CEMENT EXTRUSION FROM THE ACETABULUM IN TOTAL HIP ARTHROPLASTY: INCIDENCE AND MODIFICATION OF TECHNIQUE TO REDUCE THE RISKS.

Abstract

Introduction: Pressurization of PMMA can lead to cement extrusion. Although rare, the complications related to cement extrusion (‘CE’) are serious such as neurological, urological and vascular injuries. In a recent study the incidence of CE from acetabulum was found to be 42–50%, most of which was under transverse ligament. We advocate a technique of applying cancellous autograft on the medial floor and under the transverse ligament to provide cancellous surface for cement pressurisation, and to prevent CE. The aim of this study was to review our incidence of CE and radiolucent lines (‘RLL’).

Methods: Study group included 380 consecutive patients undergoing primary implantation of flanged cemented cup with spacers during 2002–2003. The mean age was 68 years. Surgeons of all grades, including junior doctors under supervision, performed the procedure. Early postoperative radiographs were reviewed to identify the incidence, site and extent of CE and incidence of RLL.

Results: We identified CE in 46 radiographs, 35 being inferior, 6 pelvic and 5 along retractors. The mean size of the CE was 240.5 mm². Radiolucent lines (RLL) in any of the Charnley zone were present in 58 cases. Two zone RLL were seen in seven cases (1.8%) and a circumferential radiolucency in one case (0.3%). There was no significant correlation between the grade of the operating surgeon and the incidence of CE (p, 0.15). There was no significant correlation between the grade of operating surgeon and the presence of RLL (p, 0.18).

Discussion: Results of this study confirm that incidence of CE with this technique is significantly less as compared with historic data (12% vs. 42%). Incidence of RLL is also less especially in zone 2 and 3. These findings support our hypothesis that use of autograft to convert acetabulum in contained hemisphere reduces incidence of CE and improves pressurization.