluations, as seen below.

 

Nonweightbearing

The hallux's position in relation to the second digit should be evaluated in the transverse plane. The hallux can be riding, overriding, or not riding at all. The lateral deviation of the MTP joint could indicate a subluxation at the MTP joint. The medial prominence necessitates cautious examination as well.

The first MTP joint range of motion should be evaluated for maximum possible motion (normal - plantar flexion less than 15 degrees and dorsiflexion 65 to 75 degrees). The quality of the initial MTP is then evaluated (pain, crepitation). Finally, the MTP's axis of motion is examined.

The first MTP necessitates two kinds of evaluation. First, the resting position and range of motion are evaluated (normal to 10 mm total, the resting position should be neutral). Second, movement in the transverse plane is assessed (HV deformity presents with increased motion).

 

Weightbearing

The first MTP necessitates two kinds of evaluation. First, the resting position and range of motion are evaluated (normal to 10 mm total, the resting position should be neutral). Second, movement in the transverse plane is assessed (HV deformity presents with increased motion).

 

Diagnosis

Typically, routine laboratory assessments are not required. Certain laboratory testing, however, can be considered if there is a suspicion of metabolic or systemic disease. Rheumatoid factor, antinuclear antibody, c-reactive protein, erythrocyte sedimentation rate, uric acid, and total blood count are among them. If there is a high likelihood of osteomyelitis, the practitioner may explore MRI and radionuclide imaging.

A physical exam is often used to establish a diagnosis. Imaging can assist clinicians in determining whether and how much injury has occurred to the first MTP joint. Plain radiography and X-rays of the foot (AP and lateral weight-bearing) are used largely for evaluation. A lateral hallux displacement at the first metatarsal is visible on imaging (normal hallux valgus angle is less than 15 degrees, and the intermetatarsal angle is less than 9 degrees).

The deviation is usually in the transverse plane. However, HV deformity can produce hallux rotation, resulting in the nail facing medially (pronation). The clinician can execute the most appropriate procedure once the severity of the deformity has been evaluated.

Based on the weight-bearing anteroposterior, lateral oblique, lateral, and sesamoid axial views, the classification is mild, moderate, and severe. This imaging aids in determining the structural state of the foot. The AP projection aids in determining the intermetatarsal angle, hallux abductus angle, metatarsus adductus angle, hallux abductus interphalangeal, hallux rotation, and condition of the first MTP joint.

The lateral projection is used to evaluate the first metatarsal position as well as dorsal exostosis/osteophytes. The lateral oblique projection aids in determining bone density, homogeneity, and trabeculation (bone stock). The sesamoid axial view is used to detect subluxations and degenerative joint abnormalities.

Degree: Hallux valgus angle (HVA) / Intermetatarsal angle (IMA)

• Normal: less than15 degrees / 9 degrees
• Mild: 15 to 30 degrees / 9 to 13 degrees
• Moderate: 30 to 40 degrees / 13 to 20degrees
• Severe: over 40 degrees / over 20 degrees

 

Management

Non-surgical and surgical procedures are used to treat people with HV deformity. Non-surgical treatments are usually tried first. If medical treatment is ineffective, surgical repair should be explored. Surprisingly, there is no conclusive evidence that conservative treatment works. However, the American College of Foot and Ankle Surgeons still advocates conservative therapy before considering surgery. Before considering more invasive alternatives, patients must first try on broad shoes and orthotics. The lateral projection is used to evaluate the first metatarsal position as well as dorsal exostosis/osteophytes. The lateral oblique projection aids in determining bone density, homogeneity, and trabeculation (bone stock). The sesamoid axial view is used to detect subluxations and degenerative joint abnormalities.

The goal of conservative treatment is to manage the symptoms. It does not correct the actual deformity. Non-surgical treatments options include:

• Shoe modification: Low-heeled, wide shoes.
• Orthoses: Improves alignment and support.
• Analgesics: Acetaminophen and NSAIDs.
• Ice: Icing the inflamed deformity to reduce inflammation.
• Medial bunion pads: Prevents irritation of HV deformity.
• Stretching: Helps maintain joint mobility in the affected joint.

