Simple Bunionectomy (e.g., modified McBride, Silver Procedure)

Aetna considers simple bunionectomy with soft tissue removal of the bump only without bony correction medically necessary in members with either of the following conditions:

1. Members with clinical symptoms, a hallux valgus angle (HVA) (formed by the long axis of the proximal phalanx and the first metatarsal) of 15 degrees or more with no degenerative changes at the meta-tarso-phalangeal (MTP) joint, and a history of conservative management failure; or
2. Members with diabetes who have an ulcer and/or infection stemming solely from the bunion.

Aetna considers simple bunionectomy experimental and investigational for all other indications because its effectiveness for indications other than the ones listed above has not been established.

Bony Correction Bunionectomy (e.g., Akin, Chevron Osteotomy, Keller, Lapidus, Mitchell, proximal metatarsal osteotomy procedures, etc.)

Aetna considers bony correction bunionectomy to treat symptomatic hallux valgus (bunion) in a skeletally mature individual (i.e., after epiphyseal closure) or an individual who is 18 years of age or older medically necessary when any of the following criteria is met:

1. The member's pain and symptoms over the medial bony eminence or calluses persist, making walking difficult despite at least a 6-month trial of protective pads, shoe inserts and alternative footwear that must include the following:

   1. Wearing well-fitting, low-heeled comfortable shoes made out of soft materials (e.g., canvas, cloth, soft leather) with wide toe box and padding; or
   2. Lace-ups or a combination last (front of the shoe is wider than the back of the shoe) that conforms to the bunion and minimizes irritation; and

   3. Documented evidence of the most recent weight-bearing view X-ray demonstrating both of the following:

      1. An HVA of 30 degrees or greater; and

      2. An inter-metatarsal angle (IMA) (formed by the long axis of the first and second metatarsals) of 12 degrees or greater.

2. A neuroma secondary to the bunion.
3. Problems with a dorsiflexed second toe due to over-riding of the great toe (so-called cross-over toe deformity).
4. Recurrent bursitis.

5. Demonstration of osteoarthritis on X-ray, as evidenced by any of the following:

   1. Cysts in the metatarsal head; or
   2. Loss of the cartilage space between the bones; or

   3. Mild-to-moderate bony proliferative pathology.

6. The need for relief of a predisposing factor, e.g., Achilles tendon contracture.

Aetna considers bony correction bunionectomy experimental and investigational for all other indications because its effectiveness for indications other than the ones listed above has not been established.

Note: A bilateral bunionectomy done at the same time generally is not deemed medically necessary unless extenuating circumstances are present.

Aetna considers bony correction bunionectomy not medically necessary for the following indications:

• Foot ulcer(s) secondary to peripheral vascular disease; or
• Gangrene of the foot, ankle or lower leg; or
• Non-ambulatory individuals unless being performed to relieve ulceration due to prominence; or
• Open blisters, pressure sores, and skin ulceration overlying the bunion when the bunion is not the cause of the skin lesion (bony correction may lead to osteomyelitis); or
• Poor tissues at the operative site due to excessive scarring and multiple closely placed previous incisions; or
• Severe vascular insufficiency significantly impairing circulation to the foot (e.g., absent foot pulses, intermittent claudication, ankle/arm ratio less than 0.6); or
• To improve the appearance of the foot (cosmetic).

Bunionette:

Aetna considers correction of a bunionette deformity (tailor's bunion) medically necessary in individuals with both of the following conditions:

1. Persistent pain despite a 6-month trial of conservative measures, including padding, debridement, non-steroidal anti-inflammatory drugs (NSAIDs), orthotic therapy, and shoe modifications to ones that fit comfortably with a soft upper and a roomy toe box; and
2. The IMA is 10 degrees or greater and the MTP angle is 16 degrees or greater.

Aetna considers surgical correction of a bunionette deformity experimental and investigational for all other indications because its effectiveness for indications other than the ones listed above has not been established.

Cheilectomy:

Aetna considers foot cheilectomy medically necessary for symptomatic relief of either of the following conditions:

1. Painful bony spurs in the earlier stages of an arthritic joint; or
2. Painful hallux rigidus.

Aetna considers foot cheilectomy experimental and investigational for all other indications because its effectiveness for indications other than the ones listed above has not been established.

