Descriptive Analysis of Surgeries in Patients With Multiple Osteochondromas (CHIROS)

Analisi Descrittiva di Chirurgie in Pazienti Con Osteocondromi Multipli

Multiple Osteochondromas (MO), also known as Multiple Cartilaginous Exostoses, is an autosomal dominant skeletal disorder with an incidence of approximately 1 in 50,000 in Western populations. Most cases are associated with pathogenic variants in the EXT1 and EXT2 genes, which lead to a systemic reduction of heparan sulfate, causing abnormalities in bone growth and other physiological processes.

Symptoms typically appear in childhood and include the development of bony protrusions often associated with pain due to compression of muscles and nerves. Patients are generally shorter than average and may experience dislocations, subluxations, reduced motor function, and skeletal deformities such as genu valgum, limb asymmetry, and scoliosis. The most severe complication is malignant transformation into chondrosarcoma, occurring in 0.5-5% of adult patients. Diagnosis is mainly based on imaging techniques (X-ray, CT, MRI, ultrasound) and is confirmed by the presence of at least two osteochondromas after excluding other conditions.

Following diagnosis, patients or their caregivers often raise questions regarding disease progression, the number and type of surgical interventions required, and differences between pediatric and adult surgical approaches. This retrospective observational cohort study aims to characterize the number and types of surgical procedures performed in MO patients at a European referral center, the Rizzoli Orthopaedic Institute.

Study Overview

• Status: Recruiting
• Conditions: Multiple Osteochondroma
• Intervention / Treatment: Procedure: Surgery for osteochondromas

Detailed Description

Multiple Osteochondromas (MO, OMIM: 133700, 133701), also known as Multiple Cartilaginous Exostoses, represent an autosomal dominant skeletal dysplasia with an incidence in the Western population of approximately 1 in 50,000. The pathogenic variants identified in the majority of patients involve the EXT1 (OMIM: 608177) and EXT2 (OMIM: 608210) genes. Pathogenic mutations in these genes cause a systemic reduction of the polysaccharide heparan sulfate, leading to abnormalities in bone growth and in several physiological processes.

The first symptoms of the disease are observed in childhood, with the appearance of bony protrusions often associated with pain due to the pressure exerted by the osteochondroma on muscles and nerves. Furthermore, patients affected by MO, who are generally shorter than average, experience dislocations and subluxations, reduced motor abilities, as well as deformities such as genu valgum, limb length discrepancy, and scoliosis. The most severe complication is the malignant transformation of osteochondroma into chondrosarcoma, which occurs in 0.5-5% of adult patients. Clinical diagnosis is therefore primarily based on radiological imaging (X-rays, CT, MRI, ultrasound), with confirmation in the presence of at least two osteochondromas and after exclusion of other possible diagnoses.

At the time the diagnosis is communicated to the patient, numerous questions arise. The affected individual (or their guardian, in the case of minors) may ask about the clinical course of the disease or the number of surgical procedures they may need to undergo. Additional questions concern the type of surgical intervention and, given the progressive nature of the disease, surgery performed in children differs from that in adults. The present study (a retrospective observational cohort study) aims to characterize the number and type of surgical procedures performed in cases of MO at a European referral center such as the Rizzoli Orthopaedic Institute (IOR).

• Study Type: Observational
• Enrollment (Estimated): 300

Contacts and Locations

• Study Contact: Name: Marina Mordenti, PhD; Phone Number: +39 051 6366062; Email: marina.mordenti@ior.it

Study Locations

• Italy
  • Bologna
    • Bologna, Bologna, Italy, 40136
      • Recruiting
      • IRCCS Istituto Ortopedico Rizzoli
      • Contact: Marina Mordenti, PhD; Phone Number: +39 051 6366062; Email: marina.mordenti@ior.it

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients with multiple osteochondromas who underwent surgery at the Rizzoli Orthopedic Institute

Description

Inclusion Criteria:

• Patients diagnosed with multiple osteochondromas who underwent surgery at the IOR between January 1, 2012, and February 28, 2025.
• Patients of both sexes, regardless of age.

Exclusion Criteria:

- Patients with conditions that are part of the differential diagnosis for the condition under study, such as enchondromatosis and solitary exostosis.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Number and type of surgeries for Multiple Osteochondromas	3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Conceptualization of a score based on osteochondromas location (bone site), severity (grading), and deformity/limitations (number and type)	The conceptualization of the score mentioned above will be explored as a secondary outcome.	3 years
Descriptive analysis (mean, median, variance, standard deviation, interquartile range) of malignant transformations of osteochondromas	Descriptive metrics that will be used are mean, median, variance, standard deviation, interquartile range.	3 years

Collaborators and Investigators

• Sponsor: Istituto Ortopedico Rizzoli

Study record dates

Study Major Dates

• Study Start (Actual): October 23, 2025
• Primary Completion (Estimated): October 1, 2028
• Study Completion (Estimated): October 1, 2028

Study Registration Dates

• First Submitted: April 22, 2026
• First Submitted That Met QC Criteria: April 22, 2026
• First Posted (Actual): April 29, 2026

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 13, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Bone Diseases; Musculoskeletal Diseases; Neoplasms; Genetic Diseases, Inborn; Neoplasms by Histologic Type; Neoplastic Syndromes, Hereditary; Neoplasms, Connective and Soft Tissue; Neoplasms, Bone Tissue; Neoplasms, Connective Tissue; Osteochondrodysplasias; Bone Diseases, Developmental; Exostoses; Hyperostosis; Osteochondroma; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Osteochondromatosis; Exostoses, Multiple Hereditary; Surgical Procedures, Operative
• Other Study ID Numbers: 271/2025/Oss/IOR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No