0198-0211/92/1303-0107$03.00/0 FOOT & ANKLE Copyright © 1992 by the American Orthopaedic Foot Society, Inc.
Metatarsocuneiform Arthrodesis for Management of Hallux Valgus and Metatarsus Primus Varus Mark Myerson, M.D.: Steven Allon, M.D.,t and William McGarvey, M.D.:j: Baltimore, Maryland and Meadowbrook, Pennsylvania
ABSTRACT Sixty-seven closing wedge arthrodesis procedures of the first metatarsocuneiform joint were performed in 41 females and 12 males. Follow-up averaged 28 months (range 16-49 months) and was performed in 51 of 53 patients with a questionnaire, clinical examination, and comparison of pre- and postoperative weightbearing radiographs. The average hallux valgus angle was 34.5° (range 20°-75°) and was corrected to 13.0° (range -10°22°) postoperatively. The average intermetatarsal angle was 14.3° (range 9.5°-34°) and was corrected to an average of 5.8° (range 0°-12°) postoperatively. Complications included seven superficial pin tract infections, three symptomatic dorsal bunions, one of which required repeat surgery, seven nonunions, one of which was symptomatic, one hallux varus, and three neuromas of the deep peroneal nerve. The range of motion of the hallux metatarsophalangeal joint was 85% of normal postoperatively. A total of 77% of the patients were totally relieved, 15% partially relieved, and 8% not relieved with respect to pain, comfort, appearance of the foot, and shoewear following surgery. The specific indications for performing this operation are discussed.
metatarsus primus varus and atavism played a dominant role in the development of hallux valgus. Although these concepts were introduced by Truslow" in 1925, anthropologists were the first to recognize the similarity between the divergence of the first metatarsal in human embryos and prehensile feet of primates. 20 ,27,30,33 Lapidus considered patients with metatarsus primus varus to have "atavistic" feet; hence, the metatarsocuneiform arthrodesis for management of hallux valgus associated with metatarsus primus varus evolved." In this study, we present our evolving experience with first metatarsocuneiform arthrodesis, and the modifications to the procedure which we have found useful over the past few years. MATERIALS AND METHODS
Between 1986 and 1990, 67 metatarsocuneiform fusions were performed in 53 patients, nine males and 44 females. The average age of the patients was 29 years (range 16-66 years). Bilateral procedures were performed in 14 patients (12 females and two males). Preoperative evaluation was performed in a consistent manner for each patient. The presence of generalized ligamentous laxity was noted, and the foot was examined for pes planus, hypermobility of the first ray, and any associated deformities. Hypermobility of the medial ray albeit, subjective, is defined as excessive motion of the first metatarsal in the sagittal and transverse planes, and was estimated for each patient. This is demonstrated by holding the patient's midfoot firmly and manipulating the first metatarsal with the thumb and forefinger of the opposite hand. The motion of the medial ray includes that of the metatarsocuneiform, naviculocuneiform, and talonavicular joints. The range of motion of the hallux, including congruity of the metatarsophalangeal joint (MPJ) and the extent of any adduction contracture, was noted. Weightbearing preoperative and postoperative anteroposterior and lateral radiographs were obtained. The intermetatarsal angle, hallux valgus angle, and
INTRODUCTION
Paul Lapidus popularized the procedure of closing wedge arthrodesis of the metatarsocuneiform (MC) joint. 16 - 19 This procedure had, however, been advocated by several authors prior to Lapidus, including Albrecht' in 1911, Truslow" in 1925, and Kleinberg 14 in 1932. Since then, this operation and various modifications thereof have been advocated by Armstronq" (1937), Hue and Thyes 11 (1938), Wissel 35 (1952) Goldner and Gaines6 (1976), Clarke et al." (1987), Sangeorzan and Hansen" (1989), Amis," and Mauldin et al.22 (1989). Lapidus, like many of these authors, felt that * The Union Memorial Hospital, 201 E. University Parkway, Baltimore, Maryland 21218. Address reprint requests to Dr. Myerson. t 1648 Huntington Pike, Meadowbrook, Pennsylvania 19046. Resident in Orthopedic Surgery, The Union Memorial Hospital, Baltimore, Maryland.
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sesamoid position were studied. Sesamoid position was graded using the system described by Smith et al.32 Since Smith's grading does not include medial displacement of the tibial sesamoid which may occur postoperatively, a line bisecting the mid-axis of the first metatarsal was the reference position for the medial sesamoid. Hypermobility of the first ray was felt to be expressed radiographically as cortical thickening of the second metatarsal shaft (Fig. 1). The indications for performing the MC arthrodesis were in patients with severe metatarsus primus varus, in those with moderate deformity associated with hypermobility of the first ray, in adolescents with hypermobility or generalized ligamentous laxity, and where deformity was associated with symptomatic degenerative arthritis of the MC joint. SURGICAL TECHNIQUE
Surgery was performed under regional ankle block anesthesia in 62 of the 67 feet. Bilateral procedures were not performed simultaneously. No tourniquet was used, and hemostasis was controlled and bleeding was minimized with the use of small hemostat clamps. For purposes of clarity, the technique is described as it was performed for the majority of patients (58 of 67 feet), and any recent modifications introduced over the sub-
Fig. 1. This patient was. a 32-year-old female who had marked hypermobility of the medial ray. Note the cortical hypertrophy along the medial second metatarsal shaft indicating excessive transfer of stress to this metatarsal. Note also the mild generalized metatarsus adductus and the obliquity and slight instability of the first rnetatarsocuneiform joint.
sequent 2 years are detailed separately. A medial longitudinal incision was made over the hallux MPJ at the junction of the dorsal and plantar skin. A vertical capsular ellipse was excised and the exostosis was resected flush with the medial edge of the metatarsal shaft. A soft tissue release including an adductor tenotomy with partial lateral capsUlotomy was performed in 60 of 67 feet (89%) through a separate dorsal incision over the distal first-second intermetatarsal space. In the remaining seven feet (six adolescents), no adduction contracture was present, and this part of the procedure was omitted. In four of the adolescent patients (six feet), only one incision was used for the arthrodesis, and it was not found necessary to perform either a soft tissue release or a resection of the medial eminence (Fig. 2). The third incision was made proximally, medial to the extensor hallucis longus tendon to expose the MC joint. An oscillating saw was used to remove a small biplanar wedge from the joint with the base lateral and plantar. The first cut was made on the cuneiform, removing approximately 1 mm including articular cartilage and minimal subchondral bone, and the second cut was made on the metatarsal. Minimal bone was removed to prevent shortening of the metatarsal
Fig. 2. This patient was a 17-year-old female with hypermobility of the medial ray and discomfort under the second metatarsal head. Note the medial cortical hypertrophy of the second metatarsal shaft. The correction was obtained at the metatarsocuneiforrn joint alone without distal soft tissue release or exostectomy. The position of the medial screw traversing the middle cuneiform is not optimal.
