Biofunctionalized hydrogel composed of genipin-crosslinked gelatin/hyaluronic acid incorporated with lyophilized platelet-rich fibrin for segmental bone defect repair.

Segmental bone defects can arise from trauma, infection, metabolic bone disorders, or tumor removal. Hydrogels have gained attention in the field of bone regeneration due to their unique hydrophilic properties and the ability to customize their physical and chemical characteristics to serve as scaffolds and carriers for growth factors. However, the limited mechanical strength of hydrogels and the rapid release of active substances have hindered their clinical utility and therapeutic effectiveness. With ongoing advancements in material science, the development of injectable and biofunctionalized hydrogels holds great promise for addressing the challenges associated with segmental bone defects. In this study, we incorporated lyophilized platelet-rich fibrin (LPRF), which contains a multitude of growth factors, into a genipin-crosslinked gelatin/hyaluronic acid (GLT/HA-0.5 % GP) hydrogel to create an injectable and biofunctionalized composite material. Our findings demonstrate that this biofunctionalized hydrogel possesses optimal attributes for bone tissue engineering. Furthermore, results obtained from rabbit model with segmental tibial bone defects, indicate that the treatment with this biofunctionalized hydrogel resulted in increased new bone formation, as confirmed by imaging and histological analysis. From a translational perspective, this biofunctionalized hydrogel provides innovative and bioinspired capabilities that have the potential to enhance bone repair and regeneration in future clinical applications.

Platelet-Rich Fibrin-Augmented Gap-Bridging Strategy in Rabbit Anterior Cruciate Ligament Repair.

BACKGROUND: We assessed the efficacy of a novel platelet-rich fibrin (PRF)-augmented repair strategy for promoting biological healing of an anterior cruciate ligament (ACL) midsubstance tear in a rabbit model. The biological gap-bridging effect of a PRF scaffold alone or in combination with rabbit ligamentocytes on primary ACL healing was evaluated both in vitro and in vivo. HYPOTHESIS: A PRF matrix can be implanted as a provisional fibrin-platelet bridging scaffold at an ACL defect to facilitate functional healing. STUDY DESIGN: Controlled laboratory study. METHODS: The biological effects of PRF on primary rabbit ligamentocyte proliferation, tenogenic differentiation, migration, and tendon-specific matrix production were investigated for treatment of cells with PRF-conditioned medium (PRFM). Three-dimensional (3D) lyophilized PRF (LPRF)-cell composite was fabricated by culturing ligamentocytes on an LPRF patch for 14 days. Cell-scaffold interactions were investigated under a scanning electron microscope and through histological analysis. An ACL midsubstance tear model was established in 3 rabbit groups: a ruptured ACL was treated with isolated suture repair in group A, whereas the primary repair was augmented with LPRF and LPRF-cell composite to bridge the gap between ruptured ends of ligaments in groups B and C, respectively. Outcomes-gross appearance, magnetic resonance imaging, and histological analysis-were evaluated in postoperative weeks 8 and 12. RESULTS: PRFM promoted cultured ligamentocyte proliferation, migration, and expression of tenogenic genes (type I and III collagen and tenascin). PRF was noted to upregulate cell tenogenic differentiation in terms of matrix production. In the 3D culture, viable cells formed layers at high density on the LPRF scaffold surface, with notable cell ingrowth and abundant collagenous matrix depositions. Moreover, ACL repair tissue and less articular cartilage damage were observed in knee joints in groups B and C, implying the existence of a chondroprotective phenomenon associated with PRF-augmented treatment. CONCLUSION: Our PRF-augmented strategy can facilitate the formation of stable repair tissue and thus provide gap-bridging in ACL repair. CLINICAL RELEVANCE: From the translational viewpoint, effective primary repair of the ACL may enable considerable advancement in therapeutic strategy for ACL injuries, particularly allowing for proprioception retention and thus improved physiological joint kinematics.

Proposed Guidelines for Treatment of Concomitant Distal Radius and Distal Ulna Fractures.

BACKGROUND: Concomitant distal radius and distal ulna metaphysis or head fractures (DRUF) are uncommon and acceptable results have been reported from cast immobilisation and internal fixation. METHODS: We reviewed the charts of 1094 patients treated for distal radius fracture at our institution in a two year period from 2009 to 2010. 24 patients with concomitant DRUF with were treated by cast immobilisation (group 1, n = 11), internal fixation of both bones (group 2, n = 7), internal fixation of radius alone (group 3, n = 2), and internal fixation of radius with distal ulna resection (group 4, n = 4). Patients treated by surgery underwent intraoperative assessment of distal ulna stability to determine the indication for ulna fixation. Post surgical range of motion, clinical parameters, and functional outcome scores (Gartland-Werley and modified Mayo) were measured. RESULTS: Wrist motion was comparable in each group. Radiographic parameters were better in surgical groups. 23 of 24 patients achieved excellent/good outcomes based on Gartland-Werley scores, while 12 of 24 achieved good modified Mayo wrist score. There was a case of distal ulna non-union in group 1, and another case of delayed distal radius union in group 2. CONCLUSIONS: By evaluating patients' functional requirement, and dynamic fluoroscopy examination, satisfactory outcomes can be achieved for various presentations of DRUF.