BONE STOCK AND CEMENT-BONE INTERFACE IN ONE STAGE REVISION TOTAL HIP REPLACEMENT FOR DEEP INFECTION: THE IMPORTANCE OF SHIELDING MEDULLARY SPACE WITH ANTIBIOTIC-LOADED CEMENT

Abstract

Introduction and Aims: The purpose of this study was to assess pre-operative bone stock and immediate postoperative cement-bone interface as factors affecting infection control and mechanical outcome after one stage revision THR for deep infection.

Method: This study included 115 cases which satisfied the following conditions: 1) One stage revision THR for deep infection was the primary intervention for infected hip replacement by a single surgeon (BMW) unless the bone stock was too poor for fixing implants; 2) follow-up of more than five years; 3) A complete series of radiographs was available for radiological study including pre-operative and immediate post-operative ones. Pre-operative bone stock was classified into four grades (Grade 0: No bone loss, Grade 1: Demarcation, Grade 2: Localised cavitation, Grade 3: Extensive bone loss). The immediate post-operative cement-bone interface was also graded into four categories (Grade A: White-out, obscure interface, Grade B: Clear line, no measurable gap, Grade C: Gap> 1mm, Grade D< 1mm). These two factors were analysed with regard to infection control and the mechanical survival of implants after surgery.

Results: Bone stock did not have significant influence on infection control, while it did affect mechanical outcome. The cement-bone interface was an affecting factor for not only the mechanical survival of implants but also the cure of infection.

Conclusion: There was a good chance of curing the infection even with extensive bone loss. Good cement fixation was an important factor with regard to infection control, as well as the mechanical survival of implants. The results suggested that it was important to shield the medullary space from the infected joint space with antibiotic-loaded cement in revision THR for deep infection.