The first metatarsophalangeal joint functions mainly as a weight-bearing structure and stabilizer of the medial aspect of the longitudinal arch. The static stability of the first metatarsophalangeal joint is provided by the collateral ligaments and the strong plantar plate, which consists of the plantar aponeurosis and the joint capsule. Added dynamic stability is provided by the abductor hallucis and adductor hallucis muscles, which insert along the medial and lateral sides of the metatarsal head, respectively. No muscle inserts into the metatarsal head per se, and therefore, it is suspended in a sling of muscles and tendons. This allows the metatarsal head to be pushed in a medial or lateral direction, depending on the deviation of the proximal phalanx.
The plantar aponeurosis forces the metatarsal heads into plantar flexion during the last third of the stance phase of the walking cycle. The hallux experiences greater pressure as it is transferred from the metatarsal heads to the toes (see Figure 8–5). If this windlass mechanism for the hallux is lost as occurs in a bunion deformity, pressure is no longer transferred to the toes but remains beneath the metatarsal heads. Metatarsalgia results from this transfer of load, especially beneath the lesser metatarsal heads. The second metatarsal frequently bears the load because the weight-bearing ability of the first metatarsal is disrupted.
Changes to the normal biomechanics of this joint may result in a transfer lesion, which is a hyperkeratotic lesion under the lesser metatarsal heads. The most common cause is a surgical procedure that disrupts this mechanism, such as a Keller arthroplasty. In this procedure, the base of the proximal phalanx is removed, thereby disrupting the insertion of the plantar aponeurosis into the hallux. Also, prosthetic replacement of the first metatarsal joint will result in loss of this mechanism. Metatarsal osteotomy with excessive shortening (>5–7 mm) or dorsiflexion of the first metatarsal may also cause this problem.
The first metatarsophalangeal joint is complex. It is made up of the articular surface of the metatarsal head and the base of the proximal phalanx, along with the two sesamoid bones plantarly. The sesamoids are connected by an intersesamoidal ligament, separated by a bony crista, and lie within the dual tendons of the flexor hallucis brevis. Medially and laterally, the collateral ligaments stabilize the metatarsophalangeal joint, and toward the plantar surface, they blend with the adductor and abductor hallucis tendons along the lateral and medial sides of the joint. Further toward the plantar surface, the sesamoids are stabilized by the firm attachment of the encapsulating plantar aponeurosis, which inserts into the base of the proximal phalanx. Plantar to the sesamoids passes the flexor hallucis longus tendon. Dorsally, the extensor hallucis longus tendon is stabilized by a medial and lateral hood mechanism similar to that present in the hand, and the extensor digitorum brevis muscle inserts into the proximal phalanx along the lateral aspect of the joint. Normal motion of the metatarsophalangeal joint consists of dorsiflexion and plantar flexion.
Hallux valgus is also known as a bunion deformity (ICD-9 735.0). It is a complex deformity that includes lateral deviation of the proximal phalanx and the resultant medially directed pressure exerted against the metatarsal head. The medial eminence becomes prominent as the proximal phalanx drifts into a valgus position. With chronic deformity, the medial joint capsule becomes attenuated, and the lateral joint capsule becomes contracted. As the metatarsal head is pushed medially, the sesamoids, which are firmly anchored by the adductor hallucis tendon and transverse metatarsal ligament, slowly erode the crista. This allows for lateral subluxation of the sesamoids from directly plantar to the first metatarsal. With the lateral deviation of the hallux, the extensor hallucis longus and flexor hallucis longus assume a lateral position and contribute to the lateral forces on the hallux. With a severe deformity, both the extrinsic and intrinsic muscles lie lateral to the longitudinal axis of the first metatarsophalangeal joint, thereby further enhancing the deformity. As the deformity progresses, pronation of the hallux occurs because attenuation of the weakest portion of the capsule (the dorsomedial aspect) allows the abductor hallucis tendon to slide beneath the metatarsal head and rotate the proximal phalanx into a position of pronation. More rapid progression of the deformity may occur in a small percentage of patients whose first metatarsocuneiform joint demonstrates a significant degree of instability.
