RESUMEN
INTRODUCTION: Nonunion is a challenging condition in orthopaedics as its etiology is not fully understood. Clinical interventions currently aim to stimulate both the biological and mechanical aspects of the bone healing process by using bone autografts and surgical fixation. However, recent observations showed that atrophic nonunion tissues contain putative osteoprogenitors, raising the hypothesis that its reactivation could be explored to achieve bone repair. METHODS: Here we characterized atrophic nonunion stromal cells (NUSC) in vitro, using bone marrow stromal cells (BMSC) and osteoblasts as controls cells of the osteoblastic lineage, and evaluated its ability to form bone in vivo. RESULTS: NUSC had proliferative and senescence rates comparable to BMSC and osteoblasts, and homogeneously expressed the osteolineage markers CD90 and CD73. Regarding CD105 and CD146 expression, NUSC were closely related to osteoblasts, both with an inferior percentage of CD105+/CD146+ cells as compared to BMSC. Despite this, NUSC differentiated along the osteogenic and adipogenic lineages in vitro; and when transplanted subcutaneously into immunocompromised mice, new bone formation and hematopoietic marrow were established. CONCLUSIONS: This study demonstrates that NUSC are osteogenically competent, supporting the hypothesis that their endogenous reactivation could be a strategy to stimulate the bone formation while reducing the amount of bone autograft requirements.
RESUMEN
OBJECTIVE: To present the results and conclusions of our study on surgical treatment for unstable pelvic fractures in children subjected to surgical reduction and stabilisation. METHODS: We analysed the cases of fourteen skeletally immature patients with unstable pelvic fractures who underwent surgery for this condition between March 2004 and January 2011. The surgical technique used was based on the principle of surgical reduction and stabilisation of anterior and posterior lesions of the pelvic ring. This was a retrospective study, based on clinical assessment and X-ray analyses. RESULTS: The mean age of patients at the time of the condition was 9.4 years (range 2-13 years). Eight patients were female and six were male. The cause of the trauma was being hit by a car in ten cases, falls in three cases and an accident involving a motorcycle in one case. Five patients presented with other associated injuries, including fracture of the clavicle, femur shaft, proximal humerus, tibial shaft or olecranon, and bladder damage. All the patients assessed showed excellent clinical progress. Pelvic asymmetry prior to surgery varied from 1.1 to 2.9 cm (mean 1.5 cm) and dropped to a range of 0.2 to 0.9 cm (mean 0.4 cm) after reduction. In none of the cases was there a change between the pelvic asymmetry measured immediately after surgery and at the end of the follow-up period. CONCLUSION: Pelvic fracture in skeletally immature patients is rare and surgery is not normally indicated. Various authors have questioned this conservative type of treatment due to complications encountered. Bone remodelling does not seem to be sufficient to ensure an improvement in pelvic asymmetry, which justifies opting for surgery to reduce and correct deformities in the pelvic ring.
