Excerpt from Hallux Valgus

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Lateral release sequence: (1) release of the conjoined adductor hallucis tendon, (2) release of the fibular sesamoid ligament, (3) tenotomy of the lateral head of the flexor hallucis brevis, and (4) excision of the fibular sesamoid.



Preoperative radiograph.



Postoperative radiograph shows Keller, or resectional, arthroplasty.



Preoperative radiograph shows degenerative joint disease.



Postoperative radiograph obtained after resectional arthroplasty and total joint implant placement.



Preoperative template for implant placement.

History of the Procedure

In the 19th century, the prevalent understanding of the bunion—hallux valgus—was that it was purely an enlargement of the soft tissue, first metatarsal head, or both, most commonly caused by ill-fitting footwear. Thus, treatment had varying results, with controversy over whether to remove the overlying bursa alone or in combination with an exostectomy of the medial head. These surgeries were considered to be beneath many surgeons, so the understanding of the pathology of hallux valgus was gradual in its development. Surgeons slowly began to recognize that bunions could develop as a result of numerous different factors, that they tended to be familial, and that they often were associated with other foot deformities.

As the school of thought began to shift, the first surgical treatment to address deforming pathology was developed and presented on May 4, 1881, when J. L. Reverdin gave a report on hallux abductovalgus to the Medical Society of Genfer. He described a procedure in which a curved incision medial to the extensor hallucis longus was followed by incision of the periosteum, chiseling off of the exostosis, removal of a wedge of bone from behind the capitulum of the metatarsus, and suturing of the bone with catgut. This operation is considered to be the forerunner of all operations that aim to correct hallux valgus via osteotomy.

Since its inception, the Reverdin procedure has undergone many variations and modifications, including the addition of lateral releases and proximal osteotomies, in an effort to address deformity. Indeed, more than 100 procedures have been attempted and developed for the correction of hallux valgus. However, many of these variations have been developed out of ignorance; some are even repetitions of previous procedures, both failed and successful. Surgeons have continued to reevaluate the osteotomy in search of the most stable procedure with the fewest complications.

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Hallux Varus
Hallux Rigidus
Bunion
Bunionette

Problem

Hallux valgus is considered to be a medial deviation of the first metatarsal and lateral deviation and/or rotation of the hallux, with or without medial soft-tissue enlargement of the first metatarsal head. This condition can lead to painful motion of the joint or difficulty with footwear.

Frequency

Although hallux valgus is a common condition that accounts for a significant number of office visits to foot and ankle specialists, the incidence has not been documented accurately. Relatively few studies are available, and much of the information consists of empirical data based on patient observations.

According to the National Health Interview survey conducted by the National Center for Health Statistics, this condition affects 1% of adults in the United States. Gould et al found that the incidence increased with age, with rates of 3% in persons aged 15-30 years, 9% in persons aged 31-60 years, and 16% in those older than 60 years.

Gould et al also reported a higher incidence in females versus males, with a ratio of 2:1 to 4:1. Whether this finding indicates a truly increased incidence in the female population or whether it reflects differences in footwear remains to be determined.

The role of genetic predisposition has also been noted, with evidence to suggest familial tendencies.

No conclusive results have been reported to indicate racial predisposition.

Etiology

Contrary to common belief, high-heeled shoes with a small toe box or tight-fitting shoes do not cause hallux valgus. However, such footwear does keep the hallux in an abducted position if hallux valgus is present, causing mechanical stretch and deviation of the medial soft tissue. In addition, tight shoes can cause medial bump pain and nerve entrapment. Hallux valgus is known to have numerous etiologies, including biomechanical, traumatic, and metabolic factors.

Etiologies of hallux valgus include the following:

