Use of internal callus distraction in the treatment of congenital brachymetatarsia

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1 British Journal of Plastic Surgery (2005) 58, CASE REPORT Use of internal callus distraction in the treatment of congenital brachymetatarsia Naoto Yamada*, Yoshihiro Yasuda, Nobuko Hashimoto, Hironobu Iwashiro, Eiju Uchinuma Department of Plastic and Reconstructive Surgery, School of Medicine, Kitasato University, Kitasato Sagamihara, Kanagawa , Japan Received 28 July 2004; accepted 28 April 2005 KEYWORDS Brachymetatarsia; Callus distraction; Internal distraction Summary Congenital bilateral brachymetatarsia of the fourth metatarsal bone was treated by osteotomy and bone lengthening using the internal distraction technique. The patient was cosmetically improved. This technique has some advantages over the method of external distraction. q 2005 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved. Brachymetatarsia is a congenital deformity of the metatarsus caused by premature closure of the epiphysis. Thus far, brachymetatarsia has been treated with an osteotomy of the shortened metatarsus and iliac bone grafts, but recently callus distraction has been used. An external distraction device is the most common, however, used an internal distraction device (Pediatric Distractor w, Walter Lorenz Surgical, Inc., USA), and had a successful, cosmetically improved outcome. Case report A 26-year-old female complained about the appearance of brachymetatarsia of both fourth toes. The * Corresponding author. Tel.: C ; fax: C address: ymprs@med.kitasato-u.ac.jp (N. Yamada). toes were short and located in the web space between the third and fifth toes. The family history was unremarkable as was her general physical examination. Total lengthening planned for the left fourth toe was 15 mm, and 20 mm for the right fourth toe (Fig. 1(A) (D)). The left foot was operated on first. The device was installed directly in the metatarsal bone, and was covered by skin. Only the shaft for extending the device was exposed from the skin of the foot (Figs. 2(A) and (B) and 3(A)). Z-plasty lengthening of the extensor digitorum longus tendon was not performed. Distraction was initiated from the seventh postoperative day at a rate of 0.5 mm each day. Distraction was stopped on the 30th day when lengthening of 15 mm was achieved. There was no infection nor neurovascular complication. Surgery of the right foot was performed 1 month after the left foot operation (Fig. 3(B)). Z-plasty lengthening of the extensor digitorum longus tendon was performed. Distraction was initiated S /$ - see front matter q 2005 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved. doi: /j.bjps

2 Internal callus distraction 1015 Figure 1 Preoperative views and radiographs.

3 1016 N. Yamada et al. Figure 2 The distraction device installed directly on the metatarsal bone (A) and the distraction device (B). from the seventh postoperative day at a rate of 0.5 mm each day. Distraction was stopped on the 40th day when lengthening of 20 mm was achieved. There was no infection nor neurovascular complications. The MP joint of both fourth toes were fixated by Kirschner wire, which was removed when the desired distraction was achieved. Partial weight bearing, combined with a posterior splint, was commenced 2 months after the operation. Six months after operation, the patient reported a sudden spontaneous pain in her left foot, after which fracture of the callus and breakage of the Figure 3 Radiographs during distraction; left (A), right (B).

