Hallux valgus (HV), also known as a bunion, is one of the most common forefoot deformities. It manifests with the proximal phalanx deviating laterally and the first metatarsal head deviating medially. It is usually due to the adduction of the first metatarsus, called metatarsus primus varus. The exact etiology is not fully understood. It tends to occur more commonly in women and those who wear tight shoes or heels. HV deformity is typically diagnosable through a physical exam. However, imaging is important as it can evaluate whether there is damage to the first metatarsophalangeal (MTP) joint. Treatment centers upon first trialing non-surgical approaches such as wider shoes, use of orthotics, and night splinting. If this proves to be ineffective, surgical management is the recommended followup. Patients typically tolerate the surgery well, with bony union usually occurring around 6 to 7 weeks postoperatively.
The precise etiology is not fully understood, but are many proposed theories. HV deformity is most likely a result of multiple contributing factors including genetics, short first metatarsal, dorsiflexed first metatarsal, flexible or rigid forefoot varus, rigid or flexible pes planovalgus, gastrocnemius equinus, abnormal foot mechanics, and joint hypermobility. Interestingly, certain arthritic conditions such as gouty arthritis, psoriatic arthritis, and research shows that rheumatoid arthritis predisposes patients to HV deformity. Furthermore, HV deformity is more commonly seen in connective tissue disorders such as Marfan syndrome and Ehlers-Danlos syndrome, as well as in Down syndrome.
Any muscle imbalance in the foot due to conditions such as a stroke, cerebral palsy, or myelomeningocele can also cause an HV deformity.
HV deformity is common in people who wear tight shoes and heels, which is regularly cited as the cause. However, men who wear sensible footwear not uncommonly have marked HV deformity, while women who wear footwear that significantly compresses there foot have no deformity. This fact has given rise to the thought that footwear exacerbates an underlying bony abnormality rather than acting as the primary cause.
HV deformity is a relatively common condition. It occurs in approximately 23% of adults aged 18 to 65 years and up 36% of adults older than 65 years old. When looking at adult females, HV deformity occurs as high as 30%. The prevalence is higher in those who wear shoes or heels when compared to the barefoot population. Interestingly, when comparing women and men in barefoot populations, women are found to have HV deformity twice as often.
The pathophysiology of HV is complex, but the general assumption is that an imbalance exists between the extrinsic and intrinsic muscles of the foot with the involvement of the ligaments also. Maintenance of the first metatarsals' alignment is by the tension created by the peroneus longus laterally, and the abductor hallucis muscle medially. Collateral ligaments prevent movement along the transverse plane at the first MTP joint. If there is increased pressure at the head of the first metatarsal, the metatarsal will begin to move medial-dorsally. This force increases the hallux angle, which is also worsened by muscle stabilization while walking. As these forces push the first metatarsal medially and the hallux laterally, the medial collateral ligament and the medial capsule become strained, eventually rupturing. Without stabilizing structures medially, the lateral structures (adductor hallucis muscle and collateral/lateral joint capsule ligaments) exacerbates this deformity.
HV deformity commonly presents with a chronic progressive onset. The proximal phalanx pronates and deviates laterally while the first metatarsal head deviates medially, often becoming red and painful. Patients typically present with a chronic onset of sharp or deep pain at the MTP joint that is exacerbated by ambulation. The patient occasionally describes an aching pain at the head of the second metatarsal. As HV deformity progresses, the frequency, duration, and severity of the pain gradually increase. Frequently patients describe an associated increase in the size of the deformity. Another relatively common presentation is tingling or burning pain at the dorsal part of the deformity. This symptomatology is indicative of a medial dorsal cutaneous nerve neuritis likely caused by compression from the deformity. These symptoms are primarily a result of three different processes:
Other symptoms that affect patients include blisters, ulcerations, interdigital keratosis, and irritated skin adjacent to the deformity. These symptoms can cause significant morbidity, often limiting physical activities.
For the physical exam, a biomechanical exam will look for possible causes of HV deformity. Common items to evaluate for include forefoot/rearfoot varus or valgus, subtalar joint stiffness, subtalar joint stiffness, midtarsal joint stiffness, resting calcaneal stance position, tibial torsion, and neutral calcaneal stance position. Assessment of the pathology often divides into a non-weight bearing and weight bearing evaluation, as illustrated below.
