This study has been planned as part of the Orthofix Srl post-market active surveillance plan for the collection of data on both the clinical performance and the safety profile of the JTIN.

The rationale of the proposed study is to update and support the pre-market clinical evaluation of the JTIN with Real World Evidence clinical data in a real-life surgical setting, in order to confirm the benefit/risk ratio of this medical device and to keep the CE mark under Medical Device Regulation (MDR) requirements. One selected site, experienced in the treatment of pediatric patients with OI, where the usage of JTIN is already part of the normal clinical practice, will participate in this study.

One selected site, experienced in the treatment of pediatric patients with OI, where the usage of JTIN is already part of the normal clinical practice, will participate in this study. Investigator will screen patients treated (or planned to be treated) with JTIN to verify inclusion and exclusion criteria, to achieve the enrollment of 25 cases. With lost to follow-up percentage estimated at 20%, this will lead to a total of 20 evaluable cases, i.e. 20 implanted JTIN (some patients may contribute for more than one implant). Patients are prospectively and retrospectively enrolled in the study: they may have undergone JTIN implantation from the 1st of January 2022.

Enrolled patients, since this study is non-interventional and observational, will follow the standard medical practice of the site: no requirements regarding the treatment of patients will be imposed on the site or Principal Investigator and the Sponsor will not in any manner influence the treatment decisions. Data of enrolled subjects will be collected for this study up to 1 year from surgery.

The hospital standard care usually, but not exclusively, includes: surgery, discharge and plaster removal visits, and then 3 other follow up visits up to 1 year from surgery (see "Visits and Assessments Schedule"). Visits frequency is estimated as average of the site normal clinical practice, actual visit timing for each patient will be performed according to investigators and hospital staff evaluation.

The patient data will be systematically collected by the investigator in eCRF.

Inclusion Criteria:

• is in pediatric age (> 18 month and < 18 years) at the time of surgery;
• is skeletally immature;
• has a diagnosis for OI;
• has a regular indication for surgical intervention with JTIN to treat femoral and/or tibial fractures, osteotomies, malunions and non-unions;
• patient and/or legal representative is duly informed and doesn't oppose to participation.

Exclusion Criteria:

• has a medical condition that is a contraindication according to the manufacturer's instruction for use;
• has any conditions that in the Investigator's opinion may interfere with the study execution or due to which the patient should not participate for safety reasons;
• requires the application of, or has already in-situ the application of concomitant devices that cannot be safely removed (except for permitted concomitant devices paragraph);
• is participating in other clinical trials or has taken part in any clinical study in the last 3 months with exception of analytical trials on genetics study related to OI (i.e. studies that do not include an investigational treatment for the patient such as new drugs or other medical devices);
• is likely to be lost to follow up, according to investigator's opinion.

Pediatric patients older than 18 months suffering from osteogenesis imperfecta.

The study was performed in 14 pediatric patients who had a regular indication for surgical intervention with JTIN and in this document are reported the results obtained in 25 surgical procedures.

The Adverse Event where collected from surgery to last time point indicated in the protocol (1 year + 1 month, total of 13 months post-surgery)

The investigator will follow the standard clinical practice to record data in the medical file. In addition to the above-mentioned requirements, the investigator will also record the AEs and MDDs in the eCRF. For both cases the investigator, when reporting the event in the eCRF will describe: date of the event; treatment; resolution; whether or not it is Serious and whether or not it is related to the use of the investigational device and the related procedure.