The incidence of hallux valgus deformity is 10 times greater in women than in men. The incidence is also significantly higher in shod populations than unshod ones. The conclusion can therefore be made that a major contributing cause of hallux valgus deformity is wearing constricting shoes. Other factors that may contribute to hallux valgus are familial history of bunions, bilateral involvement, female gender, a long first ray, an oval or curved metatarsophalangeal joint articular surface, spasticity, and systemic disease such as rheumatoid arthritis. Furthermore, hallux valgus deformity is not associated with chronic tightness of the Achilles tendon or gastrocnemius, increased first ray mobility, bilaterality, or pes planus.
The most common symptom is pain over the medial eminence. Patients also complain of pain in the joint and pain under the second metatarsal head (transfer lesion or metatarsalgia). The deformity may prevent shoewear, and the activity limitation may be part of the constellation of symptoms. The patient's occupation, sports activities, and typical shoewear should be noted.
A complete evaluation is performed on both lower extremities with the patient undressed from the knees to the toes. The patient is instructed to stand and walk. The posture of the foot is noted as well as the position of the hallux and lesser toes. The skin is evaluated for erythema, swelling, ulceration, or callosities. The ROM is checked for the ankle, subtalar, transverse tarsal, and metatarsophalangeal joints. The neurovascular status of the foot is carefully assessed, noting absent pulses and venous stasis changes. If there is compromise of the vascularity, then vascular studies may be obtained. Doppler studies are obtained if there is any question regarding the circulatory status of the foot. It is important to note the ROM of the first metatarsophalangeal joint in the deformed and corrected position. The amount of motion limitation will give the surgeon insight into the degree of surgical correction that can be obtained at the joint without impairing motion of the joint. The first metatarsocuneiform joint is examined for hypermobility by stabilizing the medial cuneiform and ranging the first metatarsal dorsomedially and plantolaterally.
Weight-bearing radiographs of the foot are important to evaluate the type and severity of the hallux valgus deformity. Radiographic evaluation of the first metatarsophalangeal joint includes:
The hallux valgus angle: The angle created by the intersection of the lines that longitudinally bisect the proximal phalanx and first metatarsal. A normal angle is less than 15 degrees (Figure 8–6).
The 1,2 intermetatarsal angle: The angle created by the intersection of the lines bisecting the first and second metatarsal shafts. A normal angle is less than 9 degrees (Figure 8–6).
The distal metatarsal articular angle: The angle of the distal articular surface of the first metatarsal to the long axis of the metatarsal. Normal is less than 10 degrees of lateral deviation.
Congruency of the first metatarsophalangeal joint: A congruent joint has no lateral subluxation of the proximal phalanx in relation to the first metatarsal head, and an incongruent joint has lateral subluxation of the proximal phalanx on the metatarsal head (Figure 8–7).
The first metatarsocuneiform joint: The angle is based on the distal articular surface of the medial cuneiform and the longitudinal axis of the first metatarsal. Excessive medial deviation may indicate that hypermobility may be present.
Arthrosis of the metatarsophalangeal joint has joint space narrowing, subchondral sclerosis, and osteophyte formation.
The medial eminence: The characteristics are evaluated, especially size, as measured from the sagittal groove on the medial aspect of the first metatarsal shaft.
The hallux valgus interphalangeus is present when there is lateral deviation of the proximal or distal phalanx, or both, in relation to a line drawn across the base of the proximal phalanx. Normal is less than 10 degrees of lateral deviation.
Anteroposterior weight-bearing radiograph of a patient with a symptomatic hallux valgus deformity. Lines drawn show hallux valgus angle and 1,2 intermetatarsal angle.
Example of an incongruent first metatarsophalangeal joint, with mild lateral subluxation.
As with all forefoot disorders, proper shoewear is important for successful conservative management. The patient should be encouraged to wear shoes of adequate size and shape. This simple form of management may relieve most symptoms. Padding is helpful to alleviate symptoms associated with the bunion deformity. Pads may be placed in the first web space or over the median eminence to help take pressure off a painful median eminence. Pads are also available that can be placed underneath the metatarsal heads to take pressure off painful calluses or sesamoids. In some patients, custom orthotic devices are helpful. These, too, will decrease pressure in symptomatic areas. Patients who fail these treatment options may consider surgical treatment to correct the deformity. An operation is not performed for cosmetic reasons or to allow patients to wear fashionable shoes, but rather to correct a symptomatic structural deformity.
