Distal Soft Tissue Procedure and Proximal Metatarsal Osteotomy in Hallux Valgus

Abstract

The results of a distal soft tissue procedure and a proximal metatarsal osteotomy in patients with symptomatic hallux valgus deformity were reviewed. The series consisted of 33 patients (47 feet; mean age of patients, 44 years). The average followup period was 48 months. At followup, 41 feet (29 patients, 85%) were free from pain at the first metatarsophalangeal joint. In six feet (four patients), the pain was improved but persisted. The mean hallux valgus angle was 38° before surgery and 13.8° after surgery. The mean intermetatarsal angle was 17.7° before surgery and 7° after surgery. The postoperative hallux valgus angle and intermetatarsal angle in patients who had pain at the first metatarsophalangeal joint after surgery were greater than those in patients without pain after surgery. This procedure corrects the hallux valgus deformity and relieves the symptoms, but careful attention should be paid to the surgical technique to obtain consistent and satisfactory results.

Hallux valgus deformity consists of lateral subluxation of the first metatarsophalangeal joint, metatarsus primus varus, and lateral deviation of the sesamoids. A distal soft tissue procedure alone does not always correct the deformity. ^7,8,11 Excision of the lateral sesamoid may result in hallux varus deformity. Several authors ^2,9,13,14 have discussed the results of a distal soft tissue procedure combined with a proximal osteotomy of the first metatarsal, but the surgical techniques varied, the numbers of patients were small, and few long-term results were reported. In 1992, Mann et al ⁹ reported the long-term results of a modified McBride procedure combined with a proximal crescentic osteotomy of the first metatarsal. They stated that 93% of the patients were satisfied with the result of the procedure.

Since 1989, the current authors have performed a distal soft tissue procedure combined with a proximal crescentic osteotomy for correction of hallux valgus. The purpose of this study is to describe the surgical technique and to report the results of this procedure for treatment of the symptomatic hallux valgus deformity.

MATERIALS AND METHODS

From October 1989 to February 1997, 40 patients (56 feet) with symptomatic hallux valgus deformity were treated with a distal soft tissue procedure combined with a proximal crescentic osteotomy of the first metatarsal. Seven patients (nine feet) could not be followed up. Thus, the results of 47 operations performed to correct hallux valgus in 33 patients were reviewed retrospectively.

The series consisted of 29 female patients (42 feet) and four male patients (five feet). The mean age of the patients was 44 years, with a range from 13 to 70 years. The mean duration of followup was 48 months, with a range from 12 to 106 months. All patients returned for evaluation.

All patients (47 feet) had pain at the first metatarsophalangeal joint. Sixteen patients (20 feet) had painful plantar keratosis at the second, third, or both metatarsal heads before surgery. In 10 patients (12 feet) with painful plantar keratosis, a proximal shortening osteotomy of the second, third, or both metatarsals was performed at the time of hallux valgus surgery. ¹² In the other six patients (eight feet), a proximal shortening osteotomy of the metatarsal was not performed. The indication of a shortening osteotomy of the metatarsal included clinical and radiologic criteria. ¹² The clinical criteria were metatarsalgia and tenderness and keratosis under the metatarsal head. In addition, the radiologic criterion for shortening osteotomy of the second and third metatarsals was the projection of the metatarsal greater than 12 mm and 11 mm, respectively. The projection of the second and third metatarsals was defined as the distance between the top of the each metatarsal head and the intersecting point of the line drawn through the tops of the first and fifth metatarsal heads and the axis of each metatarsal on the preoperative weightbearing dorsoplantar radiograph of the foot (Fig 1). ¹² Kumano et al ⁶ reported that the mean projection of the second and third metatarsals in healthy adult females was 11 mm and 10 mm, respectively. The amount of metatarsal shortening was determined by the projection of the second and third metatarsals. The metatarsal shortening osteotomy was performed so that the postoperative projection of the metatarsals would be 8 to 9 mm, which was slightly less than the normal mean.

