Session X - Geriatrics

Sat., 10/7/06 Geriatrics & Injury Prevention, Paper #56, 9:45 am

Stability of Intertrochanteric Femur Fracture Fixation: A Critical Analysis of Extramedullary versus Intramedullary Implants and the Effect of Lesser Trochanter Comminution

Ganesh Kamath, MD (*); Joseph Borrelli, MD (*);
William M. Ricci, MD (a,e-Smith+Nephew);
Washington University School of Medicine, St. Louis, Missouri, USA

Introduction: Both intramedullary (IM) and extramedullary (EM) implants allow for compression of intertrochanteric femur fracture fragments. The purpose of this study was to investigate the relative effect of these two implant types, and the effect of lesser trochanter (LT) comminution on collapse of intertrochanteric femur fractures.

Methods: A retrospective (IRB-approved) cohort study with control group was designed based on the different treatment methods of two fellowship-trained orthopaedic trauma surgeons (at a single Level I trauma center) for consecutive patients (age >60) with intertrochanteric femur fractures (OTA31A). The NAIL cohort included 41 patients treated with a single IM fixation device, Trigen TAN Nail (Smith & Nephew, Memphis, TN), by one of the two surgeons. Six were lost to follow-up; the remaining 35 (age 79, follow-up 9 mo) included 27 females and 8 males. The PLATE cohort included 42 treated with a single EM fixation device, DHS (Synthes, Paoli, PA), by the second surgeon. Seven were lost to follow-up, the remaining 38 (age 73, follow-up 10 mo) included 31 females and 7 males. Fracture collapse was measured by comparing immediate postoperative radiographs to those at final follow-up controlled for magnification and rotation.

Results:
Summary of Results Collapse (mm)
 LT Comminution  NAIL  PLATE
 LT intact (n=20)  0.7  7.7
 Fx through LT (n=16)  4.0  5.4
 LT off (n=37)  8.1  16.1
 Overall (n=73)   5.7  11.0

The average collapse was 2 times greater for the PLATE cohort than for the NAIL cohort (P <0.01). For the NAIL cohort, increasing LT comminution was associated with increased collapse (P <0.02). For the PLATE cohort, only complete displacement of the LT was associated with greater collapse (P <0.05). PLATE fixation was associated with more collapse than NAIL fixation when the LT was intact (7 times more, P <0.05) or off (2 times more, P <0.01) but not when the fracture was through the LT (P = 0.26). Nonunion requiring total hip arthroplasty occurred in 2 patients from the NAIL cohort and 1 from the PLATE cohort.

Conclusion: The IM buttress provided by nail fixation for intertrochanteric fractures reduces fracture collapse compared to a hip plate/screw device. Given the decreased abductor moment and limb shortening associated with such fracture collapse, an IM implant used in the setting of the unstable intertrochanteric fracture may provide a functional advantage. Although fixation of the LT is not required for fracture healing, strategies to restore the medial buttress provided by the LT may reduce malunion due to excessive fracture collapse, especially with plate fixation.

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.