A Comparison of Allograft Viable Cell Matrixes in Forefoot, Midfoot, and Hindfoot Fusion

Submission Type: Other Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Currently in foot and ankle orthopedics, the use of autograft is considered the gold standard for improving fusion rates in complicated arthrodesis procedures. However, recent studies have suggested the use of allograft is a suitable alternative to autografting. Allografts such as Augment® (Wright Medical Group), Bio4TM (Stryker), and ViviGen® (DePuy Synthes) are synthetically made, ready to use, and do not require the additional trauma of a graft acquisition procedure. Some newer generation allograft mixtures contain osteoconductive, osteoinductive and osteogenic factors, where others are simply contain osteogenic factors. However, literature to quantitatively compare the arthrodesis achieved with these different allografts is limited. Methods: The current study analyzed the rate of fusions, complications, and improvement in patient reported outcomes for patients for patients treated with allografts such as Augment®, Bio4TM, and/or ViviGen® for forefoot, midfoot, and hindfoot arthrodesis surgeries.A retrospective review was performed on patients who underwent forefoot, midfoot, or hindfoot arthrodesis procedures between March 2021 and May 2023 at a single academic institution. Demographic information, graft specifications, and postoperative outcomes were collected. Categorical and continuous data were compared using Chi-squared test and analysis of variance (ANOVA), respectively. Paired t-tests were utilized to compare preoperative and postoperative Patient Reported Outcome Measurement Information System (PROMIS) scores. All p< 0.05 were considered statistically significant. A total of 105 joints in 71 patients were included in the study. 94 joints in 61 patients were treated with Augment®, 63 joints in 39 patients were treated with Augment® + Bio4TM, 13 joints in 8 patients were treated with ViviGen®. Results: There were no significant differences between those treated with Augment®, Augment + Bio4TM, and/or ViviGen® in terms of fusion (96.81% vs 100% vs 100%, respectively), all cause revision (0%), or readmissions (3.19% vs 0% vs 0%). Time to weightbearing was higher amongst cases where ViviGen® (12.81wks ± 5.98) was used in comparison Augment® (10.19wks ± 4.30) or Bio4TM (9.68wks ± 3.02) (p=0.04). Similarly, occurrence of infection and deep infection was higher with ViviGen® in comparison to Augment® and Augment + Bio4TM (p < 0.001). Postoperative improvement in PROMIS pain (p < 0.001), function (p < 0.05), and mobility (p < 0.001) scores with Augment® and Augment® + Bio4TM. However, patients treated with ViviGen® did not demonstrate significant improvement in PROMIS pain (p=0.38), function (p=0.20), or mobility (p=0.06) scores. Conclusion: In patients undergoing a forefoot, midfoot, or hindfoot arthrodesis procedure, newer generation allograft mixtures demonstrated successful fusion with a low revision rate. However, superior outcomes were observed in those who received Augment® and/or Augment® + Bio4TM allografts in comparison to ViviGen® allograft. These results suggest that while newer allograft mixtures allow for high fusion rates and improved patient-reported outcomes, not every newer generation allograft mixture should be considered the same. Longer duration, randomized studies may be warranted to effectively expand on these findings.