Sat., 10/18/08 Femur, Paper #47, 9:21 am OTA-2008
Femoral Neck Fractures: Can They Be Healed Predictably at Length, without Shortening?
Sreevathsa Boraiah, MD1 (n); Sommer Hammoud, MD1 (n); Omesh Paul MD1 (n);
Michael J. Gardner, MD2 (n); Chris Wright, BS1 (n); David L. Helfet, MD1 (n);
Dean G. Lorich, MD1 (n);
1Hospital for Special Surgery, New York, New York, USA;
2Harborview Medical Center, Seattle, Washington, USA
Purpose: The most common implants for treatment of femoral neck fractures are multiple cannulated lag screws. By design, these exploit the biological advantages of compression across the fracture. However, normal hip anatomy and mechanics are necessarily sacrificed by allowing the femoral neck to shorten. If fracture healing is successful, the altered abductor mechanism has significant functional consequences. Constructs that allow for initial compression with subsequent maintenance of hip anatomy would be ideal. The purpose of our study was to determine the healing rate of femoral neck fractures treated with a length-stable construct, and to evaluate which factors were associated with femoral neck shortening and failure of fixation.
Methods: 54 patients with an acute femoral neck fracture were treated with open reduction and internal fixation. Reduction was achieved through a modified Smith-Petersen approach. Fractures were compressed initially, and subsequently stabilized with a lengthstable device. Patients were evaluated clinically and radiographically at an average of 17 months. Radiographs were standardized for magnification and rotation. Collapse of the femoral neck in the horizontal, vertical, and combined axes was measured using a precise geometric technique. A multinomial logistic regression was performed to determine the effect that age, gender, Garden classification, and Pauwel’s angle had on femoral neck shortening and fixation failure.
Results: The average age of the patients was 78.1 years. There were 23 Garden I, 2 Garden II, 14 Garden III, and 15 Garden IV fractures. 94% of fractures (51) healed successfully without complications. The average displacement of the femoral head was 1.23 mm, 0.86 mm, and 1.98 mm in the horizontal, vertical, and combined axes, respectively. Screw-tip migration within the femoral head was 0.7 mm and 0.9 mm in the horizontal and vertical planes, respectively. Fixation failure occurred in two patients, and one patient developed osteonecrosis. There was no statistically significant association between shortening or implant failure with any of the independent variables analyzed.
Conclusions: Femoral neck fractures treated with intraoperative compression and lengthstable fixation had a high rate of healing, with low rates of nonunion and fixation failure. Nonsliding implants for these fractures have performed poorly historically. However, due to an improved understanding of hip mechanics and fracture biology, as well as evolving implants and surgical techniques, length-stable implants may improve upon the frequent functional deficits with current treatment methods.
If noted, the author indicates something of value received. The codes are identified as a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options; e-consultant or employee; n-no conflicts disclosed, and *disclosure not available at time of printing.
• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.