Fig 1.: The radiographic measurements of the projection of the second metatarsal (M2) and the projection of the third metatarsal (M3). A1, A2, A3, and A5 = the longitudinal axis of each metatarsal; B = the line connecting the tops of the first and fifth metatarsal heads; M2 and M3 = the distance between the top of each metatarsal head and the intersection of line B and the long axis of each metatarsal.

The preoperative complications included dorsal dislocation of the second metatarsophalangeal joint in three feet and osteoarthrosis of the second metatarsophalangeal joint in one foot. Open reduction for dorsal dislocation of the second metatarsophalangeal joint was performed in two feet at the time of hallux valgus surgery.

The patients were questioned about improvement in pain. The presence of transfer lesions and any sensory abnormalities also were examined. The range of motion (ROM) of the first metatarsophalangeal joint was measured before and after surgery.

Preoperative and postoperative dorsoplantar radiographs of the foot were made with the patient in the weightbearing position. The hallux valgus angle and the intermetatarsal angle (the angle between the long axes of the first and second metatarsals) were measured. The hallux valgus angle is subtended by lines bisecting the longitudinal axis of the first metatarsal and the proximal phalanx. The intermetatarsal angle is subtended by lines bisecting the longitudinal axis of the first and second metatarsals. The longitudinal axis of the first metatarsal was defined as a line connecting the center of the articular surface of the metatarsal head with the center of the proximal articulation. The longitudinal axis of the proximal phalanx was defined as a line connecting the center of the proximal end of the diaphysis with the center of the distal end of the diaphysis. The longitudinal axis of the second metatarsal was defined as a line connecting the center of the proximal end of the diaphysis with the center of the distal end of the diaphysis. The relationships between the preoperative and postoperative hallux valgus angles and the intermetatarsal angles were examined, respectively. The position of the medial sesamoid in relation to a line drawn along the center of the longitudinal axis of the first metatarsal on the dorsoplantar radiograph was evaluated and classified according to the classification of Hardy and Clapham ³ (Fig 2).

Fig 2.: Evaluation of the position of the medial sesamoid. The first metatarsal head is bisected. The position of the medial sesamoid was classified as Grades I, II, III, IV, V, VI, and VII in relation to the central line.

The differences in the measured variables between the two groups were analyzed with the Mann-Whitney U test. Differences with p values of 0.05 or less were considered significant.

Surgical Technique and Postoperative Management

The surgical procedure was similar to the procedure of Mann et al ⁹ and consisted of the release of the distal soft tissues, excision of the medial eminence, plication of the medial part of the capsule, and proximal crescentic osteotomy of the first metatarsal. However, there are some differences between the procedure of Mann et al and that used by the current authors.

A 3-cm curved incision convexing dorsally is made on the dorsomedial side of the first metatarsophalangeal joint. The adhesion between the subcutaneous tissue and the medial part of the capsule of the first metatarsophalangeal joint is released. A longitudinal capsulotomy is begun at the dorsomedial aspect (Fig 3A). The incision in the capsule is extended along the dorsomedial aspect of the metatarsal neck, and the capsule together with the abductor hallucis tendon is reflected plantarward. The medial eminence is excised to the minimum to preserve the distal articular surface of the first metatarsal.

Fig 3A–B.: (A) A longitudinal capsulotomy at the dorsomedial aspect of the first metatarsophalangeal joint. (B) Correction of the valgus and pronation deformities of the great toe. The broad arrows show the direction of pulling capsule.

A 2-cm dorsal longitudinal skin incision is made between the first and second metatarsal heads. The adductor hallucis tendon is dissected from its insertion in the base of the proximal phalanx and the lateral sesamoid. The transverse intermetatarsal ligament is released carefully so as not to injure the neurovascular bundle located immediately plantar to this ligament. The medial part of the capsule together with the abductor hallucis tendon is pulled proximally and dorsally so that the valgus deformity and the pronation of the great toe are corrected (Fig 3B).

