Arthroscopic debridement for knee osteoarthritis

Role of the Calcified Cartilage Layer of an Integrated Trilayered Silk Fibroin Scaffold Used to Regenerate Osteochondral Defects in Rabbit Knees

The repair of osteochondral defects remains challenging, given the complexity of native osteochondral tissue and the limited self-repair capacity of cartilage. Osteochondral tissue engineering is a promising strategy. Here, we fabricated a biomimetic osteochondral scaffold using silk fibroin and hydroxyapatite, including a calcified cartilage layer (CCL). We studied the role played by the CCL in terms of cell viability in vivo. We established osteochondral defects in rabbit knees to investigate the effects of CCL-containing scaffolds with or without adipose tissue-derived stem cells (ADSCs). We evaluated osteochondral tissue regeneration by calculating gross observational scores, via histological and immunohistochemical assessments, by performing quantitative biochemical and biomechanical analyses of new osteochondral tissue, and via microcomputed tomography of new bone at 4, 8, and 12 weeks after surgery. In terms of surface roughness and integrity, the CCL + ADSCs group was better than the CCL and the non-CCL + ADSCs groups at all time points tested; the glycosaminoglycan and collagen type II levels of the CCL + ADSCs group were highest, reflecting the important role played by the CCL in cartilage tissue repair. Subchondral bone smoothness was better in the CCL + ADSCs group than in the non-CCL + ADSCs and CCL groups. The CCL promoted smooth subchondral bone regeneration but did not obviously affect bone strength or quality. In conclusion, a biomimetic osteochondral scaffold with a CCL, combined with autologous ADSCs, satisfactorily regenerated a rabbit osteochondral defect. The CCL enhances cartilage and subchondral bone regeneration.

A novel counterbalanced implementation study design: methodological description and application to implementation research

Background

Implementation research is increasingly being recognised for optimising the outcomes of clinical practice. Frequently, the benefits of new evidence are not implemented due to the difficulties applying traditional research methodologies to implementation settings. Randomised controlled trials are not always practical for the implementation phase of knowledge transfer, as differences between individual and organisational readiness for change combined with small sample sizes can lead to imbalances in factors that impede or facilitate change between intervention and control groups. Within-cluster repeated measure designs could control for variance between intervention and control groups by allowing the same clusters to receive a sequence of conditions. Although in implementation settings, they can contaminate the intervention and control groups after the initial exposure to interventions. We propose the novel application of counterbalanced design to implementation research where repeated measures are employed through crossover, but contamination is averted by counterbalancing different health contexts in which to test the implementation strategy.

Methods

In a counterbalanced implementation study, the implementation strategy (independent variable) has two or more levels evaluated across an equivalent number of health contexts (e.g. community-acquired pneumonia and nutrition for critically ill patients) using the same outcome (dependent variable). This design limits each cluster to one distinct strategy related to one specific context, and therefore does not overburden any cluster to more than one focussed implementation strategy for a particular outcome, and provides a ready-made control comparison, holding fixed. The different levels of the independent variable can be delivered concurrently because each level uses a different health context within each cluster to avoid the effect of treatment contamination from exposure to the intervention or control condition.

Results

An example application of the counterbalanced implementation design is presented in a hypothetical study to demonstrate the comparison of ‘video-based’ and ‘written-based’ evidence summary research implementation strategies for changing clinical practice in community-acquired pneumonia and nutrition in critically ill patient health contexts.

Conclusion

A counterbalanced implementation study design provides a promising model for concurrently investigating the success of research implementation strategies across multiple health context areas such as community-acquired pneumonia and nutrition for critically ill patients.

Electronic supplementary material

The online version of this article (10.1186/s13012-019-0896-0) contains supplementary material, which is available to authorized users.