Fixation of the Offset V Osteotomy: Mechanical Testing of 4 Constructs Jane Khuri, DPM, 1 Stuart Wertheimer, DPM, FACFAS, 2 Jill Krueger, MS, 3 and Roger Haut, PhD 4 The purpose of this study was to assess 4 methods of fixation for the offset V osteotomy. Maximum load, failure energy, and stiffness were determined in a control group and in 4 different test models. There were 10 specimens for each group. The control group consisted of intact first ray sawbones. An offset V osteotomy was performed on each specimen in each of the 4 test groups. The osteotomies were fixated either with two 2.0-mm cortical screws, two 2.7-mm cortical screws, two 3.5-mm cortical screws, or one 2.7-mm cortical screw and a 0.045-in Kirschner wire, respectively. Each model was then loaded to failure with a computerized hydraulic-tensile testing machine. Results for maximum load to failure for all 4 fixation constructs showed a mean ranging from 113.0 to 144.0 N, a mean energy to failure ranging from 272.2 to 365.0 J, and a mean stiffness ranging from 21.3 to 27.0 N/mm. There were no statistically significant differences detected among the individual constructs. In the group fixated with 3.5-mm screws, there were statistically significant differences in all 3 parameters compared with the control group. In the groups fixated with 2.7-mm screws, 2.0-mm screws, and the 2.7-mm screw and Kirschner wire, there were statistically significant differences in the maximum load and the failure energy, but not in stiffness, when compared with the control group. These findings suggest that all 4 constructs provide similar mechanical properties when utilized for the fixation of the offset V osteotomy. (The Journal of Foot & Ankle Surgery 42(2):63– 67, 2003) Key words: hallux valgus, offset V osteotomy H allux valgus is 1 of the most common deformities affecting the lower extremity. The chevron procedure has been commonly performed to correct mild to moderate hallux valgus deformities. A transverse V osteotomy with the apex of the V centered in the first metatarsal head has been described (1). The angle created by the dorsal and plantar arms was fashioned at 60°. The capital fragment was then translocated laterally and impacted. Internal fixation was not used during the procedure (1). Modifi- cations to this procedure have been performed to use internal fixation to achieve stability and to allow for compression osteosynthesis. Kalish (1) and Vogler (2) modified the Austin procedure by creating a longer dorsal osteotomy to allow for greater lateral translocation and use of internal fixation. Markus modified the procedure by creating a longer plantar osteotomy to also allow for internal fixation (4). Numerous clinical articles described various methods of internal and external fixation techniques that used Kirschner wires (K-wires), staples, external fixators, polyglycolide and polydioxanone pins, Herbert screws, Herbert Whipple screws, cortical screws, and plates (5– 23). Few studies that compare different forms of fixation have been performed (24,25). These studies evaluated postoperative range of motion, pain, and return to func- tion. To the authors’ knowledge, no studies have been performed to evaluate the strength and stability of the offset V osteotomy with respect to different types of fixation. The purpose of this study was to measure me- chanical stability of the various constructs frequently used for the fixation of the offset V osteotomy. Materials and Methods A control group and 4 test groups were created. Each test group and the control group consisted of 10 first ray sawbones. The control group was left intact, and an offset V osteotomy was performed on each of the specimens in each test group. The osteotomy was performed in the medial to lateral direction, with the apex at the center of From the St. John North Shores Hospital, Harrison Township, MI, and Michigan State University, East Lansing, MI. Address correspondence to: Jane Khuri, DPM, 2236 West Ridge Rd, Rochester, NY 14626. 1 Third-year Podiatric Surgical Resident, St. John North Shores Hospital. 2 Director of Podiatric Education, St. John North Shores Hospital. 3 Masters of Science/Graduate student in the Department of Materials Science and Mechanics, College of Engineering, Michigan State Univer- sity. 4 Professor and Director of the Orthopedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University. Copyright © 2003 by the American College of Foot and Ankle Surgeons 1067-2516/03/4202-0003$30.00/0 doi:10.1053/jfas.2003.50015 VOLUME 42, NUMBER 2, MARCH/APRIL 2003 63