Background: Although Fassier-Duval (FD) rods have been used for almost 2 decades, knowledge of factors predisposing to their failure is limited. Thus, the purpose of this study was to: (1) present the most common complications of FD rodding, (2) present tips on how to avoid or overcome them, and (3) identify factors predisposing to treatment failure.
Methods: Fifty-eight rod segments in 19 patients with osteogenesis imperfecta (mainly type III) underwent analysis with a median follow-up (FU) time of 4.4 years. We assessed the total number of complications clinically and radiographically. Next, the possible predisposing factors leading to failure were assessed using the Mann-Whitney U test. In addition, we evaluated the cutoff age for the increased rate of complications using the Youden index. A P<0.05 was considered significant.
Results: The total number of complications reached 44.8%. The most common complications included: migration of the male or female implant (45.7% and 25.7% out of the total number of complications, respectively), bone fracture with bending of the rod (8.6%), and rotational deformities (8.6%). Significant differences in patients' ages at the time of surgery were found between the group with and without complications (P=0.04), while sex, segment treated, preceding surgeries, length of FU, FD rod diameter, and length of bisphosphonate treatment were not significant. The Youden index showed that the risk of complications rose significantly in patients treated when younger than 5.5 years of age (P<0.05).
Conclusions: This series displays the effectiveness and utility of FD rods at a median FU of over 4 years. Complication rates were comparable with the existing literature, with a notable increase in the number of side effects observed in younger patients (below the age of 5).
Level of evidence: Level IV-therapeutic study.
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