## 4 Discussion
reported the AOFAS post-operative score average of 77.13, which is nearly identical to our updated mean score of 77.20, after salvage first MTP arthrodesis [16]. This indicates that roughly no change in alignment, pain, and patient satisfaction has occurred between 2016 and 2023 via the completion of additional studies. Additionally, our rate of successful union ranged from 41.70% to 94.70%, compared to the previously reported range of 67% to 97% [16]. These conditions can be attributed to two reasons: the first being how our review defined successful union and the second being our exclusion criteria. We defined successful union as union without the need for reoperation to achieve adequate fusion across the arthrodesis site. In the study by [PERSON] et al., successful union occurred in 10/12 feet as reported by [PERSON] et al. [3; 16]. However, reoperation occurred in 7/12 feet, which is reflected in our 41.70% success rate. As for our exclusion criteria, we did not include any studies that did not use graft for restoration of length. As salvage procedures not requiring bone graft for length restoration are less severe cases, the higher previously reported successful union rate was expected due to their meta-analysis including such studies. Differentiating by subgroups, the foot and ankle autograft subgroup had a success rate of 75% (1 study; \(n=12\)), autograft from a place other than the foot and ankle ranged from 87.50-91.70%, and allograft procedures demonstrated success rates ranging from 90.90-94.70%. While there were not enough studies to perform proper statistical analysis, allograft had the highest success rates qualitatively. Future trends in MTP arthrodesis should begin implementing allograft into more salvage procedures based on the conclusions from this review. This increase in allograft use would improve the quality of evidence surrounding this graft type for restoration of length, possibly strengthening our review's results. Additionally, with advancements in bioengineering, allograft is the only graft subgroup studied that can benefit from improved engineering due to being synthetic. Improvements in the engineering and manufacturing of allograft may show great promise in the coming years within MTP salvage arthrodiesis. It is important to acknowledge the limitations of this review. As the certainty of the evidence was listed as \"very low\" due to the observational aspect of the study, we suggest future randomized control trials to properly determine the relationship between graft type and successful salvage procedure. Additionally, future studies analyzing the cost-effectiveness of various graft types would further help physicians when deciding upon a graft type, as this systematic review was unable to comment on this factor. This systematic review also included a relatively small sample size, especially when the patients were placed into subgroups by graft type. Indeed, some graft types, such as foot and ankle autograft, only had one study, thus limiting the analysis that could be performed on this topic. As there was limited comparison of graft types within studies, a meta-analysis was not performed and so the true relationship between graft types and outcomes remains to be elucidated. However, this study performs the important task of being a foundation for this topic, as well as highlighting areas of future research. More studies are needed that compare the different bone graft types for salvage first MTP arthrodesis in order to allow for meta-analysis in the future.