OTA 2004 Posters
A Prospective Evaluation of Hip Abductor Function after Femur Fracture and Antegrade Nailing
Purpose: The purpose of this study was to prospectively analyze hip abductor function at two discrete time points after a femur fracture treated with intramedullary nailing. This investigation is a pilot study for developing methodologies required to elucidate the contributions of injury, surgery, and rehabilitation on the overall functional outcome of patients sustaining femur fracture.
Methods: We prospectively enrolled 30 patients in an Institutional Review Board- and HIPPA- approved protocol. Patients who had sustained an isolated femoral shaft fracture were treated with an antegrade, statically locked, intramedullary nail. A structured physical therapy protocol emphasizing gait training and quadriceps and abductor muscle strengthening was initiated on the first postoperative day, and patients were allowed immediate weightbearing-as-tolerated ambulation with crutches or a walker. Patients were evaluated with three-dimensional quantitative gait analysis at 2 and 8 months postoperatively. The 3-D motion analysis system consisted of eight digital cameras, two embedded force platforms and 26 retroreflective markers placed at bony landmarks on each subject and data collected via the EvaRT system (Version 3.21, Motion Analysis Corporation). Gait temporal-spatial, kinematic, and kinetic variables were processed for each trial, and a mean value for each gait variable was obtained after three trials.
Results: Minimum one-year follow-up was obtained on all studied patients, and all fractures had fully healed by 6 months after surgery. Complete gait analysis on five patients was performed at 2 months (± 0.7) and 8 months (± 1.6) after surgery (mean ± 1 standard deviation). Deficits were observed in the internal muscle torque generated at the involved hip in the frontal plane when compared with the uninvolved limb. Significant side-to-side differences were noted at 2 months in maximum hip adduction angle and maximum internal hip abduction moment during stance phase. A statistically significant difference was not found at 8 months. Two- to 8- month hip kinematics and kinetics on the involved side did not show statistically significant differences at 2 compared with 8 months.
Conclusion and Significance: The results of this study clearly demonstrate a significant negative effect of femur fracture treated with antegrade intramedullary nailing on the function of the hip abductor muscles. The orthopaedic literature is replete with data on fracture healing and treatment modalities; however, there is a paucity of information concerning the effects of injury, treatment and rehabilitation on lower extremity biomechanics after fracture. It is our contention that the injury, the surgical intervention, the magnitude of the concomitant soft-tissue injury and the rehabilitation protocol represent separate, but interrelated components of the functional outcome for patients sustaining a femur fracture. The purpose of this investigation was to develop the methodologies required to evaluate the effects of surgical intervention and structured rehabilitation on the lower extremity biomechanics of patients sustaining femur fractures treated with antegrade intramedullary nails.