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(Fig. 3). No bone was resected medially, since this makes the articulation unstable and difficult to fuse. There is a tendency to remove insufficient bone from the plantar apical joint surface, and a thin rongeur was used to remove bone from the depths of the joint. The base of the metatarsal was plantarflexed by bone resection, not by translating the metatarsal in a plantar direction. The metatarsal was held adducted and plantarflexed and was temporarily secured with O.062-in Kirschner wire. Anteroposterior and lateral radiographs were then obtained to check reduction and alignment, and followed by more stable internal fixation. Compression of the joint was achieved with 3.5-mm cortical screws introduced from the dorsal base of the metatarsal into the medial cuneiform. Supplementary medial fixation was used, introduced obliquely across the first metatarsal base into the second metatarsal base (Fig. 4). Occasionally, the second metatarsal was missed and the medial screw was inserted into the middle cuneiform, but this was not the preferred direction of securing the fixation, since it unnecessarily crosses a joint not included in the arthrodesis (Fig. 2). A K wire was only used medially if difficulty was experienced with insertion of a screw. Initially, a 4.0-mm cancellous screw was used, but when two of these were noted to break, a 3.5-mm cortical screw was used. We occasionally experienced difficulty in removing the 3.5-mm screws medially due to soft tissue swelling, and a 4.5mm malleolar screw was occasionally used since these
Fig. 3. The arthrodesis is performed with minimal bone resection, ensuring realignment without shortening. Note that the medial margin of the joint is not disturbed, and alignment of the metatarsal is achieved by adduction and plantarflexion.
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were easily palpable subcutaneously and could be removed in the office. In the first 58 feet, no medial fixation was used in five feet, a 4.0-mm cancellous screw in seven, a K wire in eight, a 3.5-mm cortical screw in 33, and a malleolar or self-tapping 4.5-mm screw in 14 feet. During the first 3 years of this review, the procedure was performed as described above. However, we experienced occasional difficulty with the fixation and were dissatisfied with the potential for shortening and malunion of the metatarsal. Recognizing the anatomic variations of the MC joint and the base of the first metatarsal, we felt that a biplanar wedge resection of the joint as described above was not necessary for all patients. We gained experience from the technique as described by Mauldin et al.,22 leading us to believe that the metatarsal may be repositioned with little, if any, bone resection. Due to the concave-convex shape of the metatarsocuneiform articulation, this is easily accomplished with a more natural movement of adduction, plantarflexion, and slight internal rotation of the first metatarsal. The technique was, therefore, modified for the last nine patients in this study, and is one which we currently recommend. Only the articular cartilage was removed lateral and plantar, leaving the medial aspect of the joint intact. The metatarsal was held in adduction and plantarflexion and temporary fixation held the metatarsal. Following radiographic evaluation, permanent fixation was performed using 3.5-mm cortical screws. The first screw was introduced dorsal to plantar from the medial cuneiform proximally into the first metatarsal distally using a lag screw technique suggested by Johnson12 (Fig. 5). The second screw was introduced medially from the first metatarsal into the second metatarsal base from slightly plantar to dorsal, avoiding the middle cuneiform (Fig. 6). A burr was used to create two or three small troughs across the joint both dorsally and medially, and local bone graft was used to fill these defects. Simultaneous associated procedures were performed on the second toe in 42% and on the third and fourth toes in 16%, and a bunionette correction was performed in 17% of patients. Postoperatively, patients used crutches until comfortable, followed by weightbearing as tolerated. Eighteen patients (21 of 67 feet) were placed in a short leg cast, with protected weightbearing for 6 weeks. The balance of the patients used a wooden shoe with protected weightbearing with or without crutches for 6 to 8 weeks. All patients used a soft bunion splint to maintain the hallux in neutral alignment for nighttime use for an additional 4 weeks. Evaluation of the patients was performed according to the recommendations of the Research Committee of the American Orthopaedic Foot and Ankle Society.32
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Fig. 4 This 34-year-old patient had severe deformity A, corrected in both the sagittal and horizontal plane postoperatively. e, The range of motion of the hallux metatarsophalangeal joint was preserved by the addition of a closing wedge osteotomy to the base of the proximal phalanx of the hallux.
throsis, recurrent deformity, and neuroma formation were evaluated. Other factors that prolonged convalescence, such as swelling, aching, and the need for hardware removal, were also studied. RESULTS
Follow-up interviews, examinations, and radiographic evaluations were performed in 51 of 53 patients (65 feet) and averaged 28 months (range 16-49 months) following surgery. Subjective Results
Patients had symptoms averaging 2.1 years (range
1-9.5 years) prior to evaluation for surgery. Subjective
Fig. 5. The arthrodesis is stabilized with two screws, one dorsally, directed from the medial cuneiform distally into the first metatarsal, and the other into the base of the second metatarsal. We recommend using 3.5-mm cortical screws.
Fifty of the 53 patients were available for evaluation at a mean interval following surgery of 28 months (range 16-49 months). The appearance of the foot, duration and location of pain, shoewear, functional limitations, level of postoperative satisfaction, and duration of convalescence were evaluated. Range of motion of the hallux MPJ and the position of the first metatarsal were checked both clinically and radiographically. Complications of surgery including infection, stiffness, pseudar-
preoperative complaints were pain in and around the hallux MPJ in 42% of patients, pain directly over the medial eminence (64%), pain involving the second toe (46%), second metatarsalgia (22%) and the third and fourth toes (18%), and a bunionette (19%). Twenty-two percent of patients had concerns about the appearance of the foot, 68% experienced pain with shoewear and activities of daily living, and 12% had discomfort at rest. Hypermobility of the medial ray was felt to be present in all five adolescents (eight feet) and in an additional 24 feet in adult patients. With regard to pain relief, 73% were satisfied, 21% satisfied with reservations, and 6% were dissatisfied. Seventy-nine percent were satisfied with the appearance of the foot, 21% had reservations, and none were dissatisfied. Stiffness was noted by 18% of patients (no adolescents), and although most were not bothered by it, four of these patients felt impaired by this sensation. Nine percent experienced persistent difficulty with shoewear postoperatively, 44% were more comfortable
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Fig. 6 This patient was a 32-year-old female with marked hypermobility of the medial ray. Note the medial cortical thickening of the second metatarsal shaft and the relative lengths of the first and second metatarsals, A. A bi-planar wedge resection of the metatarsocuneiform joint would lead to shortening of the first metatarsal with transfer of weight to the second. Excellent correction was obtained with maintenance of the length of the first metatarsal by adduction and plantarflexion without bone resection, B. Correction was satisfactory and the patient was asymptomatic.
