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Objective: To investigate whether black phosphorus (BP) promotes bone regeneration via the piezoelectric effect. Methods: A BP hydrogel complex was prepared. Rat femur defect models were established and divided into three groups: the negative control group (CTR), the untreated control group (Sham), and the BP group. Femoral specimens were collected at 2, 4, 6, and 8 weeks post-operation. Bone morphology was observed using electron microscopy, and osteogenic protein content was detected by Western blotting. Results: Electron microscopy showed that the healing ability of bone defects in the Sham group was weaker than that in the CTR group. The BP group demonstrated better bone defect recovery than the Sham group, but it did not surpass that of the CTR group. The Western bolt result of bone regeneration protein showed that both the hydrogel and BP could stimulate the upregulation of bone regeneration proteins. Still, the hydrogel appears to be more effective overall. Conclusion: Without external forces, polarized BP nanoplates may enhance bone defect healing due to their uniquely oriented electron layer properties.

We developed a model where a 2-cm full-thickness canine ulnar defect bridged with a tubular diaphyseal bone transplant was stabilized with an intramedullary Kirschner wire. This model was used to compare tubular autografts and allografts in the reconstruction of segmental ulnar defects in 12 adult beagle dogs. The dogs were followed for nine months and X-ray radiographs were taken every three weeks. The overall healing was good and all the dogs were able to walk normally during the follow-up. After nine months, the ulnas were harvested and mechanical testing and histological analyses were made. Of the ulnar defects, 4/6 in the autograft group and 3/6 in the allograft group had a complete union. Of the Kirschner wires, 6/12 had broken during the follow-up. This did not have any effect on the bone union, however. The autograft group had better results in mechanical testing although the difference was statistically significant only for maximal absorbed energy. We conclude that the segmental ulnar defect model fixed with an intramedullary wire seems to be a feasible alternative in bone transplant studies, although the semirigid fixation resulted in breakage of the wire in many cases. The overall healing was good after both autograft and allograft transplantations, but autografts seemed to be slightly better.

Traumatic bone defect is a challenging problem for both patient and doctor. The goal of treatment is the restoration of hand function with acceptable appearance of an injured hand. Especially in the injury of the thumb, length and stability are very important to achieve good holding and pinching functions. We reported a 23-year-old patient with traumatic first metacarpal bone loss after a motor vehicle accident treated with vascularized radial half of the second metacarpal bone and the first dorsal interosseous muscle composite flap.

High energy metacarpal fracture presenting with critical bone loss requires bone graft and hardware stabilisation. Early bone grafting and rigid internal fixation allow expedited patient recovery. Plate fixation is the most described technique when an autologous bone graft is being used. In this report, we present an alternative technique to secure bone grafts to metacarpal shafts with intra-medullary headless compression screws (HCS). In the presented patient, significant bone defects of the fourth and fifth metacarpals were bridged using iliac crest cortico-cancellous bone grafts and fixed with HCS. This method of fixation allowed controlled early active mobilisation. Bone graft incorporation and excellent active range of motion were demonstrated.

Level of Evidence: Level V (Therapeutic)

A 28-year-old man sustained a complex forearm injury from high-energy trauma, causing ulnar nerve injury, a bone defect, forearm malunion and synostosis. A 3D-printed titanium truss cage was used to solve these problems. This patient achieved union of the bone defect, was pain-free and had no recurrent synostosis 2 years after reconstructive surgery. The advantages of the 3D-printed titanium truss cage included anatomical fit, immediate mobilisation and low morbidity of the donor side of the bone graft. This study reported a promising result from using 3D-printed titanium truss cages to manage complex forearm bony problems.

Level of Evidence: Level V (Therapeutic)