Living Cryopreserved Bone Allograft as an Adjunct for Hindfoot Arthrodesis

Comparing Rates of Fusion and Time to Fusion in Viable Cellular Allograft and Autograft

BACKGROUND

Autograft or allograft frequently are used to enhance bone union in foot and ankle surgery. Viable cellular bone allograft uses viable cells and bone scaffolding in a gel base, but uncertainty remains around allograft's greater efficacy than autograft regarding rates of fusion (ROF) and time to fusion (TTF).

METHODS

Autograft, viable cellular allograft, and viable cellular allograft with autograft were compared in 199 forefoot, midfoot, and hindfoot arthrodeses performed over a 6-year period. Data collected from electronic medical records and radiographs were analyzed to determine ROF and TTF as well as rates of revision surgery for delayed or nonunion and compared among groups.

RESULTS

Eighty-seven patients comprised the autograft group, 81 the allograft group, and 31 the combined group. No significant differences were noted in patient demographics among the groups. No statistically significant differences in ROF were noted among the 3 groups, with 86% (75 of 87) fusion in the autograft group, 93% (75 of 81) in the allograft group, and 84% (26 of 31) in the combined group (P = .20). After conducting a multivariate analysis, we found no statistically significant difference for allograft or combined graft on TTF (P = .1379 and .2311, respectively). No significant difference was found in rate of revision surgery for nonunion, which was 1.2% (1 of 81) in the allograft group, 3.4% (3 of 87) in the autograft group, and 6.5% (2 of 31) in the combined group (P = .3).

CONCLUSION

No significant difference was found in ROF, TTF, or rate of revision surgery when comparing viable cellular allograft to autograft or combined allograft-autograft. Viable cellular allograft may be a reasonable alternative to the gold standard of autograft and should be considered an option in patients undergoing arthrodesis in foot and ankle surgery.

LEVEL OF EVIDENCE

Level III, therapeutic.

A Retrospective Analysis of Outcomes From Foot and Ankle Arthrodesis and Open Reduction and Internal Fixation Using Cellular Bone Allograft Augmentation

BACKGROUND

ViviGen is an allogeneic cellular bone matrix product containing lineage-committed bone cells, and can be used as an alternative to autograft bone or other augments to aid in arthrodesis or to enhance bony healing in open reduction and internal fixation (ORIF) procedures.

METHODS

This study included 153 consecutive patients undergoing ankle, midfoot, or hindfoot arthrodesis or ORIF procedures from January 2017 to October 2018, in which an allogeneic cellular bone matrix product was used to aid in bony healing. Retrospective chart review identified patient demographic factors and medical comorbidities and evaluated clinical and radiographic data to determine fusion/union rate and complications.

RESULTS

The overall fusion rate for the arthrodesis cohort was 97/113 (85.8%). The overall complication rate in this cohort was 22/113 (19.5%). Smokers had significantly lower rates of fusion compared with nonsmokers (P = .01). The observed bony healing rate for the ORIF cohort was 19/22 (86.4%), with a complication rate of 3/22 (13.6%).

CONCLUSION

With satisfactory fusion rates and relatively few complications, our findings suggest that ViviGen is a safe and efficacious alternative to other forms of bone graft augmentation for fusion and ORIF procedures about the foot and ankle. Further study is needed to compare the efficacy of ViviGen with autograft bone and other augments.

LEVELS OF EVIDENCE

Level IV: Case series.

A 24-month retrospective update: follow-up hospitalization charges and readmissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2)

Background

The objectives of this study were to build upon previously-reported 12-month findings by retrospectively comparing 24-month follow-up hospitalization charges and potentially-relevant readmissions in US lumbar fusion surgeries that employed either recombinant human bone morphogenetic protein-2 (rhBMP-2) or a cellular bone allograft comprised of viable lineage-committed bone cells (V-CBA) via a nationwide healthcare system database.

Methods

A total of 16,172 patients underwent lumbar fusion surgery using V-CBA or rhBMP-2 in the original study, of whom 3,792 patients (23.4%) were identified in the current study with all-cause readmissions during the 24-month follow-up period. Confounding baseline patient, procedure, and hospital characteristics found in the original study were used to adjust multivariate regression models comparing differences in 24-month follow-up hospitalization charges (in 2020 US dollars) and lengths of stay (LOS; in days) between the groups. Differences in potentially-relevant follow-up readmissions were also compared, and all analyses were repeated in the subset of patients who only received treatment at a single level of the spine.