The position of the hallux, with respect to the second digit, should be assessed in the transverse plane. The hallux can be under riding, overriding, or without contact. The lateral deviation of the MTP may represent subluxation at the MTP joint. The medial prominence also requires close evaluation.
The first MTP joint range of motion should undergo assessment for the maximum available motion (normal - plantar flexion less than 15 degrees and dorsiflexion 65 to 75 degrees). Next, the quality of the first MTP is joint is assessed (pain, crepitation). Lastly, the MTP is evaluated for its axis of motion.
The first MTP requires two types of evaluation. First, assessment of the resting position and range of motion (normal to 10 mm total, the resting position should be neutral). Second, evaluation of mobility in the transverse plane (HV deformity presents with increased motion).
HV deformity severity tends to be more obvious when the patient is weight-bearing. When weight-bearing, patients should be evaluated for increased of hallux abduction, increase in the medial prominence, first MTP joint dorsiflexion, hallux purchase, and metatarsus varus.
Typically, routine assessment laboratory studies are not required. However, if there is a suspicion for metabolic or systemic disease, certain laboratory studies can be considered. These include rheumatoid factor, antinuclear antibody, c-reactive protein, erythrocyte sedimentation rate, uric acid, and complete blood count. If there is a high degree of suspicion for osteomyelitis, the clinician can consider MRI and radionuclide imaging.
Establishing a diagnosis can be typically done on a physical exam. Imaging can help clinicians determine whether and to what extent the first MTP joint has suffered damage. Evaluation is primarily with plain radiography, with X-rays (AP and lateral weight-bearing) of the foot. Imaging demonstrates a lateral hallux deviation at the first metatarsal (normal hallux valgus angle is less than 15 degrees, and the intermetatarsal angle is less than 9 degrees). Typically, the deviation is in the transverse plane. However, HV deformity can cause rotation of the hallux resulting in the nail facing medially (pronation). Following the determination of the severity of the deformity has been determined, the clinician can perform the most appropriate procedure.
The classification is mild, moderate, and severe based on the weight-bearing anteroposterior, lateral oblique, lateral, and sesamoid axial views. This imaging helps evaluate the structural status of the foot. The AP projection helps assess the intermetatarsal angle, hallux abductus angle, metatarsus adductus angle, hallux abductus interphalangeal, hallux rotation, and the condition of the first MTP joint. The lateral projection primarily serves to assess the first metatarsal position and dorsal exostosis/osteophytes. The lateral oblique projection helps evaluate the density, uniformity, and trabeculation of the bone (bone stock). The sesamoid axial view looks primarily for subluxations and degenerative joint changes.
Degree: Hallux valgus angle (HVA) / Intermetatarsal angle (IMA)
Treatment of patients with HV deformity revolves around non-surgical and surgical treatments. Usually, non-surgical treatments are trialed first. If there is treatment failure, surgical repair should be considered. Interestingly, there is no definitive evidence that conservative treatment is effective. However, the American College of Foot and Ankle Surgeons still recommends the use of conservative therapy before perusing a surgical solution. It is essential for patients to trial wide shoes and orthotics before considering more invasive options.
The goal of conservative treatment is to manage the symptoms. It does not correct the actual deformity. Non-surgical treatments options include:
If non-surgical treatments are unable to control the pain, the treatment is deemed to have failed. At that point, surgical management should be considered. Indication for surgery is primarily based on symptoms (difficulty with ambulation, pain). Interestingly, radiographic appearance does not play a significant role. The presence of arthritis and the severity of the deformity helps guide surgeons to perform the most appropriate procedure. Over 150 surgical procedures have been described for the correction of HV deformity. Most commonly an open approach is taken resulting in a 3 to 5 cm scar. However, there are newer minimally invasive techniques that are increasing in popularity. A study comparing open osteotomy to minimally invasive surgery revealed no significant difference in the success of the surgery, but the surgical time was reduced and the scar was smaller in the minimally invasive surgery. Although there are many described procedures, they all involve one of the basic approaches outlined below:
There are very few randomized trials evaluating the efficacy of these procedures. However as surgical techniques have improved, patient satisfaction has also improved, ranging from 50 to 90%. Interestingly, surgical outcomes do not appear to correlate with patient satisfaction. This is thought to be related to the unmet post-surgical expectations of the patient.