4 Internal callus distraction 1017 Figure 4 Radiograph of left side on 6 months after operation. Fracture of the callus and breakage of the distraction device were confirmed. distraction device were radiologically confirmed (Fig. 4). Consequently, iliac bone grafting was performed on the 4th metatarsal bone. Though ossification of the right 4th toe was radiologically confirmed on 7 months after operation (Fig. 5), the distraction device was not removed until the 17th month after operation. At 3 postoperative years, reshortening was not found, and the patient had good cosmetic results (Fig. 6(A) (D)). Discussion The treatment for brachymetatarsia consist mainly of bone lengthening, however, the soft tissue such as tendons, vessels, nerves, muscles, and cutaneous tissue are resistant to elongation of the metatarsal bone. Some alternate treatments for brachymetatarsia have been proposed, including one-stage lengthening and bone grafting 1,2 and bone lengthening by callus distraction. 1,3 8 Recently, distraction methods using some kind of device are more popular than one-stage lengthening and bone grafting. The callus distraction Figure 5 Radiograph of the right side on 7 months after operation. Ossification of the right 4th toe was confirmed. method is one of the more useful and safe methods. The callus distraction method eliminates such disadvantages of the conventional elongation procedure as the harvesting of a free bone graft, which leaves a donor site scar, possible bone graft resorption and pseudo-arthrosis, and disability of the MP joint function. It also facilitates sufficient bone and soft tissue elongation, which is usually difficult in the conventional procedure. Though the callus distraction method is useful and safe, there are some disadvantages, such as long-term exposure of the device on the foot, screw-track infection, 1,5 reshortening 1,3 and fracture after removal of the device. 3 The treatment period for callus distraction varies from several weeks to a few months. 1,3 5 During the treatment, the cortical screws of the distraction device are inserted through from the skin to the metatarsal bone, and the distraction device is held in place by those screws. In such a situation, some obstacles are raised in the daily life of the patient. Furthermore, reshortening and fracture of the distracted bone may occur after removal of the device. The timing of removal of the device is decided by radiological findings of ossification. Reshortening is observed within 1 month after removal of the device and has ranged from 15 to

5 1018 N. Yamada et al. Figure 6 Postoperative views and radiographs at 3 years. 25% of the distracted length. 1,3 We think that reshortening is preventable if the fixation period using the device is lengthened. In the internal callus distraction method on which we reported, because the device is adjacent to the metatarsal bone, there is no device on the skin of the foot during treatment after bone lengthening is achieved. Only the shaft is exposed

6 Internal callus distraction 1019 until bone lengthening is achieved. The patient can put on socks and shoes, and take a bath and use a pool during treatment. The device does not have to be removed, because the device is used as reinforcement of newly formed bone after bone lengthening is achieved, reshortening, resorption and fracture are prevented. In our reported case, reshortening of the newly formed bone was not observed within 2 months, except in the case with the postoperative fracture. Though the internal distraction method is a useful and safe method, there are some disadvantages such as the strength of the device, damage to the periosteum and re-operation for device removal. We reflect that the right foot surgery should have waited until after sufficient ossification of left side was shown radiologically. If we had done so, the fracture of the callus and breakage of the device were likely not to have happened. Damage to the periosteum in internal distraction is larger than that in external distraction because the device used for internal distraction installs directly on the metatarsal bone. Though we tried in this case to protect the periosteum, the healing index of the right foot was still about 95 days/cm. This healing index is not slower than that of other case reports using external distraction. 1,3 5,7,8 We tried the method of callus distraction using an internal distraction device, and obtained had a good cosmetic improvement. References 1. Magnan B, Brayantini A, Regis D, Bartolozzi P. Metatarsal lengthening by callotasis during the growth phase. J Bone Joint Surg 1995;77B: Baek GH, Chung MS. The treatment of congenital brachymetatarsia by one-stage lengthening. J Bone Joint Surg Br 1998; 80: Kawashima T, Yamada A, Ueda K, Harii K. Treatment of brachymetatarsia by callus distraction (callotasis). Ann Plast Surg 1994;32: Robinson JF, Ouzounian TJ. Brachymetatarsia: congenitally short third and fourth metatarsals treated by distraction lengthening a case report and literature summary. Foot Ankle Int 1998;19: Masada K, Fujita S, Fuji T, Ohno H. Complications following metatarsal lengthening by callus distraction for brachymetatarsia. J Pediatr Orthop 1999;19: Houshian S, Skov O, Weeth RE. Correction of congenital brachymetatarsia by gradual callus distraction. Scand J Plast Reconstr Surg Hand Surg 2002;36: Song HR, Oh CW, Kyung HS, Kim SJ, Guille JT, Lee SM, et al. Fourth brachymetatarsia treated with distraction osteogenesis. Foot Ankle Int 2003;24: Wada A, Bensahel H, Takamura K, Fujü T, Yanagida H, Nakamura T. Metatarsal lengthening by callus distraction for brachymetatarsia. J Pediatr Orthop B 2004;13: