Pathological Fractures in Patients Affected by Pycnodysostosis: A Case Series.

Background/Objectives: Pycnodysostosis is a rare genetic disorder causing skeletal dysplasia. It is determined by a gene mutation leading to cathepsin K deficiency and predisposes a patient to osteosclerosis, resulting in increased bone fragility. The altered bone quality typical of this disease is responsible for an increased risk of fractures. The purpose of our study was to evaluate the orthopedic manifestations and potential pitfalls in the surgical treatments of pathological fractures in a series of patients treated in our institution who were affected by pycnodysostosis. Methods: We retrospectively evaluated clinical and radiographic characteristics of five patients with pycnodysostosis treated for pathological fractures at our hospital in the past 5 years. Results: Two male and three female patients were included in this study. Four patients had a family history of pycnodysostosis. All the patients were of short stature, but only two underwent growth hormone treatment. All the patients experienced fractures, mostly in their lower limbs and occurring as a result of low-energy trauma. Most of the patients experienced either consolidation delay or nonunion. Conclusions: The orthopedic management of fractures in patients with pycnodysostosis poses an ongoing challenge for orthopedic surgeons. The fact that the bone is simultaneously sclerotic and brittle makes any orthopedic surgical treatment challenging and at a high risk of nonunion in any case.

Assessment for late developmental hip dysplasia in a cohort of infants with risk factors and normal hip ultrasound.

Background: Developmental dysplasia of the hip (DDH) is a known orthopedic pathology of newborns that, if not diagnosed and treated, can lead to debilitating long-term consequences. Ultrasound has proven to be an effective method for the early diagnosis of this condition. Recently, reports of late DDH in populations at risk (breech presentation) and after negative ultrasound examination have emerged in the literature. Aim: The objective of the study was to assess the possible appearance of late DDH in Italian children with risk factors but negative ultrasound screening. Materials and methods: We selected patients with risk factors for DDH and a negative hip ultrasound from the medical records of children referred to the Hip Ultrasound Clinic (Rome, Italy) from January 2018 to November 2021. To identify possible cases of late DDH, from February 2022 to July 2022, all patients who met the inclusion criteria were submitted to orthopedic follow-up clinical evaluation. In the case of a pathological objective examination, radiography was performed. Results: Fifty-five patients (52.7% female, 52.7% with breech presentation, and 41.8% with a positive family history) met the inclusion criteria. The median age of gait onset was 13 months. The median age of orthopedic follow-up examination was 45 months. Only three patients (5.5%) had a pathological examination, but no x-ray were pathological. Conclusion: Our study has not documented cases of late DDH. Considering the small study population and the only clinical follow-up, further studies are needed to clarify the possible late development of this condition.