Sat., 10/6/12 Femur/Tibial Fx/Knee Injuries, PAPER #69, 8:06 am OTA-2012
Gait Analysis After Retrograde and Trochanteric Entry Intramedullary Nail Fixation of Femoral Shaft Fractures
Kellen L. Huston, MD; J. Tracy Watson, MD; Lisa K. Cannada, MD;
Saint Louis University Department of Orthopaedic Surgery, Saint Louis, Missouri, USA
Purpose: The starting point for femoral nailing continues to be the focus of debate. Current dogma suggests that retrograde nailing causes knee pain and dysfunction. Antegrade nailing has been reported to alter abductor mechanics. However, the effects of retrograde nailing on gait have not been thoroughly determined. The purpose of this study was to evaluate entry portal influence on gait and stair climbing following retrograde (RN) and trochanteric entry nailing (TN).
Methods: IRB-approved inclusion criteria included adult patients with isolated femur fractures treated with intramedullary nails who were clinically and radiographically healed. Patients required at least 6 months of device-free ambulation following fracture union. Demographic and fracture data were collected on the participating subjects. Subjects also completed a Musculoskeletal Function Assessment (MFA) questionnaire, walked on a treadmill, and demonstrated ascending/descending stair climbing. Digital video gait analysis of all subjects was completed using surface markers and Dartfish model software. Statistical analysis was completed using descriptive methods to calculate mean and standard deviation. Frequency tables were used for calculation of categorical data significance and Mann Whitney U tests for nominal data sets.
Results: 16 patients underwent gait analysis: 8 TN and 8 RN. The average age of the patients was 29 years (range, 22-44) in the TN group and 32 years (range, 22-45) in the RN group. The average length of time from injury to participation in the study was 24 months (range, 10-41). There was no significant difference between the groups on the MFA questionnaire (P = 0.127). No differences were noted in subjective measures of gait or stair climbing. When evaluating the kinematics of the knee via gait analysis, no significant difference was demonstrated between the normal or affected knee at heel-strike or at toe-off. When comparing the hip kinematics between entry portal groups, TN patients demonstrated significant differences on the normal limb at toe-off (P <0.05) and on the affected limb at heel-strike (P <0.05) consistent with abductor alteration.
Conclusion: Previous studies have shown significant effects from antegrade femoral nailing in terms of hip abductor function and lower extremity biomechanics. No such studies exist looking at retrograde femoral nailing or comparing the two methods. Our study demonstrated an effect on hip function at toe-off of the normal and heel-strike of the affected leg in the TN group that is not seen in the RN. Although RN does involve the knee joint for proper entry portal placement, it does not have any significant affect on gait function. In conclusion, trochanteric or retrograde nailing may lead to some of residual discomfort to the patient but TN has the potential to cause a mechanical disturbance in gait. Patients treated with RN did not demonstrate gait disturbances.
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