A 3-cm dorsomedial longitudinal skin incision is made over the first metatarsal base. The crescentic osteotomy is performed 1.5 cm distal to the metatarsocuneiform joint. The osteotomy is curvilinear. The concavity of the cut is directed proximally in early cases and distally in late cases. The osteotomy is inclined backward, making an angle of approximately 10° in relation to an axis perpendicular to the first metatarsal. After completion of the osteotomy, the distal fragment is moved laterally and the proximal fragment is moved medially, decreasing the intermetatarsal angle to approximately 5° under fluoroscopic control. A cross pinning technique with two 1.5-mm Kirschner wires (K wires) is used to fix the osteotomy site of the first metatarsal (Fig 4).

Fig 4A–B.: (A) Preoperative radiograph in a 62-year-old woman showing severe hallux valgus deformity. (B) Radiograph obtained 15 months after a distal soft tissue procedure and a proximal metatarsal osteotomy accompanied by oblique shortening osteotomies of the second and third metatarsals, showing correction of hallux valgus deformity and shortening of the second and third metatarsals.

Two drill holes are made in the medial aspect of the distal end of the first metatarsal (Fig 3B). The first hole is made in the metatarsal head, and the second hole is made in the metatarsal neck. The medial part of the capsule is secured with sutures through both drill holes, with the great toe held in the corrected position.

A 3-cm dorsal longitudinal incision is made between the second and third metatarsal base. If one metatarsal alone is to be dealt with, the incision is made over the affected bone. An oblique osteotomy at the metatarsal base is done at an angle of approximately 45° to the longitudinal axis of the metatarsal (Fig 5A). After completion of the osteotomy, the distal fragment is displaced dorsally and proximally and is fixed temporarily with a 1-mm K wire. The amount of metatarsal shortening is checked on an intraoperative dorsoplantar radiograph of the foot. If the planned metatarsal shortening is achieved, the site of the oblique osteotomy is fixed with a bone screw, and then the K wire is removed (Fig 5B).

Fig 5A–B.: (A) An oblique osteotomy at the proximal metatarsal is done at an angle of approximately 45° to the longitudinal axis of the metatarsal. The distal fragment is dorsally and proximally displaced. (B) The osteotomy site is fixed with a bone screw.

A short-leg cast and nonweightbearing walking are continued for 3 weeks. Partial weightbearing walking in a short-leg plaster shell and ROM exercise are encouraged. Full weightbearing walking is allowed, and the patient is instructed to wear ready-made shoes with an arch support 6 weeks after surgery.

RESULTS

Forty-one feet (87%) were free from pain at the first metatarsophalangeal joint at followup. In six feet, pain at the first metatarsophalangeal joint was improved but continued after surgery.

In six of 12 feet that had hallux valgus surgery accompanied by a proximal shortening osteotomy of the second, third, or both metatarsals, painful plantar keratosis disappeared at followup. In four feet, plantar keratosis was asymptomatic. In two feet, painful plantar keratosis remained, but metatarsalgia improved at followup. In six of eight feet with preoperative painful plantar keratosis that did not have a shortening osteotomy of the metatarsal, painful plantar keratosis disappeared at followup. In the other two feet, painful plantar keratosis remained, but metatarsalgia improved at followup.

The average extension of the first metatarsophalangeal joint was 68° before surgery and 61° after surgery. The average flexion of the first metatarsophalangeal joint was 33° before surgery and 18° after surgery. Only one patient (one foot, 2.5%) was dissatisfied with the limitation of the postoperative ROM of the first metatarsophalangeal joint.

The hallux valgus angle was corrected by an average of 24° after surgery. The mean angle was 38° (range, 25°–60°) before surgery and 13.8° (range, −7°–26°) after surgery. The intermetatarsal angle was corrected by 11° on average. The mean angle was 17.7° (range, 8°–25°) before surgery and 7° (range, 2°–16°) after surgery. The correlation coefficients between the hallux valgus angle and the intermetatarsal angle before and after surgery were 0.57 (p < 0.0001) and 0.54 (p < 0.0001) (two feet that had varus deformity after surgery were excluded), respectively.

