The Modified McBride Procedure: Clinical, Radiological, and Pedobarographic Evaluations

The Modified McBride Procedure: Clinical, Radiological, and Pedobarographic Evaluations

The Modified McBride Procedure: Clinical, Radiological, and Pedobarographic Evaluations D. Mittal, MRCS, MS (Orth), MCh (Orth), M Med Sci (Surgery of ...

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The Modified McBride Procedure: Clinical, Radiological, and Pedobarographic Evaluations D. Mittal, MRCS, MS (Orth), MCh (Orth), M Med Sci (Surgery of Trauma),1 S. Raja, MS (Orth), FRCS (Ed), FRCS (Tr & Orth),2 and N. P. J. Geary, FRCS3 Nineteen patients (27 feet) with symptomatic hallux valgus who underwent modified McBride procedure were studied prospectively. The outcome measures included preoperative and postoperative American Orthopaedic Foot and Ankle Society’s Hallux Metatarsophalangeal-Interphalangeal scoring, weightbearing radiographs, and pedobarography using the EMED-SF*6 System. The average patient age was 49.7 years, and all patients were women. The average follow-up was 7 months. Results showed an average improvement in rating scale score from 53 to 87/100, in the hallux valgus angle from 32° to 15°, and in the first intermetatarsal angle from 15° to 10°. Pedobarographic analysis showed a statistically significant increase in the contact area of the hallux by 17.5% (P ⬍ .001), with a reduction of peak pressures of the hallux by 29% from 67.5 ⫾ 29.5 N/cm2 to 48 ⫾ 34 N/cm2 (P ⬍ .001; confidence interval, 9.887, 29.233) and the total foot by 8% from 89 ⫾ 26 N/cm2 to 82 ⫾ 25 N/cm2 (P ⬍ .05; CI, 0.727, 14.900). The overall satisfaction rate was 96%. We conclude that the modified McBride procedure has a role in patients with passively correctable hallux valgus and a supple metatarsocuneiform joint. ( The Journal of Foot & Ankle Surgery 45(4):235–239, 2006) Key words: hallux valgus, McBride procedure, pedobarogram

T he modified McBride procedure has been widely used for the surgical management of hallux valgus. The rationale for this procedure relies on using the deforming force of adductor hallucis as a correcting force to close the first intermetatarsal gap (1, 2). Its efficacy in improving the hallux valgus angle and intermetatarsal angle has been confirmed by several clinical studies (3, 4). Pedobarography in hallux valgus has shown a reduction in contact area and an increase in peak pressures under the head of first metatarsal (5). Bony procedures have shown improvement in the contact area of the great toe with reduction in peak pressures of the great toe and the total foot (6, 7). We are not aware of any published literature on pedobarography to assess the modified McBride procedure. The aim of this study is to assess the efficacy of the

Address correspondence to: D. Mittal, 2 Lawrence Close, Norden, Rochdale, Lancs, OL12 7PJ, United Kingdom. E-mail: dkmittal@doctors. net.uk 1 Staff Surgeon, Department of Orthopaedics, Lancashire Teaching Hospitals NHS Trust, Preston, Lancs, United Kingdom. 2 Specialist Registrar, Department of Orthopaedics, Lancashire Teaching Hospitals NHS Trust, Preston, Lancs, United Kingdom. 3 Consultant Orthopaedic Surgeon, Arrowe Park Hospital, Upton, Wirral, Merseyside, United Kingdom. Copyright © 2006 by the American College of Foot and Ankle Surgeons 1067-2516/06/4504-0006$32.00/0 doi:10.1053/j.jfas.2006.04.001

modified McBride procedure in adults using clinical, radiographic, and pedobarographic methods. Materials and Methods Nineteen patients with 27 feet who underwent modified McBride procedures were studied prospectively. The inclusion criteria were as follows: 1) painful bunion with hallux valgus angle greater than 20° and first intermetatarsal angle greater than 10°; 2) passively correctable hallux valgus with no evidence of osteoarthritis; 3) supple first metatarsocuneiform joint with passively correctable first intermetatarsal gap; and 4) patient had to be available for a minimum follow-up of 6 months. The selection of patients for the study of all procedures was performed by the senior author (N. P. G.). The preoperative assessment and postoperative outcome evaluation were performed by the first author (D. M.), who was not involved in the surgery. The clinical outcome was assessed by history and examination based on the American Orthopedic Foot and Ankle Society (AOFAS) Hallux-Metatarsophalangeal-Interphalangeal score (8) preoperatively, at 6 months postoperatively, and at final review. In addition, patients were asked to rate their overall outcome with regard to the function and cosmetic appearance of the foot as satisfied, satisfied with reservations, or unsatisfied. Anteroposterior and lateral weight-bearing radiographs VOLUME 45, NUMBER 4, JULY/AUGUST 2006

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TABLE 1

Various radiological parameters before and after the operation Measurements Hallux valgus angle First intermetatarsal angle Lateral sesamoid displacement 1–2 Intermetatarsal distance 1–5 Intermetatarsal distance

