Monoflange custom-made partial pelvis replacements offer a viable solution in extensive Paprosky III defects.

Aims: Custom-made partial pelvis replacements (PPRs) are increasingly used in the reconstruction of large acetabular defects and have mainly been designed using a triflange approach, requiring extensive soft-tissue dissection. The monoflange design, where primary intramedullary fixation within the ilium combined with a monoflange for rotational stability, was anticipated to overcome this obstacle. The aim of this study was to evaluate the design with regard to functional outcome, complications, and acetabular reconstruction.
Methods: Between 2014 and 2023, 79 patients with a mean follow-up of 33 months (SD 22; 9 to 103) were included. Functional outcome was measured using the Harris Hip Score and EuroQol five-dimension questionnaire (EQ-5D). PPR revisions were defined as an endpoint, and subgroups were analyzed to determine risk factors.
Results: Implantation was possible in all cases with a 2D centre of rotation deviation of 10 mm (SD 5.8; 1 to 29). PPR revision was necessary in eight (10%) patients. HHS increased significantly from 33 to 72 postoperatively, with a mean increase of 39 points (p < 0.001). Postoperative EQ-5D score was 0.7 (SD 0.3; -0.3 to 1). Risk factor analysis showed significant revision rates for septic indications (p ≤ 0.001) as well as femoral defect size (p = 0.001).
Conclusion: Since large acetabular defects are being treated surgically more often, custom-made PPR should be integrated as an option in treatment algorithms. Monoflange PPR, with primary iliac fixation, offers a viable treatment option for Paprosky III defects with promising functional results, while requiring less soft-tissue exposure and allowing immediate full weightbearing.
Competing Interests: C. Gebert, M. Wessling, and L. M. Jeys act as academic consultants for Implantcast, unrelated to this study. C. Gebert and M. Wessling act as academic consultants for Heraeus Medical, unrelated to this study. C. Gebert has received royalties, payment for expert testimony, and support for attending meetings and/or travel from Implantcast, all unrelated to this study. M. Wessling has received royalties, speaker honoraria, payment for expert testimony, and support for attending meetings and/or travel from Implantcast, all unrelated to this study. J. Hardes has received financial support from Implantcast for scientific projects unrelated to this study. Y. Hanusrichter has received speaker honoraria from Curasan and Implantcast, unrelated to this study. L. M. Jeys has received speaker honoraria from Zimmer Biomet, Stryker, and Implantcast, as well as payment for expert testimony from Implantcast, all of which are unrelated to this study.
(© 2024 Hanusrichter et al.)