Efficacy comparison of vascularized iliac crest bone flap and Ilizarov bone transport in the treatment of traumatic bone defects of the tibia combined with large soft tissue defects.

BACKGROUND: Traumatic tibial defect complicated with soft tissue defect is a difficult problem in clinic. Vascularized iliac crest bone flap (VIBF) and Ilizarov bone transport are effective methods to treat tibial defects with limited defect length, which most need to be explored accordingly. METHODS: In this study, a total of 68 patients with traumatic tibial defect (ranging from 4 to 10 cm) and large soft tissue defect were collected retrospectively. The soft tissue defects were repaired by latissimus dorsal musculocutaneous flap (LD), anterolateral thigh flap (ALTF) or both. Thirty-three cases were treated with vascularized iliac crest bone flap transplantation and 35 cases were treated with Ilizarov bone transport. Intraoperative and postoperative follow-up data (including operation time, blood loss, bone union time, external fixation time, external fixation index, complication rate, reoperation rate, and functional evaluation) were recorded, and comparative analysis was performed. RESULTS: The median follow-up time was 32 months. Compared with Ilizarov group, the VIBF group exhibited statistically faster bone union time (6.3 ± 1.0 vs. 18.2 ± 3.0 months). Moreover, the VIBF group showed shorter EFT (7.3 ± 1.0 vs. 19.2 ± 3.0 months) and a better EFI (34.8 ± 9.2 vs. 84.2 ± 23.7 days/cm). The excellent and good rate of lower limb appearance evaluation in VIBP group was significantly better than that in Ilizarov group. The complication rate and reoperation rate were significantly higher in Ilizarov group. CONCLUSION: In summary, compared with Ilizarov bone transport, VIBP has the advantages of faster healing, shorter external fixation time, lower complication and reoperation rate, and better appearance within the limited defect length. Ilizarov bone transport is still preferred when the defect length exceeds the maximum repair length of the iliac flap. The daily handling required by bone transport process is painful. LEVEL OF EVIDENCE: III, Case-control study.

Extracellular vesicles from human urine-derived stem cells inhibit glucocorticoid-induced osteonecrosis of the femoral head by transporting and releasing pro-angiogenic DMBT1 and anti-apoptotic TIMP1.

Osteonecrosis of the femoral head (ONFH) frequently occurs after glucocorticoid (GC) treatment. Extracellular vesicles (EVs) are important nano-sized paracrine mediators of intercellular crosstalk. This study aimed to determine whether EVs from human urine-derived stem cells (USC-EVs) could protect against GC-induced ONFH and focused on the impacts of USC-EVs on angiogenesis and apoptosis to explore the mechanism by which USC-EVs attenuated GC-induced ONFH. The results in vivo showed that the intravenous administration of USC-EVs at the early stage of GC exposure could rescue angiogenesis impairment, reduce apoptosis of trabecular bone and marrow cells, prevent trabecular bone destruction and improve bone microarchitecture in the femoral heads of rats. In vitro, USC-EVs reversed the GC-induced suppression of endothelial angiogenesis and activation of apoptosis. Deleted in malignant brain tumors 1 (DMBT1) and tissue inhibitor of metalloproteinases 1 (TIMP1) proteins were enriched in USC-EVs and essential for the USC-EVs-induced pro-angiogenic and anti-apoptotic effects in GC-treated cells, respectively. Knockdown of TIMP1 attenuated the protective effects of USC-EVs against GC-induced ONFH. Our study suggests that USC-EVs are a promising nano-sized agent for the prevention of GC-induced ONFH by delivering pro-angiogenic DMBT1 and anti-apoptotic TIMP1. STATEMENT OF SIGNIFICANCE: This study demonstrates that the intravenous injection of extracellular vesicles from human urine-derived stem cells (USC-EVs) at the early stage of glucocorticoid (GC) exposure efficiently protects the rats from the GC-induced osteonecrosis of the femoral head (ONFH). Moreover, this study identifies that the promotion of angiogenesis and inhibition of apoptosis by transferring pro-angiogenic DMBT1 and anti-apoptotic TIMP1 proteins contribute importantly to the USC-EVs-induced protective effects against GC-induced ONFH. This study suggests the promising prospect of USC-EVs as a new nano-sized agent for protecting against GC-induced ONFH, and the potential of DMBT1 and TIMP1 as the molecular targets for further augmenting the protective function of USC-EVs.

Reconstructive surgery for foot and ankle defects in pediatric patients: Comparison between anterolateral thigh perforator flaps and deep inferior epigastric perforator flaps.

BACKGROUNDS: Due to the delicate tissue, small blood vessels and incomplete development of interarticular ligaments, skin and soft-tissue defects of the foot and ankle in pediatric patients remain a challenge for orthopedic and plastic surgeons. Anterolateral thigh perforator (ALTP) flap and deep inferior epigastric perforator (DIEP) flap are the most commonly used flaps for the repair of lower-extremity soft-tissue defects. The literature contains a shortage of evidence involving the differences between ALTP and DIEP flaps in the reconstruction of young patients with complex foot and ankle defects. This study was designed to determine which type of flap is better for foot and ankle repair in pediatric patients. METHODS: From January 2004 to January 2018, 79 children younger than 14 years treated with DIEP flap (41 cases) or ALTP flap (38 cases) for composite defects of the feet and ankles were retrospectively investigated. The two groups were homogeneous in terms of age, the location of the defect, etiology, and flap area. Complications, scarring, cosmetic appearance, flap sensory recovery, and functional outcome were analyzed, and statistical analysis was performed. RESULTS: The ALTP group had shorter operation time (155.0 ±â€¯12.0 min vs 212.2 ±â€¯23.9 min), flap harvested time (39.6 ±â€¯5.1 min vs 57.2 ±â€¯10.4 min), and operative blood loss (143.4 ±â€¯23.7 ml vs 170.7 ±â€¯44.7 ml) than the DIEP group (P <  0.05). In short-term follow-up, ALTP group showed a lower flap necrosis rate (5.3% vs 24.4%) and vascular insufficiency rate (2.6% vs 19.5%) than DIEP group (P <  0.05). In long-term follow-up, ALTP group showed a lower late complication rate and better cosmetic, functional, scar outcomes than DIEP group (P <  0.05). CONCLUSIONS: The study showed that an ALTP flap may brings better results than a DIEP flap in terms of short- and long-term complications, scarring, and morpho-functional outcomes for pediatric patients undergoing reconstruction of foot and ankle defects.