Photo Dynamic Nail augmentation of periacetabular bone of patients with large pelvic defects yields durable pain relief

Pathologic acetabular defects can undermine the stability and osseointegration of a primary total hip arthroplasty (THA) acetabular component. Photodynamic nails (PDNs) has been used in a modified Harrington technique to provide space-filling stability to a primary acetabular implant without impeding local osseointegration.

Marilyn Heng et al describe their experience with PDN-augmented THAs. The article has been published in "Arthroplasty Today."

PDNs demonstrate impressive resistance to compressive forces and can be delivered via a flexible catheter, permitting anatomic reconstruction of the acetabular columns. PDNs are also radiolucent, which permits effective monitoring for disease progression without a metal artifact. Of particular benefit is the ability to pass screws through the PDN material after curing without the need for a specialized drill bit, thereby permitting the integration of the nail with an endoprosthetic construct without compromising the potential for local osseointegration.

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.

Key findings of the study were:

• 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).

The authors concluded that - "Management of the compromised hip joints of patients with large acetabular defects is a challenge. Here we described our early experience using PDNs to augment a primary THA in patients with osteoporosis or metastatic disease, with satisfactory outcomes and implant survival in a small series. Findings support the continued use of this technique although intermediate and long-term outcomes are necessary to confirm its viability." 

Further reading:

Augmenting Pathologic Acetabular Bone Loss With Photodynamic Nails to Support Primary Total Hip Arthroplasty Marilyn Heng, Mitchell S. Fourman et al

Arthroplasty Today 18 (2022) 1- 6https://doi.org/10.1016/j.artd.2022.08.022