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Clinical Outcomes and Complications of the Surgical Implant Generation Network (SIGN) Intramedullary Nail

A Systematic Review and Meta-Analysis

Usoro, Andrew O., MD*; Bhashyam, Abhiram, MD*; Mohamadi, Amin, MD, MPH; Dyer, George S., MD; Zirkle, Lewis, MD§; von Keudell, Arvind, MD*

Journal of Orthopaedic Trauma: January 2019 - Volume 33 - Issue 1 - p 42–48
doi: 10.1097/BOT.0000000000001328
Review Article

Objectives: This study is a systematic review and meta-analysis of the clinical outcomes and pooled complication rate of femoral, tibial, and humeral fracture fixation using SIGN nails. We aimed at comparing the pooled rate of adverse events based on the country of study origin, acute versus delayed fracture fixation, and length of follow-up.

Methods: We searched PubMed/MEDLINE/Cochrane databases from 2000 to 2016 for English language studies. There was substantial heterogeneity among included studies. Therefore, we used subgroup analysis of varying adverse events and removal of potential outlier studies based on the “remove one” sensitivity analysis to address the heterogeneity across studies. A funnel plot was drawn and inspected visually to assess publication bias. We reported pooled complication rates for each adverse event with 95% prediction interval.

Results: There were 14 studies with 47,169 cases across 58 different low- and middle-income countries. The average age was 33 ± 14 years, with 83% men and 17% women. Sixty percent of SIGN nails used in these 14 studies were used in femur fracture fixation, 38% in tibial shaft fractures, and the remaining 2% for humeral shaft fractures. Approximately 23% of patients had follow-up data recorded. All studies that measured clinical outcome indicated that >90% achieved full weight-bearing status, favorable range of motion (knee range of motion >90 degrees according to the SIGN database), and radiographic or clinical union depending on the specific variable(s) measured in each study. The overall complication rate was 5.2% (4.4%–6.4%). Malalignment (>5 degrees of angulation in any plane) was the most common complication (7.6%), followed by delayed/nonunion (6.9%), infection (5.9%), and hardware failure, (3.2%).

Conclusions: Overall, the use of SIGN nails in fixing femoral, tibial, and humeral shaft fractures demonstrates good results with a high rate of return to full weight-bearing and radiographic/clinical union. The most common complications when using the SIGN nail are malalignment, delayed/nonunion, infection, and hardware failure.

Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

*Department of Orthopedics, Massachusetts General Hospital, Boston, MA;

Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Boston, MA;

Department of Orthopedics, Brigham and Women's Hospital, Boston, MA; and

§Department of Orthopedics, Kadlec Regional Medical Center, Richland, WA.

Reprints: Andrew O. Usoro, MD, Department of Orthopedics, Massachusetts General Hospital, Boston, MA 02114 (e-mail:

A. O. Usoro and A. Bhashyam have contributed equally.

L. Zirkle–original patent of SIGN nail, now turned over to Sign Fracture Care International. No royalties to L. Zirkle or SIGN Fracture Care International. The remaining authors report no conflict of interest.

This work was previously presented as a poster at the Annual Meeting of the Orthopaedic Trauma Association, October 12, 2017, Vancouver, Canada.

The authors whose names are listed immediately below report the following details of affiliation or involvement in an organization or entity with a financial or non-financial interest in the subject matter or materials discussed in this manuscript.

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Accepted August 27, 2018

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