BACKGROUND
Metatarsal osteotomies are commonly used in correction of hallux valgus deformities (HAV). Numerous surgical procedures have been described to correct this deformity and the choice of surgery depends on the severity and location of the pathology (1, 2). Proximal osteotomies have become more popular for severe deformities because they allow greater correction than distal osteotomies. Several proximal osteotomies have been reported with good clinical results such as the proximal chevron, Lapidus, closing and opening base wedge osteotomies (1-4). However, most proximal osteotomies lack inherent stability and are unable to resist sagittal plane forces requiring several weeks of cast immobilization (1,2,4,5). Proximal osteotomies have been associated with delayed bone healing and transfer metatarsalgia due to either dorsal malunion or shortening (1-5).
Mid shaft osteotomies such as the Scarf, Mau and Ludloff have been shown to be more resistant to sagittal plane forces in cadaveric biomechanical testing (1,2,4). The term Scarf, originally described by LSW, is an architecture term defined by notching or cutting two pieces and fastening them together so that they overlap and join firmly into one piece (10). Combined with a broad bony apposition and two screw fixation, the Scarf bunionectomy is an inherently stable osteotomy (1,2,6).
The Scarf bunionectomy is a widely used procedure and was popularized in the USA and Europe by the Weil Foot and Ankle Institute (8.9,10). The Scarf has proven to be predictable, versatile and a powerful procedure to correct various degrees of HAV (8,9). The primary purpose of this study, is to evaluate the radiographic results in severe bunion deformities and maintenance of this correction long-term.
MATERIALS AND METHODS
A retrospective review was performed of 60 patients who underwent a Scarf bunionectomy between October 2003 to November 2006. The Scarf bunionectomy as depicted in Fig. 1 was performed by the previously described technique (10).
Pre- and postoperative anteroposterior (AP) and lateral radiographs of the feet were made with the patient in the weight-bearing position. Data recorded on the pre-and postoperative AP radiographs included: intermetatarsal angle 1-2 (IM 1-2), hallux valgus angle (HVA) and tibial sesamoid position (TSP). Data recorded from the lateral radiograph evaluated first metatarsal elevation. Complications were defined as hallux varus , transfer metatarsalgia, stress fractures and recurrence of the deformity.
The postoperative course was standard for each patient and this included a bulky compressive bandage with a standard surgical shoe. Patients were allowed guarded weightbearing immediately after surgery without crutch or cane assistance. At the first postoperative visit (1 week), all patients were transitioned into a roomy athletic shoe and referred to physical therapy for strengthening and range of motion exercises on the operated first MTP joint.
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.
IMAGES AND TABLES
Figure 1. Medial exposure and release of the fibular suspensory ligament and lateral joint capsule. The adductor tendon is left intact (A). Insertion of smooth pin for osteotomy guide 3-4 mm below the dorsal medial cancellous surface of the met head. Pin is directed lateral plantar and slightly proximal (B). The osteotomy guide is directed inferior and proximal to the plantar flare of the first met. (C). Completion of long Scarf osteotomy (D). Plantar displacement of the first met head-shaft (E). Lateral translation and temporary Scarf clamp applied (F). Two threaded head screws used for fixation. Distal screw is placed obliquely into met head with care not to penetrate the plantar aspect of the metatarsal head (G).
Table 1. Pre- and postoperative radiographic results (mean ± SD).
| Follow-up |
Pre-operative |
1 month |
3 years |
P-value |
| First Intermetatarsal Angle: |
17.43°± 1.64
(range, 16-23) |
6.08°± 2.89
|
5.81°± 2.08 |
0.001 |
| Hallux Valgus Angle: |
33.44°± 8.26
(range, 20-61) |
9.46°± 7.60 |
9.41°± 7.75 |
0.001 |
| Tibial Sesamoid Position: |
5.55 ± 1.23
(range, 5-8) |
2.34 ± 0.786 |
2.07 ± 0.80 |
0.001 |
RESULTS
Follow-up was performed in 60 patients at an average of 36 months. Twenty-one (35%) bilateral cases were performed. The average age was 49.65 ± 13.93 (range, 14-78). There were 44 (73%) females and 16 (27%) males. The operative side included 34 (57%) right and 26 (43%) left feet. Secondary procedures included: 46 (77%) Akin osteotomies, 23 (38%) PIPJ arthroplasties, 16 (27%) Weil metatarsal osteotomies, 7 (12%) Scarfette osteotomies and 1 (2%) fibular sesamoidectomy. Table 1 contains radiographic data pre-operatively, 1 month and 3 years postoperatively. There was a statistical difference between the pre- and postoperative correction of the severe HAV deformity. Complications included 4 (6%) undercorrections, 4 (6%) hallux varus and 3 (5%) stress fractures. There were 5 (8%) cases of transfer metatarsalgia postoperatively. No cases of dorsal malunion or avascular necrosis.
