Session II - Femur

Thurs., 10/5/06 Femur, Paper #10, 4:00 pm

A Prospective, Randomized Functional Evaluation of Hip Function after Piriformis versus Trochanteric Femoral Nailing

Michael Archdeacon, MD, MSE (a,e-Stryker); Timothy Hewett, PhD (n); John Wyrick, MD (n); Shelley Hampton (n); Mary Beth Ludwig, RN (n); Mark Paterno (n); Kevin Ford (n);
University of Cincinnati Medical Center, Cincinnati, Ohio, USA

Purpose/Hypothesis: The purpose of this study was to prospectively compare hip function following antegrade intramedullary (IM) nailing of femur fractures using two different entry portals. Our null hypothesis was that no significant difference in hip kinematics and kinetics would be observed between femur fractures treated with piriformis fossa versus trochanteric antegrade femoral nailing.

Methods: We enrolled 47 (3 withdrew) patients in an IRB-approved, prospective, randomized study. Isolated femur fracture patients were treated with either a piriformis fossa or trochanteric entry portal IM nail. Patients were allowed immediate weight bearing as tolerated ambulation on postoperative day 1. Motion analysis was performed on a subset of 13/44 (30%) patients (8 piriformis and 5 trochanteric) when they were ambulating independently (2 mo), and repeated after complete healing (7.5 mo) in 7/44 (16%) patients (3 piriformis and 4 trochanteric).

Results: A minimum 1-year clinical follow-up was obtained for 34 (77%) of the patients, and 100% had fully healed. The null hypothesis that there would be no significant difference in hip kinematics and kinetics between piriformis and trochanteric entry portals was rejected. Ipsilateral hip abduction angle was abducted (-) more at initial contact in the piriformis group (-3.4 ± 2.6) compared to the trochanteric group (-0.4 ± 2.0; P = 0.045). At the later time point, the piriformis group (0.56 ± 0.02) had decreased internal hip abductor moments during weight release compared to the trochanteric group (0.69 ± 0.07; P = 0.025). Additionally, greater pelvic obliquity (hip up) was observed in the piriformis group (-2.9 ± 0.7) compared to trochanteric group (-4.8 ± 0.7; P = 0.016), which likely assists a lack of hip abductor function to initiate swing.

Conclusion/Significance: This study clearly demonstrates the significant effect of femur fracture treatment (entry portal) on functional outcomes after isolated femur fracture. The significance lies in the fact that uncomplicated fracture healing occurred in 100% of the studied patients, but complete functional recovery differed between the two groups. The purpose of this investigation was to clarify one component, the relative effects of two surgical interventions, on functional outcome after antegrade femoral intramedullary nailing.

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.