Preoperative 32° (range, 15° (range, 8 mm (range, 32 mm (range, 80 mm (range,

were obtained before and after the operation at 0 months, 6 months, and at final review. The hallux valgus and first intermetatarsal angles were measured with the technique recommended by the AOFAS (9). In addition, we also measured the following parameters: 1) lateral sesamoid displacement as distance between the lateral cortex of first metatarsal head and lateral cortex of lateral sesamoid; 2) first to second intermetatarsal distance as widest distance between the lateral cortex of first metatarsal head and medial cortex of second metatarsal head; and 3) first to fifth intermetatarsal distance measured by drawing a perpendicular to the second metatarsal axis until the line contacted the first and fifth metatarsal head. The pedobarographic evaluation was performed with the commercially available EMED-SF*6 system (Novel GmBh; Munich, Germany). The sensor platform accommodates 2736 capacitance transducers with data acquisition at a rate of 50 Hz. Patients were asked to walk across a pressure platform measuring 6 m long. An average of 3 walks was taken to increase the reliability of measurements (10). The measurements were recorded for both feet. Measurements of total force, peak pressures, and the area of contact were displayed on the monitor immediately after the walk, together with a color-coded pressure pattern. This information was recorded and analyzed by the computer. The assessments were done preoperatively and at a minimum period of 6 months postoperatively. Statistical analysis was performed with the paired sample t test. A level of significance was set at P ⬍ .05. Surgical Technique The modified McBride procedure was performed as described by Archibald and Hamilton (11). The first metatarsophalangeal (MTP) joint was approached through a dorsomedial incision. A medial capsulotomy was performed in a distally based V-shaped flap, and the medial eminence was excised. Through a second incision between first and second web space, the tendon of adductor hallucis was identified and released from lateral sesamoid and the base of the proximal phalanx. A transverse drill hole was made in the neck of the first metatarsal from medial to lateral. A modified Kessler stitch using a number 1 nonabsorbable suture was applied to the detached end of the adductor hallucis 236

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22–52) 10–20) 4–12) 24–40) 66–85)

Postoperative 15° (range, 0–30) 10° (range, 4–17) 4 mm (range, 0–8) 27 mm (range, 20–32) 75 mm (range, 65–83)

tendon. The two ends of the suture and tendon were then threaded into the transverse hole from lateral to medial. The first intermetatarsal space was narrowed by a single suture between adjacent first and second MTP joint capsules. Finally, the transferred adductor hallucis tendon was sutured to the apex of the V capsulotomy while the hallux was held in a corrected position. Care was taken to protect the lateral sesamoid apparatus, and medial eminence resection was kept to a minimum to prevent hallux varus deformity. Postoperatively, the foot was immobilized in a plaster slipper for 6 weeks, with weight bearing on the heel allowed at 2 weeks. Results Nineteen patients with 27 feet underwent this procedure, and all were available for follow-up. The average age was 49.7 years (range, 28 –73). All patients were women. The average follow-up was 7 months (range, 6 –14 months). The average AOFAS score improved from 53/100 (range, 34 – 88) preoperatively to 87 (range, 75–100) at follow-up. Twenty-five out of 27 feet were completely free of pain, which included 12 feet with preoperative metatarsalgia. Two patients continued to have metatarsalgia but to a lesser degree. One foot had a hallux varus deformity. Preoperative first MTP joint range of motion averaged 68° (range, 50°– 105°) and postoperatively averaged 65° (range, 28°–100°). Sixteen patients (24 feet) were completely satisfied, while 2 patients (2 feet) with mild residual hallux valgus were satisfied with minor reservations. One patient with hallux varus was dissatisfied. The preoperative hallux valgus angle averaged 32° (range, 22°–52°), whereas postoperatively it decreased to 15° (range, 0°–30°). The first intermetatarsal angle decreased from an average of 15° (range, 10°–20°) preoperatively to 10° (range, 4°–17°) (Table 1, Fig 1). With respect to the pedobarographic evaluation, the contact area of the hallux averaged 7.4 ⫾ 1.4 cm2 preoperatively; it increased by 17.5% to 8.7 ⫾ 1.4 cm2 postoperatively (P ⬍ .001; confidence interval, 1.007, 1.740). The contact area of total foot improved from 114 ⫾ 10.27 cm2 to 115 ⫾ 11.125 cm2 (P ⬎ .05; CI, – 0.756, 2.436). The ground reaction forces of the hallux increased from 95.70 ⫾ 42.47 N to 101.13 ⫾ 44 N (P ⬎ .05; CI, –18.76,

FIGURE 1 (A) Preoperative and (B) postoperative standing anteroposterior radiographs.

