Platelet-rich plasma-derived exosomes promote rotator cuff tendon-bone healing.

BACKGROUND: Rotator cuff tear (RCT) is the most common type of shoulder joint injury, platelet-rich plasma-derived exosomes (PRP-exos) are highly promising in tissue repair and regeneration. The purpose of this study was to determine the function of PRP-exos in rotator cuff tendon-bone healing. METHODS: PRP-exos were isolated from the rabbit whole blood by differential ultracentrifugation and characterized through transmission electron microscopy assay, nanoparticle tracking analysis, and western blotting. Alkaline phosphatase and Von Kossa staining were used to show tendon-derived stem cell (TDSC) differentiation. RT-qPCR and western blotting were performed to detect COL II, SOX-9, and TIMP-1. To determine the therapeutic effects of PRP-exos in vivo. Thirty New Zealand white rabbits were divided into control, model, and PRP-exos groups. The RCT animal model was constructed. The changes in tendon-bone tissue were determined by HE staining. Contents of COL-II, SOX-9, and TIMP-1 were determined by immunohistochemistry staining. RESULTS: PRP-exos were successfully isolated from rabbit blood. PRP-exos promoted TDSC proliferation and differentiation and also induced tendon-specific markers COL II, SOX-9, and TIMP-1 production. In vivo study revealed that PRP-exos promoted early healing of injured tendons. Rabbits treated with PRP-exos had better tissue arrangement in the tear site. Additionally, the contents of COL II, SOX-9, and TIMP-1 were also increased in the RCT rabbit model after PRP-exos treatment. CONCLUSIONS: PRP-exos enhanced tendon-bone healing by promoting TDSC proliferation and differentiation. This finding indicates that PRP-exos can serve as a promising strategy to treat rotator cuff tendon-bone healing.

Treatment of fifth metacarpal neck fracture in adolescents with minimally invasive surgery: percutaneous Kirschner wire fixation versus elastic stable intramedullary nailing.

OBJECTIVE: This retrospective study compared two minimally invasive surgical methods for fifth metacarpal neck fractures in adolescents: percutaneous Kirschner wire (K-wire) fixation and elastic stable intramedullary nailing (ESIN). METHODS: This study involved 42 adolescents aged 11 to 16 years with fifth metacarpal neck fractures treated by either K-wire fixation (n = 20) or ESIN (n = 22). The palmar tilt angle and shortening were compared on radiographs preoperatively and 6 months postoperatively. Total active range of motion (TAM), the visual analogue scale score for pain, and the Disabilities of the Arm, Shoulder and Hand score for upper limb function were recorded at 5 weeks, 3 months, and 6 months postoperatively. RESULTS: The mean TAM was significantly greater in the ESIN than K-wire group at all postoperative time points. The mean external fixation time was 2 weeks longer in the K-wire than ESIN group. One patient in the K-wire group developed infection. There was no statistically significant difference between the two groups in other postoperative outcomes. CONCLUSIONS: ESIN fixation has the advantages of greater stability, better activity, a shorter external fixation time, and a lower infection rate than K-wire fixation in the treatment of fifth metacarpal neck fractures in adolescents.