in the same shoes, and 47% wore narrower shoes postoperatively. The subjective sense of duration of convalescence averaged 8 months. Thirty-seven percent felt that the recovery process was more involved than anticipated, 44% anticipated the overall level of the recovery process, while 19% thought that the recovery was less than anticipated. Objective Results
The average preoperative intermetatarsal angle was 14.3° (range 9.5-34°) and was corrected postoperatively to a mean angle of 5.8° (range 0-12°). The hallux valgus angle was reduced from a mean angle of 34.5° (range 20-75°) to a mean angle of 13° (range -1020°). The sesamoid position was improved from grade 1 (16%), grade 2 (32%), and grade 3 (52%) to postoperative positions grade 0 (49%), grade 1 (36%), grade 2 (13%), and grade 3 (2%). There were three additional feet with medial sesamoid shift. The average dorsiflexion of the hallux MPJ was 75° (range 45-100°) and decreased postoperatively to a mean angle of 65° (range 20-90°). The average plantarflexion of the hallux MPJ was 30° (range 10-40°) and decreased to 20° postoperatively (range 0-35°). Overall Results
The overall result was evaluated in terms of pain relief, cosmesis, shoe wear, function (including stiffness), and postoperative complications. Seventy-seven percent of the patients experienced total relief of symptoms, 15% were partially relieved, and 8% were not relieved with respect to pain, function, and cosmesis.
COMPLICATIONS
One intraoperative fracture of the base of the first metatarsal occurred when a screw was inserted 0.5 cm from the joint surface. The screw was removed and the fixation was held secure with Kirschner wires until arthrodesis occurred. If a fracture of the metatarsal was to occur, we would currently recommend redirecting the screw from proximal to distal rather than using Kirschner wires. Two patients developed superficial postoperative would infections that resolved with oral antibiotics. Five of eight patients in whom an adjunctive K wire was used medially developed irritation and inflammation from the pin, requiring premature removal in two patients. There were seven nonunions (9.5%), four of which were initially associated with persistent swelling, aching, and intermittent pain. However, symptoms persisted in only two of these four patients, and with further follow-up, the other two were asymptomatic (Fig. 7). One of these patients underwent revision of the arthrodesis successfully, with resolution of swelling and discomfort. Eight patients required removal of the dorsal screw because of pain or prominence, and an additional 12 underwent removal of the medial screw. With careful countersinking technique of the screw head, this has seldom been required over the past few years. There were three broken screws, all of which were 4.0-mm cancellous screws and two of which were also associated with a pseudarthrosis. Three neuromas of the deep peroneal nerve occurred, two of which were symptomatic. The intermittent tingling associated with these neuromas eventually
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subsided and no further treatment was required. In these three patients, the neuroma was related to the proximal incision, which was made lateral to the extensor hallucis longus tendon in the first six patients but was discontinued when these neuromas were identified. No distal neuromas of the dorsal medial cutaneous nerve were identified. Five patients (7%) developed a dorsal bunion associated with elevation and malunion of the first metatarsal. Three of these were symptomatic and associated with discomfort and decreased range of motion of the hallux MPJ. In one patient, symptoms resolved following cheilectomy, with improvement in the range of motion of the hallux. At the last examination, one of these five patients was symptomatic with transfer of weight to the second metatarsal, which was associated with callosity. Apart from these patients with dorsal elevation of the metatarsal, no others experienced problems related to shortening of the first metatarsal. Separate mention should be made of the last nine patients in whom the modified procedure was performed as discussed in the Surgical Technique. Whether as a result of an improving "learning curve," the altered surgical technique, or a more conservative approach to ambulation postoperatively, these patients have had far better results than the overall group. Although these nine patients were included in the results above, none experienced problems with pseudarthrosis, malunion, or fixation. Furthermore, both the subjective and objective results were substantially better than those of the group as a whole. DISCUSSION
In addition to the obvious benefit of realigning the hallux, Lapidus 16-19 felt that this was achieved by a procedure performed at the apex of the deformity, simultaneously stabilizing the articulation and preventing recurrent deformity. Another advantage to this procedure is stabilization of the first ray, since metatarsus primus varus is often associated with a hypermobile first ray.3-9.15.23.24.26.27 This hypermobility is characterized by a multiplanar instability, with an increased tendency for the metatarsal to shift in both the sagittal and horizontal planes." This excessive mobility is accompanied by dorsal elevation or prominence of the first metatarsal, hallux valgus, and transfer of weight to the second metatarsal with second metatarsal overload (Fig. 1). This concept was emphasized in 1930 by Dudley Morton." who believed that a short first metatarsal was the primary problem, but attributed the weight transfer to the second metatarsal to hypermobility of the first ray. Although these findings were largely disputed in the work by Harris and Beath,"
recent developments in instrumentation of the foot have clarified these issues." Rodgers and Cavanaqh" compared the plantar pressure distribution under the forefoot in patients with and without a short first metatarsal. They demonstrated that a short first metatarsal, particularly when associated with hypermobility, is associated with markedly increased pressures under the second metatarsal. 27 Hypermobility is usually an isolated finding in the foot, but is occasionally associated with generalized ligamentous laxity.13,21 This foot pattern may be prone to recurrent deformity if these factors are not taken into consideration when planning the appropriate procedure for correction of hallux valgus. While it is easy to appreciate a subjective sense of excessive motion of the first metatarsal when examining the foot, it is fair to state that neither concepts of hypermobility nor what constitutes abnormal motion is clearly defined or understood. Fifteen percent of the feet operated upon were those of adolescents, and hypermobility was a common finding in this group, as noted previously by other authors. We found that in an adolescent with a hypermobile first ray, realignment could be accomplished with the closing wedge arthrodesis without any distal soft tissue release or exostectomy (Fig. 2). The results in these four adolescents (five feet) have been quite stable over the past 4 years. This is particularly important, since the incidence of recurrent deformity in the adolescent bunion has been noted to be as high as 35% in some series, possibly related to hypermobility or ligamentous laxity.4,31 Clarke et at." reported on this procedure in adolescents with exceptionally good results. Although only 15% of the feet operated upon in this series were in adolescents, these five patients (eight feet) had uniformly good results; we feel that this is an excellent procedure for adolescents with a closed epiphysis. Lapidus19 included the base of the second metatarsal in the arthrodesis. In a later review of this procedure, he commented on three recurrences in some of his earlier cases when a fusion of only the metatarsocuneiform joint was performed. This he attributed to widening occurring between the middle and medial cuneiforms. This is certainly a possibility, but it has not been identified in any of the more recent series to date. 2,4,22,29 Since this further increases stiffness, incorporating the base of the second metatarsal in the arthrodesis is probably unnecessary. Lapidus recognized the problem of shortening of the first metatarsal following this procedure, and recommended that only a small wedge be removed from the lateral aspect of the articular surfaces of the first metatarsal and medial cuneiform. Other authors at the time had recommended a more complete resection of the metatarsal cuneiform joint, including its most medial
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Fig. 7 This patient had satisfactory correction of the deformity postoperatively, but developed a pseudarthrosis, A. This was initially associated with swelling and aching, but her symptoms subsided completely after 15 months, B, C.