• Biomechanical instability
  • The most common yet most difficult to understand etiology is biomechanical instability. Contributing factors, if present, include gastrocnemius or gastrocsoleus equinus, flexible or rigid pes plano valgus, rigid or flexible forefoot varus, dorsiflexed first ray, hypermobility, or short first metatarsal. Most often, excessive pronation at the midtarsal and subtalar joints compensates for these factors throughout the gait cycle.
  • Some pronation must occur in gait to absorb ground-reactive forces. However, excessive pronation produces too much midfoot mobility, which decreases stability and prevents resupination and creation of a rigid lever arm; these effects make propulsion difficult.
  • During normal propulsion, approximately 65° of dorsiflexion is necessary at the first metatarsophalangeal joint, yet only 20-30° is available from hallux dorsiflexion. Therefore, the first metatarsal must plantarflex at the sesamoid complex to gain the additional 40° of motion needed. Failure to attain the full 65° because of jamming of the joint during pronation subjects the first metatarsophalangeal to intense forces from which hallux valgus develops.
  • If the foot is sufficiently hypermobile as a result of excessive pronation, the metatarsal tends to drift medially and the hallux drifts laterally, producing hallux valgus. If no hypermobility is present, hallux rigidus develops instead.
• Arthritic/metabolic conditions (see Image 1 and Image 2)
  • Gouty arthritis
  • Rheumatoid arthritis
  • Psoriatic arthritis
  • Connective tissue disorders such as Ehlers-Danlos syndrome, Marfan syndrome, Down syndrome, and ligamentous laxity
• Neuromuscular disease
  • Multiple sclerosis
  • Charcot-Marie-Tooth disease
  • Cerebral palsy
• Traumatic compromise
  • Malunions
  • Intra-articular damage
  • Soft-tissue sprains
  • Dislocations
• Structural deformity
  • Malalignment of articular surface or metatarsal shaft
  • Abnormal metatarsal length
  • Metatarsus primus elevatus
  • External tibial torsion
  • Genu varum or valgum
  • Femoral retrotorsion

Related Medscape topics:
Resource Center Joint Disorders
Resource Center Arthritis
Resource Center Rheumatoid Arthritis

Related eMedicine topics:
Gout
Rheumatoid Arthritis
Psoriatic Arthritis
Multiple Sclerosis
Charcot-Marie-Tooth Disease 
Cerebral Palsy
Genu Varum, Pediatrics
Genu Valgum, Pediatrics

Pathophysiology

Line of pull of the extensor hallucis longus causing the metatarsal to deviate medially and hallux to deviate laterally.

During the gait cycle, the hallux and digits generally remain parallel to the long axis of the foot, regardless of the degree of forefoot abduction (or pronation) occurring (see Image 3). This is because of the pull of the conjoined adductor tendon, extensor hallucis longus, and flexor hallucis longus tendons. The tendons gain greater mechanical advantage the further the joint is displaced, with tension created in the medial aspect of the joint and compression laterally.

Medial tension causes the medial collateral ligaments to pull on the dorsomedial aspect of the first metatarsal head, causing bone proliferation. Lateral tension causes the sesamoid apparatus to fixate in a laterally dislocated position. Remodeling also occurs laterally in addition to medially, as evidenced by the increase of the proximal articular set angle or structural remodeling of the cartilage. Therefore, without correction of the biomechanical factors, excessive pronation continues, with propagation of the deformity.

Clinical

History

Patients can present initially in several ways; therefore, evaluation of the history is extremely important. A patient may present with a nonacute onset of deep or sharp pain in the first metatarsophalangeal joint during ambulation, with exacerbation during particular activities. This presentation indicates degeneration of the intra-articular cartilage.

The patient may also describe aching pain in the metatarsal head secondary to shoe irritation that is relieved when the shoes are removed. This presentation is indicative of superficial bump pain. Often, both forms of pain are progressive and have been present for many years. The frequency or duration of pain may recently have begun to increase, and activity may exacerbate the pain. Patients may even describe a recent notable increase in the size of the deformity or medial bump.

Questions on limitation of physical or daily living activities are valuable for understanding the severity of the patient's pain. It is also important to ascertain what, if anything, relieves the pain and which treatments (eg, surgery) have been attempted previously. Occasionally, trauma or inflammatory arthritis is an associated finding.

Another possible presentation is burning pain or tingling in the dorsal aspect of the bunion, which indicates entrapment neuritis of the medial dorsal cutaneous nerve. The patient may also describe symptoms caused by the deformity, such as a painful overlapping second digit, interdigital keratosis, or ulceration to the medial metatarsal head, without complaint of the bunion deformity itself.

Physical examination

The physical examination includes an assessment of the vascular, dermatologic, neurologic, and musculoskeletal systems.

The musculoskeletal assessment can be divided into 2 components: determination of the etiology and evaluation of the resultant pathology (or presenting deformity). Understanding both components is essential in determining the most satisfying and successful treatment plan, whether conservative or surgical.

