Thurs., 10/4/12 Hip Fractures, PAPER #35, 4:18 pm OTA-2012
Diagnosis of Femoral Neck Fractures Present With Femoral Shaft Fractures: Do We Need Intraoperative Radiographs?
Simon L. Amsdell, MD; Catherine A. Humphrey, MD; Jonathan M. Gross, MD;
John P. Ketz, MD, John T. Gorczyca, MD; Holman Chan, MD;
University of Rochester Medical Center, Rochester, New York, USA
Background/Purpose: The association of occult femoral neck fractures with femoral shaft fractures is well established, and occurs in 1% to 9% of blunt femoral shaft fractures. The detection of femoral neck fractures can be missed in up to 50% of cases, which may have serious consequences. Previous studies have reported using protocols that include preoperative radiographs, fine-cut (2-mm spiral, or multislice) CT scans, and intraoperative radiographs to evaluate the femoral neck for fracture. Intraoperative radiographs can add significant anesthesia time and will increase radiation exposure. The purpose of this study was to evaluate the experience at a Level I trauma center using a protocol that includes intraoperative fluoroscopy, but not intraoperative radiographs, to rule out femoral neck fracture.
Methods: Billing records were reviewed for patients with femoral shaft fractures over a 10-year period. Patients who had an associated femoral neck fracture were examined in depth to determine the method and timing of diagnosis, patient specific variables, type of CT scan obtained, method of fixation, type of femoral neck fracture, and complication rates. Our protocol for detecting femoral neck fractures includes preoperative plain radiographs of the femur and pelvis, CT scan of the abdomen/pelvis obtained as part of trauma work-up (5-mm cuts were used for most of the study period), intraoperative fluoroscopy of the hip and femur, and postoperative radiographs.
Results: There were 1079 femoral shaft fractures identified over a 10-year time period. 29 patients (2.7%) had associated femoral neck fractures. 25 (86%) were identified preoperatively: 20 were visible on both plain radiographs and CT scan, and 5 were visible on CT scan alone. Two (7%) were identified intraoperatively with fluoroscopy (one before and one after insertion of the implant); in retrospect, both can be seen on preoperative CT scan. Two others (7%) were not identified until postoperative radiographs. In retrospect, both can be visualized on preoperative CT scans, although they were not detected at the time by the radiology or orthopaedic teams. Both remained nondisplaced and were stabilized with screw fixation in a second procedure. 19 of 29 femoral neck fractures (65%) were nondisplaced. All 29 femoral neck fractures were visible retrospectively on preoperative CT.
Conclusion: 2 of 29 femoral neck fractures (7%) were missed using our protocol, which compares favorably with the 20% to 50% rate reported in other studies. We do not believe that intraoperative plain radiographs are required. The two patients with femoral neck factures identified intraoperatively by fluoroscopy also were visible on preoperative CT, but not preoperative radiographs. The two missed femoral neck fractures were visible on preoperative CT. This underscores the importance of careful evaluation of the CT of the femoral neck in every high-energy femoral shaft fracture It remains uncertain if 2-mm–cut CT is required for detection, as most (79%) of the CT scans in our study had 5-mm cuts and all femoral neck fractures are visible retrospectively on CT scan.
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