aspect.'-" Excessive bone resection will, however, cause shortening of the metatarsal and this is not recommended. Sangeorzan and Hansen" have reported on the use of an interpositional iliac crest bone graft with a short first metatarsal. While this is an option, and indeed may be necessary in certain patients, we prefer not to use this procedure in the presence of a short first metatarsal. A recent modification of the metatarsocuneiform arthrodesis has been proposed by Mauldin et al.22 In this approach, only the medial and dorsomedial aspects of the joint are identified through a medial longitudinal incision. The joint is passively reduced into an adducted and plantarflexed position and then held rigidly with either a large threaded Steinmann pin or a self-tapping 4.5-mm screw introduced from the base of the first metatarsal across the base of the second metatarsal. With the metatarsal reduced, the arthrodesis is per-
formed by resecting a trough from the medial aspect of the joint and packing with cancellous bone chips obtained from the medial eminence and the depth of the metatarsal and cuneiform. Although their incidence of pseudarthrosis is far higher than in previously reported series, this is an appealing alternative, with potentially less complications inherent when performing a wedge resection of the joint as outlined above. Good results have been reported recently using this technique of plantarflexion and adduction of the first metatarsal. 2 With the modifications to the technique that we now advocate, our procedure is similar using the same adduction plantarflexion maneuver. However, the joint is minimally resected dorsolaterally rather than medially, and we use a different technique of internal fixation. Although we have not yet experienced pseudarthrosis with this technique, based on the high incidence of asymptomatic pseudarthrosis experienced by Mauldin,
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this complication may not be as significant as we previously thought it would be. Pseudarthrosis occurred in 9.5% of the patients in our series. Of these seven patients, four were initially symptomatic, but only one subsequently required treatment with revision of the arthrodesis. Clarke et al." reported no nonunions in their series of 24 adolescent bunions treated with the modified Lapidus technique. Mauldin et al.22 reported a significantly higher incidence of nonunions, most of which were asymptomatic. In the last nine patients in our series who were treated with the modified surgical technique, no nonunions were experienced. We were unable to identify any correlation between the method of fixation nor postoperative form of immobilization and pseudarthrosis. We currently recommend limited or touch-down weightbearing for 4 to 6 weeks in a short leg cast followed by 2 to 4 weeks in a surgical shoe depending on comfort. We would be more inclined to use a cast if there were problems with the fixation and stability of the arthrodesis or if the patient was excessively active. Although Lapidus 16 relied upon a heavy catgut suture through the base of the metatarsal, far more reliable methods of fixation are available to enhance the rate of arthrodesis. The problems with fixation, however, are not peculiar to this operation and are experienced with any procedure at the base of the first metatarsal. Compression of the joint was accomplished with 3.5mm cortical or 4.0-mm cancellous screws. Rarely will a single dorsal screw provide enough stability so that a second screw is not needed. However, we would recommend supplementary fixation directed from the medial base of the first metatarsal to control rotation and improve stability. Rigid fixation with screws provide the best milieu for primary bone healing with the least potential for postoperative displacement. While Kirschner wires may be used, they are also associated with an increased incidence of infection, particularly if introduced percutaneously and allowed to protrude from the skin. The presence of a pin tract infection may then compromise stability if they have to be removed prematurely. If Kirschner wires are used, we would recommend using O.062-in diameter pins or greater and burying them subcutaneously. We believe that the results of this procedure are satisfactory. However, we feel that the arthrodesis performed by resecting a biplanar wedge from the joint may be associated with potential morbidity and complications. We have reservations with the technical aspects of this procedure as originally performed by ourselves and it is possible that the method of arthrodesis as described by Mauldin may be more successful than that achieved by resecting a biplanar wedge from the joint. Our indications for the MC arthrodesis are in
patients with a hypermobile first ray, particularly when associated with generalized ligamentous laxity, or severe metatarsus primus varus. As such, this procedure is particularly suited to the adolescent patient with a closed epiphysis. An arthrodesis may also be performed to achieve correction of a degenerative arthritis at the first tarsometatarsal joint associated with pes planus. In these patients, dorsal osteophytes develop that are associated with a slight widening of the plantar aspect of the joint." There is undoubtedly a learning curve in performing this operation the procedure has evolved both in our hands and those of others performing it. We believe that metatarsocuneiform arthrodesis is an important procedure in the treatment of hallux valgus, with satisfactory results in appropriately selected patients.
REFERENCES 1. Albrecht, G.H.: The pathology and treatment of hallux valgus (in Russian). Russk. Vrach., 10:14-19, 1991. 2. Amis, J.: Personal communication. 1989. 3. Armstrong, W.: Treatment of hallux valgus. Am. J. Surg., 36:332-338, 1937. 4. Clarke, H.R., Veith, R.G., and Hansen, S.T.: Adolescent bunions treated by the modified Lapidus procedure. Bull. Hosp. Jt. Dis. Orthrop. Inst., 47:109-122,1987. 5. Durman, D.C.: Metatarsus primus varus and hallux valgus. Arch. Surg., 74:128-135, 1957. 6. Goldner, J.L., and Gaines, R.W.: Adult and juvenile hallux valgus: analysis and treatment. Orthop. Clin. North Am., 7:863887,1976. 7. Hansen, S.T., and Smith, J.: Chronic deficiency of the posterior tibial tendon and the first tarsometatarsal joint: a rationale for treatment. Presented at the AOFAS Meeting, New Orleans, 1990. 8. Hardy, R.H., and Clapham, J.C.R.: Observations on hallux valgus. J. Bone Joint Surg., 33B:415, 1951. 9. Hardy, R.H., and Clapham, J.C.R.: Hallux valgus, predisposing anatomical causes. Lancet, 1:1180,1952. 10. Harris, R.I., and Beath, T.: The short first metatarsal, its incidence and clinical significance. J. Bone Joint Surg., 31A:553565,1949. 11. Hue, G., and Thyes, T.: Tactique operatoire dan I'hallux valgus. Rev. d'Orthop, Chir., 25:720-721, 1938. 12. Johnson, K.A.: Personal communication. 1991. 13. Jones, R.L.: The human foot. An experimental study of its mechanics the role of its muscles and ligaments in the support of the arch. Am. J. Anat., 68:1-39, 1941. 14. Kleinberg, S.: Operative cure of hallux valgus and bunions. Am. J. Surg., 15:75-81, 1932. 15. Lambrinudi, C.: Metatarsus primus elevatus. Proc. R. Soc. Med., 31:1273, 1938. 16. LapidUS, P.W.: The operative correction of the metatarsus varus primus in hallux valgus. Surg. Gynecol. Obstet., 58:183-191, 1934. 17. Lapidus, P.W.: Discussion following McBride's paper. J.A.MA, 105:1068,1935.
