The use of a virtual three-dimensional model to evaluate the intraosseous space available for percutaneous screw fixation of acetabular fractures.

We created virtual three-dimensional reconstruction models from computed tomography scans obtained from patients with acetabular fractures. Virtual cylindrical implants were placed intraosseously in the anterior column, the posterior column and across the dome of the acetabulum. The maximum diameter which was entirely contained within the bone was determined for each position of the screw. In the same model, the cross-sectional diameters of the columns were measured and compared to the maximum diameter of the corresponding virtual implant. We found that the mean maximum diameter of virtual implant accommodated by the anterior columns was 6.4 mm and that the smallest diameter of the columns was larger than the maximum diameter of the equivalent virtual implant. This study suggests that the size of the screw used for percutaneous fixation of acetabular fractures should not be based solely on the measurement of cross-sectional diameter and that virtual three-dimensional reconstructions might be useful in pre-operative planning.

Preliminary results and complications following limited open reduction and percutaneous screw fixation of displaced fractures of the acetabulum.

Twenty-four patients underwent attempted closed or limited open reduction of displaced acetabular fractures. If reduction was successful, the fractures were stabilized with percutaneous screws. Group 1 was composed of elderly patients with complex fractures and radiographic findings that were felt to be predictive of post-traumatic arthritis. In these patients, percutaneous screw fixation was used to improve fracture anatomy, allow mobilization and total hip replacement later, if necessary. In group 1, anatomical reduction was not felt to be a necessity. Group 2 was composed of young patients with simple fracture types. For group 2, anatomical reduction was the goal. In 23/24 patients, closed or limited open reduction was successful. In group 1, maximum displacement averaged 10 mm preoperatively, 3 mm postoperatively. In group 2, maximum displacement averaged 7 mm preoperatively, 1 mm postoperatively. One elderly patient was lost to follow-up and one died, leaving 21 patients with an average follow-up of 12 months. All the fractures healed. One patient had a transient femoral nerve palsy, and two elderly patients had minor losses of reduction due to unprotected ambulation after surgery. Five of the elderly patients have gone on to total hip arthroplasty. The average Harris Hip scores in groups 1 and 2 were 85 and 96, respectively.