If non-surgical procedures fail to control the pain, the treatment is considered a failure. Surgical management should be considered at that stage. The primary indication for surgery is based on symptoms (difficulty with ambulation, pain). Surprisingly, radiographic appearance has no bearing on the outcome. The existence of arthritis and the degree of the deformity help doctors choose the best surgery.

Over 150 surgical methods for the treatment of HV deformity have been described. The most typical method is an open approach, which results in a 3 to 5 cm scar. There are, however, innovative minimally invasive procedures that are gaining popularity.

A research comparing open osteotomy to minimally invasive surgery found no significant difference in surgical success, however the minimally invasive procedure took less time and left a smaller scar. Despite the fact that there are numerous processes stated, they always include one of the main approaches outlined below:

Osteotomy

The first metatarsal bone is sliced and repositioned in a less adducted position. The position and contour of the cut vary depending on the surgical technique. A Wilson osteotomy, for example, uses a straight cut, but a chevron osteotomy uses a wedge-shaped cut. The cut may occur near the metatarsal base (proximal osteotomy), in the shaft (scarf osteotomy), or in the neck (distal osteotomy). The chevron osteotomy has received the greatest attention.

A randomized controlled experiment comparing chevron osteotomy to no treatment or orthosis discovered that chevron osteotomy outperformed the other treatment options. The hallux abductus angle was normal after 12 months in the osteotomy group, with an 80 percent satisfaction rate. However, roughly 61% of patients in the osteotomy group had moderate footwear issues. The surgical group also had the most sick days and the highest foot care costs.

Arthroplasty 

While relieving discomfort, the first MTP joint's mobility is preserved (replaces the joint with an implant or removing the joint). There have been advancements in both hemiarthroplasty and total joint arthroplasty. Hemiarthroplasty preserves toe length and necessitates less bone excision. In patients with severe hallux rigidus, an interpositional arthroplasty is performed to help maintain joint range of motion.

The Keller resection is the most prevalent. In this surgery, up to 50% of the proximal phalanx is excised in order to increase dorsiflexion and decompress the joint. After a Keller's arthroplasty, 75% of patients were delighted with the results, and 88 percent got total pain relief. However, around 12% of patients reported increasing discomfort.

 

Arthrodesis

Bringing the metatarsocuneiform (MTP) joint into the proper position. This procedure is only used when the joint has become substantially deteriorated and restoring functionality is doubtful. The operation is normally reserved for people over the age of 65. Up to 81 percent of patients experienced pain alleviation and better ambulation following surgery. Nonunion problems, on the other hand, have been reported to account for up to 20% of all cases. Patients frequently complain about limited footwear alternatives, metatarsalgia, and joint discomfort.

 

Soft tissue procedures 

The McBride method is largely concerned with soft tissue. The fibular sesamoid is removed in this surgery, resulting in interphalangeal joint flexion, MTP joint hyperextension, and hallux medial deviation. Surprisingly, no papers have independently evaluated soft tissue techniques for HV deformity repair. In one study, the chevron plus adductor tenotomy was compared to the chevron osteotomy alone. They discovered little variation in mechanical correction and no variation in patient satisfaction.

There have been very few randomized trials to assess the effectiveness of these procedures. However, as surgical procedures have improved, so has patient satisfaction, which now ranges from 50 to 90 percent. Surprisingly, surgical outcomes do not seem to be related to patient satisfaction. This is assumed to be related to the patient's unmet post-surgical expectations.

The type of surgery performed has the greatest influence on postoperative care. However, dressing is frequently used during surgery to provide corrective forces. The dressing also compresses the surgical wound, which aids in the reduction of postoperative edema. The weight-bearing status varies depending on the operation, however, it is usually restricted for the first two weeks. After the sutures have been removed, the patient can begin range-of-motion exercises and weight-bearing activities. Typically, post-surgical imaging is taken, as well as when the patient becomes more active.