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Foot & AnkleJVol. 13, No. 3/March/ApriI1992 18. Lapidus, P.W.: A quarter of a century of experience with the operative correction of the metatarsus varus in hallux valgus. Bull. Hosp. Jt. Dis. Orthop. Inst., 17:404-421,1956. 19. Lapidus, P.W.: The author's bunion operation from 1931 to 1959. Clin. Orthop., 16:119-135, 1960. 20. Leboucq, H.: Le developement du premier metatarsien de son articulation tarsienne chez I'homme. Arch. BioI., 3:337-344, 1882. 21. Lundberg, A., Goldie, I., Kalin, B., and Selvik, G.: Kinematics of the ankle/foot complex. Plantarflexion and dorsiflexion. Foot Ankle, 9:195-200, 1989. 22. Mauldin, D., Sanders, M., and Whitemere, W.: Correction of hallux valgus with limited metatarsocuneiform arthrodesis. AOFAS Meeting, Las Vegas, 1989. 23. Morton, D.J.: Structural factors in static disorders of the foot. Am. J. Surg., 9:315-328, 1930. 24. Morton, D.J.: The Human Foot. New York, Columbia University Press, 1935. 25. Ouzounian, T.: In vitro determination of midfoot motion. Foot Ankle, 10:140-146,1989. 26. Piggot, H.: The natural history of hallux valgus. J. Bone Joint Surg., 42B:749, 1960.
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27. Rodgers, M.M., and Cavanagh, P.R.: Pressure distribution in Morton's foot structure. Med. Sci. Sports Med., 21:23-28, 1989. 28. Root, M.L, Orien, W.P., and Weed, J.H.: Normal and Abnormal Function of the Foot. Los Angeles: Clinical Biomechanics Corp., 1977. 29. Sangeorzan, B.J., and Hansen, S.T.: Modified lapidus procedure for hallux valgus. Foot Ankle, 9:262-266, 1989. 30. schunz, A.H.: The Skeleton of the Trunk and Limbs of Higher Primates; Human Biology. 1930,2, pp. 303-438. 31. Scranton, P.E., and Zuckerman, J.D.: Bunion surgery in adolescents: results of surgical treatment. J. Pediatr. Orthop., 4:3943,1984. 32. Smith, R. W., Reynolds, C., and Stewart, M.J.: Hallux valgus assessment. Report of the Research Committee of the American Orthopedic Foot and Ankle Society. 5:92-103, 1984. 33. Strauss, W.L: Growth of the Human Foot and its Evolutionary Significance;Contribution to Embryology. 1927, No. 101,19, pp. 93-134. 34. Truslow, W.: Metatarsus primus varus or hallux valgus? J. Bone Joint Surg., 7:98,1925. 35. Wissel, H.: Beitrag zur operativen korrektur des hallux valgus mit abnorm stark abspreistellung des 1 metatarsale. Arch. Orthop. Unfall-Chir., 45:100-104, 1952.
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Metatarsocuneiform Arthrodesis for Management of Hallux Valgus and Metatarsus Primus Varus Mark Myerson, M.D.: Steven Allon, M.D.,t and William McGarvey, M.D.:j: Baltimore, Maryland and Meadowbrook, Pennsylvania
ABSTRACT Sixty-seven closing wedge arthrodesis procedures of the first metatarsocuneiform joint were performed in 41 females and 12 males. Follow-up averaged 28 months (range 16-49 months) and was performed in 51 of 53 patients with a questionnaire, clinical examination, and comparison of pre- and postoperative weightbearing radiographs. The average hallux valgus angle was 34.5° (range 20°-75°) and was corrected to 13.0° (range -10°22°) postoperatively. The average intermetatarsal angle was 14.3° (range 9.5°-34°) and was corrected to an average of 5.8° (range 0°-12°) postoperatively. Complications included seven superficial pin tract infections, three symptomatic dorsal bunions, one of which required repeat surgery, seven nonunions, one of which was symptomatic, one hallux varus, and three neuromas of the deep peroneal nerve. The range of motion of the hallux metatarsophalangeal joint was 85% of normal postoperatively. A total of 77% of the patients were totally relieved, 15% partially relieved, and 8% not relieved with respect to pain, comfort, appearance of the foot, and shoewear following surgery. The specific indications for performing this operation are discussed.
metatarsus primus varus and atavism played a dominant role in the development of hallux valgus. Although these concepts were introduced by Truslow" in 1925, anthropologists were the first to recognize the similarity between the divergence of the first metatarsal in human embryos and prehensile feet of primates. 20 ,27,30,33 Lapidus considered patients with metatarsus primus varus to have "atavistic" feet; hence, the metatarsocuneiform arthrodesis for management of hallux valgus associated with metatarsus primus varus evolved." In this study, we present our evolving experience with first metatarsocuneiform arthrodesis, and the modifications to the procedure which we have found useful over the past few years. MATERIALS AND METHODS
Between 1986 and 1990, 67 metatarsocuneiform fusions were performed in 53 patients, nine males and 44 females. The average age of the patients was 29 years (range 16-66 years). Bilateral procedures were performed in 14 patients (12 females and two males). Preoperative evaluation was performed in a consistent manner for each patient. The presence of generalized ligamentous laxity was noted, and the foot was examined for pes planus, hypermobility of the first ray, and any associated deformities. Hypermobility of the medial ray albeit, subjective, is defined as excessive motion of the first metatarsal in the sagittal and transverse planes, and was estimated for each patient. This is demonstrated by holding the patient's midfoot firmly and manipulating the first metatarsal with the thumb and forefinger of the opposite hand. The motion of the medial ray includes that of the metatarsocuneiform, naviculocuneiform, and talonavicular joints. The range of motion of the hallux, including congruity of the metatarsophalangeal joint (MPJ) and the extent of any adduction contracture, was noted. Weightbearing preoperative and postoperative anteroposterior and lateral radiographs were obtained. The intermetatarsal angle, hallux valgus angle, and
INTRODUCTION
Paul Lapidus popularized the procedure of closing wedge arthrodesis of the metatarsocuneiform (MC) joint. 16 - 19 This procedure had, however, been advocated by several authors prior to Lapidus, including Albrecht' in 1911, Truslow" in 1925, and Kleinberg 14 in 1932. Since then, this operation and various modifications thereof have been advocated by Armstronq" (1937), Hue and Thyes 11 (1938), Wissel 35 (1952) Goldner and Gaines6 (1976), Clarke et al." (1987), Sangeorzan and Hansen" (1989), Amis," and Mauldin et al.22 (1989). Lapidus, like many of these authors, felt that * The Union Memorial Hospital, 201 E. University Parkway, Baltimore, Maryland 21218. Address reprint requests to Dr. Myerson. t 1648 Huntington Pike, Meadowbrook, Pennsylvania 19046. Resident in Orthopedic Surgery, The Union Memorial Hospital, Baltimore, Maryland.