Juvenile hallux valgus deformity is considered a different entity than adult hallux valgus. These patients may be challenging to treat, but as a general rule, nonoperative management should be continued until growth is completed, after which surgery may be considered. Extra care must be taken into consideration in the juvenile population where cosmetic appearance may play a greater role in the patient's or parents' desire for surgery. Hallux valgus surgery is generally contraindicated in high-performance athletes or dancers until they are no longer able to perform at the level necessary to continue in their vocation or avocation. Premature surgery in these individuals may diminish their special abilities.
Algorithm for Surgical Treatment
The patient's symptoms, the physical signs, and the radiographic findings must be taken into account in determining the best operation for that patient. It must be emphasized that there is not a single procedure appropriate for all hallux valgus deformities. Preoperative planning with all these considerations is important.
The following factors need to be considered in the decision-making process:
Patient's chief complaint
Degree of hallux valgus and intermetatarsal angle
Distal metatarsal articular angle
Congruency or incongruency of the metatarsophalangeal joint
Presence of arthrosis of the joint
Degree of pronation of the hallux
Age of the patient
Patient expectations for outcome of operation
The algorithm in Figure 8–8 divides hallux valgus deformities into three main groups: those with a congruent joint, those with an incongruent joint, and those associated with degenerative joint disease. The algorithm lists the operative procedure that may best correct the deformity within each classification. Although no one scheme is all inclusive, this algorithm is helpful in organizing the treatment plan.
Algorithm for hallux valgus deformities. M-C, metatarsocuneiform; MPJ, metatarsal phalangeal joint; STP, soft-tissue procedure. (Redrawn, with permission, from Mann RA, Coughlin MJ: The Video Textbook of Foot and Ankle Surgery. Medical Video Productions, 1991.)
The first step is to evaluate the first metatarsophalangeal joint for congruency. A congruent metatarsophalangeal joint generally requires excision of the large and symptomatic medial eminence, and the joint does not require realignment. For a mild to moderate deformity, a chevron osteotomy with or without an Akin procedure yields good to excellent results.
With an incongruent joint, the proximal phalanx is subluxed laterally on the metatarsal head. The operative procedure necessitates that the proximal phalanx be reduced onto the metatarsal head. The procedure of choice depends on the severity of the deformity (see Figure 8–8).
If the first metatarsocuneiform joint is hypermobile, a distal soft-tissue procedure with a metatarsocuneiform arthrodesis (Lapidus procedure) may be indicated. With a severe hallux valgus deformity, a greater than 45- to 50-degree hallux valgus angle, and degenerative joint disease, arthrodesis of the joint is indicated. If routine hallux valgus repair is attempted in the patient with advanced arthrosis, stiffness of the metatarsophalangeal joint frequently results. Use of a prosthetic replacement, as a general rule, does not produce a satisfactory long-term result, particularly in active individuals.
Distal Soft-Tissue Procedure
The McBride procedure was a commonly performed operation (CPT 28292). It was modified by DuVries, followed by additional modifications, and is now called the distal soft-tissue procedure. The procedure used by itself is appropriate in mild hallux valgus deformities, where the intermetatarsal angle is less than 12–13 degrees and the hallux valgus angle is less than 30 degrees. Within this range of deformity, a satisfactory outcome can usually be anticipated from this procedure.
The distal soft-tissue procedure involves a medial incision to expose the metatarsophalangeal joint. The joint is inspected, and the medial eminence is removed 1–2 mm just medial to the sagittal sulcus and in line with the medial aspect of the metatarsal shaft. A second incision in the first interspace allows for releasing the soft-tissue contracture on the lateral side of the metatarsophalangeal joint. These structures include the lateral joint capsule, the adductor hallucis tendon, and the transverse metatarsal ligament (Figure 8–9). Once released, the medial side of the joint is plicated to hold the toe in correct alignment. Postoperatively, the patient is maintained in a firm compression dressing in the correct alignment, and the dressing is changed on a weekly basis for 8 weeks. During this period, the patient is permitted to ambulate in a postoperative shoe.
