Thursday, March 19, 1998
A study presented Thursday in poster exhibit A 101 advocates rigid fixation of acetabular fractures for revision total hip arthroplasty (especially if it involves one of the columns) followed by the restoration of acetabular bone loss and rigid implant fixation.
According to co-author Arthur L. Malkani, MD, assistant professor, department of orthopaedic surgery, University of Louisville, Louisville, Ky., the type of acetabular component should vary based on the quality of the remaining host bone. If a conventional acetabular component cannot be utilized, he said, then a hook protrusio ring is a viable alternative.
Dr. Malkani reviewed the results of 11 patients who underwent acetabular component revision due to loosening and an underlying fracture. An acetabular fracture was suspected in nine of the patients preoperatively, based on anterior/posterior radiographs along with Judet views of the acetabulum. The fractures were: transverse, seven; posterior column/posterior wall, three; and anterior column, one.
Nine of the 11 patients underwent internal fixation of the acetabular fracture followed by insertion of an acetabular component. Lag screws to enhance fixation from the posterior column to the anterior column were inserted when adequate bone stock was available. When utilized, allograft bone was incorporated into the fixation. Acetabular component fixation included an uncemented component in eight patients; a hook protrusio ring in two patients; and a cemented component in one.
Ten patients had a minimum two-year follow-up. Two of eight uncemented cups had to be revised due to loosening and one patient had persistent pain with radiographic evidence of loosening. Complications included dislocation in three patients treated successfully with abduction orthosis.
"Acetabular component revision with an uncemented component in this group of patients with an underlying acetabular fracture is unpredictable due to compromised host bone and demonstrated a high failure rate of 27 percent," said Dr. Malkani. "Often bone stock can be compromised due to osteolysis, leaving a thin sclerotic shell in patients, making them prone to fracture with minimal trauma."
Co-authors of the study are David Helfet, MD, associate professor, department of orthopaedics, Cornell University Medical College, New York City; Mark Figgie Jr., MD, director of orthopaedic trauma services, Hospital for Special Surgery, New York City; and William Renda, MD, an orthopaedic surgeon in private practice in Louisville, Ky.
|1998 Academy News Mar.19 Index C|