Kissing osteochondromata leading to synostoses

Area of Science:

• Orthopedics
• Radiology
• Medical Genetics

Background:

• Multiple cartilaginous exostosis (MCE) is a genetic disorder characterized by numerous benign bone tumors (osteochondromas).
• Synostoses, or abnormal bone fusions, are potential complications, particularly in the long bones.
• The exact incidence and mechanism of synostosis formation in the lower limbs in MCE patients require further elucidation.

Purpose of the Study:

• To determine the incidence of synostoses in the lower limbs of patients with MCE.
• To investigate the cause and mechanism of synostosis development using imaging data.
• To correlate synostosis formation with the presence and growth of osteochondromata.

Main Methods:

• Retrospective review of lower leg radiographs from 21 MCE patients.
• CT scans of proximal and distal tibiofibular joints in five patients to assess synostoses and bone deformities.
• Analysis of osteochondroma characteristics and their proximity to potential fusion sites.

Main Results:

• Synostoses were identified in 10 out of 21 MCE patients (47.6%).
• A total of 23 synostoses were observed, predominantly in the tibiofibular joints (14 distal, 9 proximal).
• Erosions and pressure atrophy were noted in some cases, suggesting mechanical interaction between osteochondromata.

Conclusions:

• Synostoses are a common finding in adult MCE patients with abundant osteochondromata.
• "Kissing" osteochondromata, arising from adjacent tibia and fibula, are the primary cause of tibiofibular synostosis.
• Interlocking growth of opposing osteochondromata leads to osseous fusion and synostosis formation.