EVALUATION OF FEMORAL, ACETABULAR, AND GLOBAL OFFSET RESTORATION FOLLOWING HIP SPACER IMPLANTATION DURING STAGED TOTAL HIP ARTHROPLASTY REVISION

Aim Prosthetic joint infection (PJI) is a challenging complication after total hip arthroplasty. The two-stage approach is still considered the gold standard for chronically infected patients. Hip spacer implantation during the interim period aims to manage infection and provide temporary stability while maintaining limb length and offset, which are crucial for functional outcomes. This study aims to evaluate the restoration of radiographic femoral (FO), acetabular (AO), and global offset (GO) following articulating hip spacer implantation in patients with chronic PJI. Methods A retrospective analysis was conducted on patients treated for chronic hip PJI with a two-stage revision at our institution. Demographic and clinical data was obtained from a prospectically collected database. Radiographic data was analyzed preoperatively and post-spacer placement to measure changes in femoral, acetabular, and global offsets. Offset measurements were performed using standardized anteroposterior radiographs of the pelvis, and results were compared to preoperative baseline values. The restoration of these parameters was correlated with functional outcomes assessed at the interstage time. Complications were recorded during the interstage and post-reimplantation period. Results The study included 40 patients with a mean age of 63,7±10,4 years. Mean follow-up was 26,7 ±8,6 Following hip spacer implantation, the mean femoral, acetabular, and global offset was 48,1 ±7,6, 36,1±5,9 and 84,2±7,1, respectively. The differences between preoperative and post spacer implantation values was considered not statistically relevant (FO P 0.2997, AO: p: 0.8, GO p: 0.3293.). A statistically significant association was observed between optimal offset restoration and improved functional scores, as assessed by the Harris Hip Score (HHS) and Oxford Hip Score (OHS) at the time of spacer placement. However, complete offset restoration was rarely achieved, with certain discrepancies noted in cases of severe bone loss or varus hip morphology. Conclusion Hip spacer placement in PJI treatment provides adequate restoration of femoral, acetabular, and global offset, which is associated with better interim functional outcomes. While spacers offer effective infection control and satisfactory mechanical stability, optimizing offset restoration remains challenging, especially in complex cases. Acetabular spacer implantation and adequate preoperative planning facilitate GO and biomechanical restoration. Future spacer designs that better approximate native hip biomechanics may improve interim functionality and facilitate the eventual reimplantation phase.