Microradiographic and histological evaluation of the bone-screw and bone-plate interface of orthodontic miniplates in patients

SummaryObjectives: To describe the tissue reactions at the bone-titanium interface of orthodontic miniplates in humans. Materials and methods: Forty-two samples, consisting of tissue fragments attached or not to miniplates or their fixation screws, were collected from 24 orthodontic patients treated with miniplate anchorage, at the time of removal of their miniplates. The samples were embedded in methylmethacrylate and cut into undecalcified sections which were submitted to microradiographic analysis. The sections were also stained and examined under ordinary light. Results: Three types of reactions were observed both on the histological sections and on the microradiographs. 1. The majority of the stable miniplates were easy to remove (34/42). The tissue samples collected consisted mainly in mature lamellar bone with some medullary spaces containing blood vessels, 2. two screws were highly osseointegrated and required the surgeon to remove them by trephining (2/42). They were surrounded by bone tissue which extended to the miniplate. The histological features were similar to the previous group, though the bone-screw contact was higher, and 3. in six samples obtained after unstable miniplate removal during the treatment, we observed either some woven bone trabeculae or loose connective tissue, without any histological sign of inflammation. Limitations and Conclusion: For evident ethical reasons, our data were limited by the size of the tissue fragments and the limited number of patients and variety of clinical presentations. The healing reactions consisted mainly in mature lamellar bone tissue sparsely in contact with the screw or the miniplate, with signs of a moderate remodelling activit

RISK FACTORS FOR ADDITIONAL SURGERY AFTER CLOSED REDUCTION OF HIP DEVELOPMENTAL DISLOCATION

Purpose: to evaluate the risk factors for additional surgery after closed reduction of hip developmental dislocationMethods: closed reduction for developmental hip dislocation was performed on 72 patients, with a total of 82 hips. All were irreducible hip dislocation who treated by overhead traction followed by closed reduction under general anaesthesia and spica casting. The mean age at the time of closed reduction was 10 months, with 82% of dislocation diagnosed after 6 months. In 28 hips (34.1%), no additional surgical procedure was necessary, while 54 hips (65.9%) needed an additional surgery, consisting in Salter osteotomy in 40 hips (48.8%) or open hip reduction in 14 (17.1%).Results: risk factors for the need of additional surgery were: older age at the time of reduction, male sex, high grade of hip dislocation and quality of hip reduction. All the patients older than 17 months at the time of closed reduction needed additional surgery. Bilateral hip dislocation had poorer Severin grading than unilateral dislocation. Poorer Kalamchi scoring was associated with older age and with the presence of the cephalic nucleus at the time of reduction.Conclusion: this study confirmed delayed diagnosis of hip dislocation leads to a more extensive treatment with poorer issue.