Long-term surveillance is aimed at determining the specific cause of the HV deformity so that it does not reoccur. Clinicians should treat the underlying causes if they are discovered. Orthotic devices may still be beneficial to postsurgical patients, particularly in illnesses that accelerate joint degradation, such as rheumatoid arthritis. Long-term post-surgical benefits can be gained by better regulating these parameters.

 

Differential Diagnosis

Conditions to consider when evaluating patients with a possible HV deformity:

• Osteoarthrosis
• Freiberg’s disease
• Hallux rigidus
• Morton's neuroma
• Turf toe
• Gout
• Septic joint

 

Staging

HV divided is deformity into four stages:

• Stage 1: Lateral displacement of the hallux at the MTP joint
• Stage 2: Progression of the hallux abduction (hallux pressing against the second toe)
• Stage 3: Increased intermetatarsal angle, possible associated second hammertoe deformity
• Stage 4: Partial/Complete hallux dislocation at the MTP joint

 

Prognosis

The prognosis for HV deformity is generally favorable. Conservative therapy should be tried on patients first. If the patient's discomfort and functionality do not improve, surgery should be considered. The procedure determines the postoperative recovery.

Healing time for any bone treatment, such as an osteotomy, is approximately 6 to 7 weeks (corresponding to the complete bony union). If the patient smokes, the healing process may take longer. Patients commonly return to work 6 to 12 weeks after surgery. Improvement can take up to a year after surgery.

 Postoperative problems differ based on the surgical procedure and technique used. Osseous non-union, hematoma, numbness, hardware failure, osteomyelitis, cellulitis, avascular necrosis, hallux varus, reduced joint range of motion, and recurrence are the most prevalent consequences.

The recurrence rate varies per procedure, ranging from 10% to 47%. The pathogenesis is usually multifaceted, but it usually includes anatomic predisposition, noncompliance with postoperative instructions, medical comorbidities, and poor surgical skill.

 

Complications

HV deformity can result in several complications, including:

• Bursitis (most common)
• A second toe hammertoe deformity
• Degenerative disease of the metatarsal head
• Central metatarsalgia
• Medial dorsal cutaneous nerve entrapment
• MTP joint synovitis

 

Conclusion 

One of the most frequent forefoot deformities is HV deformity, sometimes known as a bunion. It appears as a malformation in the big toe, which causes it to bend towards the other toes. The joint becomes inflamed and uncomfortable. The precise cause remains unknown. However, it is more common in women and those who wear tight shoes or heels. A physical exam is usually used to make the diagnosis.

Imaging, on the other hand, is necessary since it helps determine the severity of the abnormality. Treatment begins with non-surgical treatments such as larger shoes, orthotics, and night splinting. If this is ineffective, surgical management is advised. Patients normally bear the procedure well, with bone union happening 6 to 7 weeks after surgery.

If the patient smokes, healing may take longer, and problems like as non-union or wound infection are more likely. Patients commonly return to work 6 to 12 weeks after surgery. Improvement has been shown to occur up to a year after surgery.

Patients with HV deformity benefit from the expertise of an interprofessional team that includes primary care physicians, radiologists, physical therapists, pharmacists, pain experts, and surgeons. Swelling or soreness may cause the patient to visit their primary care physician. A physical exam is usually used to make the diagnosis. Further imaging can aid in determining the severity of the deformity and guiding treatment.

The initial approach is to use conservative treatment. If this strategy is ineffective, the patient should be referred to a physician for surgical management review. If surgery is undertaken, rehabilitation should follow in order to maximize post-operative functionality. A pain expert and a pharmacist can assist in managing post-surgical pain, with an emphasis on minimizing the use of opioids.

Orthopedic nurses can aid at every stage of the process, from conservative treatment to assisting during surgery and post-op care, as well as working with therapists for post-surgical rehabilitation. Patients should be followed up on for a long time to ensure they are fulfilling their recovery goals. Open communication among members of the interprofessional treatment team is essential for better outcomes.