Impact of Hip Antibiotic Spacer Dislocation on Final Implant Position and Outcomes

Background: Dislocation of dynamic antibiotic hip spacers during the treatment of periprosthetic joint infection is a well-described complication. Unfortunately, the repercussions of such events after reimplantation of the definitive prosthesis remain largely unknown. As such, we devised a study comparing the perioperative and postoperative outcomes of patients having undergone reimplantation with and without spacer dislocation. Methods: A search of our institutional database was performed. Two retrospective cohorts were created: dislocated and nondislocated hip spacers. The radiographic and clinical outcomes for each cohort were collected. Results: The two retrospective cohorts contained 24 patients for the dislocated group and 66 for the nondislocated group. Continuous variables noted to be significantly different between the dislocated and nondislocated groups were as follows: clinical leg-length discrepancy (1.35 cm vs 0.41 cm, P = .027), acetabular center of rotation (1.34 cm vs 0.60 cm, P = .011), total packed red blood cell transfusions (4.05 vs 2.37, P = .019), operative time (177.4 min vs 147.3 min, P = .002), and hospital length of stay (7.79 days vs 5.89 days, P = .018). Categorical variables noted to be significantly different were requirement for complex acetabular reconstruction (58.3% vs 13.7%, P < .001), requirement of constrained liners (62.5% vs 37.3%, P = .040), and dislocation after second stage (20.8% vs 6.1%, P = .039). Conclusion: Dislocation of dynamic hip spacers leads to inferior clinical results and perioperative outcomes after reimplantation of the definitive prosthesis. Additionally, complex acetabular reconstruction is often required. As such, every effort should be made to prevent hip spacer dislocation. (C) 2019 Elsevier Inc. All rights reserved.