Total soft-tissue procedure. A: The adductor tendon inserts into the lateral aspect of the fibular sesamoid and into the base of the proximal phalanx. B: The adductor tendon was removed from its insertion into the lateral side of the fibular sesamoid and base of the proximal phalanx. C: The transverse metatarsal ligament is passed from the second metatarsal into the fibular sesamoid. D: The transverse metatarsal ligament was transected. E: The three contracted structures on the lateral side of the metatarsophalangeal joint were released. F: The medical capsular incision begins 2–3 mm proximal to the base of the proximal phalanx, and a flap of tissue measuring 3–8 mm is removed. G: The medial eminence is exposed by creating a flap of capsule that is based proximally and plantarward. H: The medial eminence is removed in line with the medial aspect of the first metatarsal. I: The postoperative dressings are critical. Note that the metatarsal heads are firmly bound with the gauze, and the great toe is rotated so as to keep the sesamoids realigned beneath the metatarsal head. This necessitates dressing the right great toe in a counterclockwise direction and the left great toe in a clockwise direction when one is standing at the foot of the bed. (Reproduced, with permission, from Mann RA, Coughlin MJ: The Video Textbook of Foot and Ankle Surgery. Medical Video Productions, 1991.)
The most common complication consists of recurrence of the deformity, usually because the deformity was too severe to be corrected by the procedure. In these cases, a metatarsal osteotomy added to the distal soft-tissue procedure completes the correction.
Hallux varus deformity is a medial deviation of the proximal phalanx on the metatarsal head, a complication that may occur in approximately 5–7% of cases. This deformity is usually a result of excessive excision of the medial eminence or fibular sesamoidectomy, which causes joint instability. Occasionally, the medial joint capsule is overplicated or the lateral joint capsule fails to attain adequate strength. Mild hallux varus deformity, up to 7–10 degrees, usually is of no clinical significance unless the joint is also hyperextended.
Distal Soft-Tissue Procedure with Proximal Metatarsal Osteotomy
A proximal metatarsal osteotomy (CPT 28296) will increase the correction of the distal soft-tissue procedure. A proximal metatarsal osteotomy will correct an increased 1,2 intermetatarsal angle, such as a deformity greater than 12–13 degrees, whereas the distal soft-tissue procedure alone cannot. Realignment of the fixed bony deformity present between the first and second metatarsals permits the combined procedure to be used for deformities with up to 50 degrees of hallux valgus and a 25-degree intermetatarsal angle.
The distal soft-tissue procedure is performed, as previously described. Another incision, based over the base of the first metatarsal, is made. A crescentic-shaped saw blade is used to create a crescentic osteotomy, in which the concavity is directed proximally (Figure 8–10). This enables the surgeon to rotate the metatarsal head laterally as the metatarsocuneiform joint is pushed in a medialward direction. This usually results in approximately 2–3 mm of lateral displacement of the osteotomy site. A single cancellous screw placed from the distal fragment into the proximal aspect allows for stable fixation. A popular osteotomy is a chevron cut, or various oblique cuts, opening or closing wedge osteotomies.
A: The osteotomy site is reduced by pushing the proximal fragment medially with a small freer while pushing the metatarsal head laterally. This locks the lateral side of the osteotomy site so the internal fixation can be inserted. (Reproduced, with permission, from Mann RA, Coughlin MJ: The Video Textbook of Foot and Ankle Surgery. Medical Video Productions, 1991.) B: Anteroposterior postoperative radiographs of a case of proximal crescentic osteotomy. The patient underwent the same procedure to the contralateral foot.
Postoperatively, the treatment is the same as for the distal soft-tissue procedure, with 8 weeks of dressing changes and immobilization in a postoperative shoe. As a general rule, cast immobilization is not necessary.
The long-term postoperative results following the distal soft-tissue procedure with proximal osteotomy result in greater than 90% patient satisfaction. The addition of the osteotomy does create an increased risk of complications, but this risk is reported to be uniformly low. Dorsiflexion of the osteotomy site may occur but is usually not of clinical significance. Nonunion of the osteotomy is rare (<1% of cases). Excessive lateral displacement of the metatarsal head can result in hallux varus deformity, which is more resistant to treatment than when osteotomy is not included.
