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Background Osteomyelitis variolosa is a self-limiting disease triggered by variola virus that cannot be prevented or repaired. Smallpox has been eradicated for 40 years, and complications that remain after smallpox has been cured have become a remarkable diagnostic challenge for contemporary physicians. In this systematic review, we searched PubMed (MEDLINE), Web of Science, and Google Scholar for cases on complications, diagnosis, and treatment for osteomyelitis variolosa between January 1980 and February 2021. Results Ten papers and eleven finished cases, all patients from India, were included for comparison with the present case. In total, 100% of patients presented with bilateral elbow deformities, the ankle was the second most common site of lesion in 50%, and knee lesions accounted for 25% in this study. Flexion contracture, joint instability, secondary arthritis, and fracture are common complications of osteomyelitis variolosa, and most patients receive conservative treatment, while internal fixation has good results for combined fractures. Conclusions Although osteomyelitis variolosa is not a direct threat to the safety of patients, severe skeletal deformities can have a significant impact on quality of life. With advances in surgical techniques, clinicians are offering an increasing number of treatment options for patients with osteomyelitis variolosa. However, most importantly, smallpox has basically been removed from the historical arena, and for areas where smallpox was once endemic, physicians need to deepen the understanding of this disease again.

Full-thickness osteochondral defects lack the capability to self-repair owing to their complicated hierarchical structure. At present, clinical treatments including microfracture etc. have shown some efficacy; however, the newborn tissue exhibits some drawbacks, such as fibrocartilage formation and insufficient mechanical properties, eventually leading to osteoarthritis. Moreover, cartilage and bone tissues have different biological characteristics. Therefore, the simultaneous repair of full-thickness osteochondral defects is highly challenging. To achieve optimal repair, we constructed a bionic biphasic composite scaffold with on-demand osteochondrogenic factors. Kartogenin and extractive mesenchymal stem cells were introduced into a mPEG- block -poly(L-valine) thermogel set as the upper layer to accelerate cartilage repair. A poly(lactide- co -glycolide)/hydroxyapatite porous scaffold was immobilized with bone morphogenetic protein-2 as the bottom layer to facilitate subchondral repair. The intermediate interface, being a combination of the two layers was expected to reconstruct the calcification zone. Gross evaluation, micro-computed tomography, and magnetic resonance imaging indicated that at 6 months after implantation, the scaffold encapsulating mesenchymal stem cells and osteochondrogenic factors had a better effect compared with other groups. More importantly, the composition of the new cartilage and bone was confirmed by western blotting, H&E staining, immunohistochemistry, and immunofluorescence. Taken together, this bionic composite scaffold with osteochondrogenic factors offers a promising option for the repair of full-thickness osteochondral defects. Funding Information: Funding for this study was supported by National Natural Science Foundation of China grants (81671804, 81701811) and Natural Science Foundation of Jilin Province (20200201322JC). Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: This experiment was carried out in the facilities of the Experimental Animal Center of Jilin University, and was carried out under the supervision of the Animal Ethical Welfare Committee of Jilin University, in compliance with the requirements of Jilin University and the state for the ethical welfare of experimental animals.