Optimal Fixation for the Extended Trochanteric Osteotomy A Pilot Study Comparing 3 Cables vs 2 Cables Joseph H. Schwab, MD, Javier Camacho, MD, Kenton Kaufman, PhD, Qingshan Chen, MS, Daniel J. Berry, MD, and Robert T. Trousdale, MD Abstract: The extended femoral trochanteric osteotomy allows excellent exposure of the proximal femoral canal, which facilitates resection of the canal's contents during revision total hip arthroplasty. Once the proximal femoral canal has been evacuated and a new femoral component has been placed, the osteotomy should be fixed in proper position to allow healing. The purpose of our study was to compare the fixation of an extended trochanteric osteotomy using 2 vs 3 braided cables with regard to stiffness, peak force, axial displacement, transverse displacement, and angular displacement using an in vitro biomechanical model. Nine paired cadaver femurs were loaded to failure. Movement at the osteotomy site before failure was recorded using a motion analysis system. There was no statistically significant difference between 2 vs 3 cables with regard to stiffness, peak force, or displacement in the 3 planes tested. Peak force and stiffness were both greater in the 3-cable group, whereas angular and transverse displacement were less in the 2-cable construct. Key words: osteotomy, fixation, trochanter. © 2008 Elsevier Inc. All rights reserved. The number of prosthetic hip arthroplasty surgeries performed in this country is expected to increase as the population ages. More than 150 000 total hip arthroplasties are performed each year in the United States. Around 10% of those are revision surgeries [1]. Revision of a well-fixed femoral component often requires an extended trochanteric osteotomy to facilitate removal of the prosthesis and/or cement [2-9]. Several studies have demonstrated the utility of the extended trochanteric osteotomy, but there are few studies focusing on fixation of the osteotomy. The goal of fixation is to secure the osteotomized fragment in place to allow healing. This may be accomplished with braided cables or wires. Warren et al [10] have shown that cables are more effective than wires in enhancing osteotomy union and preventing subsidence. However, the question of how many cables has not been answered. We ex- pected the rigidity of our constructs to increase with more cables. The advantages of more rigid fixation need to be balanced with the dissection needed to place the additional cables. The goal of our study was to compare the rigidity provided by 2 vs 3 cables used to secure an extended trochanteric osteotomy. Materials and Methods Cadaver Model We used 9 paired, fresh frozen cadavers for a total of 18 specimens tested. Each of our comparisons was From the Mayo Clinic, Rochester, Minnesota. No benefits or funds were received in support of the study. Submitted April 3, 2006; accepted May 17, 2007. This project was supported by a grant from the Mid-American, Orthopedic Association, Rochester, MN, which was funded by Zimmer, Warsaw, Ind. Reprint requests: Robert T. Trousdale, MD, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905. © 2008 Elsevier Inc. All rights reserved. 0883-5403/08/2304-0008$34.00/0 doi:10.1016/j.arth.2007.05.028 534 The Journal of Arthroplasty Vol. 23 No. 4 2008