Augmenting Pathologic Acetabular Bone Loss With Photodynamic Nails to Support Primary Total Hip Arthroplasty

Background: Pathologic acetabular defects can undermine the stability and osseointegration of a primary total hip arthroplasty (THA) acetabular component. Our service has used photodynamic nails (PDNs) in a modified Harrington technique to provide space-filling stability to a primary acetabular implant without impeding local osseointegration. Here we describe our experience with PDN-augmented THAs. Methods: An institutional review board-approved retrospective analysis of all patients who underwent PDN-augmented THA in the management of severe (Harrington class II or III) acetabular defects from September 1, 2020 to May 1, 2021 with at least 6 months of follow-up was performed. The primary outcome was implant survivorship. Comparisons between preoperative and 6-week postoperative visual analogue pain scores were made using the Mann-Whitney U test. Results: Six patients were included in this case series, 5 with metastatic cancer and 1 with pelvic discontinuity and avascular necrosis following failed attempted acetabular fixation. The mean follow-up duration was 10.3 ± 4.3 months. The mean age was 75.5 ± 4.7 years, mean body mass index 27.3 ± 5.6, and 5 patients were female. All but 1 patient was American Society of Anesthesiologists (ASA) class III. Two patients required acetabular revisions, one for aseptic loosening and a second for a pathologic fracture secondary to disease progression. One patient passed away 90 days after the procedure. The mean visual analogue pain score significantly improved from 7.8 ± 1.6 to 2.0 ± 1.4 six weeks after surgery (P = .008). Conclusions: PDN augmentation of the periacetabular bone of patients with large pelvic defects yields durable pain relief and function in vulnerable hosts. PDN should be considered a part of the reconstructive surgeon's armamentarium.