The chevron osteotomy is the most common bunion procedure in the United States (CPT 28296). It is indicated for mild to moderate hallux valgus deformities. The procedure is used in deformities when the hallux valgus angle is less than 30 degrees and the 1,2 intermetatarsal angle is less than 12 degrees. The distal metatarsal articular angle should be less than 12 degrees, or complete correction will not be obtained. The operative procedure is based on lateral translation of the metatarsal head, along with plication of the medial joint capsule. The osteotomy is performed through a medial incision to allow removal of the medial eminence. Then, a chevron-shaped cut with the apex based distally is made with a small sagittal saw. The metatarsal head fragment is translated laterally approximately one third of the width of the metatarsal head, or 3–4 mm. The medial bony prominence created by the shift of the metatarsal head is excised and the medial joint capsule plicated. The osteotomy site is fixed with a pin or a screw (Figure 8–11).
(A) Anteroposterior and (B) lateral radiographs of a chevron osteotomy.
Postoperatively, the foot is firmly bandaged for 6–8 weeks in corrected alignment, and the patient is permitted to ambulate in a postoperative shoe. If a pin was used for fixation, it is removed after 4–6 weeks.
Radiographic improvement is seen with high patient satisfaction. In addition, a greater than 10-year follow-up showed consistent improvement with time. There was no difference between patients younger and older than 50 years; patients had equally positive outcomes. However, if the indications are stretched to include more severe deformities, then results may not be satisfactory, with a recurrence or incomplete correction. The most serious complication, occurring in 0–20% of cases, is avascular necrosis of the metatarsal head, which is probably the result of extensive stripping of the soft tissue surrounding the head, especially laterally. The major blood supply to the metatarsal head is from the plantar lateral corner of the metatarsal neck. Therefore, care must be used when performing the saw cut, and the saw should be removed once the osteotomy is completed so as to not injure the vessels on the lateral aspect of the metatarsal head. As with any type of osteotomy, the distal fragment is capable of migrating either too far laterally or medially, giving rise either to hallux varus deformity or recurrent hallux valgus deformity. Occasionally, arthrofibrosis of the joint is noted, resulting in significant joint stiffness.
The Akin procedure is useful as an adjunct to a bunion procedure of the first metatarsal (CPT 28298). It involves a medial closing-wedge osteotomy at the base of the proximal phalanx to correct the hallux interphalangeal component of the deformity. It is commonly used with simple excision of the median eminence or with a chevron osteotomy to correct a mild to moderate hallux valgus deformity with a congruent joint. The Akin procedure is indicated for a hallux valgus deformity of less than 25 degrees, with an intermetatarsal angle of 12 degrees or less.
Through a medial incision, the base of the proximal phalanx and the median eminence are exposed. After removing the median eminence in line with the metatarsal, a small sagittal saw is used to remove a wedge of bone from the medial aspect of the proximal phalanx. The osteotomy is closed down and stabilized internally with sutures or wires or externally with a Kirschner wire (K-wire) (Figure 8–12). Dressings are applied for 6–8 weeks postoperatively. Patients may ambulate in a postoperative shoe until the osteotomy has healed.
Radiograph of an Akin osteotomy of the proximal phalanx.
The Keller procedure is seldom indicated as a hallux valgus procedure (CPT 28292). It is reserved for the older, less active patient; in a patient prone to skin problems; or in the case of an arthritic joint. This procedure is contraindicated in an active person because of its known complications.
The procedure involves excision of the base of the proximal phalanx to decompress the metatarsophalangeal joint. Along with the procedure, the medial eminence is removed, and then the intrinsic muscle attachments are repaired to the remaining stump of bone (Figure 8–13). A Kirschner wire is drilled through the toe as a stabilizer until the toe heals and scar tissue forms, approximately 4–6 weeks. Postoperatively, the patient is permitted to ambulate in a postoperative shoe, and dressings are changed for 6 weeks.
Keller procedure. A: The medial eminence is removed in line with the medial aspect of the metatarsal shaft. The proximal third of the proximal phalanx is removed. B: An attempt is made to reapproximate the plantar and medial capsular structures to the remaining base of the proximal phalanx. (Reproduced, with permission, from Mann RA, Coughlin MJ: The Video Textbook of Foot and Ankle Surgery Medical Video Productions, 1991.)
Results in the older (>65 years) patient with low functional demand are satisfactory. If the procedure is used in a younger patient, there is instability and loss of weight bearing by the first metatarsophalangeal joint because the base of the proximal phalanx was removed. There is significant loss of foot function, and a transfer lesion may develop beneath the second metatarsal head because the great toe no longer carries adequate weight. The metatarsophalangeal joint develops into a cocked-up deformity with some varus malalignment.