Arthrodesis:

Aetna considers arthrodesis (fusion) of the foot medically necessary for any of the following conditions:

1. A hallux valgus deformity when the second toe is absent; or
2. Advanced hallux valgus (IMA greater than 20 degrees, HVA greater than 40 degrees); or
3. Failed bony correction bunionectomy (e.g., Keller bunionectomy); or
4. Failed cheilectomy; or
5. Painful symptoms secondary to hallux valgus with advanced degenerative joint disease; or
6. Severely subluxated or dislocated MTP joints.

Aetna considers arthrodesis of the foot experimental and investigational for all other indications because its effectiveness for indications other than the ones listed above has not been established.

See also CPB 0636 - Hammertoe Repair and CPB 0708 - Metatarsal Phalangeal Joint Replacement.

Hallux valgus (bunion) is a common affliction of the adult foot caused by long-term irritation from poorly fitting shoes, arthritis, or heredity.  The deformity usually develops after the age of 35 years and is often bilateral.  It consists of a lateral deviation of the great toe, outward angulation of the metatarsal toward the other foot, separation of the heads of the first and second metatarsals, and prominent soft-tissue thickening over the medial surface of the head of the first metatarsal, commonly referred to as a bunion.  Valgus posture of the great toe frequently causes a hammer toe-like deformity of the second toe.  In addition, the splaying of the forefoot makes the wearing of shoes more difficult.  With shoes that have a narrow toe box, corns often develop, as does bursal hypertrophy over the bunion.  With the presence of valgus subluxation of the first meta-tarso-phalangeal (MTP) joint for a prolonged time, osteoarthritis frequently develops.

Most bunions are treatable without surgery.  Prevention is always best by choosing shoes that conform to the shape of the feet, have wide insteps, broad toes and soft soles.  Patients should avoid shoes that are short, tight, sharply pointed, or with heels higher than 2¼ inches.  If a bunion is already present, the patient should try protective pads to cushion the painful bunion and must wear well-fitting, low-heeled comfortable shoes that are roomy enough to not put pressure on it.

Hallux valgus (lateral deviation of the great toe) is not a single disorder, as the name implies, but a complex deformity of the first ray that frequently is accompanied by deformity and symptoms in the lesser toes.  Often, the intermetatarsal angle (IMA) formed by the long axis of the first and second metatarsals is more than the 8 to 9 degrees, which is usually considered to be the upper limits of normal.  The hallux valgus angle (HVA), which measures the relationship of the long axis of the proximal phalanx and the first metatarsal, also is more than the 15 to 20 degrees, which is considered to be the upper limits of normal.  If the hallux valgus angle of the first MTP joint exceeds 30 to 35 degrees, pronation of the great toe usually results.

In 2002, the Cochrane Library published its review on bunionectomy stating that an HVA of greater than 15 degrees is considered abnormal since at this angle the phalanx is no longer congruent with the metatarsal head.  The joint may not become symptomatic until larger angles are reached or when the formation of a bunion begins, which is when the metatarsal head becomes very prominent and swelling develops medially over the joint.

According to the textbook Campbell's Operative Orthopaedics, bunion deformities are divided into 3 stages:

Under accepted guidelines, surgery is recommended to correct the deformity, reconstruct the bones and joint, and restore normal, pain-free function when the bunion has progressed to a level where the patient has difficulty walking and/or experiences pain despite accommodative shoes and presents itself with angular deformities corresponding to a moderate to severe stage (see above).  In addition, the presentation of a number of complications directly related to bunion formation may cause need for either soft tissue correction of the hallux valgus complex and/or concomitant bony correction.  Inadequate vascularity or sensibility should be investigated thoroughly before any bunion surgery is considered.

There are many different surgical procedures available for treatment of hallux valgus, ranging from the very simple to the highly technical.  They have endured the clinical test of adequate numbers of patients, lengthy and detailed review, and reports by multiple observers using essentially the same techniques.