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sesamoid position were studied. Sesamoid position was graded using the system described by Smith et al.32 Since Smith's grading does not include medial displacement of the tibial sesamoid which may occur postoperatively, a line bisecting the mid-axis of the first metatarsal was the reference position for the medial sesamoid. Hypermobility of the first ray was felt to be expressed radiographically as cortical thickening of the second metatarsal shaft (Fig. 1). The indications for performing the MC arthrodesis were in patients with severe metatarsus primus varus, in those with moderate deformity associated with hypermobility of the first ray, in adolescents with hypermobility or generalized ligamentous laxity, and where deformity was associated with symptomatic degenerative arthritis of the MC joint. SURGICAL TECHNIQUE
Surgery was performed under regional ankle block anesthesia in 62 of the 67 feet. Bilateral procedures were not performed simultaneously. No tourniquet was used, and hemostasis was controlled and bleeding was minimized with the use of small hemostat clamps. For purposes of clarity, the technique is described as it was performed for the majority of patients (58 of 67 feet), and any recent modifications introduced over the sub-
Fig. 1. This patient was. a 32-year-old female who had marked hypermobility of the medial ray. Note the cortical hypertrophy along the medial second metatarsal shaft indicating excessive transfer of stress to this metatarsal. Note also the mild generalized metatarsus adductus and the obliquity and slight instability of the first rnetatarsocuneiform joint.
sequent 2 years are detailed separately. A medial longitudinal incision was made over the hallux MPJ at the junction of the dorsal and plantar skin. A vertical capsular ellipse was excised and the exostosis was resected flush with the medial edge of the metatarsal shaft. A soft tissue release including an adductor tenotomy with partial lateral capsUlotomy was performed in 60 of 67 feet (89%) through a separate dorsal incision over the distal first-second intermetatarsal space. In the remaining seven feet (six adolescents), no adduction contracture was present, and this part of the procedure was omitted. In four of the adolescent patients (six feet), only one incision was used for the arthrodesis, and it was not found necessary to perform either a soft tissue release or a resection of the medial eminence (Fig. 2). The third incision was made proximally, medial to the extensor hallucis longus tendon to expose the MC joint. An oscillating saw was used to remove a small biplanar wedge from the joint with the base lateral and plantar. The first cut was made on the cuneiform, removing approximately 1 mm including articular cartilage and minimal subchondral bone, and the second cut was made on the metatarsal. Minimal bone was removed to prevent shortening of the metatarsal
Fig. 2. This patient was a 17-year-old female with hypermobility of the medial ray and discomfort under the second metatarsal head. Note the medial cortical hypertrophy of the second metatarsal shaft. The correction was obtained at the metatarsocuneiforrn joint alone without distal soft tissue release or exostectomy. The position of the medial screw traversing the middle cuneiform is not optimal.
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(Fig. 3). No bone was resected medially, since this makes the articulation unstable and difficult to fuse. There is a tendency to remove insufficient bone from the plantar apical joint surface, and a thin rongeur was used to remove bone from the depths of the joint. The base of the metatarsal was plantarflexed by bone resection, not by translating the metatarsal in a plantar direction. The metatarsal was held adducted and plantarflexed and was temporarily secured with O.062-in Kirschner wire. Anteroposterior and lateral radiographs were then obtained to check reduction and alignment, and followed by more stable internal fixation. Compression of the joint was achieved with 3.5-mm cortical screws introduced from the dorsal base of the metatarsal into the medial cuneiform. Supplementary medial fixation was used, introduced obliquely across the first metatarsal base into the second metatarsal base (Fig. 4). Occasionally, the second metatarsal was missed and the medial screw was inserted into the middle cuneiform, but this was not the preferred direction of securing the fixation, since it unnecessarily crosses a joint not included in the arthrodesis (Fig. 2). A K wire was only used medially if difficulty was experienced with insertion of a screw. Initially, a 4.0-mm cancellous screw was used, but when two of these were noted to break, a 3.5-mm cortical screw was used. We occasionally experienced difficulty in removing the 3.5-mm screws medially due to soft tissue swelling, and a 4.5mm malleolar screw was occasionally used since these
Fig. 3. The arthrodesis is performed with minimal bone resection, ensuring realignment without shortening. Note that the medial margin of the joint is not disturbed, and alignment of the metatarsal is achieved by adduction and plantarflexion.
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were easily palpable subcutaneously and could be removed in the office. In the first 58 feet, no medial fixation was used in five feet, a 4.0-mm cancellous screw in seven, a K wire in eight, a 3.5-mm cortical screw in 33, and a malleolar or self-tapping 4.5-mm screw in 14 feet. During the first 3 years of this review, the procedure was performed as described above. However, we experienced occasional difficulty with the fixation and were dissatisfied with the potential for shortening and malunion of the metatarsal. Recognizing the anatomic variations of the MC joint and the base of the first metatarsal, we felt that a biplanar wedge resection of the joint as described above was not necessary for all patients. We gained experience from the technique as described by Mauldin et al.,22 leading us to believe that the metatarsal may be repositioned with little, if any, bone resection. Due to the concave-convex shape of the metatarsocuneiform articulation, this is easily accomplished with a more natural movement of adduction, plantarflexion, and slight internal rotation of the first metatarsal. The technique was, therefore, modified for the last nine patients in this study, and is one which we currently recommend. Only the articular cartilage was removed lateral and plantar, leaving the medial aspect of the joint intact. The metatarsal was held in adduction and plantarflexion and temporary fixation held the metatarsal. Following radiographic evaluation, permanent fixation was performed using 3.5-mm cortical screws. The first screw was introduced dorsal to plantar from the medial cuneiform proximally into the first metatarsal distally using a lag screw technique suggested by Johnson12 (Fig. 5). The second screw was introduced medially from the first metatarsal into the second metatarsal base from slightly plantar to dorsal, avoiding the middle cuneiform (Fig. 6). A burr was used to create two or three small troughs across the joint both dorsally and medially, and local bone graft was used to fill these defects. Simultaneous associated procedures were performed on the second toe in 42% and on the third and fourth toes in 16%, and a bunionette correction was performed in 17% of patients. Postoperatively, patients used crutches until comfortable, followed by weightbearing as tolerated. Eighteen patients (21 of 67 feet) were placed in a short leg cast, with protected weightbearing for 6 weeks. The balance of the patients used a wooden shoe with protected weightbearing with or without crutches for 6 to 8 weeks. All patients used a soft bunion splint to maintain the hallux in neutral alignment for nighttime use for an additional 4 weeks. Evaluation of the patients was performed according to the recommendations of the Research Committee of the American Orthopaedic Foot and Ankle Society.32
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Fig. 4 This 34-year-old patient had severe deformity A, corrected in both the sagittal and horizontal plane postoperatively. e, The range of motion of the hallux metatarsophalangeal joint was preserved by the addition of a closing wedge osteotomy to the base of the proximal phalanx of the hallux.
throsis, recurrent deformity, and neuroma formation were evaluated. Other factors that prolonged convalescence, such as swelling, aching, and the need for hardware removal, were also studied. RESULTS
Follow-up interviews, examinations, and radiographic evaluations were performed in 51 of 53 patients (65 feet) and averaged 28 months (range 16-49 months) following surgery. Subjective Results
Patients had symptoms averaging 2.1 years (range
1-9.5 years) prior to evaluation for surgery. Subjective
Fig. 5. The arthrodesis is stabilized with two screws, one dorsally, directed from the medial cuneiform distally into the first metatarsal, and the other into the base of the second metatarsal. We recommend using 3.5-mm cortical screws.