Forty-seven feet were divided into two groups: Group A (41 feet) had no pain at the first metatarsophalangeal joint after surgery, and Group B (six feet) had pain at the first metatarsophalangeal joint after surgery. There were no significant differences in the preoperative mean hallux valgus angle and intermetatarsal angle between Groups A and B. However, the postoperative mean hallux valgus angle and intermetatarsal angle in Group B were significantly larger than those in Group A (Table 1). Thirty-eight (93%) feet in Group A had a postoperative hallux valgus angle of 20° or less and a postoperative intermetatarsal angle of 10° or less. However, all of the six feet in Group B had a postoperative hallux valgus angle greater than 20° and a postoperative intermetatarsal angle greater than 10° (Fig 6).

TABLE 1: The Preoperative and Postoperative Hallux Valgus Angles and Intermetatarsal Angles in Groups A and B

Fig 6.: The relationship between the postoperative hallux valgus angle and the intermetatarsal angle. ○ = Group 1, patients without pain at the final followup; • = Group 2, patients with pain at the final followup.

According to the grading system of displacement of the medial sesamoid (classification of Hardy and Clapham ³), three feet were classified as Grade V, nine as Grade VI, and 31 as Grade VII before surgery. Four feet were excluded because of absence of the medial sesamoid. Nine feet were classified as Grade II, 13 as Grade III, four as Grade IV, eight as Grade V, seven as Grade VI, and two as Grade VII after surgery. Forty-three feet were divided into two groups: Group 1 (26 feet that were classified as Grades II, III, or IV after surgery), and Group 2 (17 feet that were classified as Grades V, VI, or VII after surgery). The mean postoperative hallux valgus angle and intermetatarsal angle in Group 2 were significantly larger than those in Group 1 (Table 2).

TABLE 2: The Postoperative Hallux Valgus Angles and Intermetatarsal Angles in Groups 1 and 2

Hallux varus deformity (a hallux valgus angle less than 0°) developed in two feet (4%) after surgery. The hallux valgus angle was −2° in one patient and −7° in the other. These two patients did not have pain or a cockup deformity and were not dissatisfied with the appearance of the feet after surgery. One patient was dissatisfied with postoperative stiffness of the first metatarsophalangeal joint. In both patients, a radiograph of the foot obtained immediately after surgery showed overcorrection of the hallux valgus angle, but the hallux varus deformity did not deteriorate with time. There were no cases of nerve injury, infection, delayed wound healing, or nonunion.

DISCUSSION

The aim of surgical treatment of hallux valgus is to correct the valgus deformity of the great toe and the metatarsal primus varus deformity of the first metatarsal, restore the normal mechanics of the first metatarsophalangeal joint, and relieve the pain at the first metatarsophalangeal joint.

Mann et al ⁹ reported the results on 109 feet treated with a modified McBride procedure combined with a proximal crescentic osteotomy of the first metatarsal that was similar to that of the current authors. They stated that the hallux valgus angle and intermetatarsal angle were corrected by 21° and 8°, respectively, on average. These values were similar to the average corrections of 25° for the hallux valgus angle and 11° for the intermetatarsal angle in the current series. The average corrections of the hallux valgus and intermetatarsal angles in the current authors’ procedure were larger than those in Mitchell, Wilson, and chevron procedures. ^4,5,10 This implies that a distal soft tissue procedure combined with a proximal osteotomy can correct a large hallux valgus angle and intermetatarsal angle and is indicated for moderate or severe hallux valgus deformity.