The usual candidate for the Silver Procedure, a simple exostectomy with removal of the bunion only, is a 30- to 50-year old woman with clinical symptoms from a prominent bunion, an IMA of less than 12 degrees, an HVA of 15 to 25 degrees with no degenerative changes at the MTP joint, and a history of conservative management failure.  Typically, this procedure is performed along with other hallux valgus reconstructive procedures such as Chevron, McBride, or proximal osteotomy.

In properly selected patients with stress (weight-bearing) view roentgenograms showing the medial capsule acting as a spring on stretch of the MTP joint, the modified McBride bunionectomy may be indicated.  It involves removal of the bunion as well as rebalancing of the big toe joint by releasing the tight tendons on the lateral side (side nearest to the 2nd toe) and tightening the joint capsule on the medial side and sometimes removing one of the sesamoid bones.  This procedure is utilized when there is a positional hallux valgus, i.e., the big toe is drifted over toward the 2nd toe but there are no significant bones or structural deformities other than the bunion bump.

Candidates for the Keller procedure, combined soft tissue release and removal of the medial eminence with resection of the proximal end of the proximal phalanx, are patients between 55 and 70 years of age with moderate-to-severe hallux valgus (30 to 45 degrees) and/or significant joint arthrosis (hallux limitus or rigidus), IMAs of 12 degrees or less, and pain over the medial or dorsal eminence with any shoe worn so that the variety of shoes the patient can wear is severely limited.  An incongruous first MTP joint caused by lateral subluxation of the phalanx on the metatarsal head, severe lateral displacement of the sesamoids, and any evidence of degenerative cartilage changes in the joint are all roentgenographic indications for the Keller procedure.

The Akin procedure is used for correction of hallux valgus interphalangeus when the deformity is located at the interphalangeal joint.  In this procedure, a medially based closing-wedge osteotomy of the proximal phalanx is performed, the medial eminence of the first metatarsal head is resected, and medial capsular reefing is done.  Usually the Aiken is performed along with a Silver or McBride procedure.

First metatarsal head osteotomies are probably the most commonly performed bunionectomy procedures today.  The choice of osteotomy performed is dependent upon both the perceived etiology of the condition and the amount of correction required.  In younger patients with no joint arthrosis, and with mild-to-moderate hallux valgus deformities (IMA angle less than 16 and HVA less than 30 to 35 degrees), a Chevron (Austin) osteotomy may be the procedure of choice.  It involves a "V" shaped osteotomy of the distal metatarsal, which allows the first metatarsal head to be shifted laterally, correcting the abnormal shape from long standing valgus drift.  According to the literature, a proximal metatarsal osteotomy for hallux valgus is indicated for patients with moderate-to-severe deformities (HVA of 13 to 20 degrees), and may be combined with other hallux valgus reconstructive procedures such as resection of medial eminence (Silver procedure) or a McBride type of soft tissue release.

The literature indicates that the Mitchell bunionectomy is applicable to moderate to severe deformities of the intermetatarsal angle and hallux valgus and consists of a metatarsal osteotomy that displaces metatarsal head laterally in order to correct hallux valgus deformity and metatarsus adductus.  This procedure is carried out more proximally than the Chevron osteotomy and can correct more severe deformities than Chevron.

Lee et al (2008) noted that proximal Chevron osteotomy (PCO) for hallux valgus is inherently more stable than the other forms of proximal metatarsal osteotomy, but complications, such as, delayed union, nonunion, and malunion can occur.  These researchers compared results of two axial Kirschner wire fixation with or without transverse Kirschner wires in PCO for moderate-to-severe hallux valgus deformities.  A prospective study was conducted on 65 patients (85 feet) who underwent PCO and a distal soft tissue procedure for moderate-to-severe hallux valgus.  Patients were divided into 2 groups: (i) 2 axial Kirschner wire fixation (group I) ,and (ii) 2 axial and supplementary transverse Kirschner wire fixation (group II).  Group I comprised 41 feet of 32 patients and group II 44 feet of 33 patients.  Average American Orthopaedic Foot & Ankle Society (AOFAS) scores were 52.8 points in group I and 49.6 points in group II pre-operatively, and 92.8 and 89.6 points, respectively, at last follow-up.  Patients were very satisfied or satisfied in 92.7 % in group I and 93.2 % in group II.  Average hallux valgus angles in groups I and II changed from 34.9 degrees and 37.2 degrees pre-operatively to 12.3 degrees and 13.9 degrees post-operatively, and IMA in groups I and II changed from an average of 17.9 degrees and 17.2 degrees pre-operatively to 10.3 degrees and 10.4 degrees post-operatively.  No significant inter-group differences were found.  The authors concluded that supplementary transverse Kirschner wire fixation is not recommended for proximal metatarsal Chevron osteotomy since two axial Kirschner wires provided sufficient stability.

