Session I - Pelvis

Early Results and Complications following Limited Open Reduction and Percutaneous Screw Fixation of Displaced Fractures of the Acetabulum

Adam J. Starr, MD; Drake S. Borer, MD; Charles M. Reinert, MD; Alan L. Jones, MD; University of Texas Southwestern Medical School, Dallas, TX

Purpose: The purpose of this study was to present the complications and early results of a technique for limited open reduction and percutaneous screw fixation of displaced fractures of the acetabulum.

Methods: Between August 1994 and November 1999, 582 patients underwent surgical treatment for fractures of the acetabulum at our institution. Twenty-four of these patients had displaced fractures in which an attempt was made at closed reduction, or limited open reduction, followed by stabilization with percutaneously placed cannulated screws. These patients were divided into 2 groups.

Group 1 was composed of 13 elderly patients (average age 66) with multiple medical problems and displaced acetabular fractures. Each of these patients had findings on their injury radiographs that were thought to be predictive of the development of post-traumatic arthritis. In these patients, reduction was obtained through manipulation of the injured hip, or through use of limited open reduction using specialized clamps. Reduction was judged on fluoroscopy and was followed by percutaneous screw fixation with cannulated screws. In these patients, anatomic reduction was not considered a necessity. Reduction and stabilization were performed to allow early mobilization, to limit fracture pain, and to allow for later total hip arthroplasty (THA) if necessary.

Group 2 was composed of 11 young patients (average age 29) with displaced acetabular fractures. Each of these patients had a simple fracture pattern, according to the classification scheme of Letournel. In group 2, reduction was performed via manipulation of the injured hip, or through a limited open approach with the aid of specialized reduction clamps. Reduction was judged using fluoroscopy. When reduction was deemed to be anatomic, stabilization was carried out with percutaneously placed cannulated screws. For all cases, reduction was judged on postoperative radiographs. Complications were noted, and clinical outcome was assessed using a Harris Hip score questionnaire.

Results: Average operating room time and blood loss were 75 minutes and 50cc's, respectively. In one group #2 patient, limited open reduction failed, and the patient's fracture was stabilized through a traditional open procedure. This patient was not included in the analysis of results. In the remaining 23 patients, closed reduction or limited open reduction was successful and was followed with stabilization with percutaneous screws. In the 13 group #1 patients, fracture reduction to within 5mm was possible in each case. In the 10 group #2 patients, fracture reduction to within 2mm was possible in each case. There were no infections or wound complications. One patient in group #2 sustained a transient femoral nerve palsy. Two patients in group #1 had minor losses of reduction once mobilization was begun. Each of these patients had significant osteopenia. There were no losses of reduction in the group #2 patients. All fractures have gone on to union. One patient from group #1 was lost to follow-up, and one died. Thus, our study group is comprised of 21 patients, with an average follow-up of 12 months (range 3 to 45 months). Three patients from group #1 have gone on to THA. In each case, a standard hip arthroplasty approach was performed. The average Harris Hip score for the patients of group #1 is 84. As expected, each of these patients went on to develop radiographic signs of post-traumatic arthritis. The average Harris Hip score for the 10 patients of group #2 is 96.

Discussion: Percutaneous stabilization of acetabular fractures is a demanding procedure and must still be considered experimental. The indications, results, and possible complications of the technique are not yet fully known. The limited morbidity of the procedure makes it appealing. However, the difficulty in obtaining an anatomic reduction will limit the use of the technique in young trauma patients. So far, only simple fracture types can be adequately manipulated. Comminuted or complex fractures continue to require open procedures. In older persons, however, the technique may have broader indications for use. In elderly patients, imperfect reductions are more acceptable. Older patients with lower physical demands appear to tolerate imperfect reductions better than younger, high demand patients. Also, if it becomes necessary, the treatment for post-traumatic arthritis (total hip arthroplasty) can be expected to yield uniformly good results in elderly patients. Due to the limited soft tissue stripping during screw placement, the technique allows for the hip replacement surgeon to perform the THA through essentially "virgin" tissue. The dense scar tissue, contractures and problematic hardware commonly encountered after failed ORIF of acetabular fractures are not seen after use of this technique. Still, the screw placement techniques and reduction maneuvers required are very demanding. Thus, the procedure is probably best carried out by experienced acetabular fracture surgeons who are comfortable with percutaneous screw techniques.