Results

The adjusted cumulative mean 24-month follow-up hospitalization charges in the full cohort were significantly lower in the V-CBA group ($99,087) versus the rhBMP-2 group ($124,389; P < 0.0001), and this pattern remained in the single-level cohort (V-CBA = $104,906 vs rhBMP-2 = $125,311; P = 0.0006). There were no differences between groups in adjusted cumulative mean LOS in either cohort. Differences in the rates of follow-up readmissions aligned with baseline comorbidities originally reported for the initial procedure. Subsequent lumbar fusion rates were significantly lower for V-CBA patients in the full cohort (10.12% vs 12.00%; P = 0.0002) and similar between groups in the single-level cohort, in spite of V-CBA patients having significantly higher rates of baseline comorbidities that could negatively impact clinical outcomes, including bony fusion.

Conclusions

The results of this study suggest that use of V-CBA for lumbar fusion surgeries performed in the US is associated with substantially lower 24-month follow-up hospitalization charges versus rhBMP-2, with both exhibiting similar rates of subsequent lumbar fusion procedures and potentially-relevant readmissions.

A large database study of hospitalization charges and follow-up re-admissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2)

Background

The objective of this study was to retrospectively compare initial procedure and 12-month follow-up hospitalization charges and resource utilization (lengths of stay; LOS) for lumbar fusion surgeries using either recombinant human bone morphogenetic protein-2 (rhBMP-2) or a cellular bone allograft comprised of viable lineage-committed bone cells (V-CBA) via a large US healthcare system database. Potentially relevant re-admissions during the follow-up period were also assessed.

Methods

A total of 16,172 patients underwent lumbar fusion surgery using V-CBA or rhBMP-2, of whom 3503 (21.66%) patients had follow-up re-admission data. Initial patient, procedure, and hospital characteristics were assessed to determine confounding factors. Multivariate regression modeling compared differences in hospitalization charges (in 2018 US dollars) and LOS (in days) between the groups, as well as incidences of potentially relevant re-admissions during the 12-month follow-up period.

Results

The adjusted mean initial procedure and 12-month follow-up hospital charges were significantly lower in the V-CBA group versus the rhBMP-2 group ($109,061 and $108,315 versus $160,191 and $130,406, respectively; P < 0.0001 for both comparisons). This disparity remained in an ad hoc comparison of charges for initial single-level treatments only (V-CBA = $103,064, rhBMP-2 = $149,620; P < 0.0001). The adjusted mean initial LOS were significantly lower in the V-CBA group (3.77 days) versus the rhBMP-2 group (3.88 days; P < 0.0001), but significantly higher for the cumulative follow-up hospitalizations in the 12-month follow-up period (7.87 versus 7.46 days, respectively; P < 0.0001). Differences in rates of follow-up re-admissions aligned with comorbidities at the initial procedure. Subsequent lumbar fusion rates were comparable, but significantly lower for V-CBA patients who had undergone single-level treatments only, in spite of V-CBA patients having significantly higher rates of initial comorbidities that could negatively impact clinical outcomes.

Conclusions

The results of this study indicate that use of V-CBA for lumbar fusion surgeries performed in the US may result in substantially lower overall hospitalization charges versus rhBMP-2, with both exhibiting similar rates of 12-month re-admissions and subsequent lumbar fusion procedures.

Clinical outcome and explant histology after using a cellular bone allograft in two-stage total hip arthroplasty

Background

Although use of cellular bone allografts (CBA) in orthopedic surgery has become increasingly common, little information is available regarding their short-term clinical performance. In these two case reports of two-stage hip arthroplasties, ViviGen Formable CBA (V-CBA) was used in stage one to fill voids left by previous metal implants.

Methods

The two patients had distinctly different health profiles, but each of them had previous metal implants due to a hip fracture. In the otherwise healthy 49-year-old male patient, the total hip arthroplasty (THA) was performed 7 weeks after nail removal and V-CBA backfill. In the 64-year-old female patient with Type 1 diabetes and severe osteoporosis, stage 2 was performed after 12 weeks. At the time of THA for each patient, bone containing some V-CBA was removed to accommodate the hip implant. The explants were histologically analyzed for bone matrix, mineralization, and neovascularization.

Results

Histological staining showed substantial new bone formation and neovascularization in both explants albeit at different levels of maturity.

Conclusions

Although limited, these results suggest that V-CBA may facilitate new bone formation in healthy as well as in metabolically challenged patients.

Level of evidence

V, case report

Management of Calcaneal Fracture Malunion with Bone Block Distraction Arthrodesis: A Systematic Review and Meta-Analysis

One of the most severe complications in calcaneal fractures is a malunion. When a malunion occurs, subtalar bone block distraction arthrodesis provides restoration of calcaneal height, length, correction of varus deformity, and elimination of subtalar joint arthritis. A systematic review showed the union rate for all procedures was 95.78%. The overall complication rate was 38% for all procedures. This is the first study to categorically break down complications with statistical analysis. The data presented indicate the level of difficulty of the subtalar distraction bone block arthrodesis for calcaneal malunions and may even suggest the need for newer techniques.