Lee and colleagues (2009) stated that hallux valgus surgery has been performed on only one side, even though patients may have bilateral hallux valgus.  These investigators evaluated the results of simultaneous surgical correction for bilateral hallux valgus compared with unilateral correction.  A retrospective review of 52 patients (69 feet) who underwent proximal metatarsal Chevron osteotomy and distal soft tissue procedure for moderate-to-severe hallux valgus was conducted.  Minimum follow-up was at least 12 months.  Patients were divided into 2 groups: (i) simultaneous bilateral surgical group (group A), and (ii) an unilateral surgical group (group B).  Group A comprised 34 feet in 17 women and group B comprised 35 feet in 35 women.  Average AOFAS scores were 57.0 points in group A and 52.8 points in group B pre-operatively and at the last follow-up improved to 93.4 points and 92.2 points, respectively.  Very satisfied or satisfied levels of patient satisfaction were 94.1 % in group A and 91.4 % in group B.  Average HVA in groups A and B changed from 34.8 degrees and 37.9 degrees pre-operatively to 12.5 degrees and 12.4 degrees post-operatively, respectively.  Intermetatarsal 1-2 angles in groups A and B changed from an average of 15.7 degrees and 18.4 degrees pre-operatively to 7.4 degrees and 7.1 degrees post-operatively, respectively.  No significant inter-group differences were observed in clinical and radiographical outcomes.  The authors concluded that based on these findings, the outcomes of simultaneous bilateral correction for hallux valgus deformity was not worse than a unilateral correction.  These researchers advocate simultaneous correction for bilateral hallux valgus requiring surgical correction.

Like a bunion, a bunionette deformity (tailor's bunion, overlapping or underlapping 5th toe deformity) may be created by a wide intermetatarsal angle between the 4th and 5th metatarsals.  The normal 4th and 5th IMA is approximately 6.2 degrees, and the normal 5th MTP angle is about 10 degrees.  Pathological angles are in the range of 10 degrees for the IMA and 16 degrees for the MTP angle.  Pressure placed on the head of the 5th metatarsal exacerbated by tight shoes forms a painful osseous prominence, hypertrophy, and/or signs of inflammation on the outside of the foot near the base of the little toe.  It may be associated with a symptomatic plantar callus, a hard corn and painful bursitis.  According to accepted guidelines, treatment should initially consist of conservative measures; this includes padding, debridement, NSAIDS, orthotic therapy, and shoe modifications to ones that fit comfortably with a soft upper and a roomy toe box.  In cases where non-operative treatment can no longer control the symptoms of persistent pain, surgical intervention is warranted.  Soft tissue surgery does not solve the problem as the offending agent is usually the head of the 5th metatarsal.  A proximal osteotomy is able to correct most deformities.  The literature indicates a distal osteotomy is recommended if medial translation of the head for 1/3 of the width of the metatarsal shaft produces a normal 4th to 5th IMA.  A partial ostectomy of the 5th metatarsal may be adequate if IMA reduction is not indicated.

Degenerative joint disease may develop over the years and includes erosion of cartilage, joint space narrowing and varying amounts of bony spurs around the 1st MTP joint.  Milder cases may consist of slight limitation of motion and little pain.  More severe cases may consist of a rigid joint and considerable pain.  Cheilectomy is a procedure that may be utilized in earlier stages of an arthritic joint in which there are painful bone spurs.  The bony irregularities are shaved off and the cartilage may also be remodeled.