Fifty of the 53 patients were available for evaluation at a mean interval following surgery of 28 months (range 16-49 months). The appearance of the foot, duration and location of pain, shoewear, functional limitations, level of postoperative satisfaction, and duration of convalescence were evaluated. Range of motion of the hallux MPJ and the position of the first metatarsal were checked both clinically and radiographically. Complications of surgery including infection, stiffness, pseudar-
preoperative complaints were pain in and around the hallux MPJ in 42% of patients, pain directly over the medial eminence (64%), pain involving the second toe (46%), second metatarsalgia (22%) and the third and fourth toes (18%), and a bunionette (19%). Twenty-two percent of patients had concerns about the appearance of the foot, 68% experienced pain with shoewear and activities of daily living, and 12% had discomfort at rest. Hypermobility of the medial ray was felt to be present in all five adolescents (eight feet) and in an additional 24 feet in adult patients. With regard to pain relief, 73% were satisfied, 21% satisfied with reservations, and 6% were dissatisfied. Seventy-nine percent were satisfied with the appearance of the foot, 21% had reservations, and none were dissatisfied. Stiffness was noted by 18% of patients (no adolescents), and although most were not bothered by it, four of these patients felt impaired by this sensation. Nine percent experienced persistent difficulty with shoewear postoperatively, 44% were more comfortable
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Fig. 6 This patient was a 32-year-old female with marked hypermobility of the medial ray. Note the medial cortical thickening of the second metatarsal shaft and the relative lengths of the first and second metatarsals, A. A bi-planar wedge resection of the metatarsocuneiform joint would lead to shortening of the first metatarsal with transfer of weight to the second. Excellent correction was obtained with maintenance of the length of the first metatarsal by adduction and plantarflexion without bone resection, B. Correction was satisfactory and the patient was asymptomatic.
in the same shoes, and 47% wore narrower shoes postoperatively. The subjective sense of duration of convalescence averaged 8 months. Thirty-seven percent felt that the recovery process was more involved than anticipated, 44% anticipated the overall level of the recovery process, while 19% thought that the recovery was less than anticipated. Objective Results
The average preoperative intermetatarsal angle was 14.3° (range 9.5-34°) and was corrected postoperatively to a mean angle of 5.8° (range 0-12°). The hallux valgus angle was reduced from a mean angle of 34.5° (range 20-75°) to a mean angle of 13° (range -1020°). The sesamoid position was improved from grade 1 (16%), grade 2 (32%), and grade 3 (52%) to postoperative positions grade 0 (49%), grade 1 (36%), grade 2 (13%), and grade 3 (2%). There were three additional feet with medial sesamoid shift. The average dorsiflexion of the hallux MPJ was 75° (range 45-100°) and decreased postoperatively to a mean angle of 65° (range 20-90°). The average plantarflexion of the hallux MPJ was 30° (range 10-40°) and decreased to 20° postoperatively (range 0-35°). Overall Results
The overall result was evaluated in terms of pain relief, cosmesis, shoe wear, function (including stiffness), and postoperative complications. Seventy-seven percent of the patients experienced total relief of symptoms, 15% were partially relieved, and 8% were not relieved with respect to pain, function, and cosmesis.
COMPLICATIONS
One intraoperative fracture of the base of the first metatarsal occurred when a screw was inserted 0.5 cm from the joint surface. The screw was removed and the fixation was held secure with Kirschner wires until arthrodesis occurred. If a fracture of the metatarsal was to occur, we would currently recommend redirecting the screw from proximal to distal rather than using Kirschner wires. Two patients developed superficial postoperative would infections that resolved with oral antibiotics. Five of eight patients in whom an adjunctive K wire was used medially developed irritation and inflammation from the pin, requiring premature removal in two patients. There were seven nonunions (9.5%), four of which were initially associated with persistent swelling, aching, and intermittent pain. However, symptoms persisted in only two of these four patients, and with further follow-up, the other two were asymptomatic (Fig. 7). One of these patients underwent revision of the arthrodesis successfully, with resolution of swelling and discomfort. Eight patients required removal of the dorsal screw because of pain or prominence, and an additional 12 underwent removal of the medial screw. With careful countersinking technique of the screw head, this has seldom been required over the past few years. There were three broken screws, all of which were 4.0-mm cancellous screws and two of which were also associated with a pseudarthrosis. Three neuromas of the deep peroneal nerve occurred, two of which were symptomatic. The intermittent tingling associated with these neuromas eventually
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subsided and no further treatment was required. In these three patients, the neuroma was related to the proximal incision, which was made lateral to the extensor hallucis longus tendon in the first six patients but was discontinued when these neuromas were identified. No distal neuromas of the dorsal medial cutaneous nerve were identified. Five patients (7%) developed a dorsal bunion associated with elevation and malunion of the first metatarsal. Three of these were symptomatic and associated with discomfort and decreased range of motion of the hallux MPJ. In one patient, symptoms resolved following cheilectomy, with improvement in the range of motion of the hallux. At the last examination, one of these five patients was symptomatic with transfer of weight to the second metatarsal, which was associated with callosity. Apart from these patients with dorsal elevation of the metatarsal, no others experienced problems related to shortening of the first metatarsal. Separate mention should be made of the last nine patients in whom the modified procedure was performed as discussed in the Surgical Technique. Whether as a result of an improving "learning curve," the altered surgical technique, or a more conservative approach to ambulation postoperatively, these patients have had far better results than the overall group. Although these nine patients were included in the results above, none experienced problems with pseudarthrosis, malunion, or fixation. Furthermore, both the subjective and objective results were substantially better than those of the group as a whole. DISCUSSION
In addition to the obvious benefit of realigning the hallux, Lapidus 16-19 felt that this was achieved by a procedure performed at the apex of the deformity, simultaneously stabilizing the articulation and preventing recurrent deformity. Another advantage to this procedure is stabilization of the first ray, since metatarsus primus varus is often associated with a hypermobile first ray.3-9.15.23.24.26.27 This hypermobility is characterized by a multiplanar instability, with an increased tendency for the metatarsal to shift in both the sagittal and horizontal planes." This excessive mobility is accompanied by dorsal elevation or prominence of the first metatarsal, hallux valgus, and transfer of weight to the second metatarsal with second metatarsal overload (Fig. 1). This concept was emphasized in 1930 by Dudley Morton." who believed that a short first metatarsal was the primary problem, but attributed the weight transfer to the second metatarsal to hypermobility of the first ray. Although these findings were largely disputed in the work by Harris and Beath,"
