BACKGROUND
Numerous surgical procedures have been described for treatment of a bunionette deformity. These include lateral condylectomy (1), metatarsal head resection (2), distal metatarsal osteotomies (3), mid shaft osteotomies and proximal metatarsal osteotomies (4). Mid shaft and proximal osteotomies were performed dangerously close to the "Jones fracture" region leading to many malunion and nonunions. Choosing a specific osteotomy is largely dependant on the severity of the deformity and needs of the patient.
The etiology of a bunionette is multifactorial (3). Anatomic variations have been suggested as the underlying cause of a painful bunionette deformity. These anatomic variations include: large or dumbbell shaped metatarsal head (Type 1); lateral bowing/deviation at the meta-diaphyseal junction (Type 2); increased intermetatarsal (IM) angle (Type 3) (5). The goal of surgical treatment is to reduce the width of the foot and address the anatomic variations.
The Scarf bunionectomy was developed by the senior author (LSW) in 1983. Due to its success, LSW developed the "Reverse Scarf" or as it is now called, the Scarfette osteotomy and follows similar success as the Scarf bunionectomy. The Scarfette is a versatile procedure that can address specific etiologic factors associated with bunionette deformities.
The primary aim of this study was to show the versatility and stability of the Scarfette osteotomy in varying degrees of bunionette deformities.
MATERIALS AND METHODS
A retrospective analysis of 50 patients was completed between February 2005 and December 2007. Patients were selected consecutively from the senior authors' clinic. Surgical inclusion criteria consisted of a painful lateral prominence due to a bunionette deformity unresponsive to conservative treatment. Only Type 2 and Type 3 bunionette deformities were included for review (5).
Pre- and postoperative anteroposterior (AP) and lateral radiographs of the feet were made with the patient in the weight-bearing position. Data recorded included: intermetatarsal (IM) 4-5 angle, fifth metatarsal-phalangeal angle and lateral deviation angle (LDA). Radiographs were obtained preoperatively, 6 weeks postoperatively and one year postoperatively.
Descriptive statistics, including mean and standard deviation were used to describe demographic, radiographic and follow-up data. Pre- and postoperative radiographic variables were compared. A paired Student's t-test was performed to compare normally distributed continuous variables. Statistical differences were considered to be significant when the p-value was < 0.05.
Figure 1. A lateral incision over the 5th metatarsal (A). Orientation of the Scarfette osteotomy in the distal 1/3 of the 5th metatarsal (B). Completion of the Scarfette osteotomy and reduction of the deformity (C-D). Fixation achieved with a threaded pin, cut at the bone level (E). Closure with subcuticular suture and steri-strips (F).
TECHNIQUE
A 3 cm incision is placed on the lateral aspect of the 5th metatarsal head at the conjunction of the dorsal and plantar skin (Fig. 1). The incision is carried directly to the capsule and periosteum exposing the 5th metatarsal head and neck. The Scarfette osteotomy is outlined from dorsal distal (within the cancellous bone of the 5th metatarsal head) to plantar proximal on the fifth metatarsal neck and shaft. A bone saw is used to create a 60° angle osteotomy much like performing a chevron but slightly more distal. The second cut connects the 60 degree cut in the metatarsal head and continues along the neck and shaft of the metatarsal for about 15-20 mm (the larger the 4-5 IM angle, the longer the osteotomy). The saw may be declinated or inclinated with respect to the plantar surface of the foot. If an IPK is present under the 5th metatarsal head, inclination is performed by directing the saw blade to a imaginary line over the 4th metatarsal shaft. Lastly, a 45° proximal-plantar osteotomy is performed at the proximal plantar extent of the horizontal osteotomy. The distal segment of the 5th metatarsal is mobilized and gently displaced medially one half the width of the metatarsal head. Once adequate correction is obtained, the osteotomy fragment is impacted on the metatarsal and fixation is accomplished with a 1.6 mm threaded pin cut at bone level. The remaining lateral head, neck and shaft is carefully removed and smoothed with power bur (Fig. 2). The periosteum and capsule are repaired with 2-0 absorbable suture. A running subcuticular stuture followed by steri-strips are used to repair the skin.