The great toe is stabilized in part by the presence of 2nd toe and, when it is absent, a hallux valgus deformity is best treated by arthrodesis of first MTP joint.  Another indication for arthrodesis includes a failed Keller bunionectomy.  Fusion is the procedure of choice for hallux valgus associated with advanced degenerative joint disease, and advanced hallux valgus (IMA greater than 20 degrees, HVA greater than 40 degrees), severely subluxated or dislocated MTP joints, or for failed hallux valgus surgery.  Cheilectomy is not the procedure of choice in presence of advanced degenerative joint changes.  The Lapidus procedure is indicated for patients with severe hallux valgus deformity accompanied by a hypermobile 1st ray.  The procedure involves arthrodesis of the metatarsalcuneiform joint.

Hallux limitus and hallux rigidus is, as their names imply, a loss of flexibility of the great toe as a result of osteoarthritic or degenerative changes at the first MTP joint.  This may be more disabling than hallux valgus, because the patient is unable to achieve relief even when not wearing shoes.  It is usually unilateral and is distinguished from hallux valgus by the lack of angular deformity (the alignment remaining normal) and by the prominence of the osteoarthritic changes at the dorsal surface of the joint, asymmetrical joint-space narrowing, subchondral sclerosis, marginal spurs, and, at times, rather large subchondral cysts.  Cheilectomy, which includes not only excision of the dorsal bone spur but also the dorsal third of the metatarsal head, gives long-term pain relief in most patients.  Arthrodesis or a Keller procedure is the generally accepted treatment of choice following failed cheilectomy or where advanced degenerative changes are present.

In a case-series study, Masquijo et al (2010) evaluated the results of a 5th metatarsal sliding osteotomy for the treatment of this deformity in patients under 18 years of age.  These researchers retrospectively evaluated 13 feet in 11 consecutive patients with bunionette deformity treated from January 2003 to January 2008 at 2 referral centers.  Mean age was 14.8 years (95 % confidence limit, SD 1.5 years); mean follow-up was 32.2 months (95 % confidence limit, SD 11.7 months); and clinical evaluation was made according to the modified AOFAS score and the Coughlin score.  The IV-V IMA ( IV-V IMA), the width of the forefoot (WF), lateral deviation angle (LDA), and 5th metatarsophalangeal angle (5 MPA) were also measured pre-operatively and post-operatively.  The average post-operative AOFAS score was 91 +/- 4.1 points.  Seven patients (8 feet) had an excellent outcome and 4 patients (5 feet) a good outcome according to the Coughlin scoring rate.  The IV-V IMA averaged 12.29 degrees +/- 1.5 degrees pre-operatively, while post-operatively it was 6.18 degrees +/- 1.4 degrees (p < 0.0001).  The LDA improved from 7.74 degrees +/- 1.7 degrees pre-operatively to 4.25 degrees +/- 1 degree after surgery (p < 0.0001).  The WF decreased from 8.01 +/- 1.3 mm to 7.05 +/- 1.3 mm (p < 0.0001).  The mean 5 MPA decreased from 21.7 degrees +/- 4.1 degrees pre-operatively to 7.63 degrees +/- 3.4 degrees at final follow-up (p < 0.0001).  One patient developed a superficial infection around a K-wire.  The authors concluded that metatarsal sliding osteotomy is a safe and effective method for the correction of symptomatic bunionette in patients below 18 years of age.  Moreover, they stated that further research is needed to compare this approach with other treatment methods in this specific age group.

Guha et al (2012) noted that the bunionette or tailor's bunion is a lateral prominence of the 5fth metatarsal head.  It is usually characterized by a wide IMA between the 4th and 5th metatarsals, varus of the MTP joint, pain and callus formation.  Various distal, shaft and basal osteotomies have been described in the literature.  These investigators have described a reverse scarf osteotomy for bunionette correction.  They have used a "reverse" scarf osteotomy in 12 cases (10 females: 2 males) with a mean follow-up of 12 months (range of 5 to 22 months) with radiographs and clinical scoring.  Post-operatively, mean IMA improved from 13.1 degrees to 7.27 degrees (range of 2.0 to 11.5); mean 5th MTP angle improved from 19.9 degrees to 6.36 degrees (range of  2.8 to 9.0) and post-operative mean AOFAS improved from 54.25 to 89.58 (range of 70 to 100).  The authors concluded that "reverse" scarf osteotomy in the correction of bunionette deformity offers promising results in the short-term.