7.296), and total foot increased by 6% from 812 ⫾ 104 N to 860 ⫾ 133 N (P ⬍ .001; CI, – 62.8, –33.3). The peak pressures of the great toe decreased by 29% from 67.5 ⫾ 29.5 N/cm2 to 48 ⫾ 34 N/cm2 (P ⬍ .001; CI, 9.887, 29.233), and the total foot decreased by 8% from 89 ⫾ 26 N/cm2 to 82 ⫾ 25 N/cm2 (P ⬍ .05; CI, 0.727, 14.900). In summary, there was statistically significant improvement in the contact area of the hallux with a reduction in the peak pressures. Discussion The McBride procedure has been reported to give satisfactory results by Johnson et al (12) in 88% of their patients, by Mann and Pfeffinger (13) in 92% of their patients, and by

Archibald and Hamilton (11) in 93% of their patients. Schwitalle et al (4) reported a good to satisfactory outcome in 12 of 17 patients at an average follow-up of 14 years. In the present series, the overall satisfaction rate was 96%, which is comparable with results from previous studies. The outcome of this procedure depends on the passive correctability of the patient’s hallux valgus with closure of the first intermetatarsal gap and a supple first tarsometatarsal joint. It should be noted that patient selection was done by the senior author, creating a potential source of selection bias, and is a limitation of this study. Osteoarthritis of the first MTP joint has been reported in 24% of feet after the McBride procedure (4). In contrast, the present study found no evidence of osteoarthritis possibly VOLUME 45, NUMBER 4, JULY/AUGUST 2006

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FIGURE 2

(A) Preoperative and (B) postoperative pedobarogram showing peak pressures (red zone) in the medial part of the forefoot.

because of the short follow-up. However, the onset of osteoarthritis may be inherent in the progressive deformity, particularly in younger patients. The correction of first intermetatarsal angle in this study averaged 5°, which is comparable with previous studies (13). In this series, 1 foot (3.7%) developed hallux varus deformity. The incidence of varus after McBride procedure varied from 1.6% (14) to 13% (15). The cause for hallux varus is said to be due to damage to the lateral head of flexor hallucis brevis tendon (15), removal of lateral sesamoid 238

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(14), a round metatarsal head, ligamentous laxity and overzealous correction, and bandaging and splinting techniques (16). In this series, the lateral sesamoid was not excised, which may explain the reduction in the incidence of this complication when compared with other studies. This is the first study using pedobarography after the modified McBride procedure. Pedobarographic measurements showed statistically significant improvement in the contact area of the hallux. There was significant reduction in the peak pressures of the hallux as well as the total foot.

This suggests improved load transmission with better pressure distribution on the medial side of the foot leading to a reduction in metatarsalgia (Fig 2). It also supports the concept that structural correction may not always be necessary to redistribute weight-bearing forces. We conclude that the modified McBride procedure has a role in patients with passively correctable hallux valgus and a supple first metatarsocuneiform joint.

7. 8.

9.

10.

References 11. 1. McBride ED. A conservative operation for bunions. J Bone Joint Surg 10:735–739, 1928. 2. Gebuhr P, Soelberg M, Larsen T. McBride’s operation for hallux valgus can be used in patients older than 30 years. J Foot Surg 31:241–243, 1992. 3. Mann RA, Coughlin MJ. Hallux valgus— etiology, anatomy, treatment and surgical considerations. Clin Orthop Relat Res 157:31– 41, 1981. 4. Schwitalle M, Karbowski A, Eckardt A. Hallux valgus in young patients: long term results after McBride operation. Arch Orthop Trauma Surg 116:412– 414, 1997. 5. Yamamoto H, Muneta T, Asahina S, Furuya K. Forefoot pressures during walking in affected with hallux valgus. Clin Orthop Relat Res 323:247–253, 1996. 6. Kernozek T, Roehrs T, McGarvey S. Analysis of plantar loading

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parameters pre and post surgical intervention for hallux valgus. Clin Biomech (Bristol, Avon) 12:S18 –S19, 1997. Borton DC, Stephens MM. Basal metatarsal osteotomy for hallux valgus. J Bone Joint Surg Br 76:204 –209, 1994. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the ankle, hind foot, midfoot, hallux and lesser toes. Foot Ankle Int 15:349 –353, 1994. Smith RW, Reynolds JC, Stewart MJ. Hallux valgus assessment: report of research committee of American Orthopaedic Foot and Ankle society. Foot Ankle 5:92–103, 1984. Hughes J, Pratt I, Linge K, Clarke K, Klenerman L. The reliability of pressure measurements: the EMED F system. Clin Biomech 6:14 –18, 1991. Archibald AA, Hamilton JA. Modified McBride’s procedure: long term results. J R Coll Surg Edinb 35:317–319, 1990. Johnson JE, Clanton TO, Baxter DE, Gottlieb MS. Comparison of chevron osteotomy and modified McBride bunionectomy for correction of mild to moderate hallux valgus deformity. Foot Ankle 12:61– 68, 1991. Mann RA, Pfeffinger L. Hallux valgus repair. Clin Orthop 272:213– 218, 1991. Miller JW. Acquired hallux varus: a preventable and correctable disorder. J Bone Joint Surg 57-A:183–187, 1975. Hansen CE. Hallux valgus treated by McBride operation. Acta Orthop Scand 45:778 –792, 1974. Greenfogel SI, Glubo S, Werner J, Sherman M, Lenet M. Hallux varus—surgical correction and review of literature. J Foot Surg 23: 46 –50, 1980.

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