Clinical Outcomes After Stage-One Antibiotic Coated Molded Hip Spacer

Abstract

Two-stage exchange remains the gold standard for managing periprosthetic joint infection (PJI). We evaluated the outcomes of patients treated with a specific molded articulating antibiotic hip spacer for PJI at a tertiary referral center. An institutional database was retrospectively queried for patients who underwent implantation of spacer between 2009-2019. Patient demographics and clinical outcomes were collected. We identified 88 patients at an average age of 60.4 years who received a spacer implant, with an average of 4.2 years follow-up (standard deviation [SD] 2.5 years). A total of 34 patients (38.6%) had a "clean" two-stage course with successful reimplantation and no evidence of infection at 1-year follow-up. The remaining patients (61.4%) required 3.67 (±0.52) additional surgeries. Overall reimplantation rate was 72%. Causative bacterial agents included MSSA (n= 22), MRSA (n= 16), coagulase-negative Staphylococcus (n= 14), and polymicrobial (n= 12). Regarding complications, there were 13 (15%) dislocations, 16 (18%) periprosthetic fractures, 8 (9%) bent/fractured stems, and 16 (18%) patients had clinically significant subsidence. Patients with previous extended trochanteric osteotomy (ETO) experienced higher rates of bent/broken spacer stems (25% vs 3.1%; P= .006) periprosthetic fractures (37.5% vs 10.9%; P= .010), and dislocations (37.5% vs 6.2%; P= .001). The rate of infection clearance was lower in the prior ETO cohort (26.6% vs 54.2%; P= .029). We report outcomes in patients who underwent implantation of a specific molded articulating hip spacer at our institution. Infection eradication was roughly in line with published series of hip PJI treatment. There was a high rate of mechanical complications, especially in those patients who required an ETO.