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Background: The purpose of this study was to assess the feasibility and accuracy of computer-assisted surgery (CAS) for screw placement in different pelvic regions using intraoperative three-dimensional (3D) imaging and to evaluate the influence of surgeons' experience with such a system on procedure time, radiation time, radiation dose, and misplacement rate., Methods: Experimental study in a human cadaveric model (n=5) for percutaneous screw placement in the anterior column of the acetabulum, the posterior pelvic ring (S1, S2), and the superior pubic ramus via 3D fluoroscopic navigated procedure. Accuracy of screw placement was assessed by 3D image intensifier, including the reconstruction of multiplanar images and by computer tomography (CT) scan. Influence of surgeons' experience was assessed by direct comparison of a low- and high-volume surgeon using the same technical setting., Results: In 100% of all procedures, intraoperative Iso-C3D image analysis was sufficient to confirm a correct screw placement. The postoperative CT scan revealed no further screw misplacement. However, for a correct supraacetabular screw placement, the intraoperative 3D scan was essential. In this group, the 3D scan showed screw misplacement in three cases. Procedure time for all indications and screw failure rate were significantly lower for the higher experienced surgeon., Conclusion: The 3D fluoroscopic navigated procedure in pelvic surgery seems to be a useful tool for all surgeons and especially for less experienced ones. Furthermore, the intraoperative reconstruction of multiplanar 3D images allows a secure control of implant positioning.

Background: Because of an increasing life expectancy of patients and the rising number of joint replacements, peri- and interprosthetic femoral fractures are a common occurrence in most trauma centers. This study was designed to answer two primary questions. First, whether the fracture risk increases with two intramedullary implants in one femur; and second, whether a compression plate osteosynthesis is sufficient for stabilizing an interprosthetic fracture., Methods: Twenty-four human cadaveric femurs were harvested and four groups were matched based on the basis of bone density using a peripher quantitative computer tomography (pQCT). All groups-(I) hip prosthesis with a cemented femoral stem; (II) hip prosthesis and retrograde femoral nail; (III) hip prosthesis, retrograde femoral nail, and lateral compression plate; (IV) all three implants with an additional simulated interprosthetic fracture-were biomechanically tested in a four-point bending in lateral-medial direction., Results: The second group with two intramedullary implants exhibited 20% lower fracture strength in comparison with group 1 with proximal femoral stem only. The stabilization of an interprosthetic fracture with a lateral compression plate (group IV) resulted in a fracture strength similar to femur with prosthesis only., Conclusion: Two intramedullary implants reduce the fracture strength significantly. If an interprosthetic fracture occurs, sufficient stability can be achieved by a lateral compression plate. Because two intramedullary implants in the femur may decrease the fracture strength, the treatment of supracondylar femoral fractures with a retrograde nail in cases with preexisting ipsilateral hip prosthesis should be reconsidered.

Objective: A new device for the treatment of intertrochanteric fractures that uses 2 cephalocervical screws in an integrated mechanism allowing linear intraoperative compression and rotational stability of the head/neck fragment has been developed. The aim of this study was to describe the results using this device for the treatment of stable and unstable intertrochanteric fractures., Design: Prospective, consecutive., Setting: Academic Trauma Center., Methods: Between March 1, 2005, and July 31, 2006, 100 consecutive patients with an intertrochanteric fracture were treated with a new trochanteric antegrade nail (InterTan; Smith-Nephew, Memphis, TN). All living patients were followed up for a minimum of 1 year postoperatively (range 12-27 months). Clinical and radiographic examinations were performed until healing and at the 1-year anniversary of the index procedure. Healing, pain with ambulation, return to activities of daily living, the modified Harris hip score, and Barthel Index were used to evaluate outcomes., Results: The mean age of the patients was 81.2 (+/-11.3) years. Thirty-seven patients died, 12 were too infirmed for follow-up, and 3 could not be located, leaving 48 patients available for final evaluation. The average surgical time was 41 minutes (13-95 minutes). This rose significantly with the complexity of the fracture (OTA/AO classification: A1 versus A3, P = 0.016). All fractures healed within 16 weeks (range 10-16 weeks). Radiographic analysis at healing revealed no loss of reduction, no uncontrolled collapse of the neck, no nonunions, no femoral shaft fractures, and no implant failures. Two cases in the series were poorly reduced and settled into varus malalignment. There was no varus malposition seen in the remaining 46 fractures. The mean prefracture Harris hip score (75.1 +/- 13.4) was significantly reduced at the time of follow-up (70.3 +/- 14.5, P = 0.003); 58% of the patients recovered their prefracture status. No significant difference was seen for the Barthel Index., Conclusions: The InterTan device appears to be a reliable implant for the treatment of intertrochanteric femoral fractures. Its design provides for stability against rotation and minimizes neck malunions (shortening) through linear intraoperative compression of the head/neck segment to the shaft. As a result of the negligible complication rate and improved clinical outcomes, this implant is now the standard treatment for all intertrochanteric fractures at our institution.

Objectives/design: To assess the functional outcome after treatment of proximal humeral fractures with a new antegrade nail that provides angular and sliding stability. INTERVENTION/PATIENTS: Ninety-seven patients were treated during a 4-year period between April 2000 and March 2004. All patients were followed for 6 months, 51 patients (53%) for 12 months, and 31 patients (32%) for 24 months. This study focuses mainly on the patients with a follow up of 1 year. Their mean age was 68 years (range: 33 to 90); 22% were more than 80 years of age., Main Outcome Measurements: All fractures were radiologically graded by the Neer and AO/ASIF classifications. Clinical assessment was performed at all follow-up visits using the Constant-Murley and Neer scores, and complications were recorded., Results: There were 26.8% 2-part, 66% 3-part, and 7.2% 4-part fractures. The relative Constant-Murley score improved significantly (P < 0.001) from 72% at 6 months to 82% at 12 months after operation. No further improvement regarding functional outcome was observed after 24 months. Patients younger than 60 years of age had better results. No significant functional differences were found among 2-, 3- or 4-part fractures. Complications included backing out of the proximal screws (9.8%), secondary dislocation (1.9%), complete osteonecrosis (1.9%), and partial osteonecrosis (5.8%)., Conclusion: Treatment with this nail provides sufficient fixation of the fragments to allow early mobilization. The good functional results in the majority of the patients indicate that this nail can be used, even in complex fractures and elderly patients.