Arthrodesis of the First Metatarsophalangeal Joint
Arthrodesis of the first metatarsophalangeal joint is used in treatment of severe hallux valgus deformities (CPT 28750) with concomitant advanced degenerative arthrosis of the joint or as a salvage procedure following a previously failed surgical attempt to realign the metatarsophalangeal joint. Also, patients with deformities in which the proximal phalanx is subluxed more than 50% of the metatarsal head or who have significant stiffness of the metatarsophalangeal joint should be considered for fusion.
The procedure is performed through a dorsal longitudinal incision, and the joint surface is removed with a sagittal saw to yield two flat surfaces. Alternatively, a dome-shaped reamer may be used to create a ball-and-socket type of configuration. The arthrodesis site is stabilized with an interfragmentary screw and a dorsal plate or Steinmann pins if the bone quality is poor and inadequate screw fixation results. As with any fusion, the position of the arthrodesis is critical; the joint should be placed in 15 degrees of valgus and 10–15 degrees of dorsiflexion in relation to the ground or the plantar aspect of the foot. In relation to the first metatarsal shaft, which is inclined plantarward approximately 15 degrees, it should be in approximately 30 degrees of dorsiflexion (Figures 8–14 and 8–15). Any pronation that is present must also be corrected at the same time.
Arthrodesis of the first metatarsophalangeal joint. A: The joint is placed into approximately 10–15 degrees of dorsiflexion in relation to the floor, which is approximately 25–30 degrees of dorsiflexion in relation to the first metatarsal shaft. (Reproduced, with permission, from Mann RA, Coughlin MJ: The Video Textbook of Foot and Ankle Surgery. Medical Video Productions, 1991.)
Radiograph of a patient with a first metatarsophalangeal arthrodesis for degenerative arthritis and severe hallux valgus deformity.
The patient may ambulate on the heel while wearing a postoperative shoe and progress to full weight bearing in the postoperative shoe until radiographic union is seen, generally in 12 weeks. The unreliable patient may be treated in a short leg walking cast.
The most common complication of arthrodesis of the first metatarsophalangeal joint is malposition. If the toe is not placed into adequate dorsiflexion or valgus, excessive stress occurs against the interphalangeal joint, which may result in a painful arthritic condition of the joint. The fusion rate is 90–95%. In cases of severe hallux valgus deformities, the arthrodesis will correct the hallux valgus angle as well as the increased 1,2 intermetatarsal angle; thus, the need for a proximal osteotomy is unnecessary. Occasionally, the degree of valgus and dorsiflexion is correct but the toe is left in a pronated position, which results in pressure along the medial side of the interphalangeal joint and possible discomfort.
The patient's gait following arthrodesis of the first metatarsophalangeal joint in proper alignment is improved in propulsive power, weight-bearing function of the foot, and stability during gait. These patients are able to roll over the fusion site in an ordinary store-bought shoe, and they may expect to return to normal activities. Squatting is the only activity that is difficult because the toe must be in full dorsiflexion when this activity is carried out. Patients are able to return to most types of athletic activities, although at a somewhat slower pace.
Hallux rigidus is the name for arthrosis of the first metatarsophalangeal joint (ICD-9 715.17). It is a common entity and frequently affects patients at a much younger age than arthritis of other joints. Hallux rigidus is seen in patients from their thirties onward. The reason why arthritis of this joint is seen in younger patients is unclear but may be associated with an unrecognized chondral injury to the metatarsal head. It is also associated with hallux valgus interphalangeus, bilateral involvement in those with a family history, and female gender. Hallux rigidus is not associated with elevatus, first ray hypermobility, a long first metatarsal, Achilles tightness, abnormal foot posture, symptomatic hallux valgus, adolescent onset, shoe wear, or occupation.
Patients complain primarily of pain of the first metatarsophalangeal joint, especially with extension. Also, the dorsal eminence may prevent shoewear and have associated swelling and redness. Weight bearing and sports activities exacerbate the pain.
Weight-bearing radiographs of the foot demonstrate arthritic changes, including loss of joint space, subchondral sclerosis, and the presence of osteophytes, especially on the dorsal aspect of the metatarsal neck.