Mitchell et al ¹⁰ reported that the postoperative extension of the first metatarsophalangeal joint was decreased to less than 40° in 28 (28%) of 100 feet that were treated with Mitchell’s procedure and stated that the postoperative restriction of extension aggravated the clinical result. In the current series, the postoperative flexion and extension of the first metatarsophalangeal joint were decreased. However, only two (5%) of 40 feet had less than 40° extension of the first metatarsophalangeal joint after surgery, and only one patient reported stiffness of the first metatarsophalangeal joint after surgery. These results indicated that the postoperative restriction of extension in the current procedure is not critical enough to aggravate the clinical result.

It is not uncommon that metatarsalgia associated with hallux valgus persists, aggravates, or develops anew after surgery for hallux valgus. ^1,10,16 Mann et al ⁹ reported that metatarsalgia persisted after surgery in 18 (37%) of 48 feet that had metatarsalgia before surgery, and operative intervention was not needed for the feet in which metatarsalgia persisted. However, other authors ^5,10,15,16 reported that postoperative metatarsalgia was one of the major factors that aggravated the clinical results. The current authors believe that it is best to select a surgical procedure that will treat a hallux valgus deformity and metatarsalgia when both exist. Thus, in the current study, a distal soft tissue procedure with a proximal osteotomy accompanied by a shortening osteotomy of the second, third, or both metatarsals was performed in patients who had hallux valgus with metatarsalgia according to the clinical and radiologic criteria proposed previously. ¹² In 10 (83%) of 12 feet that underwent this combined operation, metatarsalgia disappeared by followup. In two feet, metatarsalgia improved. These results suggested that a proximal shortening osteotomy of the second, third, or both metatarsals had an effect on metatarsalgia associated with hallux valgus and improved the clinical results of surgical treatment for hallux valgus.

Mann et al ⁹ stated that the overall satisfaction of the patients who had a postoperative hallux valgus angle greater than 15° did not differ from that of the patients who had an angle less than 15°. However, Mitchell et al ¹⁰ reported on the results of their procedure and stated that most of the good and excellent results were accompanied by a significant decrease of the intermetatarsal angle with a residuum less than 10°. In the current series, the postoperative hallux valgus and intermetatarsal angles in the patients who had pain at the first metatarsophalangeal joint after surgery were significantly larger that those in the patients who had no pain. All of the patients who had pain after surgery had a postoperative hallux valgus angle greater than 20° and a postoperative intermetatarsal angle greater than 10°. These results suggested that there was a high correlation between the relief of pain and the radiologic result. In addition, the postoperative hallux valgus angle in the foot that had great dis-placement of the medial sesamoid after surgery was significantly larger than that in the foot that had little or no displacement. These results suggested that it is important to correct the hallux valgus deformity, metatarsus primus varus, and pronation deformity of the great toe to obtain satisfactory results of this procedure.

Hardy and Clapham ³ found that there was a strong correlation (r = 0.71) between the hallux valgus angle and intermetatarsal angle. To the current authors’ knowledge, there are no reports regarding the relationship between the hallux valgus angle and the intermetatarsal angle after surgery for hallux valgus. In the current study, there was a moderate correlation (r = 0.54, p < 0.0001) between the postoperative hallux valgus and the intermetatarsal angle. In the distal soft tissue procedure and proximal metatarsal osteotomy, correction of the intermetatarsal angle was performed before correction of the hallux valgus angle. Thus, if correction of the intermetatarsal angle is insufficient at surgery, correction of the hallux valgus angle may be unsatisfactory, or loss of correction of the hallux valgus angle may occur after surgery. An intraoperative radiograph should be obtained to confirm that the correction of the intermetatarsal angle is satisfactory.

The results of the current series indicated that a distal soft tissue procedure with a proximal crescentic osteotomy corrects the deformity and relieves pain to the satisfaction of the patients. However, when correction of the deformity is insufficient, it is likely that pain at the first metatarsophalangeal joint may continue after surgery. Meticulous attention should be paid to the surgical technique to obtain satisfactory correction of the hallux valgus deformity.