Postoperative care is primarily determined by the type of procedure performed. However, dressing is typically applied at the time of surgery to supply corrective forces. The dressing also compresses the surgical wound to help minimize postoperative edema. The weightbearing status is procedure dependent but is commonly limited for the first 2 weeks. Once the sutures are removed, the patient can begin range of motion exercises and increasing weightbearing activities. Post-surgical imaging is typically obtained as well as when the patient becomes more active.
Long-term monitoring is directed to understanding the exact etiology to ensure HV deformity does not recur. If identified, clinicians should treat the causes. Postsurgical patients may still benefit from orthotic devices, notably in diseases that accelerate joint degeneration such as rheumatoid arthritis. By better controlling these factors, long-term post-surgical results can be obtained.
Conditions to consider when evaluating patients with a possible HV deformity:
Root et al. divided HV deformity into four stages, as outlined below :
The overall prognosis of HV deformity is good. Patients should first have a trial of conservative treatments. If the pain and functionality of the patient do not improve, surgery should then be a consideration. The postoperative recovery is dependent on the procedure. With any bone procedure, such as an osteotomy, healing takes around 6 to 7 weeks (corresponding to the complete bony union). If the patient is a smoker, the healing may take longer. Patients typically return to work approximately 6 to 12 weeks post-surgery. Improvement has shown to take up to 1-year post-surgery. Postsurgical complications vary depending on the surgical procedure and technique. The more common complications include osseous non-union, hematoma, numbness, hardware failure, osteomyelitis, cellulitis, avascular necrosis, hallux varus, limited joint range of motion, and recurrence.
Recurrence rates differ based on procedure, ranging from 10 to 47%. The etiology is typically multifactorial, but typically includes anatomic predisposition, compliance with postsurgical instructions, medical comorbidities, and poor surgical technique.
HV deformity can result in several complications, including :
HV deformity, also known as a bunion, is one of the common forefoot deformities. It manifests as a deformity in the big toe, causing it to bend towards the other toes. The joint tends to become red and painful. The exact cause is not well understood. However, it tends to occur more often in women and people who wear tight shoes or heels. The diagnosis is typically through a physical exam. However, imaging is essential because it helps assess the severity of the deformity. Treatment centers upon first trialing non-surgical approaches such as wider shoes, use of orthotics, and night splinting. If this is ineffective, surgical management is the recommendation. Patients typically tolerate the surgery well, with bony union usually occurring around 6 to 7 weeks postoperatively. If the patient is a smoker, the healing may take longer, and there is a higher risk of complications such as non-union or wound infection. Patients typically return to work approximately 6 to 12 weeks post-surgery. Improvement has shown to occur as far out as one-year post-surgery.
The management of patients with HV deformity is best with an interprofessional team that includes primary care doctors, radiologists, physical therapists, pharmacists, pain specialists, and surgeons. The patient may present to their primary care doctor for swelling or pain. The diagnosis is typically made through a physical exam. Further imaging can help assess the severity of the deformity and guide the treatment. Conservative treatment is the first step. If this approach is ineffective, the patient should receive a referral to a surgeon for evaluation for surgical management. If surgery is performed, rehabilitation should follow to maximize post-surgery functionality. A pain specialist and the pharmacist can be used to help manage the post-surgical pain, with a focus on minimizing the use of opioids. Orthopedic nurses can assist at every step of the process, from conservative treatment to helping during surgery and post-op, as well as coordinating with therapists for post-surgical rehab. Patients should have long-term follow up to ensure they are meeting their recovery milestones. Open communication between members of the interprofessional treatment team is invaluable for improved outcomes.
This research was supported (in whole or part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author and do not necessarily represent the official view of HCA healthcare or any of its affiliated entities.
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