The postoperative course was standard for each patient and included a bulky compression bandage and a surgical shoe. Patients were permitted to guarded weightbearing, without crutches, immediately after surgery. At the first postoperative visit (1 week), all patients were transitioned into a athletic shoe and referred to physical therapy for strengthening and range of motion exercises.
RESULTS
Follow-up was performed in 50 patients at an average of 12 months. The average age was 50.23 ± 14.31. There were 44 (88%) females and 6(1.2%) males. The operative side included 27(54%) right and 23 (46%) left feet. Pre-operatively the mean IM 4-5, LDA and 5th MTPJ angles were 10.34°± 2.40, 4.15°± 4.08° and 15.56°± 6.83respectively. Nineteen(38%) patients had a type 2 deformity and 31(62%) patients had a type 3 deformity. The 19 patients who had a type 2 deformity the mean LDA was 9.0° ± 3.46. Postoperatively at one year, the mean IM 4-5, LDA and 5th MTPJ angles were corrected to 1.80°± 2.21, 0.24°± 0.46and 2.40° ± 7.94respectively. Postoperative correction of the IM 4-5, LDA and 5th MTPJ angles were statistically significant (p < 0.001). Complications included 1 undercorrection and 7 hardware removals.
Figure 2. Versatility of the Scarfette osteotomy. Pre- and postoperative radiographs of an increased IM 4-5 (A-D). Pre- and postoperative radiographs of an increased LDA (E-F).
DISCUSSION AND CONCLUSIONS
Numerous procedures have been described for the surgical treatment of bunionette deformities (3,4). A simple, lateral condylectomy can be useful for the bunionette deformity when the IM 4-5 angle is normal. However, with splaying of the 5th metatarsal, some type of osteotomy is necessary to obtain a lasting result. Distal osteotomies provide good results but are limited to mild deformities and reduction of the IM4-5 angle is dependant on the width of the metatarsal head. Fifth metatarsal shaft osteotomies can be disastrous due to a precarious blood supply and must be immobilized for several weeks to assure bony union. Most osteotomies can be technically demanding to some degree due to smaller bony contact and limitations with fixation.
Lowell Scott Weil, Sr. (LSW) reported favorable results on 60 consecutive cases of the reverse Scarf osteotomy for the bunionette deformity at the International SICOT meeting in Seoul, Korea in 1992. In a report of 10 cases with a 1 year follow-up, Seide and Peterson (7) reported significant reduction of the IM 4-5 angle (10.3°-6.8°). Few published reports are available regarding the outcomes of using a reverse Scarf or z-shaped osteotomies for bunionette deformities in a study population.
The Scarfette is a versatile osteotomy that corrects varying degrees of bunionette deformities. The unique configuration of this osteotomy allows broad bony apposition and adequate fixation. The Scarfette is inherently stable and this allows immediate postoperative weightbearing without crutch assistance.
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2. Dorris MF, Mandel MF. Fifth metatarsal head resection for correction of tailor's bunion and sub- fifth metatarsal head keratoma: a retrospective analysis. J Foot Surg 1991;30(3):269-75.
3. Weil, LS, Reverse Scarf Osteotomy for Bunionette Deformity. Results of 60 Conscutive cases. SICOT, Seoul, Korea; 1992
4. Diebold PF. Bunionette Deformity: osteotomies of the fifth metatarsal bone. In An Atlas of Foot and Ankle Surgery, chap 1393-98, edited by N., Wulker M., Stephens Cracchiolo. II Mosby, London, pp 1998.
5. Fallet LM, Bucholz J. Analysis of the tailor's bunion by radiographic and anatomic display. J Am Podiatr Assoc 1980;70(12):597-603.
6. Seide HW, Peterson W. Tailor' s bunion: results of a scarf osteotomy for the correction of an increased IM 4-5 angle: a report of 10 cases with 1 year follow-up. Arch Orthop Trauma Surg 200;121(3):166-9.
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