Acetabular fracture associated with cementless acetabular component insertion - A report of 13 cases

Acetabular fracture during insertion of a cementless acetabular component o ccurred in 13 patients. The preoperative diagnosis was osteoarthritis in 6 patients, rheumatoid arthritis in 2 patients, avascular necrosis in 3 patie nts, hip fracture nonunion in 1 patient, and developmental dysplasia of the hip in I patient. Several different components were used; however, the ace tabulum was underreamed by 1 to 3 mm in all cases. The acetabular fracture was identified in 9 of 13 cases intraoperatively. The fracture was identifi ed on postoperative radiographs for the other 4 cases. Fractures were treat ed by a variety of means, including the addition of augmentation screws in or around the cup, use of autograft bone at the fracture site, modified pos toperative weight-bearing status, and immobilization. In 2 cases, the socke t needed to be revised after it progressively migrated and failed. One pati ent had cup migration, and another had a radiolucent line about the cup but was not symptomatic enough to require revision. In 3 of these 4 cases, the fracture was not identified intraoperatively. Underreaming of the acetabul um and use of an oversized acetabular component has been recommended to imp rove the initial stability of the acetabular component during total hip art hroplasty. Impaction of an oversized component requires bone to undergo pla stic deformation if the cup is to be fully seated. Theoretically, this tech nique provides improved component stability with enhanced osseous ingrowth into the cup. The 13 cases reported in this study demonstrate that acetabul ar fracture is a complication that may occur in association with uncemented hip arthroplasty, particularly if oversized components are used. The impor tance of recognizing acetabular fractures intraoperatively and the need to institute appropriate treatment to ensure a stable acetabular component is emphasized. In patients with osteoporotic bone, line-to-line reaming with u se of a cementless acetabular component or insertion of a cemented socket m ay be considered to avoid this significant complication.