The workup is tailored to the patient's history. If neurologic complaints, systemic arthritis, or collagen vascular disease are mentioned, they should be addressed further in detail. If none of these are present, the focus then turns to the biomechanical examination, which includes assessment of the following measures, any or all of which can contribute to hallux valgus:

• Hip internal/external rotation
• Genu valgum/varum
• Tibial torsion
• Ankle joint dorsiflexion
• Subtalar joint range of motion (ROM)
• Midtarsal joint ROM
• Neutral calcaneal stance position
• Resting calcaneal stance position
• Forefoot/rearfoot varus or valgus

Assessment of resultant pathology can be divided into weightbearing and non–weightbearing evaluations, as both yield important information for determining the appropriate treatment protocol (see Image 4).

With the patient in a non–weightbearing position, examine the following:

• Hallux position: The position of the hallux in the transverse plane should be assessed relative to the second digit. The hallux can be overriding, underriding, abutting, or without contact. Lateral deviation of the hallux may result from subluxation of the metatarsophalangeal joint or structural changes to the hallux. The hallux may be rotated in the frontal plane, as noted by valgus or varus rotation of the toenail. Thus, hallux abductus indicates transverse plane deformity, while hallux abductovalgus indicates deviations in the transverse and frontal plane.
• Medial prominence: Most medial prominences are located dorsomedial and appear to be more severe in a metatarsal adductus foot type. Erythema or bursa indicates shoe pressure and irritation.
• First metatarsophalangeal joint ROM: The first aspect to assess is maximum available motion. Normal dorsiflexion is 65-75° with plantarflexion less than 15°. The next aspect is quality of joint ROM and whether pain, crepitation, or both are present; such findings indicate intra-articular cartilage degeneration. Pain without crepitation suggests synovitis. The axis of motion is the last variable to assess. The joint is considered track-bound if the hallux drifts laterally after being placed in a neutral position during ROM exercises. Degree of lateral drift indicates severity of lateral soft-tissue contracture.
• First ray ROM: The first ray should be evaluated in 2 ways. The first is determination of the ROM and resting position. Normal ROM is 10 mm total, with 5 mm dorsiflexion and 5 mm plantarflexion (see Image 5). Resting position should be neutral compared with the second metatarsal head. The second evaluation is determination of mobility in the transverse plane. In the normal foot there is little to no motion available. However, in the presence of hallux valgus motion may be detectable.
• Plantar keratosis: Keratosis at the hallux interphalangeal joint (IPJ) indicates excessive pronation at push off. If present underneath the first metatarsophalangeal joint (MPJ), this indicates excessive pressure secondary to equinus, rigidly plantarflexed first metatarsal, prominent sesamoid, rigid forefoot valgus, or cavus foot type. Keratosis underneath the second metatarsal head can indicate short first metatarsal or long second metatarsal, dorsiflexed first metatarsal with resultant transfer lesion, retrograde plantarflexion of the second digit from hammertoe deformity, or hypermobility of the first metatarsal.
• Pain location: The entire first metatarsophalangeal joint complex should be palpated for pain during passive and active ROM, including but not limited to the dorsal, plantar, and/or medial metatarsal head, sesamoid, crista, proper digital nerves, and extensor hallucis longus tendon.
• Contracture of the extensor hallucis longus: This condition is present only in long-standing lateral subluxations of the first metatarsophalangeal joint or neuromuscular disease.
• Associated deformities: Second digit hammertoes and flexible or rigid flatfoot are commonly noted. Instability of the second digit may allow a more rapid progression of hallux valgus, as the second digit is unable to act as an adequate lateral buttress.

Often, the pathology or severity of deformity is not as apparent when the patient is not bearing weight as it is when the patient is bearing weight. Therefore, weightbearing examination is an important part of the physical evaluation. In the weightbearing examination, assess the following aspects:

• Positional increase of hallux abduction in the transverse and frontal planes.
• Increase in medial prominence.
• Increase in extensor hallucis longus tendon contracture.
• First metatarsophalangeal joint dorsiflexion, characterized as decrease, increase, or no change.
• Hallux purchase, noted as good, fair, poor, or absent. (This should be normal preoperatively and serves as a baseline for postoperative examination.)
• Metatarsus adductus. (The greater the adductus, the greater the deformity appears.)

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