recent developments in instrumentation of the foot have clarified these issues." Rodgers and Cavanaqh" compared the plantar pressure distribution under the forefoot in patients with and without a short first metatarsal. They demonstrated that a short first metatarsal, particularly when associated with hypermobility, is associated with markedly increased pressures under the second metatarsal. 27 Hypermobility is usually an isolated finding in the foot, but is occasionally associated with generalized ligamentous laxity.13,21 This foot pattern may be prone to recurrent deformity if these factors are not taken into consideration when planning the appropriate procedure for correction of hallux valgus. While it is easy to appreciate a subjective sense of excessive motion of the first metatarsal when examining the foot, it is fair to state that neither concepts of hypermobility nor what constitutes abnormal motion is clearly defined or understood. Fifteen percent of the feet operated upon were those of adolescents, and hypermobility was a common finding in this group, as noted previously by other authors. We found that in an adolescent with a hypermobile first ray, realignment could be accomplished with the closing wedge arthrodesis without any distal soft tissue release or exostectomy (Fig. 2). The results in these four adolescents (five feet) have been quite stable over the past 4 years. This is particularly important, since the incidence of recurrent deformity in the adolescent bunion has been noted to be as high as 35% in some series, possibly related to hypermobility or ligamentous laxity.4,31 Clarke et at." reported on this procedure in adolescents with exceptionally good results. Although only 15% of the feet operated upon in this series were in adolescents, these five patients (eight feet) had uniformly good results; we feel that this is an excellent procedure for adolescents with a closed epiphysis. Lapidus19 included the base of the second metatarsal in the arthrodesis. In a later review of this procedure, he commented on three recurrences in some of his earlier cases when a fusion of only the metatarsocuneiform joint was performed. This he attributed to widening occurring between the middle and medial cuneiforms. This is certainly a possibility, but it has not been identified in any of the more recent series to date. 2,4,22,29 Since this further increases stiffness, incorporating the base of the second metatarsal in the arthrodesis is probably unnecessary. Lapidus recognized the problem of shortening of the first metatarsal following this procedure, and recommended that only a small wedge be removed from the lateral aspect of the articular surfaces of the first metatarsal and medial cuneiform. Other authors at the time had recommended a more complete resection of the metatarsal cuneiform joint, including its most medial
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Fig. 7 This patient had satisfactory correction of the deformity postoperatively, but developed a pseudarthrosis, A. This was initially associated with swelling and aching, but her symptoms subsided completely after 15 months, B, C.
aspect.'-" Excessive bone resection will, however, cause shortening of the metatarsal and this is not recommended. Sangeorzan and Hansen" have reported on the use of an interpositional iliac crest bone graft with a short first metatarsal. While this is an option, and indeed may be necessary in certain patients, we prefer not to use this procedure in the presence of a short first metatarsal. A recent modification of the metatarsocuneiform arthrodesis has been proposed by Mauldin et al.22 In this approach, only the medial and dorsomedial aspects of the joint are identified through a medial longitudinal incision. The joint is passively reduced into an adducted and plantarflexed position and then held rigidly with either a large threaded Steinmann pin or a self-tapping 4.5-mm screw introduced from the base of the first metatarsal across the base of the second metatarsal. With the metatarsal reduced, the arthrodesis is per-
formed by resecting a trough from the medial aspect of the joint and packing with cancellous bone chips obtained from the medial eminence and the depth of the metatarsal and cuneiform. Although their incidence of pseudarthrosis is far higher than in previously reported series, this is an appealing alternative, with potentially less complications inherent when performing a wedge resection of the joint as outlined above. Good results have been reported recently using this technique of plantarflexion and adduction of the first metatarsal. 2 With the modifications to the technique that we now advocate, our procedure is similar using the same adduction plantarflexion maneuver. However, the joint is minimally resected dorsolaterally rather than medially, and we use a different technique of internal fixation. Although we have not yet experienced pseudarthrosis with this technique, based on the high incidence of asymptomatic pseudarthrosis experienced by Mauldin,
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this complication may not be as significant as we previously thought it would be. Pseudarthrosis occurred in 9.5% of the patients in our series. Of these seven patients, four were initially symptomatic, but only one subsequently required treatment with revision of the arthrodesis. Clarke et al." reported no nonunions in their series of 24 adolescent bunions treated with the modified Lapidus technique. Mauldin et al.22 reported a significantly higher incidence of nonunions, most of which were asymptomatic. In the last nine patients in our series who were treated with the modified surgical technique, no nonunions were experienced. We were unable to identify any correlation between the method of fixation nor postoperative form of immobilization and pseudarthrosis. We currently recommend limited or touch-down weightbearing for 4 to 6 weeks in a short leg cast followed by 2 to 4 weeks in a surgical shoe depending on comfort. We would be more inclined to use a cast if there were problems with the fixation and stability of the arthrodesis or if the patient was excessively active. Although Lapidus 16 relied upon a heavy catgut suture through the base of the metatarsal, far more reliable methods of fixation are available to enhance the rate of arthrodesis. The problems with fixation, however, are not peculiar to this operation and are experienced with any procedure at the base of the first metatarsal. Compression of the joint was accomplished with 3.5mm cortical or 4.0-mm cancellous screws. Rarely will a single dorsal screw provide enough stability so that a second screw is not needed. However, we would recommend supplementary fixation directed from the medial base of the first metatarsal to control rotation and improve stability. Rigid fixation with screws provide the best milieu for primary bone healing with the least potential for postoperative displacement. While Kirschner wires may be used, they are also associated with an increased incidence of infection, particularly if introduced percutaneously and allowed to protrude from the skin. The presence of a pin tract infection may then compromise stability if they have to be removed prematurely. If Kirschner wires are used, we would recommend using O.062-in diameter pins or greater and burying them subcutaneously. We believe that the results of this procedure are satisfactory. However, we feel that the arthrodesis performed by resecting a biplanar wedge from the joint may be associated with potential morbidity and complications. We have reservations with the technical aspects of this procedure as originally performed by ourselves and it is possible that the method of arthrodesis as described by Mauldin may be more successful than that achieved by resecting a biplanar wedge from the joint. Our indications for the MC arthrodesis are in
patients with a hypermobile first ray, particularly when associated with generalized ligamentous laxity, or severe metatarsus primus varus. As such, this procedure is particularly suited to the adolescent patient with a closed epiphysis. An arthrodesis may also be performed to achieve correction of a degenerative arthritis at the first tarsometatarsal joint associated with pes planus. In these patients, dorsal osteophytes develop that are associated with a slight widening of the plantar aspect of the joint." There is undoubtedly a learning curve in performing this operation the procedure has evolved both in our hands and those of others performing it. We believe that metatarsocuneiform arthrodesis is an important procedure in the treatment of hallux valgus, with satisfactory results in appropriately selected patients.
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