Conservative treatment consists of nonsteroidal anti-inflammatory drugs (NSAIDs) and wearing a stiff-soled shoe with a deep toe box. An orthotic device with a Morton's extension or a carbon fiber plate would be beneficial. Both of the devices prevent extension in late stance phase. A rocker-bottom shoe would also be helpful. In older (>60 years), sedentary patients, these measures are usually adequate. In more active individuals, however, surgical treatment is usually indicated.
There are multiple described surgical treatment options for hallux rigidus. Of these, the simplest is a cheilectomy (CPT 28289) and is indicated in patients with mild to moderate arthrosis but who have a large dorsal osteophyte. Approximately one fourth to one third of the dorsal metatarsal head is excised with an osteotome (Figure 8–16). The medial and lateral osteophytes are also debrided, and a thorough synovectomy of the joint is performed. Postoperatively, patients regain up to 50% of their dorsiflexion and have improvement of their total motion. More than 90% of patients have improvement of pain, ability to wear shoes, and increased physical abilities. This procedure is less likely to have a favorable outcome on joints with advanced arthritis.
A: Preoperative lateral radiograph of a patient with hallux rigidus. B: Intraoperative photograph of the dorsal osteophyte. C: Following removal of the osteophyte. D: Extension of the first metatarsophalangeal joint is 70 degrees, and confirms adequate resection of the first metatarsal head.
A Keller procedure is a resection arthroplasty and may be useful in older, less active patients, but it has a high rate of complications, as previously discussed. Prosthetic replacement of the arthritic first metatarsophalangeal joint can be used in older, lower demand patients but has high rates of failure in younger, more active individuals.
First metatarsophalangeal joint arthrodesis is a predictable and durable procedure. The drawback is lost motion at the joint. However, patients can remain quite active with a first metatarsophalangeal joint fusion as described previously.
The sesamoid bones are plantar to the first metatarsal head and are part of the first metatarsophalangeal joint complex. Sesamoid disorders can be painful as they are in the weight-bearing part of the foot. Fractures, osteonecrosis, arthritis, and subluxation can affect the sesamoids. A puzzling entity is called sesamoiditis (ICD-9 733.99), which means inflammation of the sesamoids, but it encompasses painful sesamoids without an etiology.
The patient complains of pain directly under the first metatarsophalangeal joint that is worse with weight-bearing activities. The history may be significant for a trauma to the toe causing a fracture, but most commonly, the pain has an insidious onset.
Manual palpation of the area will reveal which sesamoid is affected, medial or lateral. Also, during the physical examination, postural abnormalities of the foot that may be contributing to the condition are evaluated. For example, hallux valgus deformity may cause a subluxation of the sesamoid from its normal articulation with the plantar aspect of the metatarsal head, causing pain, whereas pes cavus may result in greater pressure under the sesamoids, leading to symptoms.
Radiographs of the weight-bearing foot are taken and include a skyline or sesamoid view, which is a tangential view of the sesamoid metatarsal head articulation. On the anteroposterior view, subluxation of the sesamoids lateral to the first metatarsal head can be present with hallux valgus deformities. On the skyline view, fragmentation can be seen in cases with osteonecrosis, and joint space narrowing and osteophyte formation are seen with osteoarthritis. Displaced fractures are easy to determine, but nondisplaced fractures may be difficult to distinguish from a bipartite sesamoid that is a normal finding. A magnetic resonance imaging (MRI) or bone scan may be helpful in the case of normal radiographs to diagnose osteonecrosis or sesamoiditis.
Acute injuries involving the sesamoid can be treated with a course of cast immobilization, sometimes non–weight bearing. A toe plate on the cast will provide greater immobilization and support. For chronic problems, a stiff-soled postoperative-type shoe may be used, and a soft felt pad can be placed just proximal to the sesamoids to take the pressure off the involved area. If needed, an orthotic device with a metatarsal pad or bar will relieve sesamoid pressure. Usually the majority of symptoms resolve in a matter of weeks, although some degree of discomfort may persist for several months. If 6–12 months of conservative treatment does not relieve the symptoms, the affected sesamoid can be removed via sesamoidectomy, which relieves the pain. There is the possibility of transferring pain to the remaining sesamoid.
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