Original Article

Are Distal Femoral Traction Pins Intra-Articular? A Cadaveric Study

McElvany, Matthew MD^*; Benninger, Brion MD, MSc^†; Smith, Sawyer BS^‡; Mirza, Amer MD^§; Marshall, Lynn ScD^§; Friess, Darin MD^§

Author Information

^*Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA;

Departments of ^†Oral and Maxillofacial Surgery,

^‡School of Medicine; and

^§Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR.

Reprints: Matthew McElvany, MD, Department of Orthopaedics and Rehabilitation, University of Washington, 1959 NE Pacific St. Box 356500, Seattle, WA 98195 (e-mail: [email protected]).

L. Marshall receives funding from, and serves as a grant peer-reviewer, for the National Institutes of Health for unrelated subjects. She also has received past funding from the Society for Pediatric Dermatology for a lecture regarding epidemiologic methodology. A. Mirza is a paid consultant for Acumed Inc, Hillsboro, OR and an unpaid consultant for Seattle Information Systems, Bellevue, WA. The remaining authors report no conflict of interest.

Accepted March 07, 2013

Journal of Orthopaedic Trauma 27(11):p e250-e253, November 2013. | DOI: 10.1097/BOT.0b013e318291005c

Abstract

Objectives:

To examine the frequency of intra-articular placement of distal femoral traction pins and their proximity to the superficial femoral artery (SFA).

Methods:

Wires were placed in the distal femurs of 28 cadaveric knees at the adductor tubercle (ADT), the superior pole of the patella (SPP), and 2 cm proximal to SPP (SPP+2). A lateral fluoroscopic image was obtained after injection of radiopaque contrast to assess for joint penetration. Dissection was performed to confirm or refute fluoroscopic findings. The distance from each wire to the SFA was measured.

Results:

The percentage of intra-articular placement was higher (29%) at the ADT than the SPP+2 (0%) level. The mean (SD) distances from the ADT, SPP, and SPP+2 to the SFA were 7.4 (±1.8) cm, 5.7 (±1.7) cm, and 3.8 (±1.7) cm, respectively (P < 0.0001). None of the wires penetrated the femoral artery. The proportion of wires judged to be intra-articular was not statistically different whether judged by fluoroscopy or anatomic dissection (exact P = 1.0).

Conclusions:

Wires placed at the level of the ADT are at risk for capsular penetration. Risk of major vascular injury with transmedullary placement at all levels seems to be minimal. The optimum position for distal femoral pins remains unknown, but aiming >0.7 cm proximal to the ADT may lower the risk of intra-articular placement. No difference was detected between fluoroscopic arthrography and gross dissection.