Figure 2. Versatility of the Scarf osteotomy. Pre- and postoperative radiographs showing plantar displacement of first metatarsal head (A-B). Pre- and postoperative radiographs showing PASA correction (C-D).
DISCUSSION AND CONCLUSIONS
The Scarf bunionectomy allows for an adequate correction of severe HAV deformities. With a follow-up of 3 years, this correction was maintained. In our series few complications were encountered. There were 5 (8%) cases of transfer metatarsalgia postoperatively that required additional procedures. The Scarf bunionectomy is a powerful procedure and 4 (6%) cases of overcorrection occurred. Three were symptomatic and required successful revisional surgery. Three (5%) patients developed stress fractures through the dorsal cortex at the proximal metatarsal. These patients were placed in a walking boot for 3-4 weeks to allow healing and prevent dorsal malunion.
Dorsal malunion is a concern with other proximal osteotomies due to lack of intrinsic stability and usually requires cast immobilization with crutches for prevention (1,2,4,5). Dorsal malunion was not encountered in this study. In our study of severe HAV deformities, 21 (35%) of the operative cases were bilateral and immediate postoperative guarder weightbearing, without crutch or cane assistance, was allowed with few complications. All but 3 patients (due to stress fracture) returned to a roomy athletic shoe 7-10 days postoperatively and referred to physical therapy to strengthen plantar flexion at the first MTP joint.
On conclusion, our study revealed that the Scarf bunionectomy can predictably and accurately correct severe HAV deformities. The Scarf osteotomy is intrinsically stable thereby allowing for bilateral correction and immediate postoperative weightbearing.
1. Trnka, H.J., Parks, B.G., Ivanic, G., Chu, I.T., Easley, M.E., Schon, L.C., Myerson, M.S. Six first metatarsal shaft osteotomies: mechanical and immobilization comparisons. Clin Orthop Relat Res. 381:256-65, 2000.
2. Nyska, M., Trnka, H.J., Myerson, M.S. Proximal metatarsal osteotomies: a comparative geometric analysis conducted on sawbone models. Foot Ankle Int. 23(10):938-45, 2002.
3. Mann, R.A., Rudicel, S., Graves, S.C. Repair of hallux valgus with a distal soft-tissue procedure and proximal metatarsal osteotomy. A long-term follow-up. J Bone Joint Surg Am. 74(1):124-9, 1992.
4. Acevedo, J.I., Sammarco, V.J., Boucher, H.R., Parks, B.G., Schon, L.C., Myerson, M.S. Mechanical comparison of cyclic loading in five different first metatarsal shaft osteotomies. Foot Ankle Int. 23(8):711-6, 2002
5. Vora, A.M., Myerson, M.S. First metatarsal osteotomy nonunion and malunion. Foot Ankle Clin. 10(1):35-54, 2005.
6. Saxena, A., McCammon, D. The Ludloff osteotomy: a critical analysis. J Foot Ankle Surg. 36(2):100-5, 1997.
7. Neese, D.J., Zelichowski, J.E., Patton, G.W. Mau osteotomy: an alternative procedure to the closing abductory base wedge osteotomy. J Foot Surg. 28(4):352-62, 1989.
8. Barouk LS. Notre experience de osteotomie Scarf des premier et cinquieme metatarsiens. Med Chir Ped. 10:111-120, 1994.
9. Weil, Sr., LS, Borreli AB. Modified scarf bunionectomy; our experience in more than 1,000 cases. J Foot Surg. 30:609-622,1991.
10. Weil, Sr., LS. Scarf bunionectomy. Foot Ankle Clin. 5:149-169, 2000.
Weil Foot & Ankle Institute
(847) 390-7666
Email : info@weil4feet.com
Website : www.weil4feet.com
